A novel and effective synthetic approach to 9,10-dihydro-9-oxa-10- phosphaphenanthrene-10-oxide (DOPO) derivatives

Article abstract of DOI:10.1080/10426500701407417

DOPO and its derivatives generally exhibit an outstanding performance as flame retardants in various polymers. Starting from trivalent 10-alkoxy-10H-9-oxa-10-phosphaphenanthrenes, a broad range of DOPO derivatives was synthesized via transesterification with aliphatic alcohols and subsequent Michaelis-Arbuzov rearrangement using catalytic amounts of p-toluenesulfonic acid methylester. Due to the considerable differences in the nature of the alcohols employed, several procedures for processing them are presented.