Synthesis of New Azocompounds and Fused Pyrazolo[5,1-<i>c</i>][1,2,4]triazines Using Heterocyclic Components

Ledenyova, Irina V.; Didenko, V. V.; Shestakov, A. S.; Shikhaliev, Kh. S.

doi:10.1002/jhet.1533

Cited by 13 publications

(4 citation statements)

References 25 publications

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“…Ledenyova et al [ 169 ] have reported the synthesis of tricyclic pyrazolo[5,1- c ][1,2,4]triazines 294 , 297 , 300 and 301 from azocoupling reaction of pyrazolediazonium salts 291 with various heterocyclic components, e.g., barbituric acid and thiobarbituric acid 292 . Attempts were made to cyclize azocoupled intermediates 293 by heating with polyphosphoric acid (PPA) but only the intermediate formed from barbituric acid (X = O) provided pyrazolo[5,1- c ]pyrimido[4,5- e ][1,2,4]triazine-4(3 H )-one 294 while the intermediate (X = S) failed to cyclize with PPA and anhydrous sodium acetate in acetic acid ( Scheme 78 ).…”

Section: Reviewmentioning

confidence: 99%

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

Aggarwal

Kumar

2018

Beilstein J. Org. Chem.

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The condensation of 5-aminopyrazole with various bielectrophilic moieties results in the formation of pyrazoloazines, an interesting array of fused heterocyclic systems. The development of new synthetic routes towards pyrazoloazines for their biological and medicinal exploration is an attractive area for researchers throughout the world. The present review focuses on various synthetic methods developed in the last decade for the synthesis of differently substituted pyrazoloazines by a broad range of organic reactions by means of 5-aminopyrazole as a precursor. ReviewPyrazole and its derivatives are known to exhibit significant biological and pharmacological activities such as: anticancer [1,2], anti-inflammatory [3,4], antioxidant [5], antibacterial [6][7][8], analgesic [9], antiviral [10,11], antimicrobial [12,13], antifungal [6], antiglycemic [14], antiamoebic [15] and antidepressive [16,17]. Considering the immense biological properties pyrazole is one of the most widely studied nitrogen-containing heterocyclic nuclei. Fused pyrazole derivatives are composed of the pyrazole nucleus attached to other heterocyclic moieties which enable them to exhibit improved pharmacological activities compared to the isolated fragments. These compounds are currently used in several marketed drugs like cartazolate (1), zaleplon (2), sildenafil (3), allopurinol (4), indiplon (5), etazolate (6) etc. (Figure 1). Fused pyrazole derivatives, especially pyrazoloazines have been reported to mimic purine bases, present in DNA and RNA, due to close structural resemblance.In addition to the immense biological potential related to fused pyrazoles, their synthetic potential needs to be reviewed for further improvements and extension of interests. Various efforts have been developed for the synthesis of pyrazole-based fused heterocycles. 5-Aminopyrazoles have been extensively employed as useful synthons in designing and constructing a Beilstein J. Org. Chem. 2018, 14, 203-242. 204 A number of review articles have been published by us and others highlighting the synthetic and biological aspects of 5-aminopyrazoles [26][27][28] as well as on the synthesis of fused pyrazole derivatives [25]. However, a perusal of literature reveals that the importance of 5-aminopyrazoles as synthetic precursors for fused heterocycles has not been reported till now to the best of our knowledge. Recent literature shows resurgence of interest in the chemistry and bioactivity of 5-aminopyrazole derivatives leading to improvements in several already known reactions and syntheses of various fused heterocyclic derivatives with various biological activities. Considering the synthetic importance of 5-aminopyrazoles and synthesis of fused pyrazole derivatives with the need for a more general collection, herein we report an exhaustive overview of the main developments in the last decade in the chemistry of 5-aminopyrazoles for the design and synthesis of fused pyrazoloazines.The typical reactivity of 5-aminopyrazoles 5-Aminopyrazoles are polyfunctional co...

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Section: Reviewmentioning

confidence: 99%

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

Aggarwal

Kumar

2018

Beilstein J. Org. Chem.

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“…One of the main approaches for the synthesis of 5-pyrazole/ pyrazoline substituted 4-thiazolidinones is based on Knoevenagel reaction of 4-thiazolidinones [5]. successfully modified in diazo coupling reaction [91] using pyrazolyl diazonium chloride yielding compound 3.3 (Fig. 17).…”

Section: The Main Approaches To the Synthesis Of 4-thiazolidinones Wimentioning

confidence: 99%

Synthetic approaches, structure activity relationship and biological applications for pharmacologically attractive pyrazole/pyrazoline–thiazolidine-based hybrids

Havrylyuk

Roman

Lesyk

2016

European Journal of Medicinal Chemistry

130

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The features of the chemistry of 4-thiazolidinone and pyrazole/pyrazolines as pharmacologically attractive scaffolds were described in a number of reviews in which the main approaches to the synthesis of mentioned heterocycles and their biological activity were analyzed. However, the pyrazole/pyrazoline-thiazolidine-based hybrids as biologically active compounds is poorly discussed in the context of pharmacophore hybrid approach. Therefore, the purpose of this review is to summarize the data about the synthesis and modification of heterocyclic systems with thiazolidine and pyrazoline or pyrazole fragments in molecules as promising objects of modern bioorganic and medicinal chemistry. The description of biological activity was focused on SAR analysis and mechanistic insights of mentioned hybrids.

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“…Previously, there have been successful attempts to introduce in such reactions 6-membered heterocyclic azo components such as derivatives of pyridine-2,4-dione, pyran-2,4-dione, pyrimidine-2,4-dione, barbituric and thiobarbituric acids. [4][5][6] In continuation of research in this field, we found that pyrazole-3(5)-diazonium chlorides 1a-с undergo facile coupling with 4-hydroxy-2Н-chromen-2-one (2) under azo coupling reaction conditions (Scheme 1). Upon mixing, the reactants form colored intermediates, namely, azo compounds 3a-с or hydrazones 3'a-с.…”

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confidence: 99%