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.
Efficient One-Pot Synthesis of Tetrahydrobenzo[<i>c</i>]xanthene-1,11-dione Derivatives Under Microwave Irradiation
作者:Xiao-Jun Sun、Jian-Feng Zhou、San-Jun Zhi
DOI:10.1080/00397911.2010.551285
日期:2012.7.1
Abstract An efficient one-pot condensation of 4-hydroxylcoumarin, aromatic aldehydes, and 5,5-dimethylcyclohexane-1,3-dione has been achieved with molecular iodine as a catalyst via conventional heating and microwaveirradiation techniques, and thus a variety of new tetrahydrobenzo[c]xanthene-1,11-dione derivatives were prepared in good yields. GRAPHICAL ABSTRACT
Efficient and highly selective production of 10,11-dihydrochromeno[4,3-b]chromene-6,8(7H,9H)-diones using a mesoporous silica-based nanocatalyst
作者:Alireza Kohzadian、Abdolkarim Zare
DOI:10.1007/s11164-019-03913-1
日期:2019.11
An efficient and highly selective protocol for the production of 10,11-dihydrochromeno[4,3-b]chromene-6,8(7H,9H)-dione derivatives has been developed. The one-pot multi-component condensation of arylaldehydes with 4-hydroxycoumarin and dimedone in the presence of a mesoporous acidic nanocatalyst, namely nano-N,N,N′,N′-tetramethyl-N-(silica-n-propyl)-N′-sulfo-ethane-1,2-diaminium chloride (nano-[TSPSED][Cl]2) selectively afforded the mentioned compounds in high yields and in relatively short reaction times. The nanocatalyst was reusable for four times without significant loss of activity. Our catalyst was better than the reported catalysts in terms of three or more of these factors: the reaction temperatures, times, yields, turnover number and turnover frequency.
1,3-(4,4′-bipyridinium disulfonic acid) propane-dihydrogen sulfate as highly effectual bi-functional catalysts for the rapid preparing chromeno[4,3-b]chromenes and pyrido[2,3-d:6,5-d′]dipyrimidines
a novel Brønsted-acidic ionicliquid 1,3-(4,4′-bipyridinium disulfonic acid)-propane-dihydrogen sulfate (BPDSPDH) was synthesized as a bi-functional catalyst. BPDSPDH was characterized using various analytical techniques such as FTIR, TGA, 13CNMR, 1HNMR, and mass spectrometry. Afterward, the catalytic ability of BPDSPDH was explored in the synthesis of chromeno[4,3-b]chromene and pyrido[2,3-d:6,5-d′]dipyrimidine
在这项研究中,合成了一种新型布朗斯台德酸性离子液体1,3-(4,4′-联吡啶二磺酸)-丙烷硫酸二氢盐(BPDSPDH)作为双功能催化剂。使用各种分析技术(例如 FTIR、TGA、13 CNMR、1 HNMR 和质谱)对 BPDSPDH 进行表征。随后,探索了BPDSPDH在色烯[4,3- b ]色烯和吡啶并[2,3- d :6,5- d ']二嘧啶衍生物合成中的催化能力。BPDSPDH是一种离子液体催化剂,其优点是由于其酸性和碱性位点而具有较高的催化活性,使用廉价且易于获得的催化剂生产原料,催化剂可循环使用高达4次而不会显着损失催化活性、反应时间短、收率高、反应条件温和。 图形概要