Synthesis of (+)-agelasine C. A structural revision
An efficient synthesis of (+)-agelasine C has been achieved from ent-halimic acid. The structure and absolute configuration of the natural product (-)-agelasine C was established and a structure for epi-agelasine C, is proposed.
Microsomal N-oxygenation of adenine to adenine 1-N-oxide
During investigations on the N-oxygenation of adenine (1) the enzymatic formation of adenine 1-N-oxide 3 was demonstrated for the first time. The identity of this metabolite was confirmed by its chromatographic behaviour and UV-spectrum recorded after HPLC separation. Adenine 1-N-oxide (3) and similar oxygenated derivatives of adenine were synthesized as reference substances. The enzymatic formation of 3 exhibits the typical characteristics of a reaction catalysed by microsomal mono-oxygenases. In induction experiments, an increase in the rate of formation of after 3 pretreatment with phenobarbital was observed. A participation of those isoenzymes of the cytochrome P-450 enzyme system which can be induced by phenobarbital is assumed.
Synthesis and biological activities of C-2, N-9 substituted 6- benzylaminopurine derivatives as cyclin-dependent kinase inhibitor
In this study, C-2, N-9 substituted 6-benzylaminopurine derivatives were synthesized and their inhibitory effects on cyclin-dependent kinase (CDK2) were evaluated. The effect of substituents at the C-2 and N-9 positions of substituted purine was investigated. Among the compounds tested, compound 7b- iii (6-benzylamino-2-thiomorpholinyl-9-isopropylpurine) was the most active inhibitor (IC50 = 0.9 μM). Compound 7b-iii showed 10-fold higher activity compared to olomoucine and almost the same activity as roscovitine. Results from structure-activity relationship studies should allow the design of more potent and selective CDK inhibitors, which may provide an effective therapy for cancer or other CDK dependent diseases.