Da. Efremov et al., PHOSPHORYLATION OF BENZANILIDES BY PHOSPHORIC ANHYDRIDE, Phosphorus, sulfur and silicon and the related elements, 86(1-4), 1994, pp. 81-83
Phosphoric anhydride reacts with benzanilides (1a-e) to give N-phospho
rylated amides (2a-e) which readily rearrange to give O-phosphorylated
products (3a-e) as a mixture of E and Z isomers.