Synthesis and NMR spectroscopic study of new furan-derived bis(aminophosphonates)

The synthesis of two novel furyl-containing bis(aminophosphonates) 1,5-bis[N-methyl(dimethoxyphosphonyl)-1-(2-furyl)]diaminonaphthalene (1) and 1,5-bis[N-methyl(diethoxyphosphonyl)-1-(2-furyl)]diaminonaphthalene (2) through an addition of dialkyl phosphites to N,N'-difurfurylidene-1,5-naphthalenediamine is reported. The compounds have been characterized by elemental analysis, TLC, IR and NMR (H-1, C-1 and P-31) spectra. Some new P-31 NMR data of three previously described analogues (3-5) of the above bis(aminophosphonates) is also presented. The P-31 NMR study reveals that in most of the cases (1, 3-5), the addition reaction is completely stereoselective, and only one diastereomer is formed. By the preparation of compound 2, this reaction proceeds not completely stereoselectively with the predominant formation (in 90%) of one of the two possible diastereomers.