HMG-CoA reductase inhibitors: design, synthesis, and biological activity of tetrahydroindazole-substituted 3,5-dihydroxy-6-heptenoic acid sodium salts
摘要:
Compounds comprising a series of 7-[2-(4-fluorophenyl)-4,5,6,7-tetrahydro-2H-indazol-3-yl]-3,5-dihydroxy-6-heptenoic acid sodium salts (18) were synthesized and tested for their ability to inhibit HMG-CoA reductase in a partially purified enzyme preparation and cholesterol biosynthesis from acetate in cultured HEP-G2 cells. Changing the size of the saturated ring of the tetrahydroindazole nucleus did not improve potency, but incorporation of substituents at the 7-position resulted in up to 1700-fold improvement in inhibitory potency. Structure-activity studies revealed that the most potent compounds possess a substituted benzyl group at the 7-position, with a preference for steric bulk at the para position of the benzene ring. The most potent enzyme inhibitor (18t, IC50 = 3.0 nM) is approximately 3-fold more potent than lovastatin sodium salt (2). The most potent cholesterol biosynthesis inhibitor in HEP-G2 cells (18q, IC50 = 0.078 muM) is slightly less potent than 2 (sodium salt). Molecular modeling studies suggested that, when compared to the parent compound (18b) lacking the appropriate 7-substituent, 18t overlaps better with 2 and literature inhibitors 5 and 6 in a hydrophobic binding region adjacent to the enzyme active site.
Synthesis and structural characterization of facile ruthenium(II) hydrazone complexes: Efficient catalysts in α-alkylation of ketones with primary alcohols via hydrogen auto transfer
successfully applied as catalysts in α -alkylation of aliphatic and aromatic ketones with alcohols via borrowing hydrogen strategy. Various parameters such as base, solvent, temperature, time and catalyst loading on the catalytic activity were analyzed. From the results, the catalyst1 was found to be the best catalyst for α-alkylation reaction to obtain excellent yield. The catalytic system has a broad
Catalytic Carbonyl-Olefin Metathesis of Aliphatic Ketones: Iron(III) Homo-Dimers as Lewis Acidic Superelectrophiles
作者:Haley Albright、Paul S. Riehl、Christopher C. McAtee、Jolene P. Reid、Jacob R. Ludwig、Lindsey A. Karp、Paul M. Zimmerman、Matthew S. Sigman、Corinna S. Schindler
DOI:10.1021/jacs.8b11840
日期:2019.1.30
carbon-carbon bond formation. However, currently available synthetic protocols rely exclusively on arylketone substrates while the corresponding aliphatic analogs remain elusive. We herein report the development of Lewis acid-catalyzed carbonyl-olefin ring-closing metathesis reactions for aliphatic ketones. Mechanistic investigations are consistent with a distinct mode of activation relying on the in
Bifunctional phosphonium/thioureas derived from tert-leucine behaved as highly selective catalysts for enantioselective protonation of enol esters, providing α-chiral ketones in yields of up to 99% with high enantioselectivities (up to 98.5:1.5 er). Control experiments clarified that a bulky tert-butyl group and phosphonium and thiourea moieties were necessary to achieve such high stereoselectivity
efficiency of this thermodynamically controlled deracemization was strongly influenced by the mixture ratio of the solvent, H2O/MeOH. Based on this finding, an improved method of preparing (R)-2-monosubstituted cycloalkanones with higher optical purity was developed. For example, (R)-2-(4-methylbenzyl)cyclohexanone (5) was obtained in 85% yield with 98% ee, when a 1:1 mixture of H2O/MeOH was used as the solvent
当在碱性MeOH水溶液中将TADDOLs(例如1a,b)用作主体分子时,外消旋的2-单取代的环烷酮被转化为R-异构体。该热力学控制的脱硝的效率受到溶剂H 2 O / MeOH的混合比的强烈影响。基于该发现,开发了制备具有更高光学纯度的(R)-2-单取代的环烷酮的改进方法。例如,(- [R)-2-(4-甲基苄基)环己酮(5以85%的产率得到98%ee的,当1):H 1混合物2中使用O / MeOH作为溶剂中的存在1a。