p-Toluenesulfonic acid → Ethyl 2-(2-p-chlorophenyl-5-benzoxazolyl)acetate

Reaction equation

[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[O:9][C:10]3[CH:16]=[CH:15][C:14]([CH2:17][C:18]([OH:20])=[O:19])=[CH:13][C:11]=3[N:12]=2)=[CH:4][CH:3]=1.[C:21]1(C)C=CC(S(O)(=O)=O)=C[CH:22]=1>C1C=CC=CC=1.C(OCC)(=O)C>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]([C:8]2[O:9][C:10]3[CH:16]=[CH:15][C:14]([CH2:17][C:18]([O:20][CH2:21][CH3:22])=[O:19])=[CH:13][C:11]=3[N:12]=2)=[CH:6][CH:7]=1

Participants

Procedure

A suspension of 2-(p-chlorophenyl)-5-benzoxazolylacetic acid (26 g.) and p-toluene sulphonic acid (4.6 g.) in dry benzene (156 ml.) and dry absolute ethanol (78 ml.) was refluxed for 38 hours. Evaporation gave a solid which was dissolved in ethyl acetate (2 l) and washed with an aqueous saturated sodium bicarbonate solution (6 × 50 ml.). Evaporation of the organic phase gave ethyl 2-(2-p-chlorophenyl-5-benzoxazolyl)acetate as a solid (24.1 g.); m.pt. 133° C.