Organo Sulfur Compounds Sulfur S S and O

Organo. Sulfur Compounds Sulfur (S) ü ü S and O : : atomically similar Sulfur also intimately involved in biological processes Sulfur forms two bonds in a manner similar to O But sulfur may form more because of the presence of d-orbitals, e. g. , –S(O)– and –S(O 2)– MEDC 527 Fall 2008 1

Organo. Sulfur Compounds Sulfur compounds that have an O analog MEDC 527 Fall 2008 … without O analog 2

Organo. Sulfur Compounds Nomenclature Thiols: CH 3 SH methane thiol or methylmercaptan or mercaptomethane Ph. SH benzene thiol or phenylmercaptan or mercapto benzene Sulfoxides and Sulfones CH 3 S(O)CH 2 CH 3 methyl sulfoxide CH 3 S(O 2)CH 2 CH 3 methyl sulfone MEDC 527 Fall 2008 3

Organo. Sulfur Compounds • Common and Important Sulfur Compounds — Glutathione ü ü ü +H 3 NCH(COO -)CH 2 CONHCH(CH 2 SH)CONHCH 2 COO or +H NCH(COO-)CH CH CO-CYS-GLY 3 2 2 Involved in a variety of detoxification, transport and metabolic processes Substrate for peroxidase reactions Maintains balance of sulfhydryl groups (-SH of Cys) in proteins — Coenzyme A ü - Plays a major role in the biosynthesis and metabolism of a number of important molecules, including fatty acids MEDC 527 Fall 2008 4

Organo. Sulfur Compounds • Common and Important Sulfur Compounds — S-Adenosylmethionine ü Plays a major role in the methyl transfer reactions, e. g. onto phenolic groups or DNA … — Heparin, Heparan Sulfate, Chondroitin Sulfate … ü Glycosaminoglycans have numerous physiological roles MEDC 527 Fall 2008 5

Heterocycles Containing Sulfur ü Basic Ring Systems ü Examples in Drugs (Antihistamine) (Antibiotic) MEDC 527 Fall 2008 (Antimalarial) 6

Organo. Phosphorus Compounds Phosphorus (P) ü ü N and P : : atomically similar Phosphorus is an important part of most important biological materials, DNA, RNA, ATP, … Phosphorus forms three bonds like N But P may form more because of d-orbitals MEDC 527 Fall 2008 7

Organo. Phosphorus Compounds Comparison of reactions of P and N • Similarities …. in acidification …. in quaternary salt formation …. in oxidation • Differences • • Maximum # bonds with N = 4; it is 5 or 6 with P depending on the number of dorbitals involved P does not form many unsaturated compounds because of poor p-p overlap, e. g, no – P=P- known (diazo are known); nor are phosphorus analogs of nitriles or amides Few unsaturated P compounds known, nearly all have P=O (double bond with oxygen) P does not give stable aromatic compounds, e. g. , no phosphorus analog of pyrrole or pyridine is known MEDC 527 Fall 2008 8

Organo. Phosphorus Compounds Phosphate buffer ATP RNA MEDC 527 Fall 2008 9