Adamantyl chlorides, hydrolysi

The transition structures for the hydrolysis reactions of methyl, /-butyl, and ada-mantyl chlorides in the gas phase and in water were calculated using the B3LYP/6-31-G(d) level of theory and the PCM solvation model.82 In the gas phase, backside attack is strongly favoured for the methyl chloride reaction and slightly favoured for the t -butyl chloride reaction. Frontside attack is favoured for the adamantyl chloride... 

Diethyl pyrocarbonate has been used to convert uridine 2 - or 3 -phosphate into the 2, 3 -cyclic phosphate in high yield, and an adamantyl 2, 3 -cyclic phosphonate (421) was obtained when uridine reacted with I-adamantylphos-phonyl chloride. Phosphorylation of ribonucleosides with pyrophosphoryl chloride followed by hydrolysis in neutral solution afforded a simple synthesis of ribonucleoside 2, 3 -cyclic phosphate 5 -phosphates. Two phosphorylating agents mentioned earlier in this section can also yield 3, 5 -cyclic phosphates either by treatment of nucleoside 5 -(2-iV7V-dimethylamino-4-nitrophenyl phosphates) with acetic acid in pyridine (Scheme I4i) i, 83 qj. treatment of nucleoside 5 -(5 -methyl phosphorothioates) with iodine in pyridine. Another route to 3, 5 -cyclic phosphates involved cyclization of the nucleoside 5 -trichIoro-methylphosphonates (422) (obtained by the action of trichloromethylphosphonyl... 

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