Heterogeneous ditopic ZnFe<sub>2</sub>O<sub>4</sub>catalyzed synthesis of 4H-pyrans: further conversion to 1,4-DHPs and report of functional group interconversion from amide to ester
Highly stable, environmentally benign ZnFe2O4 nanopowder was prepared, characterized and applied in the one-pot, three-component synthesis of 4H-pyrans in water. The ZnFe2O4 catalyst provides both acidic (Fe3+) and basic functionalities (O2−) as the reaction requires. The advantages of this method lie in its simplicity, cost effectiveness, environmental friendliness and easier scaling up for large scale synthesis. Water was exploited both as a reaction medium as well as a medium for synthesis of the catalyst. Moreover, water was the only byproduct. The present report puts forward an application of 4H-pyrans for the synthesis of 1,4-DHPs. This is the first attempt towards the synthesis of 4H-pyran-3-carboxylate from 4H-pyran-3-carboxamide. The corresponding functional group interconversion from amide to ester is rare in organic synthesis.
DBU: a highly efficient catalyst for one-pot synthesis of substituted 3,4-dihydropyrano[3,2-c]chromenes, dihydropyrano[4,3-b]pyranes, 2-amino-4H-benzo[h]chromenes and 2-amino-4H benzo[g]chromenes in aqueous medium
作者:Jitender M. Khurana、Bhaskara Nand、Pooja Saluja
DOI:10.1016/j.tet.2010.05.082
日期:2010.7
We have reported DBU catalyzedone-potsynthesis of 3,4-dihydropyrano[3,2-c]chromenes, dihydropyrano[4,3-b]pyranes, 2-amino-4H-benzo[h]chromenes and 2-amino-4H-benzo[g]chromenes from aldehydes, active methylene compounds malononitrile/ethyl cyanocacetate, and 4-hydroxycoumarin/4-hydroxy-6-methylpyrone/1-naphthol/2-hydroxynaphthalene-1,4-dione in water under reflux. The attractive features of this process
我们已经报道了DBU催化一锅合成3,4-二氢吡喃并[3,2- c ]苯并二氢吡喃并[4,3- b ]吡喃,2-氨基-4 H-苯并[ h ]苯并二胺回流下得自醛,活性亚甲基化合物丙二腈/氰基乙酸乙酯和4-羟基香豆素/ 4-羟基-6-甲基吡喃酮/ 1-萘酚/ 2-羟基萘-1,4-二酮的-4 H-苯并[ g ]色酮。该方法的吸引人的特征是温和的反应条件,反应介质的可重复使用性,较短的反应时间,易于分离的产物以及优异的产率。
Serendipitous Observation of Liquid-Phase Size Selectivity inside a Mesoporous Silica Nanoreactor in the Reaction of Chromene with Formic Acid
product switches from pyrimidine to enol lactones and δ‐keto acids inside the nanoreactor. The shape/size selectivity in the liquid phase is a highly desired phenomenon in organic synthesis. We prepared four different varieties of porous silica materials to obtain this product selectivity. Very high yields of these biologically relevant compounds surpass that achieved by existing methodologies. Again
Organocatalytic Cascade Knoevenagel–Michael Addition Reactions: Direct Synthesis of Polysubstituted 2-Amino-4H-Chromene Derivatives
作者:Sanjay N. Jadhav、Seema P. Patil、Dipti Prava Sahoo、Dharitri Rath、Kulamani Parida、Chandrashekhar V. Rode
DOI:10.1007/s10562-019-03089-8
日期:2020.8
isotherms measurements, and they were successfully examined for the cascade type Knoevenagel–Michael addition reactions. The product yields associated with these substrates were optimized, and key reaction parameters affecting the yields were identified. The present catalytic method is simple and robust for diversity oriented synthesis which proceeds good to excellent yields without generating any hazards
In view of developing effective xanthine oxidase (XO) enzyme inhibitors, a series of 100 pyrano[3,2-d]pyrimidine derivatives was synthesized and evaluated for its in vitro XO enzyme inhibition. Structure activity relationship has also been established. Among all the synthesized compounds, 4d, 8d and 9d were found to be the most potent enzyme inhibitors with IC50 values of 8μM, 8.5μM and 7μM, respectively