Synthesis and Characterisation of Some Novel Fused Thiazolo[3,2-A] Pyrimidinones and Pyrimido[2,1-B][1,3]Thiazinones

Arylidenemalononitriles as Versatile Synthons in Heterocyclic Synthesis

BACKGROUND

Arylidenemalononitriles are valuable synthons for the construction of a variety of novel complex heterocyclic motifs, fused heterocycle derivatives and spirocyclic compounds. They are versatile chemical intermediates and have increasing applications in industry, agriculture, medicine, biological science.

OBJECTIVE

The aim of this review is to highlight the preparation methods and reactions of arylidenemalononitriles in the synthesis of various heterocyclic compounds.

CONCLUSION

In this review, we have presented the application of arylidenemalononitriles to construct a variety of heterocycles. Various catalysts for the preparation of arylidnemalononitriles have been described.

Recent Developments on the Synthesis and Biological Activities of Fused Pyrimidinone Derivatives

Heterocyclic compounds constitute a unique class of organic compounds endowed with a wide range of synthetic and pharmaceutical applications. Pyrimidinones and their fused analogues have received focused attention in this regard, partly due to their mimicry of nucleobases which consequently forges their interesting medicinal properties. Over the years, the medicinal chemistry research community has experienced an upsurge in articles describing the exploration of these scaffolds to develop effective therapeutic agents. Several biological activities, including antimicrobial, antiviral, anticancer, antidiabetic, anti-inflammatory, anticonvulsive, and antihistaminic, have been well documented. This minireview presents a compendium of recent developments (2017-2020) focused on the synthesis and biological activities of fused pyrimidinones. The goal is to update medicinal chemists on the therapeutic relevance of fused pyrimidinones and the molecular architecture of clinic-worthy drug candidates. A brief account of the structure-activity relationships (SAR) revealed from different biological assays is also discussed.

One-Pot Three-Component Synthesis and Molecular Docking of Some Novel 2-Thiazolyl Pyridines as Potent Antimicrobial Agents

BACKGROUND

Thiazoles and pyridines are versatile synthetic scaffolds possessing wide spectrum of biological effects including potential antimicrobial activity.

OBJECTIVE

In the efforts to develop suitable antimicrobia drugs, medicinal chemists have focused on thiazole derivatives. A novel series of 2-thiazolyl pyridines was prepared in a one-pot three-component reaction using 2-bromoacetyl pyridine as a starting precursor.

METHOD

Structure of the synthesized compounds was elucidated by spectral data (FT-IR, 1H NMR, 13C NMR, and mass) and elemental analyses. The prepared compounds were screened for their in vitro antimicrobial activity.

RESULTS

The results revealed that compounds 4a,b,e-g and 12 showed promising activity. Molecular docking studies using MOE software were carried out for compounds 4a and 4b which exhibited potent activities indicated by the diameter zones (4a; 3.6, 4.0, 1.2 mm) (4b; 4.2, 3.5, 1.5 mm) and the binding affinities (4a; -5.7731, -5.3576, -4.6844 kcal mol-1) (4b; -5.9356, -2.8250, -5.3628 kcal mol-1) against Candida albicans, Bacillus subtilis and Escherichia coli, respectively.

CONCLUSION

This paper describes a facile and efficient MCR for synthesis of 2-thiazolyl pyridines from reaction of 2-bromoacetyl pyridine with different reagents. There was an agreement between the values of binding affinities and interactions and the data obtained from the practical antimicrobial screening of the tested compounds.

A facile access and evaluation of some novel thiazole and 1,3,4-thiadiazole derivatives incorporating thiazole moiety as potent anticancer agents

BACKGROUND

Many heterocyclic compounds containing thiazole or 1,3,4-thiadiazole ring in their skeletons have been reported to possess various pharmacological activities especially anticancer activities.

RESULTS

4-Methyl-2-phenylthiazole-5-carbohydrazide (2) was used as a synthon to prepare 2-(4-methyl-2-phenylthiazole-5-carbonyl)-N-phenylhydrazinecarbothioamide (3) and 2-(2-(4-methyl-2-phenylthiazole-5-carbonyl)hydrazono)-N'-phenylpropane hydrazonoyl chlorides 5a-c. In addition, thioamide 3 was used as starting material for preparation of a new series of thiadiazole derivatives via its reaction with hydrazonoyl chlorides 5a-c in dioxane using triethylamines as catalyst. In addition, a series of thiazole derivatives was synthesized by reaction of thioamide 3 with a number of α-halo compounds, namely, 3-chloropentane-2,4-dione (8) or 2-chloro-3-oxo-N-phenyl butanamide (10) phenacyl bromide 12 ethyl chloroacetate (14) in EtOH in the presence of triethylamine. The structures assigned for all the new products were elucidated based on both elemental analyses and spectral data and the mechanisms of their formation was also discussed. Moreover, the new products was evaluated in vitro by MTT assays for their anticancer activity against cell lines of Hepatocellular carcinoma cell line (HepG-2). The best result observed for compounds 7b (IC₅₀ = 1.61 ± 1.92 (μg/mL)) and 11 (IC₅₀ = 1.98 ± 1.22 (μg/mL)). The structure-activity relationships have been suggested based on their anticancer results.

CONCLUSIONS

A novel series of new pharmacophores containing thiazole moiety have been synthesized using a facile and convenient methods and evaluated as potent anticancer agents.