Organic phosphorus compounds : LXXI. Preparation,properties, and structure of bis(aminomethyl)phosphinic acid, (H2NCH2)2P(O)OH

Bis(aminomethyl)phosphinic acid, (H₂NCH₂)₂P(O)OH · HCl, was prepared by debenzylation of (C₆H₅CH₂NHCH₂)₂P(O)OH · HCl with hydrogen using 5% Pd on C as catalyst, and from bis(t-butylaminomethyl)phosphinic acid, (t-C₄H₉NHCH₂)₂P(O)OH, by isobutylene elimination in concentrated aqueous hydrobromic acid at 175°C in sealed tube. Interaction of bis(chloromethyl)phosphinic acid with ammonia in an autoclave produced methylaminomethylphosphinic acid, CH₃NHCH₂P(O)(OH)₂. A mechanism for the formation of this product is proposed. Several derivatives of (H₂NCH₂)P(O)OH such as (RNHCH₂)₂P(O)OH, R = C₆H₅CO, CICH₂CO, H₂NHNC(=NH)NHCH₂]₂P(O)OH and (CH₃)₃SiNHCH₂]₂P(O)OSi(CH₃)₃ were prepared.