Methyl methylphosphate

Also, Chin s dihydroxy-bridged dicobalt(III) complex 10 provides one of the largest rate enhancements ever observed for phosphodiester hydrolysis [36]. Reaction with the activated phosphodiester methyl(p-nitrophenyl)phosphate (MNPP) yields 11. A crystal structure is available for the analogous dimethylphosphate complex in which the Co ions are 2.9 A apart. At pH 7 and 45 °C 11 releases p-nitrophenolate with k = 0.1 s 1 which corresponds to a nearly 10I2-fold rate enhancement over spontaneous hydrolysis of the substrate. The product of the reaction is a methylphosphate-bridged complex. Based on the pH rate profile and on... 

Both the 5 -methyl ester of pdT and thymidine 5 -fluorophosphate are poor substrates. The products are methylphosphate and fluorophosphate plus dT. When PNP-pdTp-PNP is used as a substrate, there is a rapid release of PNP-phosphate from the 5 position along with a slow release of PNP from the 3 position (18). Other substrates with a 3 -PNP consistently give rise to some PNP as a product. This secondary activity of SNase is poorly understood. 2, 3 -Cyclic phosphate esters are not substrates for SNase (5). 

The preparation of 0-methyl [1-(substituted phenoxyacetoxy)alkyl]methylphosph-inates IIIA-IIIG involved the condensation of substituted phenoxyacetyl chlorides MS and 0-methyl (1-hydroxyalkyl)methylphosphinates M12 (Scheme 4.6) [24]. 

Scheme 9.20 Synthesis of O-methyl [l-(5-methylisoxazol-3-yloxyacetoxy)alkyl]methylphosph-inates im...

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