Search

1,3,5-Triazine scaffold has garnered considerable interest due to its wide-ranging pharmacological properties, particularly in the field of cancer research. Breast cancer is the most commonly diagnosed cancer among women. Approximately one in eight women will receive a diagnosis of invasive breast cancer during their lifetime. The five-year survival rate for invasive breast cancer is less than 30 %, indicating a need to develop a more effective therapeutic agent targeting breast cancer. This review discusses bioactive 1,3,5-triazines targeting breast cancer cells by the inhibition of different enzymes, which include PI3K, mTOR, EGFR, VEGFR, FAK, CDK, DHFR, DNA topoisomerase, ubiquitin-conjugating enzyme, carbonic anhydrase, and matrix metalloproteinase. The anticancer agent search in some drug discovery programs is based on compound screening for antiproliferative activity. Often, multiple targets contribute to the anticancer effect of 1,3,5-triazines and this approach allows identification of active molecules prior to identification of their targets., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Masson SAS.. All rights reserved.)

N 2 ,6-Substituted 1,3,5-triazine-2,4-diamines (N 2 -substituted guanamines) attracted significant interest due to their potential in the development of bioactive molecules. With just two points of diversity, this scaffold is proved to be suitable for constructing compounds targeting various enzymes, receptors, transporters, and nucleic acids with an array of therapeutic applications, particularly in cancer, inflammation, and CNS disorders. This review discusses progress in the synthesis of N 2 ,6-substituted 1,3,5-triazine-2,4-diamines and their biological activities ranging from the inhibition of cancer-related enzymes (e.g. DNA topoisomerase IIα, carbonic anhydrases, ubiquitin-conjugating enzyme 2B, lysophosphatidic acid acyltransferase β and various kinases) to the binding to CNS-relevant receptors (e.g. histamine H 4 , serotonin 5-HT 6 , adenosine A 2a , and α7 nicotinic acetylcholine receptors)., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

A new, effective one-pot synthesis of the 6, N 2 -diaryl-1,3,5-triazine-2,4-diamines under microwave irradiation was developed. The method involved an initial three-component condensation of cyanoguanidine, aromatic aldehydes, and arylamines in the presence of hydrochloric acid. Without isolation, the resulting 1,6-diaryl-1,6-dihydro-1,3,5-triazine-2,4-diamines were treated with a base to initiate Dimroth rearrangement and spontaneous dehydrogenative aromatization, affording the desired compounds. The developed method was found to be sufficiently general in scope, tolerating various aromatic aldehydes and amines; by using their combinations in the first step, a representative library of 110 compounds was successfully prepared and screened for anticancer properties.

Purine isosteres present excellent opportunities in drug design and development. Using isosteres of natural purines as scaffolds for the construction of new therapeutic agents has been a valid strategy of medicinal chemistry. Inspired by the similarity to isoguanine, we attempted to develop a practical method for the preparation of 5-aza-isoguanines. Several synthetic approaches were explored to establish a robust general protocol for the preparation of these compounds. The significant difference in the reactivity of the C-5 and C-7 electrophilic centers of 1,2,4-triazolo[1,5- a ][1,3,5]triazines (5-azapurines) towards nucleophiles was demonstrated. The most practical and general method for the preparation of 5-aza-isoguanines involved a regioselective reaction of ethoxycarbonyl isothiocyanate with a 5-aminotriazole. The intramolecular ring closure of the resulted product followed by the S-methylation afforded 7-methylthio-2-phenyl-1,2,4-triazolo[1,5- a ][1,3,5]triazin-5-one, which could be effectively aminated with various amines. The resulted 5-aza-isoguanines resemble a known purine nucleoside phosphorylase inhibitor and could be interesting for further investigations as potential anticancer agents.

Purines can be considered as the most ubiquitous and functional N-heterocyclic compounds in nature. Structural modifications of natural purines, particularly using isosteric ring systems, have been in the focus of many drug discovery programs. Fusion of 1,3,5-triazine ring with pyrrole, pyrazole, imidazole, 1,2,3-triazole or 1,2,4-triazole results in seven bicyclic heterocyclic systems isosteric to purine. Application of the isosterism concept for the development of new compounds with therapeutic potential in areas involving purinergic regulation or purine metabolism led to significant advances in medicinal chemistry of the azolo[1,3,5]triazines. These 1,3,5-triazine-based purine-like scaffolds significantly increase level of molecular diversity and allow covering chemical space in the important areas of medicinal chemistry. Some of these azolo[1,3,5]triazine systems have become privileged scaffolds in the development of inhibitors of various kinases, phosphodiesterase, xanthine oxidase, and thymidine phosphorylase, antagonists of adenosine and corticotropin-releasing hormone receptors, anticancer and antiviral agents., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

