Ammonia → rac-(4aR,12bS)-12b-ethyl-1,2,4,4a,5,6,9,12b-octahydrospiro[benzo[4,5]oxepino[3,2-f]indazole-3,2'-[1,3]dioxolane]

Participants

Reaction Steps

A solution of rac-1-((4aR,12bS)-12b-ethyl-1,4,4a,5,6,12b-hexahydro spiro[benzo[4,5]oxepino[3,2-f]indazole-3,2′-[1,3]dioxolan]-9(2H)-yl)ethanone (89, R2=Ethyl) (3.02 g, 8.15 mmol) in a mixture of THF (54 mL) and MeOH (27 mL) was treated with ammonia (7 M in MeOH, 3.49 mL, 24.5 mmol) and stirred at rt overnight. The reaction mixture was concentrated under reduced pressure to give rac-(4aR,12bS)-12b-ethyl-1,2,4,4a,5,6,9,12b-octahydrospiro[benzo[4,5]oxepino[3,2-f]indazole-3,2′-[1,3]dioxolane] (90, R2=Ethyl) (2.68 g, 100%). The material was used without further purification. LC/MS, method 3, 2.09 min, MS m/z 329 (M+1)+. 1H NMR (400 MHz, CDCl3) δ 7.97 (s, 1H), 7.57 (s, 1H), 7.07 (s, 1H), 4.33-4.24 (m, 1H), 4.00-3.84 (m, 4H), 3.75-3.64 (m, 1H), 2.79-2.66 (m, 1H), 2.51-2.40 (m, 1H), 2.33-2.19 (m, 2H), 2.09-1.98 (m, 1H), 1.88-1.78 (m, 1H), 1.76-1.29 (m, 5H), (t, J=7.5 Hz, 3H).

Provenance & Evidence