HCID 18641982, compound → HCID 87940634, compound

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Reaction Steps

N-tert-butoxycarbonyl-L-alanyl-beta-(3-bromo-4,5-dihydroisoxazol-5-yl) alanine, 0.8 gm, was taken in 50 ml of 20% CF3CO2H/CH2Cl2 at room temperature for 2 hours. Concentration gave a residue which was purified by HPLC, (reverse phase, eluting with water), to give two isomers as fluffy white material after lyophilization. 1H NMR (80 MHz, D2O): delta 1.55 (d, 3H, J=7.5 Hz, CH3), 2.0-2.4 (m, 2H, CH2), 2.9-3.7 (ABX, 2H, CH2CHO), 4.1 (q, 2H, J=7.3 Hz, OCH2), 4.4-5.0 ppm (m, CHN, CHO, plus HOD solvent peak). Most polar set of isomers from the HPLC: 13C NMR (20 MHz, D20): delta 173.2, 173.1 (CO), 143.5 143.4 (BrC=N), 82.7, 81.8 (CHO), 51.8, 50.5 (broad, CHN), 49.0, 48.9 (CH2), 38.6 (CH2), 19.2 ppm (CH3). Least polar isomer: 13C NMR (20 MHz, D20): delta 180.2, 173.0 (CO), 143.5, 143.4 (BrCN), 83.6, 82.4 (CHO), 55.9, 54.9 (broad, CHN), 52.0 (CHN), 49.1, 48.7 (CH2), 39.3, 38.9 (CH2), 19.4 (CH3).

Provenance & Evidence