Novel routes to aminophosphonic acids: Interaction of dimethyl H-phosphonate with hydroxyalkyl carbamates

It was found that the reaction of dimethyl H-phosphonate (1) with 2-hydroxyalkyl-N-2′-hydroxyalkyl carbamates at 135°C includes several chemical reaction steps: (i) chemical transformations of 1-methyl-2-hydroxyethyl-N-2′-hydroxyethyl carbamate (2) and 2-methyl-2-hydroxyethyl-N-2′-hydroxyethyl carbamate (3); (ii) transesterification of dimethyl H-phosphonate with 2 and 3, and with secondary hydroxyl-containing compounds that are formed during the course of the chemical transformation of 2-hydroxyalkyl-N-2′-hydroxyalkyl carbamates; (iii) hydrolysis of 1 and dialkyl H-phosphonates, formed via transesterification of 1 with secondary hydroxyl-containing compounds. The interaction was studied by means of ¹H, ¹³C, ³¹P NMR, and FAB mass spectroscopy. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:119–124, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20404