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Thiols contain the sulfhydryl functional group and their nomenclature involves numbering the main chain to give the SH group the lowest number. Thiols have various odors and are important in biochemistry for forming disulfide linkages in proteins.
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Organic Chemistry Oxygen and Sulfurin Organic Compounds
Chapter 12Part 05Thiols Page 102
H R S S H H 1. Thiols -contain the sulfhydryl or mercapto functional group, -SH - general formula RSH - derivatives of hydrogen sulfide gas where one H is replaced by an R group
2. Nomenclature of Thiols -determine main chain (longest continuous chain of C atoms that contains the –SH). Keep the entire name; don’t remove any letters - add the suffix –thiol - If two thiol groups – dithiol - If three thiol groups – trithiol - number the chain to give the C bearing the –SH the lowest possible number - place this number in front of the name of the thiol, separated by a hyphen - if branched chain, always number giving the - SH group priority and name the substituents like you would for any other organic compound (lowest numbers, alphabetical, etc.)
H H H H C C H C SH C H H H H 2. Nomenclature Name the following thiol. 1-butanethiol
H H H H C C H C H C H H H SH 2. Nomenclature Name the following thiol. 2-butanethiol
H SH H H H C C H C H C C H H SH H H 2. Nomenclature Name the following thiol. 1,1-pentanedithiol
H H H Br SH H C C C H C H C C H H H H H H 2. Nomenclature Name the following thiol. 4-bromo-3-hexanethiol
SH H2N 2. Nomenclature Name the following thiol. trans-3-amino-1-cyclopentanethiol
SH SH 3. Nomenclature Name the following thiol. cis-1,2-cyclohexanedithiol
3. Thiols -hydrogen sulfide gas smells like rotten eggs - thiols have offensive odors - Examples 1-propanethiol (found in onions & garlic – makes eyes tear (lachrimator)) 3-methyl-1-butanethiol & trans-2-butene-1-thiol (found in skunk urine) 2-chloroethylsulfide (mustard gas)
3. Thiols methanethiol & ethanethiol - added to odorless natural gas after the New London, Texas gas explosion in 1937 http://www.youtube.com/watch?v=ZqCRNtZ12mo&playnext=1&list=PL0BAC9A84ED0009A7
3. Thiols -important in biochemistry - two –SH groups can be oxidized (hydrogens removed between them) to form disulfide linkages (hold protein chains together) - helps to determine the shapes of protein molecules