Reconstructive Methodology in the Synthesis of 2-Aminopurine.

A fundamentally new synthetic approach to the synthesis of 2-aminopurine has been developed. It consists in the combination of the creation of a condensed polyazotic heterocyclic tetrazolopyrimidine structure, its transformation into triaminopyrimidine, and its subsequent cyclization into 2-aminopurine. The structure of the obtained compounds was established based on spectral characteristics, and the structure of the intermediate compound was established directly by X-ray diffraction analysis.

CK2 Inhibition and Antitumor Activity of 4,7-Dihydro-6-nitroazolo[1,5-a]pyrimidines.

Today, cancer is one of the most widespread and dangerous human diseases with a high mortality rate. Nevertheless, the search and application of new low-toxic and effective drugs, combined with the timely diagnosis of diseases, makes it possible to cure most types of tumors at an early stage. In this work, the range of new polysubstituted 4,7-dihydro-6-nitroazolo[1,5-a]pyrimidines was extended.

Oxidative Aromatization of 4,7-Dihydro-6-nitroazolo[1,5-a]pyrimidines: Synthetic Possibilities and Limitations, Mechanism of Destruction, and the Theoretical and Experimental Substantiation.

The reaction tolerance of the multicomponent process between 3-aminoazoles, 1-morpholino-2-nitroalkenes, and aldehydes was studied. The main patterns of this reaction have been established. Conditions for the oxidation of 4,7-dihydro-6-nitroazolo[1,5-a]pyrimidines were selected.

Benzimidazoazapurines: Design, Synthesis, and Photophysical Study.

A highly efficient approach to a new class of polycyclic 8-azapurines, benzo[4,5]imidazo[1,2-][1,2,3]triazolo[4,5-]pyrimidines (BITPs), with good photophysical characteristics is proposed. The approach comprises condensation of aminobenzimidazoles with 3-oxo-2-phenylazopropionitrile to form 3-(arylazo)benzo[4,5]imidazo[1,2-]pyrimidine-4-amines, which undergo oxidative cyclization by the catalytic action of copper(II) acetate, resulting in BITPs with 73-84% yield. Spectral investigations demonstrated the fluorescent properties of BITPs, exhibiting good quantum yields (up to 60%) with maxima absorption at 379-399 and emission at 471-505 nm.

Pyrimido[1,2-]benzimidazoles: synthesis and perspective of their pharmacological use.

The review presents data on the synthesis as well as studies of biological activity of new derivatives of pyrimido[1,2-]benzimidazoles published over the last decade. The bibliography of the review includes 136 sources.

Methods of Synthesis and Antiviral Activity of New 4-Alkyl-3-Nitro-1,4-Dihydroazolo[5,1-][1,2,4]Triazin-4-ols.

Unlabelled: An azo coupling reaction of α-nitro ketones with 5-diazoazoles was used to obtain 4-alkyl-3-nitro-1,4-dihydroazolo[5,1-][1,2,4]triazines, which were characterized with respect to their antiviral activity against influenza and Coxsackie B3 viruses.

Supplementary Information: The online version contains supplementary material available at 10.1007/s10593-021-02926-2.

A New Family of Fused Azolo[1,5-]pteridines and Azolo[5,1-]purines.

The nitration of azolo[1,5-]pyrimidin-7-amines with several nitration agents (such as acetic nitric anhydride, nitronium tetrafluoroborate, and a mixture of concentrated nitric acid and sulfuric acid) has been investigated. It has been shown that, depending on the conditions, the nitration of pyrazolopyrimidin-7-amines bearing electron-withdrawing groups in the pyrazole ring leads to nitration products in the pyrimidine and/or pyrazole ring. The nitration of triazolo[1,5-]pyrimidin-7-amines with "nitrating mixture" has been optimized, thus allowing us to obtain a series of 6-nitro[1,2,4]triazolo[1,5-]pyrimidin-7-amines, followed by their reduction into the corresponding [1,2,4]triazolo[1,5-]pyrimidin-6,7-diamines (yields 86-89%).

Three-Component Coupling of Aromatic Aldehydes, 1-Morpholino-2-nitroalkenes, and 3-Aminoazoles via Boron Trifluoride Etherate Catalysis: Reaction Pathway and Features of the Formation of Intermediates.

4,7-Dihydro-6-nitro-7-Ar-5--azolo[1,5-]pyrimidines were obtained by the multicomponent reaction of aminoazoles, morpholino-nitroalkenes, and aromatic aldehydes in the catalysis of boron trifluoride etherate. The optimal reaction conditions were determined, and the formation of the target regioisomer was demonstrated. The pathway for multicomponent transformation, including the formation of azolyl-nitroalkene, was determined.

Nitrothiadiazolo[3,2-a]pyrimidines as promising antiglycating agents.

Managing the advanced glycation end-products (AGEs) concentration is a reliable approach to achieve control over the pathogenesis of diabetic vascular complications. Inhibition of dipeptidyl peptidase-4 (DPP-4) is also an attractive way to tackle type 2 diabetes mellitus (T2DM). We showed previously that azoloazine heterocycles have the potential to prevent the formation of AGEs and in this work, we conducted docking studies with DPP-4 of 5-alkylamino-6-nitro-1,3,4-thiadiazolo[3,2-a]pyrimidines.

6-Nitroazolo[1,5-a]pyrimidin-7(4H)-ones as Antidiabetic Agents.

Prevention of the formation of advanced glycation end-products (AGEs) is a reliable approach to achieve control over hyperglycemia and the associated pathogenesis of diabetic vascular complications. In these terms, new synthetic approaches to 6-nitroazolo[1,5-a]pyrimidines have been developed on the basis of the promising antiglycation activity of their structural analogues, such as azolo[5,1-c][1,2,4]triazine-4(1H)-ones. A number of nitroazolopyrimidines were obtained by using nitration, chlorodeoxygenation, and amination reactions, and their antidiabetic properties were elucidated in vitro.