In our drug discovery program, a series of 2-thioxo-pyrazolo[1,5-a][1,3,5]triazin-4-ones were designed, synthesized and evaluated for their TP inhibitory potential. All the synthesized analogues conferred a varying degree of TP inhibitory activity, comparable or better than positive control, 7-deazaxanthine (7-DX, 2) (IC50 value = 42.63 μM). A systematic approach to the lead optimization identified compounds 3c and 4a as the most promising TP inhibitors, exhibiting mixed mode of enzyme inhibition. Moreover, selected compounds demonstrated the ability to attenuate the expression of the angiogenic markers (viz. MMP-9 and VEGF) in MDA-MB-231 cells at sublethal concentrations. In addition, molecular docking studies revealed the plausible binding orientation of these inhibitors towards TP, which was in accordance with the experimental results. Taken as a whole, these compounds would constitute a new direction for the design of novel TP inhibitors with promising antiangiogenic properties., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

In our lead finding program, a series of 5-thioxo-[1,2,4]triazolo[1,5-a][1,3,5]triazin-7-ones and their 5-thio-alkyl derivatives were designed and synthesized which contained different substituents at ortho-position of 2-phenyl ring attached to the fused ring structure. The preliminary pharmacological evaluation demonstrated that the synthesized compounds exhibited a varying degree of inhibitory activity towards thymidine phosphorylase (TP), comparable to reference compound, 7-Deazaxanthine (7-DX, 2) (IC50 value=42.63 μM). The study also inferred that the ortho-substituted group at the phenyl ring and 5-thio-alkyl moiety imparted steric hindrance effects in the binding site of the enzyme, leading to a reduced inhibitory response. In addition, compound 3a was identified as a mixed-type inhibitor of TP. Moreover, computational docking study was performed to illustrate the important structural information on the plausible ligand-enzyme binding interactions., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Thirty-three 1,2,4-triazolo[1,5-a][1,3,5]triazin-5,7-dione and its 5-thioxo analogues were designed and synthesized which contained different substituents at meta- and/or para-positions of 2-phenyl or 2-benzyl ring attached to the fused ring structure. The preliminary pharmacological evaluation demonstrated that the 5-thioxo analogues of 1,2,4-triazolo[1,5-a][1,3,5]triazine exhibited a varying degree of inhibitory activity towards thymidine phosphorylase, comparable or better than reference compound, 7-Deazaxanthine (7-DX, 2) (IC50 value = 42.63 μM). Moreover, compounds 5q and 6i displayed a mixed-type of inhibitory mechanism in the presence of variable concentrations of thymidine (dThd). In addition, selected compounds were found to have a noticeable inhibitory effect on the expression of angiogenesis markers, including VEGF and MMP-9 in MDA-MB-231 breast cancer cells., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

5-Chlorouracil-linked-pyrazolo[1,5-a][1,3,5]triazines were designed as new thymidine phosphorylase inhibitors based on the fragment based drug design approach. Multiple-step convergent synthetic schemes were devised to generate the target compounds. The intermediate 5-chloro-6-chloromethyluracil was synthesized by a 4-step reaction. A series of the second bicyclic intermediates, namely pyrazolo[1,5-a][1,3,5]triazin-2-thioxo-4-one, was obtained from various substituted 3-aminopyrazoles. These two intermediates were coupled finally in the presence of sodium ethoxide and methanol to yield the desirable target compounds. The methylthio coupling spacer was found to be suitable in enabling the interaction of the two fragments at the active site and allosteric site of the enzyme. The best coupled compound (9q) inhibited the thymidine phosphorylase with an IC₅₀ value as low as 0.36 ± 0.1 μM. In addition, 9q demonstrated a mixed-type of enzyme inhibition kinetics, thus suggesting that it might indeed potentially bind at two different sites on the enzyme., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

