Synthesis of Some New Pyrimidine and Pyrimido[4,5-d]pyrimidine Derivatives

Synthesis, computational and antimicrobial evaluation of some new pyridine derivatives

A series of pyridine compounds were prepared by using 3-(dimethylamino)-1-(pyridin-4-yl)prop-2-en-1-one (14) as a precursor. The reaction of 14 with different reagents afforded different new heterocyclic compounds. All the new compounds were characterized by spectroscopic analyses. Moreover, the density function theory study was made to establish the geometry of the tested compounds. The antimicrobial activities of the newly prepared pyridine derivatives were studied against Gram-positive bacteria (Bacillus subtilis and Bacillus thuringiensis) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and fungi (Fusarium oxysporum and Botrytis fabae) by the minimal inhibitory concentration method. Compounds belonging to the pyran 32, pyridine 33, indenopyran 34, thiazolopyridine 35, and chromene 39 series displayed a high antimicrobial activity. It was found that the experimental results of the biological evaluation were in agreement with the molecular modeling studies.

Microwave assisted synthesis of some new thiazolopyrimidine and pyrimidothiazolopyrimidopyrimidine derivatives with potential antimicrobial activity

Background and objective

A series of thiazolopyrimidine derivatives have been synthesized via multicomponent reaction and tested for biological activities. This research aims to develop a new synthetic method of poly fused pyrimidines under microwave irradiation. 6-Amino-4-aryl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitriles reacted with bromomalono-nitrile to give 3,7-diamino-5-aryl-5H-thiazolo[3,2-a]pyrimidine-2,6-dicarbonitrile more willingly than the isomeric 7H-thiazolo[3,2-a]pyrimidines. Thiazolopyrimidine derivatives reacted with carbon disulphide to produce 11-aryl-11H-1,2,3,4,7,8,9,10-octahydropyrimido[4″,5″:4′,5′]thiazolo[3′,2′-a]pyrimido[4,5-d]pyrimidine-2,4,8,10-tetrathione. The above mentioned reactions were established by using both conventional methods and microwave-assisted irradiation.

Conclusion

This work provides a new method for preparing poly fused pyrimidines. The microwave-assisted technique is preferable due to the yield enhancements attained, time saving, and environmental safety reactions. The newly prepared compounds were verified for their antimicrobial activities. Also, the absorption and emission of some of the prepared compounds were studied.

Nanoformulation and antimicrobial evaluation of newly synthesized thiouracil derivatives

The present work reports the synthesis of a new series of pyridopyrimidine derivatives. The newly synthesized compounds were characterized by various analytical and spectral techniques. In addition, their antimicrobial activity was evaluated as well as modeling studies were performed to investigate their ability to recognize and bind to the biotin carboxylase (BC)-active site. The results showed a broad spectrum antibacterial and antifungal profile of the synthesized derivatives. Docking results demonstrated that all members of this class of new derivatives were able to recognize the active site of Escherichia coli BC and form different types of bonding interactions with key active site amino acid residues. Besides the compounds with promising antimicrobial activity in addition to 6-aminothiouracil, as control, were incorporated into polycaprolactone nanoparticles to improve their water solubility, permeability through physiological barriers and consequently enhanced therapeutic efficacy. The compounds-loaded nanoparticles were prepared using single emulsion-solvent evaporation technique, and their diameters were found to be in the range 136 ± 30 to 213 ± 28 nm. Transmission electron microscopy (TEM) showed a spherical and dense morphology of the nanoparticles. The results also showed high entrapment efficiency of the synthesized bioactive compounds in the nanoparticles (85 ± 5% to 91 ± 2%) with a desirable in vitro biodegradation and release profiles.