Cyclohexylamine → 3-Cyclohexyl-7-methoxy-3,4-dihydro-benzo[e][1,3]oxazin-2-one

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Reaction Steps

40 g of cyclohexylamine are added to a solution of 26 g of 2-hydroxy-4-methoxy-benzaldehyde in 800 ml of absolute EtOH at RT. The mixture obtained is stirred for 1.5 hours, cooled to 0°, and 20 g of NaBH4 are added in portions. The mixture obtained is stirred for 3 hours at RT, poured into H2O and the mixture obtained is extracted with CH2Cl2. Two phases are formed and are separated. The organic layer obtained is dried, 42 g of carbonyl-diimidazole are added and the mixture obtained is stirred for 16 hours at RT. Additional 21.5 g of carbonyl-diimidazole are added, the mixture obtained is stirred for 3 hours, washed with 1N HCl, a saturated, aqueous solution of NaHCO3 and brine, dried and concentrated in vacuo. 3-Cyclohexyl-7-methoxy-3,4-dihydrobenzo[e][1,3]-oxazin-2-one is obtained. m.p.: 76-77°.

Provenance & Evidence