Diisopropylethylamine → HCID 86632309, compound

Participants

Reaction Steps

2.7 g of 3,4-dihydro-2H-benzo[1,4]oxazine and 50 ml of dichloromethane are introduced into a 250 ml three-necked flask equipped with a magnetic stirrer and placed under an inert atmosphere. After cooling to +4° C., 9.92 ml of diisopropylethylamine and 2.97 g of triphosgene are successively added. The reaction medium is stirred at ambient temperature for 3 h. 4.52 ml of diisopropylethylamine and 3.04 g of trifluoromethanesulfonic acid 2,5-dihydro-1H-pyrrol-3-yl ester are then introduced and the mixture is stirred at ambient temperature for 18 h. The reaction medium is washed with a saturated aqueous sodium hydrogencarbonate solution; the aqueous phase is extracted twice with ethyl acetate. The organic phases are combined, dried over sodium sulfate and concentrated under reduced pressure. The residue is chromatographed on silica gel eluted with a gradient of ethyl acetate from 0% to 10% in dichloromethane. 4.4 g of trifluoromethanesulfonic acid 1-(2,3-dihydrobenzo[1,4]oxazine-4-carbonyl)-2,5-dihydro-1H-pyrrol-3-yl ester are obtained.

Provenance & Evidence