Dimethyl acetylenedicarboxylate → HCID 68919114, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of 1-benzoyl-2,3-dihydro-1H-indole-2-carboxylic acid (7.48 g, 28 mmol) and dimethyl acetylenedicarboxylate (4.55 g, 32 mmol) in acetic anhydride (40 mL) was heated for 4.5 h at 120° C. until no gas was eliminated. The dark solution was concentrated in vacuo to dryness and the solid residue was recrystallized from methanol to yield 3-phenyl-8H-3a-azacyclopenta[a]indene-1,2-dicarboxylic acid dimethyl ester, 7.5 g (77%): mp 149-151° C.; 1H NMR (DMSO-d6) δ 3.62 (3H, s, OMe), 3.79 (3H, s, OMe), 4.15 (2H, s, CH2), 6.60-6.67 (1H, m, ArH), 7.18-7.23 (2H, m, 2×ArH), 7.51-7.67 (6H, m, 6×ArH). Anal. Calcd for C21H17NO4: C, 69.40; H, 5.21; N, 3.85. Found: C, 69.42; H, 4.65; N, 3.83.

Provenance & Evidence