Dimethyl acetylenedicarboxylate → HCID 60165811, compound

Participants

Reaction Steps

To a solution of 3-acetyl-2,3-dihydrobenzo[d]thiazole-2-carbonitrile (5 g, 24.5 mmol) in dichloromethane (50 mL) was added dropwise 7 mL of tetrafluoroboric acid (HBF4). The solution was stirred for 3 h at room temperature. The brown precipitates appeared were collected by filtration and the filter cake was washed with ether. The solid salt was added to a solution of dimethyl acetylenedicarboxylate (10.4 g, 73.0 mmol) in DMF (30 mL) and then warmed at 35° C. for 13 h. The reaction mixture was concentrated in vacuo and the residue was recrystallized from methanol to give dimethyl 1-methylbenzo[d]pyrrolo[2,1-b]thiazole-2,3-dicarboxylate, 1.7 g (23%); mp 143-144° C. 1H NMR (DMSO-d6) δ 2.85 (3H, s, Me), 3.83 (3H, s, COOMe), 3.85 (3H, s, COOMe), 7.50 (1H, t, J=7.6 Hz, ArH), 7.58 (1H, t, J=7.6 Hz, ArH), 8.07 (1H, d, J=8.0 Hz, ArH), 8.12 (1H, d, J=8.0 Hz, ArH). Anal. Calcd. for (C15H13NO4S): C, 59.39; H, 4.32; N, 4.62; S, 10.57. Found: C, 59.02; H, 4.23; N, 4.87; S, 10.42.

Provenance & Evidence