Hydrochloric Acid → methyl 7H-indolo[2,1-a][2]benzazepine-6-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A solution of 11-cyclohexyl-N-[(dimethylamino)sulfonyl]-6-hydroxy-8-methoxy-6H-isoindolo[2,1-a]indole-3-carboxamide (cyclic hemiaminal) (63.0 g, 130 mmol), methyl 2-(dimethoxyphosphoryl)acrylate (60 g, 261 mmol), cesium carbonate (106 g, 326 mmol) in DMF (400 mL) was heated at 60° C. (bath temp) for 4.5 h. Additional methyl 2-(dimethoxyphosphoryl)acrylate (15 g, 65 mmol) and cesium carbonate (21.2 g, 65 mmol) were added and the reaction was heated at 60° C. overnight then and cooled to rt. The stirring reaction mixture was diluted with H2O (1 L), slowly neutralized with 1N aqueous HCl (800 mL), stirred 3 h, and then the precipitates were collected by filtration. The solids were triturated with Et2O (800 mL) and dried to yield methyl 7H-indolo[2,1-a][2]benzazepine-6-carboxylic acid, 13-cyclohexyl-10-[[[(dimethylamino)sulfonyl]amino]carbonyl]-3-methoxy-, methyl ester (70.2 g, 127 mmol, 98%) as a yellow solid which was used without further purification. 1HNMR (300 MHz, CDCl3) δ 8.67 (s, 1H), 8.09 (s, 1H), 7.86 (d, J=8.4 Hz, 1H), 7.80 (s, 1H), 7.50 (d, J=8.4 Hz, 1H), 7.42 (d, J=8.8 Hz, 1H), 7.08 (dd, J=2.6, 8.8 Hz, 1H), 6.98 (d, J=2.6 Hz, 1H), 5.75-5.51 (m, 1H), 4.29-4.01 (m, 1H), 3.89 (s, 3H), 3.82 (s, 3H), 3.05 (s, 6H), 2.87-2.73 (m, 1H), 2.11-1.12 (m, 10H). LCMS: m/e 550 (M−H)−, ret time 3.21 min, column A, 4 minute gradient.

Provenance & Evidence