Cyclobutylamine → 9-Bromo-4-cyclobutylamino-4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulene-2-carboxylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 4,9-Dibromo-4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulene-2-carboxylic acid methyl ester (400 mg, 0.95 mmol) in DMF (9 mL) were added cyclobutanamine (81.5 mg, 1.15 mmol), DIPEA (370 mg, 2.86 mmol). The reaction mixture was stirred in autoclave at 90° C. overnight. Then the mixture was cooled to room temperature and partitioned between EtOAc and H2O, and the aqueous layer was extracted with EtOAc (2×20 mL). The combined organic layers were washed with brine, dried over Na2SO4, filtered, concentrated in vacuo and purified by flash column chromatography (silica gel, EtOAc in hexane from 10% to 20%) to afford 9-Bromo-4-cyclobutylamino-4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulene-2-carboxylic acid methyl ester (110 mg, 28%). NMR (400 MHz, DMSO-d6): δ 8.44 (d, J=2.5 Hz, 1H), 7.47 (dd, J1=8.6 Hz, J2=2.5 Hz, 1H), 7.05 (d, J=8.6 Hz, 1H), 4.42 (m, 2H), 3.96 (m, 1H), 3.14 (m, 1H), 2.15 (m, 1H), 1.74 (m, 2H), 1.55 (m, 2H).

Provenance & Evidence