Bożena Krawiecka

Synthesis of phosphocarnitine

Abstract Stereoselective synthesis of phosphocarnitine has been achieved for the first time starting from R(−)-epichlorohydrin.

Convenient synthesis of propane aminophosphonic acids, aminodiphosphonic acids and their structural analogues, mediated by azetidinium salts

Abstract The reactions of azetidinium salts with phosphorus nucleophiles R2P(O)H have been investigated. Treatment of O-benzyl-N,N-diethyl-3-hydroxyazetidinium salt 2 with R2P(O)H in the presence of sodium hydride gave the corresponding γ-N,N-diethylamino-β-benzyloxypropylphosphonate 6a or phosphine oxide 6b. After debenzylation γ-N,N-diethylamino-β-hydroxypropylphosphonate 3a and phosphine oxide 3b were obtained. The compound 6a was converted into its sulfonate ester 8 which underwent elimination to yield 4. The structure 4 has been employed in Michael addition of R2P(O)H to form compounds 5 containing two phosphorus centers. Further compounds of type 3 have been transformed into compounds 5 by reaction with R2P(O)H in the presence of 1.1 equivalents of NaH in boiling toluene. Finally, azetidinium salts 1 have been converted into compounds 5a by reaction with two equivalents of R2P(O)H in the presence of 2.1 equivalents of NaH. Molecular mechanics with implementation of the Allinger MM2 force field and semiempirical AM1 and PM3 methods were used to investigate structures 5d and 5f.

Synthesis of polyfunctional phosphorodithioates and structural analogues mediated by azetidinium ions and epoxides

Abstract The nucleophilic ring opening reactions of N , N- dialkyl-3-hydroxy(benzyloxy)azetidinium salts 1 and N , N -dibenzyl-2,3-epoxypropylamine 10 with anions of mono- and dithioacids of phosphorus 2 affords phosphorodithioates (and structural analogues) 3 and 11 possessing S -propyl substituents incorporating 2-hydroxy and 3-dialkylamino functionalities. A strong dependence of the stability of these compounds on structural factors is discussed.

Synthesis of multifunctionalized phosphonic acid esters via opening of oxiranes and azetidinium salts with phosphoryl-substituted carbanions

Ring-opening of N,N-diethyl-3-benzyloxyazetidinium salt 1b and N,N-dibenzyl-2,3-epoxypropylamine 6 by phosphoryl-substituted carbanions generated from phosphonates 2a–e furnishes the multifunctional phosphonates 3a–e and 7a, 7b, 7e bearing the same carbon skeleton. The reaction of the heterocyclic electrophiles 1b and 6 with the P-allyl anion generated from 2f demonstrates the strong dependence of the α/γ-regioselectivity on the reaction conditions. Depending on the character of the electrophile and/or the reaction medium the regioselective synthesis of both α- and γ-regioisomers is realized.

Stereochemistry of acid-catalysed solvolysis at the sterically hindered thiophosphoryl centre

t-Butylphenylphosphinothioic methanesulphonic anhydride undergoes acid-catalysed hydrolysis and methanolysis with inversion of configuration at the sterically hindered thiophosphoryl centre.

Application of the Arbuzov reaction for the synthesis of phosphonate analogues of myo-inositol 1,2-bis- and 1,2,6-trisphosphates and methyl α-D-mannopyranoside 2,3,4-trisphosphate

The reaction of perbenzylated (±)-myo-inositol 1,2-bis- and 1,2,6-tris-phosphites with benzyl bromoacetate, followed by catalytic (PdC) hydrogenolysis affords (±)-myo-inositol 1,2-bis- and 1,2,6-tris(carboxymethylphosphonate). The same procedure is used for the synthesis methyl α-D-mannopyranoside 2,3,4-tris(carboxymethylphosphonate).

Reaction of Selenoesters of Phosphorus Acids with Halogens

Abstract Reaction of phosphinoselenoates 1a-b with elemental chlorine, bromine, iodine as well as sulfuryl chloride involves halogenolysis of P-Se bond and formation of tert-butyl-phenylphosphinohalogenate 7. Intermediate products, containing one and two phosphorus atoms were detected by 31P NMR. The similarities and differences in the behavior of phosphorus sele-noesters and their thio-analogues are discussed.

Stereochemistry of desulphurisation and deoxygenation of oxophosphoranesulphenyl chlorides by trivalent phosphorus compounds

The ratio of desulphurisation to deoxygenation of oxophosphoranesulphenyl chlorides, >P(O)SCI, by trivalent phosphorus compounds depends on the nature of the PIII compounds and is accompanied by inversion of configuration at the chiral phosphorus atom of the sulphenyl chloride.

Reaction of thiolo and selenolo esters of phosphorus acids with halogens. Part 3. Interaction of O, O,S-trialkyl phosphorothioates and O,S-dialkyl t-butylphosphonothioates with sulphuryl chloride and halogens

The reaction of the title phosphon- and phosphoro-thiolates with sulphuryl chloride and halogens involves in every case the formation of intermediates containing two phosphorus atoms > P(SR)OP(O) < X–(X = SO2Cl or halogen). The formation of the latter in the course of chlorinolysis of phosphorus thiolesters is suggested to be responsible for the occurrence of a mechanism involving retention of configuration. The effect of the structure of the reactants and the nature of solvent on the reaction stereochemistry is discussed.

Mechanism of the Chlorolysis Reaction of P-S Bond in Phosphorus Thioloesters. The Effect of the Substituent at Sulfur Atom on the Stereochemistry

Abstract The effect of the substituent at sulfur atom on the stereochemistry of the chlorolysis reaction of P-S bond in phosphorus thioloesters was studied. It was found that the presence of the substituents lowering electron density at this atom reduces the reaction rate. Stereochemical aspects of this fact are discussed.