Reaction Steps
Sodium cyanoborohydnide (40 mg, 0.64 mmol) then 2N HCl (0.5 mL) were added to a solution of 30 (96 mg, 0.24 mmol) and formaldehyde (0.18 mL of a 40% w/v aq. solution, 2.4 mmol) in MeOH (15 mL) and THF (5 mL) and the mixture stirred at 20° C. for 45 min. The solvent was evaporated, the residue was diluted with water and extracted with CH2Cl2 (×2), and the extracts dried (Na2SO4) and evaporated. Dry column chromatography (eluting with 1:2 EtOAc:petroleum ether) gave 3-(chloromethyl)-1-(methanesulfonyl)-6-[N-methyl-N-(4-nitrobenzyl)amino]indoline (31) (73 mg, 73%), mp (benzene-petroleum ether) 138-139 C. 1H NMR (CDCl3) a 8.18 (d, J=8.8 Hz, 2 H, ArH o to NO2), 7.39 (d, J=8.8 Hz, 2 H, ArH m to NO2), 7.05 (d, J=8.4 Hz, 1 H, H-4), 6.82 (d, J=2.4 Hz, 1 H, H-7), 6.3 5 (dd, J=8.4 2.4 Hz, 1 H, H-5), 4.63 (s, 2 H, NCH2Ar), 4.04 (dd, J=10.8, 8.8 Hz, 1 H, CHHN), 3.93 (dd, J=10.8, 4.7 Hz, 1 H, CHHN), 3.71 (dd, J=10.4, 4.1 Hz, 1 H, CHHCl), 3.68-3.61 (m, 1 H, H-3), 3.55 (dd, J=10.4, 7.8 Hz, 1 H, CHHCl), 3.11 (s, 3 H, NCH3), 2.81 (s, 3 H, NSO2CH3). 13C NMR a 150.3, 147.1, 146.5, 143.5, 118.9 (C-6,8,9,1,4), 127.4, 123.9 (C-2 and 6, 3 and 5), 125.5, 107.7, 97.9 (C-4,5,7), 56.5, 54.7 (C-2, NCH2Ar), 46.9 (CH2Cl), 41.8 (C-3), 39.5 (NCH3), 34.5 (SO2CH3). Anal. Calculated for C18H20ClN3O4S): C, 52.8; H, 4.9; N, 10.3; Cl, 8.7. Found: C, 52.6; H 5.1; N, 10.1; Cl, 8.9%.
