Hybridization (Review of Material from Lectures 15 and 16)

University:
Massachusetts Institute of Technology
Course:
5.111 | Principles of Chemical Science
Academic year:

2020
Views:

333

Pages:

1
Author:

folclord7m

Hybridization (review of material from lectures 15 and 16) See lecture 15 and lecture 16 (pages 1-2) for hybridization. Example from page 1 of Lecture 17 notes: Identifying molecules that follow the “morphine rule” Morphine, a potent and addictive analgesic (“painkiller”), and related molecules share a characteristic set of four features called the morphine rule: H C 1) a phenyl ring 2) an sp3 hybridized carbon atom 3) a CH2-CH2 sequence 4) an sp3 hybridized nitrogen atom HC CH HC C 1) phenyl ring H2 C a C H Nb C 4) _______ N C H2 3) CH2CH2 2) _______ C These structural elements are responsible for the bioactivity of morphine and other molecules that are pharmacologically similar to morphine. Examples are shown below with the “morphine rule” features highlighted in purple. H C HO C H C O CH H 3C C H3C C H C O C CH O C H2 C O C HC CH HO C C C H C CH C H morphine H2 C O CH2 C HC N CH3 CH HO C C C CH2 H C CH C H codeine H C H2 C O CH2 C O N HC CH HC C C CH2 HC CH H2 C CH2 H C CH C CH2 OCH2CH3 C C H 2C N O CH2 C CH3 H3C CH O CH C H diacetylmorphine* N CH3 H3C C H2 Demerol These molecules fit into a pain receptor in the brain, mimicking the action of endorphins, which are natural pain relievers produced by the body. Endorphins do not have all of the elements of the morphine rule, but do have significant structural similarities. • Pure morphine was first isolated in 1803. The chemical structure was determined in 1925. Two hundred years later, morphine and related compounds remain the most potent painkillers known. Unfortunately, morphine is also highly addictive. • Codeine is less addictive, but also less effective. It is approximately a tenth as strong as morphine. • Diacylmorphine was synthesized in 1898 by Bayer (the company best known for Bayer’s aspirin). Diacylmorphine is much more potent than morphine, and this potency initially masked some major side effects. Bayer marketed this as a “hero” drug. We now know it as the “hero” derived name heroin, and few people associate it with the company Bayer. • Until the 1980’s, Demerol was thought to be a safer alternative to morphine. While Demerol is less addictive than morphine, it can have dangerous side effects, including seizures, and has become much less widely used. This example is based on Chapter 13 of Napoleon's Buttons: How 17 Molecules Changed History by Penny LeCouteur and Jay Burreson. The morphine rule can be used as a VSEPR or as a hybridization example.

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