Synthesis of thiophene-2-carboxamidines containing 2-aminothiazoles and their biological evaluation as urokinase inhibitors

Synthesis of novel thiazole, pyranothiazole, thiazolo[4,5-b]pyridines and thiazolo[5',4':5,6]pyrano[2,3-d]pyrimidine derivatives and incorporating isoindoline-1,3-dione group

Background

Thiazole is a core structural motif presents in a wide range of natural products. Thiazole derivatives also have a wide range of medicinal and biological properties.

Results

The reaction of hydrazonoyl halides with 2-(1-(4-(1,3-dioxoisoindolin-2-yl)phenyl)ethylidene)hydrazinecarbothioamidein ethanol and triethylamine yielded 2-(4-(1-(2-(4-(2-Arylhydrazono)-5-s-4,5-dihydrothiazol-2-yl)hydrazono)-ethyl)phenyl)isoindoline-1,3-dione and 2-(4-(1-(2-(5-(2-Arylhydrazono)-4-oxo-4,5-dihydrothiazol-2-yl)hydrazono)ethyl)-phenyl)isoindoline-1,3-dione.The reaction of 2-(4-(1-(2-(4-oxo-4,5-dihydrothiazol-2-yl)hydrazono)ethyl)phenyl)isoindoline-1,3-dione with arylidenemalononitrile also yielded 5-amino-2-(2-(1-(4-(1,3-dioxoisoindolin-2-yl)phenyl)ethylidene)hydrazinyl)-7-substituted-7H-pyrano[2,3-d]thiazole-6-carbonitrile. The structures of the newly synthesized compound were elucidated whenever possible on the basis of elemental analysis, spectral data, and alternative synthetic routes. Three of them were evaluated against a breast cancer cell line for their antitumor activity.

Conclusions

Compound (1) has been shown to be useful in the synthesis of a new series of 1,3-thiazole, pyrano[2,3-d]thiazole and 4,5-dihydrothiazolo[4,5-b]pyridine derivatives using hydrazonoyl halides as precursors. The anticancer efficacy of compounds (9b), (9e), and (9f) against MCF-7, a breast cancer cell line, was also compared to the standard anticancer drug doxorubicin.

Electronic supplementary material

The online version of this article (10.1186/s13065-019-0559-x) contains supplementary material, which is available to authorized users.

A Review on Recent Synthetic Strategies and Pharmacological Importance of 1,3-Thiazole Derivatives

Thiazole is the most common heterocyclic compound in heterocyclic chemistry and in drug design. Presence of several reaction sites in the thiazole moiety extends their range of applications and leads to new solutions for challenges in synthetic and medicinal chemistry. Thiazole derivatives are widely used as bioactive agents, liquid crystals, sensors, catalysts, etc. The motivating molecular architecture of 1,3-thiazoles makes them suitable moieties for drug development. In this review, our aim is to corroborate the recent data available on various synthetic strategies and biological properties of 1,3- thiazole derivatives.

UV-light intervened synthesis of imidazo fused quinazoline and its solvatochromism, antioxidant, antifungal and luminescence properties

The photochemical preparation of benzo[4,5]imidazo[2,1-b]quinazoline was assessed under the illumination of UV wavelength (>360 nm). The compound 3,4-dihydronaphthalen-1(2H)-one 1 with 1H-benzo[d]imidazol-2-amine 2 in the existence of KOH/DMF which lead to the aromatized compound 3. The notable remark of this reaction is that the UV irradiation (312 nm) plays a vital part in the formation of compound, 3 in shorter duration (2 h) which resulted in higher yield of 96%. Compound 3 was analyzed by H¹, C¹³ NMR, and HRMS. Solvatochromism impacts of the compound 3 was computed with different solvents (DCM < methanol< DMF < DMSO). The compound, 3 was presented to in-vitro free radical screening strategy. The standard ascorbic acid has less IC₅₀ value - than compound 3. Further, it was subjected to in-vitro fungicidal action against two Aspergillus species (A. flavus & niger). The anti-fungal activity of compound 3 additionally demonstrated great action, when compared antifungal specialist Fluconazole.

Synthesis of novel (E)-1-(2-(2-(4(dimethylamino) benzylidene) hydrazinyl)-4-methylthiazol-5-yl)ethanone derivatives as ecto-5'-nucleotidase inhibitors

Ecto-5'-nucleotidase (e5'NT), a membrane-bound enzyme and an essential member of ecto-nucleotidases which regulates extracellular purinergic signalling. Their upregulation results in various disease conditions, for example, inflammation, hypoxia and cancer. Therefore, efforts have been made to synthesize potent and selective inhibitors of e5'NT. Here we have synthesized, characterized and evaluated six thiazole derivatives (3a-3f) as potent e5'NT inhibitors. Among all derivatives, the compound (E)-1-(4-methyl-2-(2-(pyridin-3-ylmethylene)hydrazinyl) thiazol-5-yl)ethanone (3a) exhibited maximum inhibition towards both human and rat enzymes. However, their potency against h-e5'NT was 24-fold higher than r-e5'NT. Only two compounds exhibited inhibitory behaviour towards r-e5'NT. The molecular structures of these derivatives were confirmed with the help of solid-state characterization through NMR (¹H and ¹³C), FTIR and elemental analysis. Additionally, molecular docking was also implemented to explain putative bonding interaction between the active site of an enzyme and potent inhibitors.

