However, despite the relatively high yields of phospho- rylureas in the reaction, the efficiency and practicability of the whole two-step process markedly decreases due to the need to isolate phosphoryl isocyanate II in a pure state. 2 In addition, the starting organophosphorus com- pound used in the two-step procedure, phosphinic chlo- ride III, is rather expensive, which increases the cost of the target diphenylphosphorylureas I. ... In order to optimize the synthesis of N- ...
