An unusual oxidation–dealkylation of 3,4-dihydropyrimidin-2(1H)-ones mediated by Co(NO3)2·6H2O/K2S2O8 in aqueous acetonitrile
摘要:
4-Aryl-6-methyl-3,4-dihydropyrimidin-2(1H)-one (DHPM) scaffolds of Biginelli type were oxidized using Co(II)/S2O82- and the reaction afforded 6-unsubstituted pyrimidin-2(1H)-ones through an unprecedented dealkylation process. 4-Alkyl DHPMs under similar conditions afforded yet another unusual product, ethyl tetrahydropyrimidin-2,4(1H,3H)-dione-5-carboxylate. (c) 2006 Elsevier Ltd. All rights reserved.
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
A mild and practical method for the regioselective synthesis of N-acylated 3,4-dihydropyrimidin-2-ones. New acyl transfer reagents
作者:Kamaljit Singh、Sukhdeep Singh
DOI:10.1016/j.tetlet.2006.09.039
日期:2006.11
The treatment of 3,4-dihydropyrimidin-2-ones with n-BuLi at −78 °C, followed by quenching with various electrophiles furnished N3-substituted derivatives, regioselectively. Further, N1,N3-diacyl derivatives were found to transfer N1-acyl groups to nucleophilic sites.
Metalation of Biginelli Compounds. A General Unprecedented Route to C-6 Functionalized 4-Aryl-3,4-dihydropyrimidinones
作者:Kamaljit Singh、Sukhdeep Singh、Aman Mahajan
DOI:10.1021/jo050675q
日期:2005.7.1
4-Aryl-6-methyl-3,4-dihydro-2(1H)-pyrimidinone esters (DHPMs) readily undergo metalation at the C-6 methyl (vinylogous ester) position on treatment with lithium diisopropylamide at −10 °C. The resulting anion intermediates can be treated with electrophilic reagents to afford functionalized DHPMs that have been chemically elaborated mainly at the C-6 position. Di- and trianion formation is also possible
USE OF COMPOSITIONS OBTAINED BY CALCINING PARTICULAR METAL-ACCUMULATING PLANTS FOR IMPLEMENTING CATALYTICAL REACTIONS
申请人:CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE
公开号:US20150376224A1
公开(公告)日:2015-12-31
The use of metal-accumulating plants for implementing chemical reactions especially catalytical reactions.
金属积累植物用于实现化学反应,特别是催化反应的使用。
An expedient protocol of the Biginelli dihydropyrimidine synthesis using carbonyl equivalents
作者:Kamaljit Singh、Jasbir Singh、Prasant K. Deb、Harjit Singh
DOI:10.1016/s0040-4020(99)00760-7
日期:1999.10
A one - pot condensation of perhydro-1,3 heterocycles - aldehyde equivalents with ethyl acetoacetate and ureas provides a convenientsynthesis of the title compounds with a variety of substituents at C-4. Yields are equivalent or significantly higher than the conventional methods.
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