Organic Chemistry – Some Basic Principles and Techniques

Organic Chemistry – Some Basic Principles and Techniques HISTORICAL INTRODUCTION It was observed that initially compounds were found from two sources living organism and non living matter. The compounds which were derived from living organism were called as organic compounds while those from non living matter were named as inorganic compounds. Berzilius thought that organic compounds were produced from their element by laws different from those governing the formation of inorganic compounds. This led him to the belief that organic compounds are formed under the influence of a vital force and they couldn't be prepared artificially.This myth continued till Wohler converted inorganic compound ammonium cyanate found from non living matters into urea an organic compound. SOME IMPORTANT DEFINITIONS (i) Catenation : The property of atoms of an element to link with one another forming chains of identical atoms is called catenation. (ii) Homologous series : Homologous series may be defined as a series of similarly constituted compounds in which the members possess the same functional group, have similar chemical characteristics and have a regular gradation in their physical properties. The two consecutive members differ in their molecular formula by CH2. (iii) Isomerism : Compounds which have the same molecular formula but differ in physical and chemical properties are called isomers and the phenomena is heat called isomerism. NH 4CNO   NH2CONH2 Isomerism can be broadly classified into two ammonium cyanate urea categories The myth of vital force theory was completely ended 1. Structural Isomerism 2. Stereoisomerism with the synthesis of acetic acid from its elements by Kolbe in 1845,and the synthesis of methane by CLASSIFICATION OF ORGANIC Berthelot in 1856. COMPOUNDS Since then millions of compounds have been If we look at the vast number of organic compounds, produced in laboratory. Basically organic compounds two things will strike our mind –the skeleton is either are made of essentially carbon and other elements open or closed. Based on this, organic compounds like Hydrogen, Oxygen, Nitrogen Phosphorus, are classified as acyclic (open–chain) or cyclic Sulphur etc.. (closed–chain) 1 Organic Chemistry – Some Basic Principles and Techniques e.g. 1. Alkanes CH3 – CH2 – CH3 Propane 2. Alkenes CH3 – CH = CH2 Propene 3. Alkynes HC  CH Ethyne 4. Aliphatic compounds with other functional groups CH3 – CH2 – OH Ethanol CH3 – CH2 – COOH Propanoic acid 5. Homo alicyclic compound Cyclohexane 6. Heteroalicyclic compound Pentahydropyran 7. Heterocyclic aromatic compound Pyridine 8. Homo cyclic benzenoid aromatic compounds Phenol Napthalene 9.Homo cyclic Non-benzenoid aromatic compound [18] annulene 2 Organic Chemistry – Some Basic Principles and Techniques 3. Alkenes ORGANIC COMPOUNDS AND FUNCTIONAL GROUPS Number of known organic compounds is much more than inorganic compounds but, it has been possible to group them into classes or families based on their structural features. This has given organic chemistry a logical and systematic shape. In these compounds, there are a number of atoms or groups which show constancy of properties. Such groups are called functional groups. Examples of functional groups are : 1. 2. Alkanes These are open–chain aliphatic compounds which have no functional groups. These are represented by the general formula, CnH2n + 2 where n = 1, 2, 3, ............ The names of the alkanes for n = 1, 2, ..........., 10 must be committed to memory since all of organic nomenclature is related directly or indirectly to the name of alkane CnH2n + 2 n = 1 means CH4 – Methane n = 2 means C2H6 – Ethane n = 3 means C3H8 – Propane n = 4 means C4H10 – Butane n = 5 means C5H12 – Pentane n = 6 means C6H14 – Hexane n = 7 means C7H16 – Heptane n = 8 means C8H18 – Octane n = 9 means C9H20 – Nonane n = 10 means C10H22 – Decane Alkyl Groups When we remove a hydrogen from alkane, we get an alkyl group : –H  CnH2n  1 General formula CnH2n  2  – ane alkane   alkyl  yl e.g. e.g. CH2 = CH2 ethylene CH3 – CH = CH2 propylene CH3 – CH2 – CH = CH2 butylene 4. CH 3 | CH 3  C  CH 2 Isobutylene Alkenyl Groups Like alkyl groups (alkane – H), there are three commonly encountered alkenyl groups which are given common names. e.g. CH2 = CH2 remove H     CH2 = CH – vinyl group 5. Alkynes Unsaturated aliphatic hydrocarbons containing a carbon–carbon triple bond are called alkynes. In the common system, they are called acetylenes, after the name of the first member of this family. i.e. acetylene General formula CnH 2n-2 – ane methane   methyl  yl –H CH 4    CH3 e.g. Alkenes are open chain hydrocarbons and having carbon–carbon double bonds, C = C. They have the general formula CnH2n where n = 2, 3, 4 ... etc. and are also called alkylenes or olefins. The first three members are commonly named by their common names – ane propane   propyl  yl where n = 2, 3, 4....... etc. Common Names Acetylene and its alkyl derivatives. –H C 3H8    C 3H7 3 Organic Chemistry – Some Basic Principles and Techniques Functional groups IUPAC names Alkane – ane + yne = Alkyne Name The position of the triple bond on the parent chain is designated by lowest possible arabic numerals The common IUPAC names of a few simple alkynes are given below. n = 2  CH  CH n = 3  CH3–CCH Acetylene Methyl acetylene n = 4  CH3 – CH2 – C  CH Ethylacetylene n = 6  Methyl isopropyl acetylene 6. Alkynyl Groups H HC  CH   HC  C – (-e + yl = Ethynyl) H H3C – C  CH   H3C – C  C – (-e + yl = propynyl) 7. Functional group and Residue Examples of Compound containing The characteristic group of atom which decided the different functional groups physical and chemical properties of an organic (1) – COOH group molecule is called functional group. (i) HCOOH Formic acid Functional group is that portion of molecule which is (ii) CH3COOH Acetic acid highly reactive and takes part in chemical reactions. Rest of the molecule is called Residue. (iii) CH3 – CH2 – COOH Propionic acid e.g. CH3CH2CH2CH2 – COOH Residue Functional Group (2) – SO3H group (i) CH3SO3H Methane sulfonic acid (ii) CH3CH2SO3H Ethane sulfonic acid (iii) CH3 – CH2 – CH2 – SO3H Propane sulfonic acid 4 (3)  COC || || O O Organic Chemistry – Some Basic Principles and Techniques (6)  C  NH2 group group || O (i) O O || || CH 3  C  O  C  CH 3 (ii) O O || || CH3  CH2  C  O  C  CH2  CH3 Acetic anhydride (i) O || H  C  NH 2 Formamide (ii) O || CH3  C  NH2 Acetamide (iii) O || CH3  CH2  C  NH2 Propanamide Propionic anhydride (iii) O O || || CH3  CH2  CH2  C  O  C  CH2  CH2  CH3 (7) – C  N group Butanoic anhydride (i) CH3 – CN Methyl cyanide or Acetonitrile (4)  C  O  R group (i) || O (ii) CH3 – CH2 – CN Ethyl cyanide or propionitrile O || H  C  OCH 3 (iii) CH3 – CH2 – CH2 – CN n–Propyl cyanide or n–Butyronitrile Methyl formate (8) O || (ii) H  C  O  C 2H5 (iii) Ethyl formate O || CH3  C  O  C 2H5 C  H || O (i) Ethyl acetate group O || HCH Formaldehyde (ii) CH3 – CHO (5) C  X || O Acetaldehyde (iii) CH3 – CH2 – CH2 – CHO n-Butyraldehyde group (i) H  C  Cl Formyl chloride (ii) CH3  C  Br Acetyl bromide || O || O (9) C  R || O group (i) CH3  C  CH3 Dimethyl ketone or acetone || O (ii) CH3  C  CH2  CH3 (iii) CH3  CH2  CH2  C  Cl Ethylmethyl ketone || O || O n-Butyryl chloride (iii) CH3  C  CH2  CH2  CH3 || O Methyl n–propyl ketone 5 Organic Chemistry – Some Basic Principles and Techniques (10) – OH group (i) CH3 – OH Methyl alcohol (ii) CH3  CH  CH3 Isopropyl alcohol | OH Note: Iso alkyl group name can be used in IUPAC Nomenclature and its first letter 'I' is consider for alphabetical seniority e.g. (iii) CH3 – CH2 – CH2 – OH n-Propylalcohol 1 (11) – SH group (i) CH3 – SH Methane thiol (ii) CH3 – CH2 – SH Ethane thiol (iii) CH3 – CH2 – CH2 – SH Propane thiol (12) – NH2 group (i) CH3 – NH2 1 Iso Alkyl group A compound having CH3 |  CH  CH3 group is called iso alkyl group e.g. CH3  CH  | CH3 Iso propyl CH3  CH  CH 2  | CH 3 Iso butyl CH3  CH  CH 2  CH3 | CH3 4 5 6 Neo Alkyl group Compound having CH3   |   CH 3  C  CH 2  |  CH 3         group is called neo alkyl group. SOME COMMON NAMES OF HYDROCARBON ALKYL GROUPS 3 3–Isopropyl–2–methylhexane 2. Methylamine or Aminomethane (ii) CH3 – CH2 – NH – CH3 Ethyl methyl amine or N-Methylaminoethane (iii) (CH3)3N Trimethylamine or N, N–Dimethyl aminomethane 2 C H3  C H  C H  C H2  C H2  C H 3 | | CH3 CH  CH3 | CH3 e.g. CH3 | CH3  C  CH2 – | CH3 Neopentyl CH 3 | CH 3  C  CH 3 | CH 3 Neopentane CH3 | CH3  C  CH 2  CH 3 | CH3 Neohexane Iso pentane 6 Organic Chemistry – Some Basic Principles and Techniques The hydrogen atoms attached to 1°, 2° and 3° TYPES OF CARBON AND HYDROGEN carbon atoms are called primary (1°) secondary (2°) ATOMS IN ALKANES and tertiary (3°) hydrogen atoms. It may be noted The carbon atoms in an alkane molecule may be here that there is nothing like quaternary hydrogen classified into four types as primary (1°), secondary atom. Since a quarternary carbon does not carry (2°), tertiary (3°) and quaternary (4°) as follows any hydrogen. (i) A carbon atom attached to one another (or no other) carbon atom is called a primary carbon atom and is designated as 1° carbon 1 1 e.g. (i) C H3  C H3 1 1 Ex.1 How many 1°, 2°, 3° and 4° carbon atoms are present in following molecule. (ii) C H3  CH2  C H3 CH 3 | CH3 – CH – C – CH 2 – CH – CH 3 | | | CH3 CH 3 CH2 – CH 3 (ii) A carbon atom attached to two other carbon atoms is called a secondary carbon atom and is designated as 2° carbon 2 e.g. (i) C H3  C H2  C H3 2 2 Sol. 1° Carbon atoms = 6 , 3° Carbon atoms = 2 , 2° Carbon atoms = 2 , 4° Carbon atom = 1 (ii) CH3 – C H2 – C H2 – CH3 (iii) A carbon atom attached to three other carbon atoms is called a tertiary carbon atom and is designated as 3° carbon. CH3 | e.g. (i) CH3  C H  CH3 Note : Primary, secondary, tertiary & quaternary carbon atoms in a molecule are denoted by the letters p, s, t and q respectively. Ex.2 How many 1°, 2°, 3° and 4° carbon atoms are present in following molecule 3 (ii) CH3 | CH3  C  CH2  CH  CH3 | | CH3 CH3 CH3 | CH3  C H  CH2  CH3 3 (iv) A carbon atom attached to four other carbon atoms is called a quaternary carbon atom and is designated as 4° carbon CH3 | CH3  4 C  CH3 e.g. (i) | CH3 CH3 | 4 (ii) CH3  C  CH2  CH3 1o C H3 | Sol. 1o 4o 2o 3o 1o C H3  C  C H2  C H  C H3 | | 1o C H3 1o CH3 1° Carbon atoms = 5 , 3° Carbon atom = 1, 2° Carbon atom = 1 , 4° Carbon atom = 1 | CH2  CH3 7 Organic Chemistry – Some Basic Principles and Techniques NOMANCLATURE SYSTEM The organic compounds are generally named in three systems : 1. Trivial name System (Common names) 2. Derived names system 3. IUPAC name system CH4 – Marshgas , Oxalic acid – oxalus (Marshy place) Acetic acid –acetum, Urea – urine (vinegar) Formic acid – formica, Glucose RMgX Pentane Glycerol Grignard's reagent Hexane Glycol R2Zn Octane (Glycus = sweet) Frankland's reagent Uric acid – urine (Red ants) Malic acid – pyrusmallus, Citric acid – citrus Note : Ethylene glycol is poisonons in nature. Methyl alcohol – wood spirit Common names of Saturated Hydrocarbons : - (CnH2n+2) (1) According to trivial or common name system of nomenclature, unbranched alkanes are named according to the number of carbon atoms. (b) Prefix iso : It is used when one methyl group is attached to the second or second last C-atom of the continuous chain. Alk - means number of carbon atoms. (2) As first three members of alkanes have no isomers, so their common names and IUPAC names are same. Chain isomerism starts from butane. All isomeric paraffines have same parent name. They are distinguished by the use of prefixes such as - n, iso, neo etc. (a) Prefix n : It is used for unbranched and normal alkanes. Ex. Iso butane (consists 3° carbon) (c) Prefix neo : When two methyl groups are attached to the second or second last C-atom of the continuous chain - Ex. Ex. CH3 — CH2 — CH2 — CH3 n — butane CH3 — CH2 — CH3 Propane [n is not used because it has no isomers] Neo - pentane (consists 4° C-atom) 8 Organic Chemistry – Some Basic Principles and Techniques Note : Prefixes sec., tert. are not used in (b) Compounds Containing Carbon - Carbon triple hydrocarbons. bond : General Formula is CnH2n-2 Exceptions : There names are derived by replacing H-atoms of acetylene by alkyl group. Isopropyl Acetylene Ex. Methyl acetylene or Allylene (as it is isomer of Allene CH2 C CH2) Dimethyl acetylene Isooctane or crotonylene Isoheptane(Triptane) (1) Common Name of Hydrocarbon Derivatives : Ex. R—H     Unsaturated Hydrocarbons : (a) Compounds Containing Carbon - Carbon double bond : These are called alkylene or olifins (General formula CnH2n), because their halogen derivatives are used for the manufacture of oil. (Olium - oil, fiant - making) Ex. Ethylene Propylene –Butylene –Butylene Isobutylene (A) Common names of organic compounds depends on the basis of hydrocarbon radical. Functional group — OH — NH2 —O— —S— —X — CN —N C — CO — Prefix Alcohol Amine Ether Thio ether Halide Cyanide Iso cyanide Ketone Saturated Hydrocarbon Radical :  Ex. Alkane    Alkyl (monovalent radical)    Bivalent radical   Trivalent radical MonovalentRedicals : 9 Organic Chemistry – Some Basic Principles and Techniques  neo-pentane 10 Organic Chemistry – Some Basic Principles and Techniques While writing IUPAC names of hydrocarbon radicals, (b) Alkyne    Alkynyl numbering of C-atom is started from free bond-CEx. atom. Ex. 1 — methyl propyl Bivalent : Two valency free Bivalent radical of ethylene :- From same carbon atom - Alkylidene From vicinal carbon atom - Alkylene From terminal carbon atom - Polymethylene  Trimethylenedichloride Ex. (i) vinylidene radical (ii) Acetylene radical Trivalent radicals :Trivalent : CH3—CH3  CH3C  Alkane   Trivalent (Alkylidyne) Ethylidyne Aromatic Hydrocarbon Radical - Bivalent radicals Ex. CH4  CH2 Methylidene (Methylene) CH3 — CH3  CH3—CH CH3—CH2—CH3  (i) CH3—CH2—CH (ii) (i) Ethylidene (ii) Propylidene Iso-propylidene  Propylene Ethylene  Unsaturated Hydrocarbon Radicals   Alkenyl (a) Alkene  Ex.  Ethenyl (vinyl) Ex.  1–propenyl Iso propenyl or 1–methyl ethenyl 2–Propenyl (Allyl) 11 Organic Chemistry – Some Basic Principles and Techniques (B) Common names of Hydrocarbon derivatives. Note : Three Carbon with one double bond  Which don't depend on hydrocarbon radical Acryl [C C — C] Prefix  Number of carbon atoms Suffix  Functional group No. of Carbon atoms 1 2 3 4 5 Functional group —CHO Prefix Form Acet Propion Butyr Valer Four carbon with one double bond  croton [C — C C — C] Functional Group — CHO — COOH — COOR Suffix aldehyde ic acid alkyl ------- ate ic anhydride — COCl — CONH2 — CN —N C yl chloride amide onitrile oisonitrile Structure Common name HCHO Formaldehyde (Form –1C atom) CH 3CHO Acetaldehyde (acet – 2C atom) CH3CH2CHO Propionaldehyde CH3CH2CH2CHO n - butyraldehyde Iso - butyraldehyde Acrylaldehyde Crotonaldehyde —COOH CH3 — CH2 — COOH Propionic acid CH2 Acrylic acid CH — COOH Isovaleric acid —COOR HCOOCH3 Methyl formate Iso propyl acetate CH2 CHCOO C2H5 Ethyl acrylate Acetic anhydride Acetic Propionic anhydride 12 —COCl —CONH2 —CN Organic Chemistry – Some Basic Principles and Techniques CH3CH2COCl Propionyl chloride HCOCl Formyl chloride HCONH2 Formamide CH3CH2CONH2 Propionamide HCN Formonitrile or Hydrogen cyanide CH 3CN Acetonitrile or Methyl cyanide Acetoisonitrile —N C Isobutyroisonitrile or Isopropylisocyanide Note.(1) If suffix isocyanide is used then carbon atom of -NC not counted. (2) If suffix carbyl amine is used then Carbon atom of -NC not counted. (3) If oisonitrile is used then Carbon atom of -NC counted. (2) Derived Names : In a homologous series the homologues are considered to be the derivative of the first homologue.  Unsym. dimethyl ethylene Exceptions - aldehydes and acids (second member)  Ethyl ethylene (First homologue of alkyne series)  Acetylene Methane  Methyl acetylene or Allylene Methyl methane  Dimethyl acetylene or crotonylene CH3OH Dimethyl methane Carbinol (First member of alcoholic series) first homologue of alkane series encircled H atom will be replaced by any substituents/functional group  Methyl carbinol Similarly :  Ethylene is the first homolgue of the alkylene series.  Dimethyl carbinol Names derived from ethylene are  Methyl ethylene  Symm. dimethyl ethylene  Iso propyl carbinol CH3CHO Acetaldehyde  Methyl acetaldehyde  Dimethyl acetaldehyde 13 Organic Chemistry – Some Basic Principles and Techniques 2. Primary Suffix. A primary suffix is always added IUPAC SYSTEM OF NOMENCLATURE to the word root to indicate whether the carbon chain The basic criteria for naming a structure by IUPAC is saturated or unsaturated. The three basic primary system is choice of a parent name or the basic carbon suffixes are given below : skeleton. Nomenclature of alkanes is fundamental to naming whole class of organic compounds because it helps us to identify the basic carbon skeleton. General rules for IUPAC nomenclature The IUPAC system is the most rational and widely used system of nomenclature in organic chemistry. The most important feature of this system is that any given molecular structure has only one IUPAC name and any given IUPAC name denotes only one molecular structure. Type of carbon chain 1. Word root 2. Primary suffix 3. Secondary suffix 4. Primary prefix 5. Secondary prefix Secondary prefix + Primary prefix + Word root 3. + Primary suffix + Secondary suffix Chain length Word root Chain length Word root C1 Meth- C7 Hept(a)- C2 Eth- C8 Oct(a)- C3 Prop(a)- C9 Non(a)- C4 But(a)- C10 Dec(a)- C5 Pent(a)- C11 Undec(a)- C6 Hex(a)- C12 Dodec(a)- (a) Saturated – ane Alkane (b) Unsaturated with one double bond – ene Alkene (c) Unsaturated with one triple bond – yne Alkyne Type of carbon chain Primary suffix (a) Unsaturated with – diene two double bonds (b) Unsaturated with – diyne two triple bonds Thus, a complete IUPAC name of an organic compound consists of the following parts : Word root : It is the basic unit of the name. It denotes the number of carbon atoms present in the principal chain (the longest possible continuous chain of carbon atoms including the functional group and based upon the common names of alkanes) of the organic molecules. General name If the parent carbon chain contains two, three or more double or triple bonds, numerical prefix such as di (for two), tri (for three), tetra (for four) etc. are added to the primary suffix. For example, The IUPAC name of any organic compound consists of five parts, i.e., 1. Primary suffix General name Alkadiene Alkadiyne Secondary suffix. A secondary suffix is then added to the primary suffix to indicate the nature of the functional group present in the organic compounds. Secondary suffix of some important functional groups are given below : Class of organic compounds Alcohols Functional group – OH Secondary suffix – ol Aldehydes Ketones Carboxylic acids Acid amides – CHO >C=O – COOH – CONH2 – al – one – oic acid – amide Acid halide Esters Nitriles Thioalcohols Amines – COX – COOR – CN – SH – NH2 – oyl halide alkanoate - nitrile - thiol - amine 14 Organic Chemistry – Some Basic Principles and Techniques The following examples illustrate the use of word Substituent Secondary Substituent Secondary root, primary suffix and secondary suffix in naming group prefix group prefix of organic compounds. – OCH (– OMe) Methoxy –F Fluoro 3 4. Primary prefix. A primary prefix is used simply to distinguish cyclic from acyclic compounds. For example, in case of carbocyclic compounds, (cyclic compounds containing only carbon atoms in the ring), a primary prefix, cyclo is used immediately before the word root. Thus. e.g. – Cl Chloro – OC2H5(–OEt) Ethoxy – Br Bromo –R Alkyl –I Iodo – CH3 (– Me) Methyl – NO2 Nitro – C2H5 (– Et) Ethyl – NO Nitroso – CH2CH2 CH3(n-Pr) n-Propyl  Diazo – CH(CH3)2 (– iPr) Isopropyl – OR Alkoxy – C(CH3)3 (t-But) N  N Organic compounds Secondary prefix CH3CH2 – Br Bromo CH3 – NO2 Nitro C2H5 – OC2H5 Ethoxy Word root Primary suffix t-Butyl IUPAC name eth ane Bromoethane meth ane Nitromethane eth ane Ethoxyethane + In case of carbocylic compounds, primary prefixes are also used. + = If the prefix cyclo is not used, it simply indicates that the compound is acyclic or open chain. 5. Secondary prefix. In IUPAC system of nomenclature, certain groups are not considred as functional groups but are treated as substituents. These are called secondary prefixes and are added immediately before the word root (or the primary prefix in case of carbocyclic compounds) in alphabetical order to denote the side chains or substituent groups. The secondary prefixes for some groups which are always treated as substituent groups (regardless of the fact whether the organic compound is monofunctional or polyfunctional) are given below : e.g. + + + + 15 Organic Chemistry – Some Basic Principles and Techniques IUPAC Nomenclature of Ex.3 Write IUPAC name of following compound Branched / Complex Alkanes (1) (a) Select the longest chain of carbon atoms in the molecule. I Sol. (b) Count the number of carbon atoms in that chain and name according to the following rules. I e.g. 2 – Iodo – 3 – methylcyclopentanesulfonic acid. Longest chain has 7 carbons. Here Secondary prefix hept ane  It is a word root  primary suffix = 2 – Iodo – 3 – methyl Ex.4 Primary prefix = cyclo Word root = pent Primary suffix = ane Secondary suffix = sulfonic acid When chains of equal lengths are competing for selection, that chain is selected which has more number of substituents. Write the IUPAC name of following compound Here the chain shown is selected. (2) Carbon atoms in the longest chain selected as above is numbered consecutively from one end to the other such that the substituents attached get the lowest number. Sol. 2 – Isopropyl – 5 – methylcyclohexanol Here Secondary prefix In the above example, according to this rule, the numbering will be done as : = 2 – Isopropyl – 5 – methyl Primary prefix = cyclo Word root = hex Primary suffix = an(e) Secondary suffix = ol By this numbering, locant (substituents) get the number 2, 3 and 4 compared to 4, 5 and 6 if numbering is done from other end. 16 Organic Chemistry – Some Basic Principles and Techniques (3) write the name of the compound as a single word (3) Each substituent, which, obviously, is an alkyl group (with no space between) is named according to number of carbon atoms present in it and it is prefixed by the number to which e.g. Write the IUPAC name of it is located in the main chain. In the above example, substituents are as follow : –CH3 (methyl) group at carbon No. 2 1. 2. 3. 4.  2–methyl –C2H5 (ethyl) group at carbon no. 3  3–ethyl –CH2CH2CH3 (propyl) group at carbon no. 4  4–propyl 5. Hence, the above compound is named as : 3–Ethyl–2–methyl–4–propylheptane Primary suffix is ane as all are single bonds Chain is numbered as shown Root word is hex Prefixes methyl appears twice  it is 2, 4–dimethyl and 3 – ethyl While arranging in alphabetical order Replicators di, tri, tetra are not considered.  3 – Ethyl–2, 4–dimethylhexane (4) If the same substituent occurs more than once in the molecule, the prefix di (for two), tri (for three), etc. are used to indicate how many times it appears. Ex. 5 Write the IUPAC name of following compounds The above example can be written with a little modification as : (i) (ii) e.g. Methyl at No. 2,3, Ethyl at no. 3, Propyl at no. 4 This will be named as : Ans. (i) 2,2,3–Trimethylpentane (ii) 5–(1, 2 – Dimethylpropyl)nonane 3–Ethyl–2,3–dimethyl–4–propylheptane (5) The name of the compound is composed in such a Ex.6 Write IUPAC name of the following compounds:manner that each substituent with its number and (a) name is written alphabetically just before the word root. Prefixes di, tri, tetra etc. are not considered in deciding alphabetical order. (b)  Ethyl will be written before methyl which will be written before propyl. Note that in the above examples, this pattern has been compiled with. (c)  Also, as per convention, Ans.(a) 5-Ethyl-3-methyloctane (1) numbers are separated each other by commas(,). (b) 4-Ethyl-2,2,6-trimethylheptane (2) numbers are separated from words by hyphens and (c) 3-Methylhexane 17 Organic Chemistry – Some Basic Principles and Techniques IUPAC Nomenclature of Alkenes Functional group : –C=C– Ex.-7 Write the IUPAC name of the following (1) Select the longest chain containing carbon–carbon compounds:double bond. This need not be the longest chain in the compound as a whole. Parent name will be (a) CH3 – CH2 – – CH = CH – CH2 – CH3 alkene corresponding to number of carbon atoms in the longest chain. e.g. Longest chain is as shown above. It has 6 atoms  hexene = parent name (b) Ans. (a) 5-Methylhept-3-ene (b) 5-Ethyl-2,6-dimethyl-4-(3-methylbutyl) oct-2-ene (2) Carbon atoms in the longest chain is numbered so that doubly bonded carbon atom gets the lowest number. The position of double bond is indicated by Ex.8 Draw the bond line structures of the following compounds. the smaller of the numbers assigned to two carbon (a) 2-Methylhept-3-ene atoms of double bond. (b) 2, 6–Dimethylhepta – 1, 5–diene  The above example can be rewritten as, Ans.(a) (b) Position of double bond will be indicated as no. 1. Hence, name will be, IUPAC Nomenclature of alkynes 3–Ethyl–3–methylhex–1–ene (–C  C– group) e.g. Numbering of longest chain is exactly same as that for naming alkenes. e.g. 2, 2, 5, 5-Tetramethylhex-3-ene 4,4–Dimethylpent–1–yne 18 Organic Chemistry – Some Basic Principles and Techniques Ex.9 Write the IUPAC name of the following compounds:- Ex.11 Write IUPAC name of the following compounds. (a) (a) CH3 – – C  C – CH3 (b) (b) Ans. (a) 3-(2-Methyl propyl)hept-1-en-4-yne (b) Oct-1-en-4-yne Ans. (a) 4-Methylpent-2-yne (b) 4-Propylhept-2-yne Ex.12 Write IUPAC name of the following compounds. Ex.10 Write the IUPAC name of the following compounds:(a) CH3 – C  CCH(CH3 ) 2 (a) HC  CCH2 CH  CH2 (b) Ans. (a) Pent-1-en-4-yne (b) Hepta-3,6-dien-1-yne (b) IUPAC Nomenclature of Alicyclic Compounds 1. The names of alicyclic compounds are obtained by adding the prefix "cyclo" Sol. (a) 4-Methyl-pent-2yne (b) 3,4,4-Trimethylhex-1-yne IUPAC nomenclature of hydrocarbons e.g. containing both double and triple bonds occuring only once (i) Such hydrocarbon is named as alkenyne (not alkynene). (ii) Numbering is done in a manner that double and triple bonds get the lowest possible number. If double bond and triple bond both have same number then double bond is given preference our triple bond. Cyclobutane Cyclopentene 2. The numbering of the carbon atoms in the ring is done in such a way that the substituent which comes first in the alphabetical order is given the lowest possible number and it does not violate the lowest set of locants rule. e.g. HC  C – CH2 – CH = CH2 (wrong) 1 2 3 4 5 (numbering is done from alkyne) (write) 5 4 3 2 1 (numbering is done from alkene) 1 – Ethyl – 3 – methyl cyclohexane 2 – Ethyl – 1, 4 – dimethyl cyclohexane 19 Organic Chemistry – Some Basic Principles and Techniques (5) If ring has unsaturation and side chain is saturated then ring is selected as parent chain. If side chain has unsaturation and ring is saturated then side chain is selected as parent chain. 3 – Ethyl – 1, 1 – dimethyl cyclohexane 2 – Bromo – 1 – chloro – 3 – iodocyclohexane (3) When the ring contains more or equal number of carbon atoms than the alkyl group attached to it, then it is named as a derivative of cycloalkane and the alkyl group is treated as substituent If both have unsaturation the chain with maximum unsaturation has selected as parent chain. If equal unsaturation then longest chain is selected as parent chain. If unsaturation and number of carbon atoms both are equal then ring is selected as parent chain. e.g. e.g. 1 – Ethylcyclohex – 1 – ene Propylcyclopropane 1, 3, 5 Trihexylcyclohexane Cyclohexylcyclohexane 6 – Ethyl – 3, 3 – dimethylcyclohex – 1 – ene Methylenecyclohexane (4) The alkane chain contains greater number of carbon atoms than present in the ring, the compound is considered as the derivative of alkane and the ring is designated as substituent. 3 – Cyclopropylprop – 1 – ene e.g. 2 – Cyclopropylbutane 1–(Hex–3–enyl)cyclohex–1–ene 3 – Cyclopentylhexane 20 Organic Chemistry – Some Basic Principles and Techniques (6) If more than one alicyclic ring is attached to a single chain, the compound is named as a derivative of alkane and the ring is treated as a substituent e.g. group. 2 – Propylcyclohexan – 1 – ol e.g. Dicyclopropylmethane 1 – Cyclohexylpropan – 2 – ol 1 – Cyclohexyl – 4 – cyclopropylbutane (7) If a multiple bond and some other substitutents are present in the ring, the numbering is done in such a way that the multiple bond gets the lowest number (10) When chain terminating functional group is directly attached with ring then ring is taken as parent chain & special suffix used for functional group. Functional Group Suffix CHO Carbaldehyde COOH Carboxylic Acid COX Carbonyl halide COOR Alkyl Carboxylate CONH2 Carboxamide CN Carbonitrile e.g. 3 – Nitrocyclohex – 1 – ene (8) If a compound contains an alicyclic ring directly linked to the benzene ring. It is named as a derivative of benzene. e.g. e.g. Cyclohexylbenzene Cyclohexanecarbonitrile Cyclohexanecarbaldehyde 1 – (2 – Methylcyclohexyl) – 4 – nitrobenzene (9) If functional group is present in cyclic compounds than the main chain is taken in which principal functional lie's, if the principal functional group is present in ring also then main chain will be taken for the maximum no. of carbon atoms. Ethyl (2–oxo)cyclohexane – 1 – carboxylate 21 Organic Chemistry – Some Basic Principles and Techniques IUPAC Nomenclature of Compounds Ex.13 Write the IUPAC name of following compound Containing Functional Groups (A) (B) Sol. (A) 4 – Cyclohexylbut – 3 – en– 2-one 1. (B) 1,5–Dimethylcyclopent–1–ene Ex.14 The correct IUPAC name of following compound is Rules for non chain terminating functional groups (1) Parent chian : Select the longest possible chain with maximum functional group and maximum unsaturation without caring whether it also denotes the longest possible chain or not. e.g. (Parent chain contains four rather than five carbon atoms) Sol. 2 – (2 – hydroxybutyl) cyclohexan – 1 – ol (2) Lowest number for the functional group Numbering is done from