A novel thermal rearrangement, involving pyrimidine ring opening and subsequent ring closure leading to recyclization of the system, was identified in the reaction of (6-oxo-1,6-dihydropyrimidin-2-yl)guanidines 3 (where NR(1)R(2) = NH(2), NH alkyl, NH aralkyl, NHCH(2)Ph(R)) with triethyl orthoacetate, affording 4-substituted-2-methyl-6H-pyrimido[1,2-a][1,3,5]triazin-6-ones 6 and their ring opened products. However, no such rearrangement was observed with (6-oxo-1,6-dihydropyrimidin-2-yl)guanidines 3 bearing a tertiary amino or anilino substituent (i.e. where NR(1)R(2) = N(CH(3))(2), indoline, morpholino, NHAr). As expected, 2-substituted-4-methyl-6H-pyrimido[1,2-a][1,3,5]triazin-6-ones 4 were obtained as the final products. Experimental structural determination and theoretical studies were carried out to get an understanding of the observed thermal rearrangement. In addition, an attempt to obtain similar pyrimido[1,2-a][1,3,5]triazin-6-ones using N,N-dimethylacetamide dimethyl acetal (DMA-DMA) as one carbon inserting synthon had furnished triazine ring annulated product 14 bearing N,N-dimethyl enamino substituent at position 4 as a result of further reaction with a second molecule of DMA-DMA.

A microwave‐assisted synthesis of 7‐amino‐1,2,4‐triazolo[1,5‐a][1,3,5]triazine‐2‐propanamides was developed using a three‐component, catalyst‐free reaction of cyanamide and trimethyl orthoformate with 3‐(5‐amino‐1H‐1,2,4‐triazol‐3‐yl)propanamides (3). The reaction tolerated structurally diverse substrates and proceeded chemo‐ and regio‐selectively, affording the target compounds in high purity in 5–10 minutes. The convenient chromatography‐free isolation and purification of the products add practicality to this method. The structural features of the prepared compounds were investigated using dynamic NMR spectroscopy, X‐ray crystallography and computational chemistry calculations. X‐ray crystallography performed on a representative compound, 3‐(7‐amino‐1,2,4‐triazolo[1,5‐a][1,3,5]triazin‐2‐yl)‐N‐(4‐benzyl)propanamide (4 l), showed the overall molecular conformation to adopt the shape of the letter C. Notable localisation of π‐electron density is found within the 1,2,4‐triazolo[1,5‐a][1,3,5]triazine system; a relatively short C−NH2 bond is consistent with restricted rotation about this bond. This study also presents a detailed analysis of the molecular interactions in 4 l using DFT and QTAIM methods with a focus on the hydrogen‐bonding and π‐stacking interactions that influence the molecular packing of 4 l. The findings reveal the significant roles of N−H⋅O, N−H⋅N and C−H⋅N interactions, along with electrostatically enhanced π⋅π contacts. A broad screening for insecticidal, fungicidal and herbicidal properties identified several compounds with potent herbicidal activity against Matricaria inodora. [ABSTRACT FROM AUTHOR]

A new method for the synthesis of bis(1,3,5‐triazine‐2,4‐diamines) was developed using a one‐pot multicomponent approach. The synthesis was performed using the acid‐catalyzed reaction of cyanoguanidine with amines and aldehydes, followed by dehydrogenative aromatization of the dihydrotriazine intermediates upon heating with alkali. Two types of bis(1,3,5‐triazine‐2,4‐diamines) were prepared using either piperazine as the bifunctional amine or terephthaldehyde as the bifunctional aldehyde thus affording products with a piperazine or p‐phenylene link between two 1,3,5‐triazine rings. The microwave‐assisted method allows fast and convenient synthesis of diverse bis(1,3,5‐triazine‐2,4‐diamines). [ABSTRACT FROM AUTHOR]

A new method for the fast synthesis of diverse 4-aryl-6-cycloamino-1,3,5-triazin-2-amines was developed. The synthesis is performed under microwave irradiation in a one-pot manner from cyanoguanidine, aromatic aldehydes, and cyclic amines. Their three-component reaction in the presence of hydrochloric acid produced dihydrotriazines, which were then converted (without isolation) into the targeted compounds via aromatic dehydrogenation in the presence of alkali. The reaction tolerated various aromatic aldehydes (including heterocyclic) and cyclic amines. Crystal structures of two representative 4-aryl-6-morpholino-1,3,5-triazin-2-amines were established by X-ray crystallography. The results of preliminary biological screening identified potent antileukemic activity for 6-[3,4-dihydroisoquinolin-2(1 H)-yl]-4-phenyl-1,3,5-triazin-2-amine. [ABSTRACT FROM AUTHOR]