Synthesis and Biological Evaluation of Bisthiazoles and Polythiazoles

Small heterocyclic compounds containing nitrogen and sulfur atoms, such as thiazole derivatives, represent a significant class of organic azoles that exhibit promising bioactivities and have a great potential in medicinal and agricultural fields. A convenient and high-yielding synthetic approach for a range of organic molecules is presented. The nuclease-like activities of compounds were studied with the aid of E. coli AB1157 DNA and agarose gel electrophoresis. The antioxidant evaluation of the compounds was carried out with different antioxidant techniques, such as ABTS and NO scavenging efficiency. The antibacterial behavior was evaluated against various bacterial strains, both Gram-positive and -negative, and the minimum inhibitory concentration (MIC) values of these compounds were determined. The antiproliferative activities and IC50 values of the synthesized organic molecules compounds against HEPG-2, MCF-7, and HCT-116 cell lines were evaluated.

Design, synthesis and antimalarial evaluation of novel thiazole derivatives

As part of our medicinal chemistry program's ongoing search for compounds with antimalarial activity, we prepared a series of thiazole analogs and conducted a SAR study analyzing their in vitro activities against the chloroquine-sensitive Plasmodium falciparum 3D7 strain. The results indicate that modifications of the N-aryl amide group linked to the thiazole ring are the most significant in terms of in vitro antimalarial activity, leading to compounds with high antimalarial potency and low cytotoxicity in HepG2 cell lines. Furthermore, the observed SAR implies that non-bulky, electron-withdrawing groups are preferred at ortho position on the phenyl ring, whereas small atoms such as H or F are preferred at para position. Finally, replacement of the phenyl ring by a pyridine affords a compound with similar potency, but with potentially better physicochemical properties which could constitute a new line of research for further studies.

Recent applications of 1,3-thiazole core structure in the identification of new lead compounds and drug discovery

1,3-Thiazole is one of the most important scaffolds in heterocyclic chemistry and drug design and discovery. It is widely found in diverse pharmacologically active substances and in some naturally-occurring compounds. Thiazole is a versatile building-block for lead generation, and is easily access of diverse derivatives for subsequent lead optimization. In the recent years, many thiazole derivatives have been synthesized and subjected to varied biological activities. In this article we intended to review the most important biological effects of thiazole-based compounds and highlight their roles in new leads identification and drug discovery. This article is also intended to help researches for finding potential future directions on the development of more potent and specific analogs of thiazole-based compounds for various biological targets.

Solvent-free and catalysts-free chemistry: a benign pathway to sustainability

In the past decade, alternative benign organic methodologies have become an imperative part of organic syntheses and chemical reactions. The various new and innovative sustainable organic reactions and methodologies using no solvents or catalysts and employing alternative energy inputs such as microwaves, sonication, conventional and room temperature heating conditions, mechanochemical mixing, and high-speed ball milling are discussed in detail. Environmentally benign and pharmaceutically important reactions such as multicomponent, condensation, and Michael addition reactions; ring opening of epoxides; and oxidation and other significant organic reactions are discussed. An overview of benign reactions through solvent- and catalyst-free (SF-CF) chemistry and a critical perspective on emerging synergies between SF-CF organic reactions are discussed.

N-(2,4,6-Trimethyl-phen-yl)-1,3-thia-zol-2-amine

In the title compound, C₁₂H₁₄N₂S, the dihedral angle between the 1,3,5-trimethyl­benzene and 1,3-thia­zol-2-amine groups is 73.15 (4)°. In the crystal, inversion dimers linked by pairs of N—H⋯N hydrogen bonds generate R₂²(8) loops.

Efficient one-pot three-component synthesis of N-(4-arylthiazol-2-yl) hydrazones in water under ultrasound irradiation

A highly efficient and facile one-pot three-component synthesis of N-(4-arylthiazol-2-yl) hydrazones was carried out in excellent yield without any catalyst in water under ultrasound irradiation.

Design, synthesis of some new (2-aminothiazol-4-yl)methylester derivatives as possible antimicrobial and antitubercular agents

A series of (2-aminothiazol-4-yl)methylester (5a-t) derivatives were synthesized in good yields and characterized by (1)H NMR, (13)C NMR, mass spectral and elemental analyses. The crystal structure of 5a was evidenced by X-ray diffraction study. The compounds were evaluated for their preliminary in vitro antibacterial, antifungal activity and were screened for antitubercular activity against Mycobacterium tuberculosis H37Rv strain. The synthesized compounds displayed interesting antimicrobial activity.