Novel 2-amino-1,4-dihydropyridine calcium antagonists. I. Synthesis and antihypertensive effects of 2-amino-1,4-dihydropyridine derivatives having nitroxy-alkoxycarbonyl groups at 3- and/or 5-position

The contribution of a 2-amino group on receptor tyrosine kinase inhibition and antiangiogenic activity in 4-anilinosubstituted pyrrolo[2,3-d]pyrimidines

Comparison between a series of pyrrolo[2,3-d]pyrimidines with and without the 2-amino group is presented in order to determine the validity of our hypothesis that inclusion of this group improves potency against receptor tyrosine kinases (RTK). The 2-amino analogs were better against epidermal growth factor receptor (EGFR) and platelet derived growth factor-beta (PDGFR-beta) in whole cell inhibition assays and in the A431 cytotoxicity assay compared to the 2-desamino analogs. However, the 2-desamino analogs were more potent inhibitors against vascular endothelial growth factor-2 (VEGFR-2) than the corresponding 2-amino compounds. In addition, none of the 2-desamino compounds exhibited better anti-angiogenic activity in the chorioallantoic membrane (CAM) assay as compared to the standard and were only micromolar inhibitors. This study validates our original hypothesis that the inclusion of a 2-amino group in pyrrolo[2,3-d]pyrimidines improves multiple RTK inhibition and antiangiogenic activity.

Synthesis and biological activity of N(4)-phenylsubstituted-6-(2,4-dichloro phenylmethyl)-7H-pyrrolo[2,3-d]pyrimidine-2,4-diamines as vascular endothelial growth factor receptor-2 inhibitors and antiangiogenic and antitumor agents

A series of eight N(4)-phenylsubstituted-6-(2,4-dichlorophenylmethyl)-7H-pyrrolo[2,3-d]pyrimidine-2,4-diamines 8-15 were synthesized as vascular endothelial growth factor receptor-2 (VEGFR-2) inhibitors with varied substitutions in the phenyl ring of the 4-anilino moiety. In addition, five N(4)-phenylsubstituted-6-phenylmethylsubstituted-7H-pyrrolo[2,3-d]pyrimidin-4-amines 16-20 were synthesized to evaluate the importance of the 2-NH(2) moiety for multiple receptor tyrosine kinase (RTK) inhibition. Cyclocondensation of alpha-halomethylbenzylketones with 2,6-diamino-4-hydroxypyrimidine afforded 2-amino-6-(2,4-dichlorophenylmethyl)-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-one, 23 and reaction of alpha-bromomethylbenzylketones with ethylamidinoacetate followed by cyclocondensation with formamide afforded the 6-phenylmethylsubstituted-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-ones, 40-42, respectively. Chlorination of the 4-position and displacement with appropriate anilines afforded the target compounds 8-20. Compounds 8, 10 and 14 were potent VEGFR-2 inhibitors and were 100-fold, 40-fold and 8-fold more potent than the standard semaxanib, respectively. Previously synthesized multiple RTK inhibitor, 5 and the VEGFR-2 inhibitor 8 from this study, were chosen for further evaluation in a mouse orthotopic model of melanoma and showed significant inhibition of tumor growth, angiogenesis and metastasis.

(1)H,(13)C and (19)F NMR data of N-substituted 6-(4-methoxyphenyl)-7H-pyrrolo[2,3-d]pyrimidin-4-amines in DMSO-d(6)

Chemical shift assignment of seven N-substituted 6-(4-methoxyphenyl)-7H-pyrrolo[2, 3-d]pyrimidin-4-amines, six of which are fluorinated, have been performed based on (1)H, (13)C, (19)F, and 2D COSY, HMBC and HSQC experiments.

Tetrahydro-beta-carboline alkaloids occur in fruits and fruit juices. Activity as antioxidants and radical scavengers

Tetrahydro-beta-carbolines are biologically active alkaloids that occur and accumulate in mammalian tissues, fluids, and brain, but their ultimate origin or biological role is still uncertain. Four tetrahydro-beta-carboline alkaloids: 1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid, 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid, 1-methyl-1,2,3,4-tetrahydro-beta-carboline, and 6-hydroxy-1-methyl-1,2,3,4-tetrahydro-beta-carboline, are found as naturally occurring substances in some fruit and fruit juices. These compounds occur in the microg/g level in those products, and a characteristic and distinct profile appears to exist depending on the type of fruit and juice involved. Thus, 1-methyl-1,2,3,4-tetrahydro-beta-carboline may appear in tomato, tomato juice, and kiwi; 6-hydroxy-1-methyl-1,2,3,4-tetrahydro-beta-carboline in bananas, pineapple, tomato, and their corresponding juices; and 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid in oranges and grapefruits, although it also occurred in most juices. Fruit-occurring tetrahydro-beta-carboline alkaloids acted as antioxidants and free radical scavengers in the ABTS assay when compared with ascorbic acid and Trolox. This suggests that tetrahydro-beta-carboline alkaloids might act as antioxidants when absorbed and accumulated in the body, contributing to the antioxidant effect of fruit products containing these compounds.