2-(Carbomethoxy)thiophene 2-(Methoxycarbonyl)thiophene 2-Thiophenecarboxylic acid methyl ester 2-Thiophenecarboxylic acid, methyl ester 5380-42-7 Methyl 2-thiophenecarboxylate NSC19879 Thiophenate methyl Thiophenate-methyl