A General Approach to 4-unsubstituted and 4-alkyl-substituted 5-acyl-1,2,3,4-tetrahydropyrimidine-2-thiones(ones) via α-(thio)ureidoalkylation of 1,3-diketones or β-oxoesters
Synthesis of 2-substituted pyrimidines and benzoxazoles via a visible-light-driven organocatalytic aerobic oxidation: enhancement of the reaction rate and selectivity by a base
作者:Lin Wang、Zhi-Gang Ma、Xiao-Jing Wei、Qing-Yuan Meng、Deng-Tao Yang、Shao-Fu Du、Zi-Fei Chen、Li-Zhu Wu、Qiang Liu
DOI:10.1039/c4gc00337c
日期:——
An efficient visible-light-driven photocatalytic oxidation of various 2-substituted dihydropyrimidines and phenolic imines has been achieved using an organic photocatalyst eosin Y bis(tetrabutyl ammonium salt) (TBA-eosin Y) and inexpensive oxidant molecular oxygen. With the aid of a base, significantly enhanced photoinduced electron transfer from substrates dihydropyrimidines or phenolic imines to the excited state of TBA-eosin Y has enabled the aerobic oxidation to yield 2-(methylthio)pyrimidines or 2-arylbenzoxazoles selectively.
Effect of high pressure on Biginelli reactions. Steric hindrance and mechanistic considerations
作者:Gérard Jenner
DOI:10.1016/j.tetlet.2004.05.106
日期:2004.8
The effect of highpressure is examined in 3-CC Biginelli reactions. This effect is small when moderately hindered aldehydes or ureas are involved. However, particularly in the case of bulky aldehydes, the sensitivity of the reaction to pressure increases with increasing steric congestion in line with earlier studies described in the reference list. The results also provide insights into the mechanism
Facile Biginelli-Type Reactions Catalysed by Super Acidic Ionic Liquid under Solvent-Free Conditions
作者:Liang Wang、Min Zhou、Qun Chen、Ming-Yang He
DOI:10.3184/174751912x13518654161237
日期:2012.12
[MeC(OH)2]+ClO4- as a super acidicionicliquid is an extremely active catalyst for Biginelli-type reactions. The present method is especially effective for the inactive aliphatic aldehydes. The solvent-freeconditions, high catalytic activity, wide substrates tolerance and convenient product isolation make the protocol more advantageous.
Synthesis of some 2-oxo and 2-thioxo substituted pyrimidines using solvent-free conditions
作者:Akbar Mobinikhaledi、Naser Forughifar、Jil A. Alipour Safari、EhsaN. Amini
DOI:10.1002/jhet.5570440329
日期:2007.5
three components cyclocondensation reaction of β-ketoester, aldehyde and urea/thiourea using benzyltriethylammonium chloride as a catalyst under solvent-freeconditions. The yields of products following recrystallization from ethanol were of the order of 65-87%. IR and 1HNMR spectroscopy and elemental analysis were used for identification of these compounds.