4-Amino-2-thiophenecarboxylic Acid, is involved in the preparation of (S)-4-Amino-4,-dihydro-2-thiophenecarboxylic Acid, which is a heterocyclic mimimc of the natural product Gabaculine (G111000), a mechanism-base inactivator of γ-aminobutyric acid aminotransferase (GABVIP(LA) AT).