IISelected data for 9c: Mpt 91-92C; FAB-MS (M++1) 319.06227, C11H15N2O7S requires 319.06000; 1H NMR (250 MHz, CDCl3) 1.3 (s, 9H, But), 7.8 (bs, 1H, NH), 8.3 (AB quat., 4H, p -SO2C6H4NO2);13C NMR ( 62.5 MHz, CDCl3) 153.6 (C=O), 151.1, 139.2, 131.1, 123.9, 84.6 (quat. C), 27.6 (But); FTIR max 3282 (s, NH), 1737 (s, C=O), 1538, 1375 (s, NO2), 1346, 1162 (s,SO2) cm1.