Yield:-

Steps:

Multi-step reaction with 5 steps
1: ethanol / 4 h / 70 °C
2: diphenylether / 0.8 h / 260 °C
3: lithium hydroxide monohydrate; sodium hydroxide / 6 h / 100 °C
4: diphenylether / 0.8 h / 260 °C
5: trichlorophosphate / 1 h / 120 °C

References:

Zhang, Chao;Tang, Yun-Sang;Meng, Chu-Ren;Xu, Jing;Zhang, De-Liang;Wang, Jian;Huang, Er-Fang;Shaw, Pang-Chui;Hu, Chun [International Journal of Molecular Sciences,2022,vol. 23,# 11,art. no. 6307]