Make me a molecule Rearrangement of atoms cleaving

Make me a molecule Rearrangement of atoms: cleaving and making bonds Aspirin Tagamet® Tamiflu®

SYNTHESIS Make me a molecule “Chemists make molecules… they study the properties of these molecules; …” “At heart of their science is the molecule that is made. ” ― Roald Hoffmann― Constructing complex molecules is both an art and a science which stretches the chemist’s knowledge and insight, practical skills and imagination. Synthesis is the bedrock on which the chemical and pharmaceutical industries are built.

In the beginning synthesis was unnecessary. Chemistry was founded upon the study of those materials which were available from natural sources. Many of the materials we use today are made by chemical synthesis. Most of the new compounds made today are organic.

Organic Chemistry Organic Compounds Most of the new compounds made today are organic, that is, they are composed largely of carbon. stable and versatile unstable

Product e. g. paint and pigment vitamin synthetic fiber pesticide plastic explosive pharmaceutical

Synthesis involves breaking and making new chemical bonds to create new chemical structures. e. g. Aspirin In 400 B. C. , the Greek physician Hippocrates recommended chewing bark of the willlow tree to alleviate the pain of childbirth and to treat eye infections. *It is known in ancient Egypt. Salicin active component Hydrolysis of salicin in aqueous acid gives salicyl alcohol, which can be oxidized to salicylic acid. Salicylic acid proved to be an even more effective pain reliever. Unfortunately, it causes severe irritation of stomach. In 1883, chemists at Bayer division of I. G. Farben in Germany prepared aspirin. It proved to be less irritating to the stomach than salicylic acid and also more effective in relieving the pain and inflammation of rheumatoid arthritis. Salicyl alcohlol Saliciylic acid Acetylsalicylic acid (Asprin)

Organic Synthesis: 1. Carbon-Carbon Bond Formation 2. Functional Group Interconversion Efficiency and selectivity are important characteristics that have to be taken into account. [Efficiency: yields, number of steps] [Selectivity: chemoselectivity, regioselectivity, stereoselectivity]

Organic Synthesis: Stereoselectivity 1. Carbon-Carbon Bond Formation 2. Functional Group Interconversion

Organic Synthesis: Enantioselectivity 1. Carbon-Carbon Bond Formation 2. Functional Group Interconversion

분자식 입체이성질체(Stereoisomers) cis-1, 2 -dichloroethylene (bp: 60 Chiral compounds “Enantiomer” o. C) trans-1, 2 -dichloroethylene (bp: 48 o. C) cis trans (+)-2 -iodobutane (bp: 119 o. C) (-)-2 -iodobutane (bp: 119 o. C)

Chiral Compounds (+)-2 -iodobutane (bp: 119 o. C) (-)-2 -iodobutane (bp: 119 o. C) [ ]D = +15. 9 [ ]D = -15. 9 Enatiomers Optical isomers They are optically active.

Some Physical Properties of the Stereoisomers of Tartaric Acid

Louis Pasteur was born on December 27, 1822 in Dole, in the region of Jura, France. Louis Pasteur Chemist 1822 -1895 Resolution of enantiomers in 1848 Twenty years later, J. H. van’t Hoff and J. -A. Le Bel independently explained the origins of enantiomers based on the tetrahedral nature of carbon bonding. “Chance favors only prepared mind. ” -Louis Pasteur

Resolution diastereomeric salts seperation by selective crystallization or some other means Once separated, acidification of the two diastereomeric salts with strong acid gives pure enantiomers and recover the chiral amine.