反应详情

A solution of trans-diene (27) (0.30 g, 1.06 mmol) prepared as described in example 37 and maleic anhydride (0.16 g, 1.59 mmol) in xylene (30 mL) were heated at reflux for 18 hours, before being concentrated in vacuo and chromatographed on silica eluting with ethyl acetatelhexane (1:2). Crystallisation from ethyl acetate/hexane then gave anhydride (286) (0.29 g, 72%) as a pale brown powder, mp 189–191° C. 1H NMR δ (CD3)2SO] 11.16 (br s, 1H), 7.69 (dd, J=7.7, 1.4 Hz, 1H), 7.51 (dd, J=7.7, 1.4 Hz, 1H), 7.43 (ddd, J=7.7, 7.7, 1.4 Hz, 1H), 7.36 (ddd, J=7.7, 7.7, 1.4 Hz, 1H), 7.25 (d, J=8.6 Hz, 1H), 7.15 (d, J=2.4 Hz, 1H), 6.77 (dd, J=8.6, 2.4 Hz, 1H), 4.70 (d, J=7.7 Hz, 1H), 4.47 (dd, J=7.7, 3.5 Hz, 1H), 3.78 (s, 3H), 3.71–3.66 (m, 1H), 3.36 (dd, J=15.9, 13.0 Hz, 1H), 2.99 (dd, J=15.9, 4.1 Hz, 1H). Found: C, 65.85; H, 3.95; N, 3.70. C21H16ClNO4 requires: C, 66.06; H, 4.22; N, 3.67.

1. temperaturewere heated
2. temperatureat reflux for 18 hours
3. concentrationbefore being concentrated in vacuo
4. customchromatographed on silica eluting with ethyl acetatelhexane (1:2)
5. customCrystallisation from ethyl acetate/hexane