35948-25-5

22749-43-5

35948-25-5

General procedure for the synthesis of 9,10-dihydro-9-oxa-10-phosphaphenanthrene from 10-chloro-9,10-dihydro-9-oxa-10-phosphaphenanthrene: 10 g of 6-chloro-6H-dibenzo[c,e][1,2]oxaphosphorine (0.0426 mol), 1.2 g of hydrochloric acid (0.0335 mol), and 2.1 g of water were added to a reactor and stirred for 5 minutes to form a homogeneous solution. The reaction mixture was heated at 80 °C for 1 h. Upon completion of the reaction, the system was divided into an organic layer and an aqueous layer. The temperature of the organic layer was maintained at 80 °C, and the organic layer was separated and transferred to another reactor. Reduced pressure distillation was carried out at 165 °C and 0.3 mbar to give 9.03 g of the white solid product 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide [Yield: 98%; Color: 8 Hazen; Purity: 99.25% (major component: minor component = 99.25%: 0.75%); Melting point: 122.13 °C (DSC peak)] .