Ethyl orthoformate → 3-[(E)-2-Phenylethen-1-yl]-1,2,4-oxadiazole

Cinnamamidoxime (6.5 g.) (H. Wolff, Ber., 1886, 19, 1507) was refluxed in triethylorthoformate (60 ml.) containing two drops of boron trifluoride etherate. Thin layer chromatography showed that receiving was complete after 1 hr. and the reaction mixture was evaporated in dryness in vacuo. The residue was dissolved in chloroform (100 ml.) and washed consecutively with 2N-hydrochloric acid (100 ml.), saturated sodium bicarbonate solution (100 ml.) and water (100 ml.). The chloroform solution was evaporated to dryness in vacuo and the resultant yellow crystals were recrystallised from aqueous methanol to yield needle-like crystals of 3-(β-trans-styryl)-1,2,4-oxadiazole 5.82 g. (84%), m.p. 82°, λmax (EtOH) 275 nm., ε23200, τ(CDCl3) 1.33 (1H), 2.56 (aromatic multiplet), 2.24 (doublet, J=16 c./sec.), 2.88 (doublet, J=16 c./sec.) (Found: C, 69.9; H, 4.7; N, 15.9. C10H8N2O requires C, 69.75; H, 4.7; N, 16.3%).

1. customand the reaction mixture was evaporated in dryness in vacuo
2. dissolutionThe residue was dissolved in chloroform (100 ml.)
3. washwashed consecutively with 2N-hydrochloric acid (100 ml.), saturated sodium bicarbonate solution (100 ml.) and water (100 ml.)
4. customThe chloroform solution was evaporated to dryness in vacuo
5. customthe resultant yellow crystals were recrystallised from aqueous methanol

ORD record

ord-1aa91ef47d9e4f7692d9ba72f4df6a87

Source dataset

uspto-grants-1977_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04012377