Synthesis of chiral amino cyclic phosphoric acids
Chiral amino cyclic phosphoric acids, 5-amino-2-hydroxy-4-(4-nitrophenyl)-1,3,2-dioxaphosphorinane 2-oxide and 2-hydroxy-4-(4-methylsulfonylphenyl)-5-phthalimido-1,3,2-dioxaphos phorinane 2-oxide are synthesized in good over yields (64.2% and 72.8% respectively) from 2-amino-1-aryl-1,3-propanediols. The different reaction conditions are necessary in hydrolysis reactions of amino cyclic phosphonyl chlorides.
Phenyl phosphorodichloridate in the synthesis of cyclic phosphate diesters of biological interest
The general usefulness of phenyl phosphorodichloridate (PPDC) in the synthesis of non-nucleoside cyclic phosphates is described. The method is illustrated with several examples including cyclic phosphates incorporating six to nine members. However, the reagent could not be used for the preparation of five-membered cyclic phosphates or 3′,5′-cycloadenylic acid (cAMP) from adenosine. Based on a number of observations, the conclusion was reached that PPDC cannot be used for the synthesis of strained or reactive cyclic phosphates. A convenient synthesis of cis- and trans-2-hydroxycyclopentanemethanol and a simple, quantitative method of separation of the two isomers is described. A number of cyclic phosphates were tested as substrates and inhibitors for cyclic purine phosphodiesterase and protein kinase.
Improvement of scopolamine-induced memory impairment by Z-ajoene in the water maze in mice
Z-ajoene, a major compound containing sulfur in oil-macerated garlic products, exhibited inhibitory effects against scopolamine-induced memory impairment in mice using the Morris water maze test. The effects of Z-ajoene were observed dose-dependently (0.25-25 mg/kg). At the highest dosage, the memory performance of mice was improved compared to normal mice. The acetylcholinesterase (AChE) activity in the brain was reduced by administration of Z-ajoene dose-dependently. However, alliin and diallyl disulfide, organosulfur compounds from garlic, did not improve memory performance nor AChE inhibitory effect. These results suggest that Z-ajoene may act on the cholinergic system and on memory impairment caused by excess activity of AChE.