The reaction of 12-(chlorosulfonyl)dehydroabietic acid ethyl ester with methyl esters of amino acids (glycine, methionine, leucine, glutamic acid, tyrosine, proline, and histidine) afforded previously unknown sulfonamides which were selectively converted to amino acid hydrazides without involving the ethyl ester moiety of dehydroabietic acid. In the reaction with glutamic acid dimethyl ester, the corresponding dihydrazide was obtained. 12-(Chlorosulfonyl)dehydroabietic acid ethyl ester reacted with cystine dimethyl ester to give bis-sulfonamide as the only product, while the same reaction carried out in acetone-containing medium was accompanied by cleavage of the cystine S–S bond with the formation of acetone dithioacetal. Treatment of the bis-sulfonamide and thioketal with chlorine dioxide selectively produced the same chlorosulfonyl derivative as a result of oxidation of the disulfide or thioketal moiety [ABSTRACT FROM AUTHOR]