Synthesis and properties of methanesulfonyl derivatives of diethyl esters of 5-(hydroxyalkylamino)-1,3-oxazol-4-yl-phosphonic acids

A number off[4-(diethoxyphosphoryl)-2-R-1,3-oxazol-5-yl]aminogalkyl methanesulfonates were synthesized and the peculiarities of their reaction with triethylamine were studied. The influence of the structure of the 5-alkanolamine substituent on the efficiency of their transformation into 7-R-1-ethoxy-5-methyl-1,3,4,5-tetrahydro-1?(5)-[1,3]oxazolo[4,5-c][1,5,2]oxazaphosphepine-1-ones was clarified. The structure of the [1,3]oxazolo[4,5-c][1,5,2]oxazaphosphepine derivatives has been reli-ably proven by elemental analysis, IR, H-1, C-13, and P-31 NMR spectroscopy (including 1D and 2D experiments), mass spectrometry and single crystal X-ray diffraction. The oxazole cycle in [1,3]oxa-zolo[4,5-c][1,5,2]oxazaphosphepines is easily cleaved by water in an acidic environment, which leads to the formation of derivatives of the new heterocyclic system - N-(2-ethoxy-5-methyl-2-oxido-4-oxo-1,5,2-oxazaphosphepan-3-yl)arylamides.