3095-94-1Relevant articles and documents
Selective Substitution of POCl 3 with Organometallic Reagents: Synthesis of Phosphinates and Phosphonates
Verbelen, Bram,Dehaen, Wim,Binnemans, Koen
, p. 2019 - 2026 (2018/04/14)
The selectivity of the substitution reaction of phosphoryl chloride with organometallic reagents was investigated using NMR spectroscopy. This led to the discovery that the selectivity of the substitution reaction can be tuned by choosing a proper organometallic reagent. A phosphinate could be obtained by using a Grignard reagent whereas an organozinc reagent provided a phosphonate. Based on these results, one-pot synthetic methods for the preparation of phosphinates and phosphonates using commercially available starting materials were developed. Both methods allow the synthesis of a broad range of either phosphinate or phosphonate derivatives in a straightforward and general procedure. Moreover, using these one-pot procedures, mixed systems substituted with different alkyl/aryl groups can be prepared.
STEREOSPECIFIC INTRAMOLECULAR CYCLIZATION FOR ASYMMETRIC SYNTHESIS OF (Rp)- AND (Sp)-ENANTIOMERS OF 2-OCTYL- AND 2-PHENYL-4H-1,3,2-BENZODIOXAPHOSPHORIN 2-OXIDES
Wu, Shao-Yong,Casida, John E.
, p. 177 - 184 (2007/10/02)
Our earlier studies established that: 1) 2-octyl- and 2-phenyl-4H-1,3,2-benzodioxaphosphorin 2-oxides (octyl- and phenyl-BDPOs) induce delayed neuropathy in adult hens at 3 and 200 mg/kg, respectively; 2) phenyl-BDPO also significantly potentiates the acute toxicity of the insecticide malathion to mice; 3) the (Rp) and (Sp) enantiomers of these compounds, resolved on a mg scale by chiral HPLC, differ in potency by 92- and 137-fold, respectively, as inhibitors of neuropathy target esterase.In order to further study the stereospecificity in their toxic effects, the individual enantiomers of octyl- and phenyl-BDPOs are prepared here be a general method of asymmetric synthesis from the corresponding TLC-resolved diastereomeric precursors (Rp)- and (Sp)-methyl N- L-prolinates through acid-catalyzed intramolecular cyclization.This occurs under mild conditions in high yields and involves inversion of configuration at phosphorus.HPLC with the CHIRALCEL OC column established their absolute configurations, based on a previously-published assignment, and 97-100percent e.e. for (Rp)- and (Sp)-octyl- and phenyl-BDPOs. Key words: Asymmetric synthesis, 1,3,2-benzodioxaphosphorin 2-oxide, cyclization, NTE inhibitors, L-propinates, stereochemistry.
Process for the preparation of phosphonic acid dihalides
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, (2008/06/13)
Process for preparing phosphonic acid dihalides of the formula EQU1 wherein R is alkyl of 1 to 18 carbon atoms, cycloalkyl of 4 to 8 carbon atoms, alkenyl of 2 to 18 carbon atoms, phenyl, phenalkyl or alkyl-phenyl of 7 to 8 carbon atoms, phenyl, phenalkyl or alkyl-phenyl of 7 to 8 carbon atoms, all radicals R optionally being substituted by chlorine, bromine, cyano or lower acyloxy, and wherein X is halogen such as 2-chloroethane phosphonic acid dichloride, by reacting phosphonic or thio-phosphonic acids of the formula EQU2 wherein Y is oxygen or sulfur, their salts or functional derivatives, with acid halides of the formula wherein X is chlorine or bromine and n is 1 or 2, in the presence of 0.2 - 5% or in the presence of 0.01 to 0.2% by weight of 1. compounds containing at least one tri- to pentavalent nitrogen or phosphorus atom, which in the case of nitrogen is bound with 1 to 4, in the case of phosphorus with at least 3 valences to organic radicals having up to 20 carbon atoms, two of these valences optionally forming a double bond, or 2. mono-di- or tribasic organic or inorganic fully amidated acids or tri- or pentavalent phosphorus, the N atom of which optionally being substituted by aliphatic radicals having up to 20 carbon atoms, and the organic radicals of which contain up to 20 carbon atoms, If required, in the presence of an inert solvent.