that side of the chain which gives lowest locant to the principle functional group followed by double and triple bonds. e.g. 22 Organic Chemistry – Some Basic Principles and Techniques ( ( 2 group gets lowest number 3) group gets number 4 which is not lowest) (4) If the organic molecule contain more than one similar complexes substitutents, then the numerical prefixes such as di, tri, tetra etc. are replaced by bis, tris, tetrakis etc. respectively. Rules for chain terminating functional groups (1) When a chain terminating functional group such as – CHO, – COOH, –COOR, –CONH2, –COCl, – C N etc. is present, it is always given number 1 (one.) e.g. e.g. Ex.15 Write IUPAC Name (a) (2) If a compound contains two or more like groups, the numerical prefixes di, tri, tetra etc. are used CH2  CH  CH2 | | | OH OH OH e.g. Propane  1,2,3  triol (b) (CH3)3COH (c) Sol. (a) Methyl-2-ethylbutanoate (b) 2-Methylpropan-2-ol (c) 3-Methylbutanoic acid 3 (3) The name for benzene as substituent is phenyl. In case the phenyl ring is further substitued, the carbon atoms of the ring directly attached to the parent chain in such a ways that the substituent on the ring gets the least possible number. For example Rules for IUPAC nomenclature polyfunctional compounds : of (1) When an organic compound contains two or more different functional groups than senior functional group is selected as the principal functional group while other groups are treated as substituents. (2) Some functional group such as all halo groups (fluoro, bromo, chloro, iodo), nitroso (NO) nitro (– NO2) and alkoxy (–OR) are always treated as substituent groups. 23 Organic Chemistry – Some Basic Principles and Techniques e.g. (c) Ethyl 3-methylpent-4-en-1-oate Numbering the principal chain order is [Principal functional group > double bond > triple bond > substituents] (d) e.g. 3,3 Dimethyl –2 – (1–methylethyl)butanamide (4) If more than one same chain terminating group are present then the principal chain is selected including the functional groups and numbring is done from that side which gives lowest locant to unsaturation substituent. [– COOH > – CO] e.g (a) 1 (b) 2 3 4 5 N C C H  C H2  C H2  C N | CH3 2  Methylpentanedinitrile e.g. Write the IUPAC name of (3) The longest possible chain of carbon atoms containing the functional group and the maximum number of multiple bonds is selected as parent chain. 4 e.g. 3 2 (a) C H3 – C H2 – C H – CH2 – CH3 | C H 2OH 1 parent chain contains four rather than five carbon atoms . (b) parent chain contains five rather than six carbon atoms 3 4 5 CH3  CH2  CH  CH2  CH  CH3 | | 7 1 2 6 CN  CH2 CH2  CH3 1. The longest chain containing functional group is of 7 carbon atoms. Therefore, the word root is hept & the chain is numbered as shown. 2. There is no multiple bond in it. Hence, the primary suffix is ane. 3. The functional groups is – CN. Hence, secondary suffix is nitrile 4. Moreover, there is a methyl group on carbon 5 and ethyl group on carbon 3. 5. The IUPAC name is, therefore, 3-Ethyl-5-methylheptanenitrile 24 Organic Chemistry – Some Basic Principles and Techniques e.g. Write the IUPAC name of 7 6 5 4 3 2 1 CH3  CH2  CH  CH  CH  CH2  CHO | CH3 1. The longest chain containing functional group is of seven carbon atoms. Therefore, word root is hept. 2. As C = C double bond is present in the molecule. Thus, the primary suffix is ene. Ex.16 Write IUPAC Name (a) (b) (c) 3. The secondary suffix is al because the presence of – CHO group. 4. The chain is numbered as shown so that carbon atom of – CHO groups gets number 1. Ans. (a) 4-Oxopentanoic acid (b) Propane-1,2,3-tricarboxylic acid The methyl group is present on carbon 5 while (c) 4-(But-2-enyl)non-6-enoic acid position of double bond is 3. Thus, IUPAC name is 5-Methylhept-3-en-1-al. Ex.17 Write IUPAC Name e.g. Write the IUPAC name of (a) (b) (c) 1. Primary suffix is ene, due to presence of double bond between C4 & C5 2. Senior functional group is alcohol hence secondary suffix is -ol 3. Root word is undec (d) Ans. (a) 1-Chloro-5-methylhexan-2-one 4. Chain is numbered as shown (b) 3-Chlorobutan-1-ol 5. 6–nitro–7–methyl–8–Bromo–10–amino are prefixes. Arrange them in alphabaetical order & give the name. (c) N-methyl-2-Methoxyethan-1-amine (d) 3-Bromo-2-chloro-5-methyloctane 10 – Amino– 8 – bromo – 7 – methyl – 6 – nitroundec – 4 – en – 2 – ol 25 Organic Chemistry – Some Basic Principles and Techniques Nomenclature of Aromatic Compounds The aromatic compounds are cyclic compounds which contain one or more benzene type rings. Benzene is the simplest hydrocarbon of aromatic series which has planar cyclic ring of six carbon atoms having three double bonds in alternate positions as shown below. 1, 4 – Dimethyl benzene (p – Xylene) Isopropylbenzene (Cumene) or (i) Nuclear Substituted – The functional group is directly attached to the benzene ring in the IUPAC system, they are named as derivatives of benzene. The position of the substituents in disubstituted benzenes are indicated either by prefixes such as O–(ortho) for 1, 2, m – (meta) for 1, 3 and p (para) for 1, 4 position. However, many of their common names have also been adopted by the IUPAC system Phenylethene (Styrene) Phenylethyne The IUPAC and common names of a few important members of each family are given below. (Allyl benzene) 3-Phenylprop-1-yne (Propargyl benzene) (ii) Side – Chain Substituted – The functional group is present in the side chain of the benzene ring in the IUPAC systems, these are usually named as phenyl derivatives of the corresponding aliphatic compounds. 