Phosphorus oxychloride → 3-(2-Thienyl)-2-propenenitrile

Reaction equation

[S:1]1[CH:5]=[CH:4][CH:3]=[C:2]1[CH:6]=[CH:7][C:8]([NH2:10])=O.S(S([O-])=O)([O-])(=O)=O.[Na+].[Na+].P(Cl)(Cl)(Cl)=O>O>[S:1]1[CH:5]=[CH:4][CH:3]=[C:2]1[CH:6]=[CH:7][C:8]#[N:10]

Participants

Procedure

β-(Thien-2-yl) acrylamide (5.2 g.) was mixed with sodium metabisulphite (12.9 g.) and heated with phosphoryl chloride (2.4 ml.) on a steam bath. After 1 hr., more phosphoryl chloride (10 ml.) was added and the mixture heated for a further 3.5 hrs. The mixture was cooled in an ice-bath and iced water cautiously added. The mixture was extracted into chloroform and the chloroform layer was washed with saturated sodium hydrogen carbonate solution, dried over sodium sulphate, and evaporated in vacuo to a brown oil. Distillation gave β-(thien-2 -yl) acrylonitrile, 1.50 g. (33%), b.p. 82- 86° /0.5 mm., λmax. (EtOH) 306 nm, (ε 18600).