(3R,10S)-5-methyl-3-(9-oxo-1,8-diaza-tricyclo-[10.6.1.013,18]nonadeca-12(19), 13(18), 14,16-tetraen-10-ylcarbamoyl)hexanoic acid t-butyl ester → 5-Methyl-3-(9-oxo-1,8-diaza-tricyclo(10.6.1.013,18)nonadeca-12(19),13,15,17-tetraen-10-ylcarbamoyl)-hexanoic acid

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Reaction Steps

Alternatively, (3R,10S)-5-methyl-3-(9-oxo-1,8-diazatricyclo-[10.6.1.013,18 ]nonadeca-12(19),13(18),14,16-tetraen-10-ylcarbamoyl)hexanoic acid t-butyl ester (3.24 g, 6.5 mmol) was taken up in 95% TFA (aqueous) (30 mL) at 0° C. and then stirred for 20 minutes. The ice bath was then removed and the mixture was stirred for another 1 hour. After concentrating it to an oil, the residue was taken up in ethyl acetate (250 mL) and washed with water (7×150 mL). The organic layer was dried over Na2SO4, filtered and evaporated to dryness to yield a single stereoisomer of (3R,10S)-5-methyl-3-(9-oxo-1,8-diaza-tricyclo[10.6.1.013,18 ]nonadeca-12(19),13(18),14,16-tetraen-10-ylcarbamoyl)hexanoic acid as a white powder, 2.83 g (98.4% yield); MS: 442 (M+H)+

Provenance & Evidence