Search

Oligonucleotides containing 3'- S -P(S) and 5'- S -P(S) fragments in the deoxy-series are available only by tedious multistep procedures. We have developed a novel and efficient methodology based on ring opening of anhydronucleosides by phosphorus dithioacids. This approach allows efficient synthesis of modified dinucleotides of the ribo-series.

Stereoselective synthesis of the P-chiral thioxaphosphoranesulfenyl (dicyclohexyl)amide (l-menthyl-O)PhP(S)SN(C6H11)2 and its conversion into the P-chiral thioxaphosphoranesulfenyl chloride (l-menthyl-O)PhP(S)SCl is described. First synthesis of P-chiral thioxaphosphoranesulfenyl bromides (l-menthyl-O)PhP(S)SBr via the bromolysis of the bis-thiophosphoryl disulfide [(l-menthyl-O)PhP(S)S-)]2 is presented. Transformations of P-chiral thioxaphosphoranesulfenyl chlorides and bromides into the corresponding sulfenamides proceed with the preservation of stereochemical integrity at the chiral P-center.

Synthetic oligonucleotides bearing modifications in the backbone have potentials as tools in studying and controlling biological processes.

Fluoroderivatives of phosphorus are important in the chemistry and biochemistry of both elements.1. Recently, our attention has been Focused on the synthesis of non-ionic oligodeoxynucleoside-phosphoro fluoridates and their thio− and selenoanalogues. Existing methods were, in our opinion, not suited for the synthesis of oligonucleoside− phosphorofluorides. So we devised new ones.

The interaction of 1,2-aIkadienephosphonic derivatives with phosphorus containing pseudohalogenes affords 2,5-dihydro-1,2-oxaphospholene derivatives. The structure of the new compounds is determined by NMR and IR spectroscopy.

Phosphoranesulphenyl halides of the general formula RR'P(Y)SX and their selenium analogues RR'P(Y)SeX (X=Cl,Br; Y=O,S) have been shown to be useful intermediates for access to many new classes of compounds con-taining phosphorus, sulphur, or selenium centers.'

Reaction of trifluoroacetic anhydride with chloroanhydrides of phosphorus acids R2P(O)CI results in formation of mixed anhydrides R2P(O) OCOCF3 and trifluoroacetic acid halides CF3COX (X=Cl, Br, I) in quantitative yield.

As part of our studies on the synthesis of mono- and bis-phosphonic acids, phosphine oxides and phosphines containing amino and hydroxy groups attached to tricarbon or tetracarbon chains [I], we now report our efforts to find a rational synthesis of compounds 2,3 and 4: Reagents: (a):R5R6PCH2Y, BuLi; (b): R3R4P(O)H, NaH; (c): 1. Pd/C, H2, 2 TsCl, Py; (d): 1 BuOK, BuOH, 2 R7 R2 P(Z)H, NaH.

Continuing our studies on new reaction of trimethylsilylphosphites 1 we now report the conversion of compounds 1 to the corresponding phosphorazolides or phosphoranilidates by the reaction of readily available trimethylsilylphosphites 1 and 1,l'-oxalyldiazolides or anilidates.

Organic monopyrophosphates, structural analogues of biologically important diphosphates, undergo spontaneous thiolo-thiono isomerization (1). On the basis of the detailed kinetic mechanistic studies of the isomerization of bis(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinane) 1 in 1-methylnaphtalene (MN), beiizoiiitryle or propylerie carbonate solutions the dissociative mechanism has been proposed (2): To support this mechanism we hove studied the kinetics of isomerization of 1 labelled with 35S in pyridine (Py) solutions. As To support this mechanism we hove studied the kinetics of isomerization of 1 labelled with 35S in pyridine (Py) solutions. As expected the reaction is very fast. The first-order reaction rate constant in Py at 25°C is about 107 times greater then the value obtained by extrapolation of the kinetic data for the reaction in MN. The reaction rate constant in Py solutions is almost not sensitive to triethylanunonium salt of the acid AH. This demonstrates that the dissociative step (k1...

Interaction between some 1,2-alkadienephosphonic derivatives and dimethyl(diisopropyl)phosphonic sulfenyl chlorides in weak polar media was investigated. We established that in all cases the oxaphospholic cyclization of 1,2-alkadienephosphonic system took place, and 4-thiodi-alkoxyphosphonyl-2,5-dihydro-l,2-oxaphospholic derivatives were obtained.

Organophosphorus acids and dithioacids are transformed in almost quantitative yield into the corresponding fluoridates by reaction with thionyl fluoride under very mild conditions.