Stereoselective Addition of Dimethyl Thiophosphite to Imines

Abstract

Dimethyl thiophosphite (DMTP) was synthesized from dimethyl phosphite, and the diastereoselective addition of DMTP to benzaldimines bearing chiral auxiliary groups was examined. Yields of the product alpha-aminophosphonothionates ranged from 17% to 75% after chromatography. The addition of DMTP to the benzaldimine derived from (S)-phenylglycinol afforded the highest diastereoselectivity (83:17), whereas addition of DMTP to the benzaldimine derived from threonine methyl ester and alanine methyl ester were far less diastereoselective, affording 38:62 and 61:39 ratios, respectively. Addition of DMTP to the benzaldimine derived from (R)-alpha-methylbenzylamine (78:22) and (S)-serine methyl ester (73:27) were intermediate in selectivity. DMTP addition to the imines formed between serine methyl ester and acetaldehyde and isobutyraldehyde gave 55:45 and 70:30 ratios, respectively, with the diastereoselectivity corresponding roughly to the size of the alpha-alkyl group. The stereochemistry of the newly formed alpha-stereocenters resulting from the addition of DMTP to (S)- and (R)-phenylglycinol benzaldimines was confirmed by conversion of the product alpha-aminophosphonothionates to the known enantiomers of phosphonophenylglycine.

Green Synthesis and Bioactivity of 2-Amino-4<i>H</i>-chromen-4-yl-phosphonates

“…The products were obtained as semi solids and purified by column chromatography using silica gel as adsorbent and ethyl acetate-hexane (2 : 3) as eluent. The chemical structures of 4a-l were confirmed by elemental analysis, IR, 1 H-, 13 C-, 31 P-NMR and mass spectral data. Compounds 4a-l exhibited characteristic IR stretching frequencies in the regions 3217-3413, 1215-1238 and 723-777 cm −1 for N-H, P= O (phosphonates), and P-C respectively.…”

Benzimidazolium dicationic ionic liquid as an efficient and reusable catalyst for the synthesis of α-aminophosphonates and bis (α-aminophosphonates) under solvent-free condition

“…33 The 1 H NMR spectra of compounds, recorded in CDCl 3 solution, exhibit the signal of CHP proton as a doublet of doublet at 4.64and 4.70 ppm (1a). 34 The NH proton signal of (3a) appears as a triplet. There is a correlation between NH,CHP and P that decouplage P indicate correlation between NH, CHP and on addition of D 2 O the NH signal disappeared and the signal of CHP that appeared as doublet, and the doublet at 55.4 ppm with 1 J PC =155 Hz, observed in its 13 C NMR spectrum ( Figure S3).…”

“…The values are typical for the proton and carbon atom from a CHP fragment. 34 The methyl protons from the ethoxy groups give two triplets, owing to the Bis(α-aminophosphonates) are interesting compounds, as they are multidentate ligands which may be used for the extraction of metals from solutions and they can be employed as the monomers for the preparation of macrocyclic or polymeric compounds carrying phosphonate and amine moieties. In addition, and more importantly, investigation of their biological activity would be of great interest.…”

A High-Performance Multifunctional Lubricant Additive for Water–Glycol Hydraulic Fluid

“…Grade) were procured commercially and used to synthesize BTP without further purification. BTP was prepared in a manner similar to that described in previous reports [27,28], and its synthetic process is shown in Fig. 1.…”