after administration to rats of methyl acrylate ( i ) , methyl methacrylate ( ii ) and methyl crotonate ( iii ) , urinary mercapturic acids were isolated and identified as the dicarboxylic acids n-acetyl-s- ( 2-carboxyethyl ) cysteine ( iv , r = h ) , n-acetyl-s- ( 2-carboxypropyl ) cysteine ( v , r = h ) and n-acetyl-s- ( 1-methyl-2-carboxyethyl ) cysteine ( vi , r = h ) and for a minor part as their monomethyl esters iv ( r = ch3 ) and vi ( r = ch3 ) .
C0001047
mercapturic acids
C0010654
cysteine