Isopropylamine → 14′-Cyclohexyl-1-(1-methylethyl)spiro[azetidine-3,7′(8′H)-[6H]indolo[1,2-e][1,5]benzoxazocine]-11′-carboxylic acid

Participants

Reaction Steps

A catalytic amount of para-toluenesulfonic acid monohydrate was added to a suspension of methyl 14′-cyclohexyl-2,2-dimethylspiro[1,3-dioxane-5,7′-indolo[1,2e][1,5]benzoxazocine]-11′-carboxylate in MeOH/THF 1:2 (0.03 M), and the solution was stirred for 3 h at RT. Filtration over a pad of neutral alumina with EtOAc afforded after evaporation of the solvent in vacuo, methyl 14-cyclohexyl-7,7-bis(hydroxymethyl)-7,8-dihydro-6H-indolo[1,2-e][1,5]benzoxazocine-11-carboxylate (quant). Triflic anhydride (2.8 eq) was added at 0° C. to a solution of methyl 14-cyclohexyl-7,7-bis(hydroxymethyl)-7,8-dihydro-6H-indolo[1,2-e][1,5]benzoxazocine-11-carboxylate in dry MeCN (0.05M), DIPEA (3.0 eq) was added and the mixture was stirred for 15 min at 0° C., then further 3.0 eq of DIPEA were added, followed by iPrNH2 (2 eq). The mixture was transferred into a closed vessel and stirring was continued at 70° C. for 4 h. EtOAc was added, the organic phase was washed with water and brine, dried over Na2SO4 and the solvent was removed in vacuo. The residue was hydrolysed with aqueous 1N KOH in dioxane (65° C., overnight); evaporation to dryness gave a residue that was purified by RP-HPLC to afford the title compound (4%). 1H NMR (300 MHz, DMSO-d6, 330 K) δ 8.50 (s, 1H), 7.87 (d, 1H, J 8.3), 7.70 (d, 1H, J 8.3), 7.51-7.46 (m, 1H), 7.24-7.15 (m, 3H), 5.16 (b.d, 1H, J 15.9), 4.28 (d, 1H, J 12.7), 4.20 (d, 1H, J 12.7), 4.1-3.5 (m, 6H), 2.75-2.66 (m, 1H), 2.01-1.58 (m, 7H), 1.39-1.17 (m, 9H); MS (ES+) m/z 459 (M+H)+.

Provenance & Evidence