3 – Phenylprop-1-ene (b) Hydrocarbon containing condensed or fused ring Naphthalene (1) Aromatic hydrocarbons (arenes) hydrocarbons which contain both aliphatic and aromatic units are called arenes . These are of two types (a) Hydrocarbon containing one ring only. Anthracene e.g. 1, 2 – Dimethyl benzene (o – Xylene) 1, 3 – Dimethyl benzene (Phenanthrene) (m – Xylene) 26 Organic Chemistry – Some Basic Principles and Techniques 4. Hydroxy derivaties 2. Aryl Groups : The nuclear hydroxy derivatives are called phenols while the side chain substituted hydroxy derivatives are called aromatic alcohols. (i) Phenols – monohydric Phenyl (Benzyl) (Benzal) (Benzo) Hydroxybenzene 4 – methyl phenol (phenol) (p –cresol) (ii) Dihydric and polyhydric phenols 2 – Tolyl or (o – Tolyl) 3 – Tolyl 4 – Tolyl or (m – Tolyl) or (p – Tolyl) 3. Halogen derivatives Benzene – 1, 2 – diol Benzene – 1, 3 – diol (Catechol) Chlorobenzene (Resorcinol) 1,2 – Dichlorobenzene or o – Dichlorobezene Benzene – 1, 4 – diol (Quinol) (iii) Aromatic Alcohols 1, 4 – Dichlorobenzene Phenyldicholoromethane or p – Dichlorobenzene (Benzyl chloride) Phenyl methanol (Benzyl alcohol) 1 – Bromo – 3 – phenylpropane 1 – phenylethanol (–phenyl ethyl alcohol) 1 – chloro – 2 – phenylethene 27 Organic Chemistry – Some Basic Principles and Techniques (vii) Nitro Compounds (iv) Aromatic ethers Methoxy benzene Phenoxybenzene (Anisol) (Diphenyl ether) Nitrobenzene 1, 3 – Dinitrobenzene (m – Dinitrobenzene) 2 – Nitro toluene (O – Nitro toluene) 2, 4, 6 – Trinitrophenol (T.N.P) (Picric acid) (v) Aldehydes Benzenecarbaldehyde (Benzaldehyde) (viii) Amines (a) Aryl amines 2 – Hydroxybenzenecarbaldehyde (Salicylaldehyde) Benzenamine (Aniline) Benzene –1, 2 – diamine (O – phenylenediamine) 3 – Phenylpropanal (  – phenylpropionaldehyde) (vi) Ketones N, N – Dimethylbenzenamine N – Phenyl benzenamine (N, N – Dimethylaniline) (Diphenyl amine) (b) Aryl alkyl amine Methyl phenyl ketone Diphenyl ketone (Acetophenone) (Benzophenone) Phenylmethamine 2 – Phenyl ethanamine (Benzylamine)  – phenyl ethyl amine) 28 Organic Chemistry – Some Basic Principles and Techniques (ix) Arenediazonium Salts Ex.18 Write IUPAC name of following aromatic compounds Benzene diazonium chloride Benzene diazonium hydrogen sulphate (x) Cyanides and Isocyanides Benzenecarbonitrile (Benzonitrile) Benzeneisonitrile (Phenyl isocyanide) (a) (b) (xi) Carboxylic Acids Some Important 1993 Recommendations Benzenecarboxylic acid 2 – Methylbenzene of IUPAC Nomenclature of carboxylic acid (O – toluic acid) Organic Compounds 1. Locants (numerals and / or letters) are placed immediately before the part of the name to which they relate. For example. Benzene – 1, 2 -dicarboxylic acid (Phthalic acid) (xii) Anhydrides : O O || || C6H5  C  O  C  C6H5 CH3CH2CH = CH2 should be named as but-1-ene CH3CH2OH should be named as ethan-1-ol similarly, a few more examples are given as following: Benzenecarboxylic anhydride (xiii) Esters : 4–Methylphenyl ethanoate (xiv) Amides : Benzenecarboxamide 29 Organic Chemistry – Some Basic Principles and Techniques 2. The locant 1 is often omitted when there is no (ii) The name of a prefix for a substituted substituent ambiguity. For example. is considered to begin with the first letter of its complete name. e.g. In all the above examples locant 1 for the functional group is omitted because the position of the functional group is unambiguous. However, in the following cases the position of the functional group must be mentioned. for the substituted 1-chloropropyl, 'C' is taken as the first letter. Here, we cannot write simply propanol (or propanamine) because there are two propanols ; propan-1-ol and propan-2-ol. 3. Arrangement of Prefixes (i) Simple prefixes such as methyl, ethyl, chloro, nitro, hydroxy, etc. are arranged alphabetically. (iii) When two or more prefixes consist of identical roman letters priority for citation is given to the group which contains the lowest locant at the first point of difference. For example, The prefixes di, tri, etc. are however not considered for comparison. e.g. Here, 1-chloroethyl gets priority over 2-chloroethyl. 30 Organic Chemistry – Some Basic Principles and Techniques ADDITIONAL ILLUSTRATIONS AND SOLVED EXAMPLES Compound Prefix Wordroot – But ane – 2–Methyl But ane – 2–Methylbutane – Pent 2-ene – Pent–2-ene 2–Methyl Pent 2-ene – 2-Methylpent-2-ene – Prop yne – Propyne – But ane 1–ol Butan–1–ol 3–Methyl But ane 1–ol 3–Methylbutan–1–ol 4 – Methyl Pent 3–ene 1–ol 4-Methylpent-3-en-1-ol – Prop 2–yne 1–ol Prop–2–yn–1–ol CH  C – C  CH – Buta diyne – Butadiyne CH3–CH =C=CH–CH3 – Penta 2, 3 diene – Penta-2, 3–diene Cyclo But 2-ene 1-ol 4-Nitro Benz – CH3 – CH2 – CH2–CH3 CH3–CH=CH–CH2–CH3 0CH  C – CH3 Pri. Suffix Sec. Suffix Name Butane Cyclobut-2-en-1-ol oyl Bromide 31 Organic Chemistry – Some Basic Principles and Techniques WOOD ROOTS Number of Carbon Atoms Word Root 1 Meth 2 Eth Ethane 3 Prop Propane 4 But Butane 5 Pent Pentane 6 Hex Hexane 7 Hept Heptane 8 Oct Octane 9 Non Nonane 10 Dec Decane 11 Undec Undecane 12 Dodec Dodecane 13 Tridec Tridecane 14 Tetradec Tetradecane 15 Pentadec Pentadecane 16 Hexadeca Hexadecane 17 Heptadec Heptadecane 18 Octadec Octadecane 19 Nonadec Nonadecane 20 Icos 21 Heneicos 22 Docos Docosane 23 Tricos Tricosane 30 Triacont 31 Hentriacont 40 Tetracont Tetracontane 50 Pentacont Pentacontane 60 Hexacont Hexacontane 70 Heptacont Heptacontane 80 Octacont Octacontane 90 Nonacont Nonacontane 100 Cent & Hect Name Methane Icosane Heneicosane Triacontane Hentriacontane Centane or Hectane 32 Organic Chemistry – Some Basic Principles and Techniques FUNCTIONAL GROUPS IN DECREASING ORDER OF SENIORITY Class 1 R – COOH 2 R – SO3H 3 R–C–O –C–R || || O O 4 R – COOR 5 R–C–X || O 6 R – C – NH2 || O 7 R–CºN 8 R–C–H || O 9 R–C–R || O 10 R – OH 11 R – SH 12 R – NH2 Name Suffix Alkanoic Acid – oic Acid (carboxylic acid) Alkane sulphonic Acid – sulphonic Acid Prefix Carboxy sulpho Alkanoic Anhydride – anhydride ------------ Alkyl alkanoate Alkanoyl halide – alkanoate (carboxylate) Alkoxy carbonyl – oyl halide (carbonyl halide) halo carbonyl Alkanamide – amide (carboxamide) Carbamoyl Alkanenitrile Alkanal – nitrile (carbonitrile) – al (carbaldehyde) cyano formyl / oxo Alkanone – one Oxo / Keto Alkanol Alkanethiol Alkanamine – ol – thiol – amine hydroxy mercapto amino 33 Organic Chemistry – Some Basic Principles and Techniques COMMON AND IUPAC NAMES OF SOME ORGANIC COMPOUNDS S.No. 1. Compound CH4 Common names IUPAC name Methane or Marsh gas or Fire damp or Carbane Methane 2. H3 C  CH  CH3 | CH3 Isobutane 2-Methylpropane 3. H3 C  CH  CH2  CH3 | CH3 Isopentane 2-Methylbutane Neopentane 2, 2-Dimethylpropane Isohexane 2-Methylpentane 6. CH3 | CH3  C  CH2CH3 | CH3 Neohexane 2-2-Dimethylbutane 7. CH2 = CH2 Ethylene Ethene 8. CH3CH = CH2 Propylene Propene 9. CH3CH2 – CH = CH2 -Butylene But-1-ene 10. CH3CH = CHCH3 -Butylene But-2-ene 11. CH3(CH2)2CH = CHCH3 -Hexylene Hex-2-ene Isobutylene 2-Methylpropene 4. 