Thiophene → ethyl 6-amino-3,4-dihydro-2H-1-benzopyran-2-carboxylate

Participants

Reaction Steps

A mixture of 59.8 parts of ethyl 3,4-dihydro-6-nitro-2H-1-benzopyran-2-carboxylate, 3 parts of a solution of thiophene in methanol 1% and 480 parts of methanol was hydrogenated at normal pressure and at room temperature with 5 parts of palladium-on-charcoal catalyst 10%. After the calculated amount of hydrogen was taken up, the catalyst was filtered off and the filtrate was evaporated, yielding 48 parts (90%) of ethyl 6-amino-3,4-dihydro-2H-1-benzopyran-2-carboxylate as a residue (intermediate 24).

Provenance & Evidence