Reaction Steps
Sodium formate (0.074 g, 0.108 mmol) was added to a suspension of compound of Example 37 (0.20 g, 0.547 mmol) in formic acid (2 mL) and refluxed for 1.5 h. The reaction mixture was cooled and poured into ice water (50 mL). The solid precipitated was filtered, washed with water and dried. The crude product was purified by trituration with chloroform/methanol (3:1) to obtain the title compound. Yield: 0.18 g (84%); mp: 280-282° C.; 1H NMR (DMSO-d6, 300 MHz): δ 2.48 (s, 3H, CH3), 3.82 (s, 3H, OCH3), 4.91 (s, 2H, CH2, trans minor isomer), 4.97 (s, 2H, CH2, cis major isomer), 7.30 (d, 1H, Ar, trans minor isomer), 7.47 (d, 1H, Ar, trans minor isomer), 7.56 (s, 1H, Ar, cis major isomer), 7.63 (s, 1H, Ar, cis major isomer), 7.89 (s, 1H, Ar), 7.94 (s, 1H, Ar), 8.26 (s, 1H, CHO, cis major isomer), 8.29 (s, 1H, NH), 8.78 (d, 1H, CHO, trans minor isomer), 10.40 (d, 1H, NH, trans minor isomer), 10.46 (s, 1H, NH, cis major isomer); MS: m/e (ES+) 395 (M+1); analysis: C17H14ClNO6S requires C, 51.72H, 3.83, N, 7.10, Cl, 8.98, S, 8.12; found C, 51.24,H, 3.80, N, 6.79, Cl, 9.22, S, 7.84%.