5. 12. CH3 | H3 C  C  CH3 | CH3 CH3 | CH3  CHCH2 CH 2CH3 34 Organic Chemistry – Some Basic Principles and Techniques Allene Propadiene 13. CH2 = C = CH2 14. HC  CH Acetylene Ethyne 15. H3C – C  CH Methyl acetylene Propyne 16. CH3 – Cl Methyl chloride Chloromethane 17. CH3  CH  CH3 | Isopropyl iodide 2-Iodopropane sec-Butyl chloride 2-Chlorobutane I 18. 19. 20. CH3CH2  CH  CH3 | Cl CH3 | CH3  CH  CH2  Cl CH3 | CH3  C  Cl | CH3 Isobutyl chloride 1-Chloro-2-methylpropane tert-Butyl chloride 2-Chloro-2-methyl propane 21. CH2  Br | CH2  Br Ethylene dibromide 1, 2-Dibromoethane 22. CH3  CH  Br | Br Ethylidene bromide 1, 1-Dibromoethane 23. CH2 = CH – Cl Vinyl chloride Chloroethene 24. CH2 = CH – CH2 – Br Allyl bromide 3-Bromo-1-propene 25. CH3 – CH2 – OH Ethyl alcohol or (Methylcarb inol ) Ethanol 26. CH3CH2CH2 – OH n  Propyl alcohol or (Ethyl carbinol) Propan-1-ol 27. CH3  CH  CH3 | OH Isopropyl alcohol Propan-2-ol 35 Organic Chemistry – Some Basic Principles and Techniques 28. CH2 = CH – CH2 – OH Allyl alcohol Prop-2-en-1-ol 29. CH  C – CH2 – OH Propargyl alcohol Prop-2-yn-1-ol 30. CH3  CH  CH 2 | | OH OH Propylene glycol Propane-1, 2-diol 31. HO – CH2 – CH2 – CH2 – OH Trimethylene glycol Propane-1, 3-diol 32. CH2  CH  CH2 | | | OH OH OH Glycerol or Glycerine Propane-1, 2, 3-triol 33. H – CHO Formaldehyde Methanal 34. CH3 – CHO Acetaldehyde Ethanal 35. CH3CH2CH2 – CHO n-Butyraldehyde Butanal Isobutyraldehyde 2-Methylpropanal 36. 37. CH2 = CH – CHO Acrolein Propenal 38. CH3CH = CH – CHO Crotonaldehyde But-2-enal 39. CH3 – CO – CH3 Dimethyl ketone or Acetone Propanone 40. CH3 – CO – CH2CH3 Ethyl methyl ketone Butanone 41. CH3 – CO – CH2CH2CH3 Methyl n-propyl ketone Pentan-2-one 42. CH3CH2 – CO – CH2CH3 Diethyl ketone Pentan-3-one 43. CH3CO – CH = CH2 Methylvinyl ketone But-3-en-2-one 44. H – COOH Formic acid Methanoic acid 36 Organic Chemistry – Some Basic Principles and Techniques 45. CH3 – COOH Acetic acid Ethanoic acid 46. CH3CH2CH2 – COOH n-Butyric acid Butanoic acid 47. CH3CH2CH2CH2COOH n-Valeric acid Pentanoic acid Iso-butyric acid 2-Methylpropanoic acid 48. 49. CH2 = CH – COOH Acrylic acid Propenoic acid 50. COOH | COOH Oxalic acid Ethanedioic acid Malonic acid Propanedioic acid succinic acid Butanedioic acid Glutaric acid Pentanedioic acid Lactic acid 2-Hydroxypropanoic acid Pyruvic acid 2-Oxopropanoic acid Tartaric acid 2,3  Dihydroxyb u tan e dioic acid Citric acid 2  Hydroxypro pane  1,2, 3  tricarboxy lic acid 51. 52. H 2C  COOH | H 2C  COOH 53. 54. 55. 56. 57. H | H3C  C  COOH | OH O || H 3C  C  COOH HOCHCOOH | HOCHCOOH 37 Organic Chemistry – Some Basic Principles and Techniques Malic acid 2  Hydroxy  bu tan e dioic acid 59. Maleic acid cis-But-2-enedioic acid 60. Fumaric acid trans-But-2-enedioic acid 58. HO  CH  COOH | CH2COOH 61. CH2 = CH – COOH Acrylic acid Propenoic acid 62. H3C – CH = CH – COOH Crotonic acid But-2-enoic acid 63. H – COOCH3 Methyl formate Methyl methanoate 64. H – COOC2H5 Ethyl formate Ethyl methanoate 65. CH3 – COOC2H5 Ethyl acetate Ethyl ethanoate 66. H – COCl (unstable) Formyl chloride Methanoyl chloride 67. CH3 – COCl Acetyl chloride Ethanoyl chloride 68. (CH3CO)2O Acetic anhydride Ethanoic anhydride 69. (CH3CH2 CO)2 O Propionic anhydride Propanoic anhydride 70. H – CONH2 Formamide Methanamide 71. CH3 – CONH2 Acetamide Ethanamide 72. CH3 – CH2 – CONH2 Propionamide Propanamide 73. CH3 – O – N = O Methyl nitrite Methyl nitrite 74. CH3CH2 – O – N = O Ethyl nitrite Ethyl nitrite 38 Organic Chemistry – Some Basic Principles and Techniques Methylamine Methanamine 75. CH3 – NH2 76. (CH3CH2)2NH Diethylamine N-Ethylethanamine 77. (CH3)3N Trimethylamine or N,N-Dimethylaminomethane N,N-Dimethyl methanamine 78. H2N – SO3H Sulphamic acid Aminosulphonic acid 79. CH3 – CN Methyl cyanide or Acetonitrile Ethanenitrile 80. CH3 – N+  C¯ Methyl isocyanide or Methyl carbylamine Methane isocyanide 81. CH3CH2 – N+  C¯ Ethyl isocyanide or Ethyl carbylamine Ethaneisocyanide 82. Dioxane 1, 4-Dioxacyclohexane 83. Trioxane 1,3,5-Trioxacyclohexane 84. Toluene 85. Xylene (o,m,p) (o,m,p) Dimethylbenzene 86. Mesitylene 1, 3, 5  Trimethyl benzene 87. Cumene Methylbenzene or Toluene Isopropylbenzene 39 Organic Chemistry – Some Basic Principles and Techniques 88. Benzyl chloride Chlorophenylmethane 89. Benzal chloride Dichlorophenylmethane 90. Benzochloride Trichlorophenylmethane 91. Benzonitrile Benzenecarbonitrile 92. (Gammexane or Lindane or 666 ) Hexachlorocyclohexan e BHC [Benzene hexachloride]] 93. Carbolic acid Phenol 94. Catechol Benzene-1,2-diol 95. Resorcinol Benzene-1,3-diol 40 Organic Chemistry – Some Basic Principles and Techniques 96. Hydroquinone Benzene-1,4-diol 97. Oil of bitter almonds Benzenecarbaldehyde 98. Salicylaldehyde 2  Hydroxy benzaldehyde (2  Hydrobenzene carbaldehyde ) 99. Phthalaldeyde 100. Acetophenone 101. Bennzophenone 102. Phenacyl chloride Chloroacetophenone 103. Cinnamic acid 3  Phenylprop  2  en oic acid Acetopheno ne or Methylphen yl ketone 41 Organic Chemistry – Some Basic Principles and Techniques 104. Aspirin ( Acetyl salicylic acid) (Methyl salicylate) Methyl 2  hydroxy benzenecarboxylate 106. Oil of mirbane Nitrobenzene 107. Picric acid 2, 4, 6-Trinitrophenol 108. Acetanilide N-Phenylethanamide 109. Styrene Phenyl ethene or Ethenylben zene 110. Anisole Methoxybenzene 111. Phenetol Ethoxybenzene 105. Oil of winter green 42 Organic Chemistry – Some Basic Principles and Techniques 112. Aniline Aniline (Benzenamine) 113. (o, m, p) Toluidine Methylaniline 114. (o, m, p) cresol Methylphenol 115. Napthalene Naphthalene 116. Anthracene Anthracene 117. Phenanthrene Phenanthrene 118. Pyrene Pyrene 43