Oxidation of thiazolo[3,2-a]pyrimidin-3(2H)-ones with DMSO and Lawesson’s reagent
摘要:
2,2'-Dimers with a central double bond were prepared by the oxidation of 5,6-disubstituted 7-methyl-5H-[1,3]thiazolo[3,2-a]pyrimidin-3(2H)-ones with DMSO and Lawesson's reagent at room temperature. The role of DMSO as an oxidizing reagent was confirmed by NMR spectroscopy. The E-configuration of the central C=C bond for the two diastereomers of compound 8m was proven by single crystal X-ray data. The dimeric thiazolopyrimidines were orange or red colored and absorption bands at 283-330 and 459-476 nm were observed in the UV spectra. (C) 2018 Elsevier Ltd. All rights reserved.
Nitrosation of 5H-thiazolo[3,2-a]pyrimidin-3(2H)-ones
作者:Evgenia A. Lashmanova、Andrey K. Shiryaev
DOI:10.1007/s10593-015-1710-9
日期:2015.4
The reaction of 2,3-dihydro-5H-thiazolo[3,2-a]pyrimidin-3-ones with sodium nitrite in acetic acid at room temperature gave 2-(hydroxyimino)-5Н-thiazolo[3,2-a]pyrimidin-3(2Н)-ones, which exist as a single isomer according to NMR data. Calculations by the B3LYP/6-311++G(d,p) method indicated that the Е-isomer of hydroxyimino derivative was favored by 15.7 kJ/mol over the Z-isomer.
A Practical and Green Approach towards Synthesis of Dihydropyrimidinones without Any Solvent or Catalyst
作者:Brindaban C. Ranu、Alakananda Hajra、Suvendu S. Dey
DOI:10.1021/op0255478
日期:2002.11.1
A simple, efficient, green, and cost-effective procedure has been developed for the synthesis of dihydropyrimidinones by a solvent-free and catalyst-freeBiginelli's condensation of 1,3-dicarbonyl compound, aldehyde, and urea. This approach of direct reaction in neat without solvent and catalyst shows a new direction in green synthesis.
Compounds belonging to the 5-acyl-3,4-dihydropyrimidine-2-thione family were obtained using a solvent-free Biginelli condensation with or without the use of a catalyst. An unprecedented solid-phase procedure involving a polymer-supported aldehyde allowed the preparation of a series of 5-aroyl derivatives starting with crude diketones obtained from their corresponding aryl esters.
Synthesis of 3,4‐Dihydropyrimidine‐2(1<i>H</i>)‐thiones and Quinazolin‐4(3<i>H</i>)‐ones over Yb(III)‐Resin Catalyst Under Solvent‐free Conditions
作者:Zhidong Jiang、Ruifang Chen
DOI:10.1081/scc-200049766
日期:2005.3
reagent supported on ion exchange resin is applied to the multicomponent condensation reactions under solvent‐freeconditions. One‐pot synthesis of a library of 3,4‐dihydropyrimidine‐2(1H)‐thiones and quinazolin‐4(3H)‐ones were described. The advantages of easy separation and recyclability of the catalysts were demonstrated.
Sulfated zirconia has been demonstrated as an efficient catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H)-onesundermicrowaveirradiation and conventional heating. The solid acid catalyst i...