Trifluoroacetic acid → HCID 57318853, compound

Participants

Reaction Steps

To a solution containing (3S-trans)-[2-[(6-cyano-3,4-dihydro-3-hydroxy-2,2-dimethyl-2H-1-benzopyran-4-yl)amino]-2-oxo-1-phenylethyl]carbamic acid, 1,1-dimethylethyl ester (2.27 g, 5.03 mmol; the title compound of Example 1) in dichloromethane (20 mL) was added trifluoroacetic acid (5.0 mL) and the reaction mixture was stirred at room temperature for 16 hours. The volatile materials were removed under vacuum and the residue in chloroform was washed with sodium bicarbonate solution and brine. After drying over anhydrous magnesium sulfate, the solvent was evaporated and the residue was purified by flash chromatography (7.5% methanol in dichloromethane) to give two diastereomers. The faster moving material was triturated with ether to give (3S-trans)-α-amino-N-(6-cyano-3,4-dihydro-3-hydroxy-2,2-dimethyl-2H-1-benzopyran-4-yl)benzeneacetamide, isomer A (620 mg, 35.2%) as a colorless solid, mp 243°-246° C. Analysis calculated for C20H21N3O3.0.3H2O: C, 67.32; H, 6.10; N, 11.78. Found: C, 67.50; H, 5.99; N, 11.65. [α]D =-17.2° (c=1, Dimethylformamide). The slower moving material was triturated with ether to give (3S-trans)-α-amino-N-(6-cyano-3,4-dihydro-3-hydroxy-2,2-dimethyl-2H-1-benzopyran-4-yl)-benzeneacetamide, isomer B (940 mg, 53.4%) as a colorless solid, mp 109°-111° C. (with foaming). Analysis calculated for C20H21N3O3.0.45H2O: C, 66.82; H, 6.14; N, 11.69. Found: C, 67.14; H, 6.32; N, 11.14. [α]D=+29.2° (c=1, Dimethylformamide).

Provenance & Evidence