反应详情

Demethylation of 820 prepared as described in example 419 with BBr3 using the procedure described in example 80 gave (821) (89%), mp 335–345° C. 1H NMR δ [(CD3)2SO] 11.50 (s, 1H), 11.10 (s, 1H), 9.26 (d, J=2.4 Hz, 1H), 8.30 (d, J=2.4 Hz, 1H), 7.77–7.75 (m, 2H), 7.65–7.61 (m, 3H), 7.56–7.52 (m, 1H), 7.46 (d, J=8.7 Hz, 1H), 7.06 (dd, J=8.7, 2.4 Hz, 1H). Found: C, 72.71; H, 3.55; N, 8.16. C20H12N2O3 requires: C, 73.16; H, 3.68; N, 8.53.