Hydrazine hydrate (1:1) → Ethyl 5-(hydrazinecarboxamido)-3-methylthiophene-2-carboxylate
Reaction equation
[CH3:1][C:2]1[CH:6]=[C:5]([NH:7][C:8](OC2C=CC=CC=2)=[O:9])[S:4][C:3]=1[C:17]([O:19][CH2:20][CH3:21])=[O:18].O.[NH2:23][NH2:24]>O1CCCC1>[NH:23]([C:8]([NH:7][C:5]1[S:4][C:3]([C:17]([O:19][CH2:20][CH3:21])=[O:18])=[C:2]([CH3:1])[CH:6]=1)=[O:9])[NH2:24]Participants
4
Procedure
To a stirred suspension of ethyl 3-methyl-5-(phenoxycarbonylamino)-thiophene-2-carboxylate (18.89 g, 61.86 mmol) in tetrahydrofuran (130 mL) was added hydrazine monohydrate (19.0 mL, 391.7 mmol). The resulting reaction mixture was stirred for 2.5 h, and then concentrated in vacuo. The residue was triturated with ethyl acetate to afford ethyl 5-(hydrazinecarboxamido)-3-methylthiophene-2-carboxylate as a yellowish solid in 89% yield (13.30 g): MS (ES+) m/z 244.2 (M+1).