Cesium carbonate → 3H-3-Benzazepine

HRID 1468730Notes

Reaction equation

C(=O)([O-])[O-].[Cs+].[Cs+].O1[C:11]2[CH:12]=[CH:13][C:14]([CH:16]3[CH2:18][N:17]3[C:19]3[CH:23]4OC(C)(C)OC4C(=O)C=3)=[CH:15][C:10]=2OC1>O1CCOCC1>[CH:16]1[C:14]2[CH:13]=[CH:12][CH:11]=[CH:10][C:15]=2[CH:23]=[CH:19][NH:17][CH:18]=1

Participants

Conditions

Temperature: 100 °C

Procedure

Cesium carbonate (3.2 g, 9.8 mmol, 4.0 equiv) was added to a stirred solution of aziridine 54 (770 mg, 2.4 mmol, 1.0 equiv) in 1,4-dioxane (350 mL) at 25° C. The reaction vessel was sealed under argon and heated to 100° C. via oil bath for 18 h. The reaction mixture was gravity filtered and concentrated by rotary evaporation. The residue was purified by passage through a plug of silica gel (ethyl acetate) to afford 55 (590 mg, 76% yield) as a tan foam. Rf=0.27 (50% ethyl acetate in benzene); 1H NMR (500 MHz, CDCl3) δ 7.82 (br s, 1H, ArH), 6.54 (s, 1H, ArH), 5.93 (d, 1H, J=1.5 Hz, OCH2O), 5.91 (d, 1H, J=1.5 Hz, OCH2O), 5.77 (br s, 1H, NH), 4.97 (d, 1H, J=6 Hz, CH(OR)), 4.65 (d, 1H, J=6 Hz, CH(OR)), 3.80-3.85 (m, 1H, ArCH2CH2N), 3.60-3.65 (m, 1H, ArCH2CH2N), 2.95 (br t, 2H, J=4 Hz, ArCH2CH2N), 1.44 (s, 3H, CH3), 1.43 (s, 3H, CH3); 13C NMR (125 MHz, C6D6) δ 195.02, 165.26, 146.76, 146.28, 133.02, 126.24, 113.71, 109.55, 109.10, 109.00, 100.84, 78.98, 76.30, 47.65, 36.87, 27.89, 26.87; IR (neat film) 3266 (w), 2924 (s), 2855 (m), 1705 (w), 1585 (s) cm−1; HRMS (ESI) m/z: Calcd for C17H18NO5 (MH+) 316.1185, observed 316.1189.

Workup

customThe reaction vessel was sealed under argon
filtrationfiltered
concentrationconcentrated by rotary evaporation
customThe residue was purified by passage through a plug of silica gel (ethyl acetate)

Sources & evidence

ORD record: ord-53f58f2bfd7548eaa35c34d954de39c2
Source dataset: uspto-grants-2015_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09006231B2

Reaction notes

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