Reaction of resorcinol with phosphorous triamides containing various aliphatic radicals was studied. The preferential cleavage from phosphorus of the diisopropylamino group compared with the less bulky dimethylamino group was observed for the first time. It was shown that resorcinol is easily phosphorylated under mild conditions independent of the nature of substituent on nitrogen, but sterically hindered bulky radicals on nitrogen slow down phenolysis not only of the first, but also of the second amido group.