Trifluoroacetic acid → 4-Chloro-2-isobutylamino-6-methyl-10,10-dioxo-10,11-dihydro-5-oxa-10lambda*6*-thia-dibenzo[a,d]cycloheptene-8-carboxylic acid

Participants

Reaction Steps

To a mixture of the methyl ester of Example 35j (0.1 g, 0.27 mmol), isobutyraldehyde (0.098 g, 1.35 mmol)), trifluoro acetic acid (0.27 mmol) and sodium cyanoborohydride (0.67 mmol) was added MeOH (15 mL) at 0-5° C. The reaction mixture was stirred overnight at room temperature, treated with chilled water, neutralized with 10% aqueous NaHCO3, extracted with EtOAc, concentrated and subjected to hydrolysis as described in Example 1i to obtain the title compound (Tet. Lett. 38, 5831-5834, (1997)). Yield: 64.74%; 1H NMR (DMSO-d6): δ 0.90 (d, 6H, 2CH3), 1.80 (m, 1H, CH), 2.60 (s, 3H, CH3), 2.90 (d, 2H, N—CH2), 5.10 (s, 2H, CH2), 6.70 (s, 2H, Ar), 8.10 (d, 2H, Ar); MS: m/e (EI+) 409 (M+).

Provenance & Evidence