Diethyl Oxalate → Thieno[2,3-b]pyrazine-2,3(1H,4H)-dione

Participants

Reaction Steps

A mixture of di-t-butyl thiophene-2,3-dicarbamate (1.53 g, 4.87 mmol), diethyl oxalate (15 ml) and acetic acid (15 ml) was refluxed for 48 hours. The precipitate was filtered off, washed with water and dried to yield 0.64 g (78%) of the title compound. M.p. >340° C. 1H-NMR (DMSO-d6, δ): 6.74 (d, 1H), 7.13 (d, 1H), 12.28 (s, 1H).

Provenance & Evidence