Cysteine

SMELLY STUFF

Organic compounds having SH or Sulfhydryl functional group with strong and disagreeable odors. “ Also called mercaptans “ Derivatives of hydrogen sulfide.

In 1834, W. C. Zeise discovered THIOLS. ZEISE named THIOLS as MERCAPTANS because they readily react with mercury to form an insoluble salt.mercury The term MERCAPTAN comes from the Latin mercurius captans, meaning 'laying hold of mercury,' because the –SH group binds tightly to the element mercury. Latinmercury

CH 3 – SH methanethiol CH 3 CH 2 – SH ethanethiol methyl mercaptan IUPAC IUPAC COMMON COMMON IUPAC IUPAC COMMON COMMON ethyl mercaptan

dibutylaminotriazinethiol

Glutathione

2-amino-5-{[2-[(carboxymethyl)amino]-1-(mercaptomethyl)-2-oxoethyl]amino}-5-oxopentanoic acid

CH 3 CH 2 CH 2 – SH propanethiol

CH 2 ═ CH – CH 2 – SH 2 – propene – 1 – thiol CH 2 ═ CH – S – CH ═ CH 2 Divinyl sulfide

CH 3 – CH – CH 2 – CH 2 – SH CH 3 3 – methyl – 1 – butanethiol C ═ C H H CH 2 – SH 3 HC Trans – 2 – butene – 1 – thiol

THIOLS tend to be a clear liquid or white crystalline form. Characteristic of other sulfur-containing compounds, THIOLS have a stench that smells similar to rotten eggs. The odor of THIOLS is often strong and repulsive, particularly for those of low molecular weight. THIOLS show little association by hydrogen bonding.hydrogen bonding They have lower boiling pointsboiling points Less soluble in water and other polar solvents than alcohols of similar molecular weight.solublepolar solvents

When a thiol group is a substituent on an ALKANE, there are several ways of naming the resulting THIOL: The preferred method (used by the IUPAC) is to add the suffix -thiol to the name of the alkane. The common name is obtained by writing the alkyl group name followed by the word mercaptan.

CH 3 – SH CH 3 – CH 2 – SH CH 3 – CH 2 – CH 2 – SH

CH 3 – CH 2 – C – CH 2 – CH 2 – SH OH CH 3

SH CH 2 ═ CH – CH 2 – CH 2 – SH

SH CH 2 ═ CH – C – C ≡ CH SH NO2

SH OH

Thiol + Thiol  Disulfide + Water (O) Pt/Ni CH 3 – CH 2 – SH + HS – 2 HC – CH  CH 3 CH 2 – S – S – 2 HCCH 3 + H2O (O)(O) Pt/Ni

SH + HS – CH3 ---  (O) Pt/Ni S – S – CH 3 H2OH2O

Organic compounds containing – S – S – functional group.

CH 3 – CH 2 – CH 2 – S – S – CH 2 – CH 3 CH 3 – CH – S – S – HC – CH 3 CH 3

SS SSNO 2

Disulfides + Hydrogen → 2 Thiols Pt/Ni SS + H → Pt/Ni SHSH H – H 2

CH 3 – CH – S – S – HC – CH 3 CH 3 + H → Pt/Ni H – H HS – HC – CH 3 CH 3 2 SS + H → Pt/Ni H – H SHSH + CH 3 SH

Sulfur analogs of ETHER containing the – S – functional group and they are name by using the word SULFIDE to show the presence of the - S – group.

CH 3 – CH 2 – CH 2 – S – CH 2 – CH 3 S(CH 2 ) 3 – CH 3

S(CH 2 ) 5 – CH 3 S