Selective and clean synthesis of aminoalkyl-H-phosphinic acids from hypophosphorous acid by phospha-Mannich reaction.

ABSTRACT: Aminoalkyl-H-phosphinic acids, also called aminoalkylphosphonous acids, are investigated as biologically active analogues of carboxylic amino acids and/or as valuable intermediates for synthesis of other aminoalkylphosphorus acids. Their synthesis has been mostly accomplished by phospha-Mannich reaction of a P-H precursor, an aldehyde and an amine. The reaction is rarely clean and high-yielding. Here, reaction of H₃PO₂ with secondary amines and formaldehyde in wet AcOH led to aminomethyl-H-phosphinic acids in nearly quantitative yields and with almost no by-products. Surprisingly, the reaction outcome depended on the basicity of the amines. Amines with pK _a > 7-8 gave the desired products. For less basic amines, reductive N-methy

SUBMITTER: Urbanovsky P 

PROVIDER: S-EPMC9059144 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature