Carbon Dioxide → HCID 59252976, compound

Participants

Reaction Conditions

Reaction Steps

A solution of 4-acetyl-3-((S)-1-phenyl-propylamino)-2-benzopyran-1-one (4.330 g, 13.47 mmol) and tert-butyl carbazate (1.959 g, 14.82 mmol) in acetonitrile (20 mL) was heated under microwave irradiation at 140° C. for 30 min. LC-MS the formation of the intermediate [3-methyl-1-oxo-4-((S)-1-phenyl-propylcarbamoyl)-1H-isoquinolin-2-yl]-carbamic acid tert-butyl ester as a major component (tR=1.36, UV 60%, ELSD 95%.). Then it was heated under microwave irradiation at 180° C. for total of 30 min (caution: CO2 gas formation; the reaction mixture was cooled automatically three times then the excess CO2 was released by puncture before heating continued to keep the pressure below the maximum limit of 20 bar). After cooling, the excess CO2 was carefully removed by puncture with needle, then by gentle shaking, then with stirring, then under sonication (caution: very intensive gas evolution). White precipitate formed, which was filtered, washed with acetonitrile and water to give pure title compound (3.07 g; Yield=67.9%). LC-MS (m/z) 336.6 (MH+); tR=1.04. 1H NMR (250 MHz, 70° C., DMSO-d6, DMSO-d5=2.5 ppm): 0.96 (t, J=7.3 Hz, Me of Et), 1.7-1.96 (m, 2H, diastereotopic CH2 of Et), 2.38 (s, 3H, Me), 5.0 (q (unres. dt), J (d)=6.8, J (t)=8.1, 1H, CH—NH), 5.82 (br. s, 2H, NH2), 7.27 (tm, J (t)=6.7 Hz, J (m)=ca 1.5 Hz, 1H), 7.32-7.49 (m, 6H), 7.61 (t (unresolved tdd), J (t)=8.1 Hz, J (d)=1 Hz, J (d)<1 Hz, 1H), 8.25 (dd, J=8 Hz, J=0.8 Hz, 1H), 8.68 (br. d, J=8.1 Hz, 1H, NHCO).

Provenance & Evidence