Hydrochloric Acid → (8-Benzyl-10-vinyl-11-oxa-3,8-diazaspiro[5.5]undecan-3-yl)-(4-isopropoxy-3-methyl-phenyl)methanone

Participants

Reaction Steps

To tert-butyl 8-benzyl-10-vinyl-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate (600 mg, 1.61 mmol) in ethanol (1 mL) was added HCl (4.028 mL of 4 M in dioxane, 16.11 mmol) and the reaction mixture was stirred for 30 minutes. The reaction mixture was concentrated in vacuo, then DMF (4 mL), 4-isopropoxy-3-methyl-benzoic acid (313 mg, 1.61 mmol) and HATU (613 mg, 1.61 mmol) were added and the reaction mixture was stirred for 10 minutes. Triethylamine (898 μL, 6.44 mmol) was added and the reaction mixture was stirred for 16 hours, The reaction mixture was concentrated in vacuo, diluted with DCM (5 mL), washed with 1 N aq. NaOH (2 mL) and brine (2 mL), dried over MgSO4, filtered and concentrated in vacuo. The crude material was purified by silica gel column chromatography using 0-100% EtOAc/hexanes eluent to give (8-benzyl-10-vinyl-11-oxa-3,8-diazaspiro[5.5]undecan-3-yl)-(4-isopropoxy-3-methyl-phenyl)methanone (715 mg, 99%) as a pale yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.35-7.22 (m, 5H), 7.20-7.14 (m, 2H), 6.79 (d, J=8.2 Hz, 1H), 5.83-5.74 (m, 1H), 5.34-5.26 (m, 1H), 5.15 (d, J=10.6 Hz, 1H), 4.59-4.50 (m, 1H), 4.33-4.14 (m, 2H), 3.59-3.14 (m, 7H), 2.79 (d, J=11.0 Hz, 1H), 2.56 (d, J=11.1 Hz, 1H), 2.19 (s, 3H), 1.91-1.80 (m, 2H), 1.69-1.39 (m, 2H), 1.34 (d, J=6.0 Hz, 6H); ESI-MS m/z calc. 448.6. found 449.5 (M+1)+; Retention time: 1.48 minutes (3 min run).

Provenance & Evidence