Phosphorothioate analogues

In this context, it is interesting to note that the first synthesis of 2, 3 -0,0-cyclic phosphorothioate 22a was reported by Eckstein in 1968 [25], He also isolated pure Rp diastereomer by fractional crystallization of the triethylammonium salts [26] and used it as reference to determine the absolute configurations of the other phosphorothioate analogues [27], 2, 3 -0,0-Cyclic H-phosphonate 20a was used as a key substrate for the synthesis of uridine 2, 3 -0,0-cyclic boranophosphate 27. Silylation of H-phosphate 20a gave the phosphite triester 25 (two diastereomers). Its boronation, with simultaneous removal of the trimethylsilyl group, was achieved by its reaction with borane-A.A-diisopropylethylamine complex (DIPEA-BH3). 

Bigelow, J.C., L.R. Chirin, L.A. Mathews, and J.J. McCormack. 1990. High-performance liquid chromatographic analysis of phosphorothioate analogues of oligo-deoxynudeotides in biological fluids. 

Using two enzymes, a mammalian adenylate cyclase and myosin ATPase, as examples the application of phosphorothioate analogues to the study of the mechanism of nucleotidyl and phosphoryl transfer will be described. 

Other phosphorothioate analogues that have been examined include methylthiophosphonate oligonucleotides,and the biochemical properties of N3 -P5 thiophosphoramidates ° and thiophosphonoacetates. ° Phosphor-oselenoates have been used for heavy atom replacement for phase determination in X-ray crystallography. 

Phosphorothioate analogues of 2, 5 -oligoadenylates have promising antiviral and anticancer properties and are able to elicit RNase L activation [61]. Short tri- and tetra-2, 5 -oligoadenylates were recently synthesized as a mixture of diastereomers and then separated into diastereomerically pure compounds [62]. For the purpose of their stereocontrolled synthesis, AT6-benzoyl-5 -0-DMT-3 -0-ferf-butyldimethylsilyl adenosine-2 -0-(2-thio-l,3,2-oxathiaphospholane) was synthesized and chromatographically separated into P-diastereomers [63]. The separated monomers were used for synthesis of 2, 5 -tri- and tetra-adenosine analogues, which were cleaved from the support, deprotected, and identified by physicochemical and enzymatic methods. The step-yields 94-95% were achieved for attachment of consecutive adenosine 2 -0-phosphorothioate moieties. 

The pH dependent chemical hydrolyses of the phosphorothioate analogues 2 -, 3 - and 5 -UMPS have been investigated. Between pH 2 and 5 dethio-phosphorylation is between 200 and 300 times faster than dephosphorylation due to the higher stability of the intermediate thiometaphosphate compared to the metaphosphate anion. At pH values less than 1, no migration of the thio-phosphoryl group takes place but rather, desulfurisation occurs. 

However, conversion of the dinucleoside //-phosphonate diester 10 to the phosphorothioate analogue 11 effected by a 0.02 M solution of 2 in 2% aqueous pyridine is relatively slow it reportedly takes 3 h for a complete reaction. While a solution of 2 in 2% aqueous acetonitrile containing triethylamine can completely transform 10 into 11 within 30 s, the use of this sulfurization mixture is incompatible with automated solid-phase oligonucleotide synthesis given the rapid formation of a yellow precipitate caused by triethylamine. In the absence of triethylamine, 10 is not sulfurized under these conditions. Nonetheless, 10 is completely converted to 11 within 20 min when a 0.02 M solution of 1 in 2% aqueous pyridine is used for the sulfurization reaction. Thus, 3i/-l,2-benzodithiol-3-one in aqueous pyridine is compatible with automated solid-phase synthesis of both DNA and RNA oligonucleoside phosphorodithioates or phosphorothioates from appropriate //-phosphonate derivatives. ... 

A full account of an earlier paper (Vol. 25, p. 217, ref. 125) on the preparation of iL-chiro-inositol 2,3,5-triphosphate from L-quebrachitol and the synthesis of L-chiro-inoatol 1,4,6-triphosphate and the corresponding triphosphorothioate also from L-quebrachitol has been reported. Also, a full account (Vol. 23, p. 186, ref 70) on the preparation of racemic /nyo-inoatol 1,4,5 triphosphate and 1,4-bisphosphate-5-phosphorothioate has been reported as well as the preparation of phosphorylated intermediates for the nthesis of both chiral and racemic myo-inoatol 1,43-triphosphate and its phosphorothioate analogue. ... 

A similar mechanistic study on DNA-dependent RNA polymerase from E. coli using phosphorothioate analogues has been carried out by the group of F. Eckstein (27). 

Agrawal, S. and Tang, J -Y. (1990) Efficient synthesis of oligoribonucleotide and its phosphorothioate analogue using H-phosphonate approach. Tetrahedron Lett. 31, 7541-7544... 

Matsukura, M, Zon, G., Shinozuka, K, Stein, C. A., Mitsuya, H., and Broder, S. (1988) Synthesis of phosphorothioate analogues of oligodeoxyribonucleo-tides and their antiviral activity against human immunodeficiency virus (HIV) Gene 72, 343-347. 

Agrawal, S, Ikeuchi, T, Sun, D., Sann, P. S Konopk, A., and Zamecnik, P. C. (1989) Inhibition of human immunodeficiency virus in early infected and chronically infected cells by antisense oligodeoxynucleotides and their phosphorothioate analogues. Proc. Natl Acad. Sci, USA 86, 7790-7794... 

Stec, W. J., Zon, G, Egan, W., and Stec, B. (1984) Automated solid-phase synthesis, separation, and stereochemistry of phosphorothioate analogues of oligodeoxyribonucleotides. J Am Chem. Soc 106,6077-6079. 

Geiser, T. (1990) Large-scale economic synthesis of antisense phosphorothioate analogues of DNA for preclinical investigations. Ann. NY Acad. Sci. 616, 173-183. 

Stec,W J.,Zon, G and Uznanski,B. (1985) Reversed-phase high-performance liquid chromatographic separation of diastereomeric phosphorothioate analogues of oligo-deoxyribonucleotide and other backbone-modified congeners of DNA. 7. Chromatogr, 326,263-280... 

Kariko, K., Sobol, R. W, Suhadolnik, L., Li, S W., Reichenbach, N. L., Suhadolnik, R. J, Charubala, R., and Pfleiderer, W (1987) Phosphorothioate analogues of 2, 5 -oligoadenylate. Enzymatically synthesized 2, 5 -phosphorothioate dimer and trimer Unequivocal structural assignment and activation of 2, 5 -oligoadenylate-dependent endoribonuclease. Biochemistry 26,7127-7135. 

Bogachev, V. S., Kumarev, V. P., and Rybalkov, V. N. (1986) Phosphorothioate analogues of nucleic acids. V. synthesis of S -phosphorothioate analogues of oligodeoxynbonucleotides with the aid of zwitterionic monomers. Sov. J. Bioorg. Chem. 12,64-70. 

In another contribution the Fischer s team showed that dAMP and dGMP molecules decorated with an additional 3 -0-phosphate (26) and adenosine phosphorylated at both 2 and 3 -positions (27), as well as their phosphorothioate analogues, exert a dual antioxidant activity, acting as both metal-ion chelators and radical scavengers. ... 

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