Dimethyl acetylenedicarboxylate → HCID 68914640, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of 5-methoxy-1-(4′-methoxybenzoyl)-2,3-dihydro-1H-indole-2-carboxylic acid (4.24 g, 12.9 mmol) and dimethyl acetylenedicarboxylate (2.4 mL, 19.5 mmol) in acetic anhydride (24 mL) was heated for 4.5 hours at 120° C. until no gas eliminated. The dark solution was concentrated in vacuo to dryness and the solid residue was recrystallized from methanol to yield 6-methoxy-3-(4-methoxy-phenyl)-8H-3a-azacyclopenta[a]indene-1,2-dicarboxylic acid dimethyl ester, 3.75 g (71%): mp 240-242° C.; 1H NMR (DMSO-d6) δ 3.60 (3H, s, COOMe), 3.73 and 3.77 (each 3H, s, 2×OMe), 3.85 (3H, s, COOMe), 4.09 (2H, s, CH2), 6.55 (1H, d, J=8.8 Hz, ArH), 6.77 (1H, dd, J=2.6 Hz and J=8.8 Hz, ArH), 7.08 (2H, d, J=8.7 Hz, 2×ArH), 7.19 (1H, d, J=2.4 Hz, ArH), 7.42 (2H, d, J=8.7 Hz, 2×ArH). Anal. Calcd. for C23H21NO5: C, 67.84; H, 5.20; N, 3.44. Found: C, 67.83; H, 5.19; N, 3.39.

Provenance & Evidence