ABSTRACT
Twenty-five compounds of novel quinoxaline-based scaffold with antiplatelet activity were designed and synthesized on the basis of previous quinoxaline analogues, and the structures were confirmed by 1H NMR, 13C NMR, and MS. The antiplatelet activity was evaluated, structure-activity relationship (SAR) study was summarized and the selectivity of PAR4 was confirmed by calcium mobilization assays. It was indicated that compound 14a, 14g, 13i, 13p showed moderate activity against PAR4, especially, the activity of compound 14g (IC50 = 0.26 μmol·L-1) was 6.7 times than the lead compound A (IC50 = 1.73 μmol·L-1). Therefore, 2,3-dihydro-[1,4]dioxino[2,3-g]quinoxaline and [1,3]dioxolo[4,5-g]quinoxaline derivatives are promising compounds for the discovery of novel antiplatelet agents. It is worthy of further research to develop highly effective and selective PAR4 antagonists.
ABSTRACT
@#To strengthen the quality control of palbociclib, three related substances were separated from the bulk drug. These substances were identified as 8-cyclopentyl-5-methyl-2-((5-(piperazin-1-yl)pyridin-2-yl)amino)pyrido ［2, 3-d］ pyrimidin-7(8H)-one(A), 8-cyclopentyl-5-methyl-2-((5-(piperazin-1-yl)pyridine-2-yl)amino)-6-vinylpyrido ［2, 3-d］ pyrimidin-7(8H)-one(B), tert-butyl4-(6-((6-acetyl-8-cyclopentyl-5-methyl-7-oxo-7, 8-dihydropyrido ［2, 3-d］ pyrimidin-2-yl)amino)pyridin-3-yl)piperazi-ne-1-carboxylate(C). Based on the structures of the impurities, the possible routes to them were discussed, and their structures were elucidated by 1H NMR and MS.
ABSTRACT
The complete nucleotide sequence of a cDNA clone encoding weever ribosomal protein L8, WeevL8, is described here. The WeevL8 cDNA has 848 nucleotides in full length and encodes a 257 amino-acid protein with a calculated molecular mass of 28.02 kDa. Two conserved domains have been identified in WEEVL8. It was concluded fromsequence alignment that WeevL8 gene was quite conservative, consistent with its role as a house-keeping gene. A phylogenetic analysis made by L8 protein showed the similar phylogenetic relationship to that with 18s rDNA. The high similarity supports the notion that ribosomal protein L8 can also be used as phylogenetic criterion.
ABSTRACT
The complete nucleotide sequence of a cDNA clone encoding weever ribosomal protein L8, WeevL8, is described here. The WeevL8 cDNA has 848 nucleotides in full length and encodes a 257 amino-acid protein with a calculated molecular mass of 28.02 kDa. Two conserved domains have been identified in WEEVL8. It was concluded fromsequence alignment that WeevL8 gene was quite conservative, consistent with its role as a house-keeping gene. A phylogenetic analysis made by L8 protein showed the similar phylogenetic relationship to that with 18s rDNA. The high similarity supports the notion that ribosomal protein L8 can also be used as phylogenetic criterion.