Thioesters, like methanethiol,
are primarily sulfur based except are formed from sulfur bonding with an Acyl group.
Salicylates are excreted mainly by the kidneys as salicyluric acid(75%), free salicylic acid(10%),
salicylic phenol(10%), and Acyl glucuronides(5%), gentisic acid(< 1%), and 2,3-dihydroxybenzoic acid.
The Acyl chains in the fatty acids are extended by a cycle of
reactions that add the Acyl group, reduce it to an alcohol, dehydrate it to an alkene group and then reduce it again to an alkane group.