Reaction Steps
The procedure used for the preparation of 9a was repeated with 8b (390 mg, crude from previous reaction), Et3SiH (0.80 mL, 5.0 mmol), and trifluoroacetic acid (1.50 mL, 19.5 mmol ) in dry ClCH2CH2Cl (8 mL ) at 0° C. under nitrogen to give 9b (50.0 mg, 35% for two steps) as a white solid after chromatographic separation on RP C-18 (gradient CH3CN/H2O: 25-30%, containing 1% HOAc). mp 155° C. (dec); IR (KBr) 3600-2800 (br), 3280, 1780, 1661 cm-1 ; 1H NMR (DMSO-d6) δ3.63 (1H, d, J=18.0 Hz), 3.74 (2H, s, CH2), 3.93 (1H, d, J=18.0 Hz), 5.15 (1H, d, J=4.7 Hz), 5.70 (1H, dd, J=8.0 and 4.7 Hz), 6.88 (1H, t, J=7.7 Hz), 6.96 (1H, d, J=7.7 Hz), 7.25 (1H, t, J=7.7 Hz), 7.40 (1H, s), 7.94 (1H, d, J=7.7 Hz), 9.16 (1H, d, J=8.0 Hz, NH), 11.30 (1H, s, OH), 13.80 (1H, br s, CO2H); FDMS m/z 451 (M+, 35Cl), 452 (M+ +1, 35Cl), 453 (M+, 37Cl), 454 (M+ +1, 37Cl); Anal. Calcd for C18H14ClN3O5S2 : C, 47.84; H, 3.12; N, 9.30. Found: C, 48.12; H, 3.16; N, 9.36
