The role of hydration and stereoelectronic effects in the hydrolysis of cAMP
作者:Marcel H. P. Van Genderen、Leo H. Koole、Raymond J. L. Van Kooyk、Henk M. Buck
DOI:10.1021/jo00213a038
日期:1985.6
A Mild Preparation of Protected Phosphate Esters From Alcohols
作者:Vibha B. Oza、Robert C. Corcoran
DOI:10.1021/jo00117a018
日期:1995.6
Treatment of a wide variety of alcohols with trimethyl phosphite and carbon tetrabromide in pyridine leads to the formation of the corresponding dimethyl phosphate esters in high yields. The reaction is presumed to proceed by formation of an intermediate alkoxy trimethoxyphosphonium salt which undergoes selective demethylation by bromide. Poor yields are generally obtained if solvents other than pyridine are employed or if carbon tetrabromide is replaced by carbon tetrachloride. The mildness of the procedure is illustrated by the conversion of the highly acid sensitive 2-(4,4'-dimethoxytrityloxy)-1-phenylethanol to its dimethyl phosphate ester (74%) and the base sensitive N-CBZ-tyrosine-p-nitrophenyl ester to the corresponding O-(dimethyl phosphate ester) (82%). The availability of methods for the demethylation of methyl phosphate esters makes this oxidative phosphorylation reaction a mild and inexpensive method for the synthesis of protected phosphate esters.
Conformational transmission in four- and five-coordinated phosphorus compounds. Solvent effects on the conformation in 5'-phosphorylated model nucleosides
作者:Leo H. Koole、J. L. Van Kooyk、Henk M. Buck
DOI:10.1021/ja00299a045
日期:1985.6
The C4,-C5, conformation of the 5’-PIV modelcompounds 1-3 and the 5’-Pv TBP modelcompounds 4-6 has been determined in various solvents with 300- and 500-MHz ‘H NMR. It is found that lowering the solvent polarity results in a substantial increase of the g- populations for the modelcompounds 1, 2, 4, and 5 (e.g., for 1 in D20, x(g) = 0.00; CCI4, x(g-) = 0.23). This effect can be attributed to an enhanced