Synthesis of Condensed Heterocycles, Containing Partially Saturated Pyrimidine Nuclei, from Aromatic Pyrimidine Derivatives

2017 ◽  
Vol 54 (5) ◽  
pp. 2575-2597 ◽  
Author(s):  
Grigoriy Ya. Remennikov
Keyword(s):  
Pyrimidine Derivatives ◽  
Partially Saturated ◽  
Condensed Heterocycles

The Use of Electrophilic Cyclization for the Preparation of Condensed Heterocycles

Synthesis ◽  
2021 ◽  
Author(s):  
Mikhailo Slivka ◽  
Mikhailo Onysko
Keyword(s):  
Biological Effects ◽  
Electrophilic Cyclization ◽  
Chemical Transformations ◽  
Cyclization Reactions ◽  
Reaction Conditions ◽  
Electrophilic Reaction ◽  
Partially Saturated ◽  
Current State ◽  
Derivatives Of ◽  
Condensed Heterocycles

AbstractCondensed heterocycles are well-known for their excellent biological effects and they are undeniably important compounds in organic chemistry. Electrophilic cyclization reactions are widely used for the synthesis of mono-heterocyclic compounds. This review highlights the utility of electrophilic cyclization reactions as an effective generic tool for the synthesis of various condensed heterocycles containing functional groups that are able to undergo further chemical transformations, such as nucleophilic substitution, elimination, re-cyclization, cleavage, etc. This review describes the reactions of unsaturated derivatives of different heterocycles with various electrophilic agents (halogens, arylsulfanyl chlorides, mineral acids) resulting in annulation of an additional partially saturated heterocycle. The electrophilic reaction conditions, plausible mechanisms and the use of such transformations in organic synthesis are also discussed. The review mainly focuses on research published since 2002 in order to establish the current state of the art in this area. 1 Introduction2 Electrophilic Cyclization Pathways Involving a Nitrogen Nucleo­philic Center3 Electrophilic Cyclization Pathways Involving a Chalcogen Nucleophilic Center3.1 Sulfur Centers3.2 Oxygen Centers3.3 Selenium Centers4 Strategies and Mechanisms5 Conclusion

Condensed heterocycles with a thiazole ring. 1. Thiazolo[3,4-a]pyrimidine derivatives

1982 ◽  
Vol 18 (5) ◽  
pp. 476-480
Author(s):  
E. K. Mikitenko ◽  
A. D. Kachkovskii ◽  
N. N. Romanov
Keyword(s):  
Thiazole Ring ◽  
Pyrimidine Derivatives ◽  
Condensed Heterocycles

Environmental microscopy of capillary stress-induced strain behavior in ambient-pressure aerogels

1996 ◽  
Vol 54 ◽  
pp. 850-851
Author(s):  
Sudeep M. Rao ◽  
Joshua Samuel ◽  
Sai S. Prakash ◽  
C. Jeffrey Brinker
Keyword(s):  
Silica Aerogel ◽  
Ambient Pressure ◽  
Drying Shrinkage ◽  
Pore Filling ◽  
Silica Network ◽  
Strain Behavior ◽  
Partially Saturated ◽  
Capillary Stress ◽  
Wetting Liquid ◽  
Aerogel Films

Ambient pressure silica aerogel thin films have recently been prepared by exploiting reversible drying shrinkage caused by derivatization of the internal gel surface. Aerogels have porosities of upto 99.9% and due to the small size of the pores (few nanometers), large capillary stresses are produced in gels that are partially saturated with a wetting liquid. As a result of these capillary stresses, the flexible silica network undergoes strain which has been observed using environmental microscopy. This technique allows variation of the equilibrium vapor pressure and temperature, and a simultaneous monitoring of the deformation of the unconstrained film thickness. We have observed >600% deformation during the pore-filling and pore-emptying cycles. In this presentation, we discuss the unique stress-strain behavior of these films.Ref.: Sai S. Prakash, C. Jeffrey Brinker, Alan J. Hurd & Sudeep M. Rao, "Silica aerogel films prepared at ambient pressure by using surface derivatization to induce reversible drying shrinkage", Nature. Vol. 374, 30 March, 1995, 439-443.

Synthesis of Some New Tetracyclic Pyrimidine Derivatives Using Exocyclic α,β-Unsaturated Ketone and Evaluation of Their Antitumor Activities

2016 ◽  
Vol 12 (8) ◽  
pp. 311-317
Author(s):  
Kamelia El-Mahdy
Keyword(s):  
Antitumor Activity ◽  
Spectroscopic Data ◽  
Acid Hydrazide ◽  
Chloroacetic Acid ◽  
Equimolar Amount ◽  
Unsaturated Ketone ◽  
Cyanoacetic Acid ◽  
Antitumor Activities ◽  
Pyrimidine Derivatives ◽  
Cyanoacetic Acid Hydrazide

Thiazolopyrimidine 2 was obtained from the reaction of dihydropyrimidinone with chloroacetic acid and benzaldehyde. Thiazolopyrimidine 2 containing an α,β-unsaturated ketonic function [-CH=CH-CO-] has been used as a component of Michael addition with an equimolar amount of dinucleophiles to give a series of novel tetracyclic pyrimidine derivatives. Treatment of thiazolopyrimidine 2 with uracil, aminotriazole, cyanoacetic acid hydrazide, o-phenylenediamine or diaminopyridine afforded the corresponding pyridopyrimidine, triazolopyrimidine, pyrazolone, benzodiazepine and triazepine derivative, respectively. The detailed synthesis, spectroscopic data, and antitumor activity for synthesized compounds were reported.

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