1,1'-Carbonyldiimidazole → ethyl 3-(1-t-butoxycarbonylmethyl-2-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepin-3-yl)2-oxo-6-phenyl-[1,3]oxazinan-4-carboxylate

Participants

Reaction Steps

Ethyl 3-benzoylacrylate (13a) (55.6 g, 250 mmoles) is dropped into a solution of (3S)-3-amino-1-t-butoxycarbonylmethyl-2,3,4,5-tetrahydro-1H-benzazepin-2-one (11) (66.2 g, 227 mmoles) in 200 ml of toluene, at room temperature in 1 h. The resulting mixture is left under stirring for 18 h, then added with 10% Pd—C (26 g, 22 mmoles) and hydrogenated at 3 atm for 18 h at room temperature. The catalyst is filtered off and carbonyldiimidazole (272.4 mmoles, 44.16 g) is added. After reacting for 4 h the mixture is washed 3 times with 100 ml of water. After completion of the reaction the solvent is evaporated off and the residue is purified by chromatography (eluent: hexane-ethyl acetate 7:3). A mixture of isomeric products is isolated.

Provenance & Evidence