反应详情

trans-5-Methyl-3-p-nitrostyryl-1,2,4-oxadiazole (6.93g) was dissolved in acetone (400 ml) at about 30°. 15% Acidic titanous chloride solution (250 ml) was added with stirring during 30 min. after which the reaction mixture remained purple in colour The acetone was then removed under reduced pressure and the residual mixture cooled to 5°. The crystalline precipitate was filtered off and washed with cold 2N-hydrochloric acid (15 ml). The solid was dissolved in water (400 ml) and the solution neutralized by the addition of sodium carbonate. The mixture was extracted with chloroform (400 ml). The extract was dried (MgSO4) and the chloroform removed under reduced pressure to give title compound as pale yellow needles, 5.61g (93%), m.p. 139°-140°. λmax. (EtOH) 231, 335 nm., (ε 10,700, 22,000) ξmax. (CHBr3) 3490, 3398 (NH2), 967 cm.-1 (trans CH=CH), τ (CDCl3) values include 2.39 and 3.18 (AB quartet, J = 16; trans CH=CH), 7.42 (CH3).

1. customwas then removed under reduced pressure
2. temperaturethe residual mixture cooled to 5°
3. filtrationThe crystalline precipitate was filtered off
4. washwashed with cold 2N-hydrochloric acid (15 ml)
5. dissolutionThe solid was dissolved in water (400 ml)
6. additionthe solution neutralized by the addition of sodium carbonate
7. extractionThe mixture was extracted with chloroform (400 ml)
8. dry with materialThe extract was dried (MgSO4)
9. customthe chloroform removed under reduced pressure