p-Toluenesulfonic acid → 2-(4'-Chloromethylphenyl)-7-chlorobenzoxazole
Reaction equation
[NH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([Cl:8])[C:3]=1[OH:9].[Cl:10][CH2:11][C:12]1[CH:20]=[CH:19][C:15]([C:16](Cl)=O)=[CH:14][CH:13]=1.C1(C)C=CC(S(O)(=O)=O)=CC=1>ClC1C=CC=CC=1Cl>[Cl:10][CH2:11][C:12]1[CH:20]=[CH:19][C:15]([C:16]2[O:9][C:3]3[C:4]([Cl:8])=[CH:5][CH:6]=[CH:7][C:2]=3[N:1]=2)=[CH:14][CH:13]=1Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Procedure
158.5 g of 2-(4'-chloromethylphenyl)-7-chlorobenzoxazole (produced by condensation of 2-amino-6-chlorophenol with 4-chloromethyl-benzoyl chloride and subsequent cyclisation in o-dichlorobenzene in the presence of p-toluenesulfonic acid, melting point 141° to 142° C.) is heated with 400 ml of triethyl phosphite in the course of 2 hours at 155° C., and the mixture is subsequently stirred at 155° to 158° C. for a further 7 hours. After cooling to 90° C., the unreacted triethyl phosphite is distilled off in vacuo. The reaction product, which is still oily, is stirred into 1000 ml of petroleum ether, and after a short time crystallisation occurs. The product is filtered off, washed with petroleum ether and dried. The yield is 210 g (97% of theory) of 2-(4'-diethylphosphonomethylphenyl)-7-chlorobenzoxazole having a melting point of 92° to 93° C.
Sources & evidence
- ORD record
- ord-f0aac0c2f0354f27a3966e3406326137
- Source dataset
- uspto-grants-1980_06
- Patent number
- US04208513
Reaction notes
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