Exploring the pharmacologically important pyrazolo[1,5-a][1,3,5]triazin-7(6H)-one scaffold for the construction of new bioactive compounds, we developed a synthesis of 4-phenethylthio-2-phenylpyrazolo[1,5-a][1,3,5]triazin-7(6H)-one (4) via S-alkylation of 2-phenyl-4-thioxopyrazolo [1,5-a][1,3,5]triazine-7(6H)-one (3), prepared by the double ring closure of pyrazole and triazine rings upon the treatment of 1-cyanoacetyl-4-benzoylthiosemicarbazide (2) with alkali. The antiproliferative activity of 4 against human lung cancer (A549) and human breast cancer (MDA-MB231) cell lines was investigated. Compound 4 was found to be more active against lung cancer cells than breast cancer cells. [ABSTRACT FROM AUTHOR]

The trichloromethyl moiety was successfully employed as a leaving group in nucleophilic substitutions with various amines for the synthesis of 4-amino-substituted pyrazolo[1,5- a ][1,3,5]triazin-2-amines. The key precursor for this reaction, 4-trichloromethylpyrazolo[1,5- a ][1,3,5]triazin-2-amine, was prepared via the solvent-dependent condensation of 5-guanidino-3-phenylpyrazole with trichloroacetonitrile. In a broad biological activity screening, some of the prepared compounds were identified as CGRP receptor antagonists. [ABSTRACT FROM AUTHOR]

Abstract: From the reaction of biguanide with ethyl benzoylacetate, N-(6-oxo-4-phenyl-1,6-dihydropyrimidin-2-yl)guanidine (1) and 6-benzoylmethyl-1,3,5-triazin-2,4-diamine (2) were isolated. The structural evaluation of 2 was performed theoretically (DFT calculations) and experimentally (NMR spectroscopy and X-ray crystallography). The effects of solvents and temperature on keto-enol-enaminone tautomeric equilibrium were explored. [Copyright &y& Elsevier]

C12H11N5, monoclinic, P21/n (no. 14), a = 7.3455(1) Å, b = 12.2470(1) Å, c = 12.1689(1) Å, β = 103.505(1)°, V = 1064.45(2) Å3, Z = 4, Rgt(F) = 0.0365, wRref(F2) = 0.0987, T = 100 K. [ABSTRACT FROM AUTHOR]

C12H11N5, monoclinic, P21/n (no. 14), a = 7.3455(1) Å, b = 12.2470(1) Å, c = 12.1689(1) Å, β = 103.505(1)°, V = 1064.45(2) Å3, Z = 4, Rgt(F) = 0.0365, wRref(F2) = 0.0987, T = 100 K. [ABSTRACT FROM AUTHOR]

Title compounds are obtained by reaction of guanidine derivatives with alkyl and aryl aldehydes. [ABSTRACT FROM AUTHOR]

Abstract: A new, efficient, catalyst-free, one-pot, three-component method for the synthesis of 2-amino-substituted 7-amino-1,2,4-triazolo[1,5-a][1,3,5]triazines using 3,5-diamino-1,2,4-triazoles, cyanamide, and triethyl orthoformate is developed. The reaction proceeds smoothly under microwave-assisted heating. Advantages of the method include using easily available reagents, short reaction times, and operational simplicity. [Copyright &y& Elsevier]

Abstract 3-Amino-substituted 5-aminopyrazoles were found to be suitable substrates for the synthesis of new 4-aminopyrazolo[1,5- a ][1,3,5]triazines (5-aza-9-deaza-adenines) when used in the one-pot, three-component reaction with cyanamide and triethyl orthoformate under microwave irradiation. The reaction proceeded selectively and its scope was demonstrated by the preparation of a library of 4-aminopyrazolo[1,5- a ][1,3,5]triazines. Some structural aspects of the prepared compounds were investigated using dynamic NMR spectroscopy and X-ray crystallography. The operational simplicity, short reaction time, and good reproducibility are attractive features of the developed robust and practical approach for the synthesis of 7-amino-substituted 4-aminopyrazolo[1,5- a ][1,3,5]triazines. Graphical abstract Image 1 Highlights • A multicomponent synthesis of adenine isosteres. • A one-pot, three-component triazine ring annulation. • A microwave-assisted synthesis of 5-aza-9-deazapurines. • Thermodynamic parameters of hindered rotation of amino group by the dynamic NMR spectroscopy. [ABSTRACT FROM AUTHOR]

The facile catalyst-free one-pot protocol allows the synthesis of the title species from aminopyarzoles (I), orthoformate (II), and cyanamide in short reaction times. [ABSTRACT FROM AUTHOR]