Synthesis of Imidazo[1,2-c]pyrazolo [4,3-e]pyrimidines Derived From Indole and Related Heterocycles

Synthesis of novel pyrroles and fused pyrroles as antifungal and antibacterial agents

Pyrroles and its fused forms possess antimicrobial activities, they can easily interact with biomolecules of living systems. A series of substituted pyrroles, and its fused pyrimidines and triazines forms have been synthesised, all newly synthesised compound structures were confirmed by spectroscopic analysis. Generally, the compounds inhibited growth of some important human pathogens, the best effect was given by: 2a, 3c, 4d on Gram-positive bacteria and was higher on yeast (C. albicans), by 5c on Gram-negative bacteria and by 5a then 3c on filamentous fungi (A. fumigatus and F. oxysporum). Such results present good antibacterial and antifungal potential candidates to help overcome the global problem of antibiotic resistance and opportunistic infections outbreak. Compound 3c gave the best anti-phytopathogenic effect at a 50-fold lower concentration than Kocide 2000, introducing a safe commercial candidate for agricultural use. The effect of the compounds on DNA was monitored to detect the mode of action.

Preparation and biological properties of 2-thio-containing pyrimidines and their condensed analogs

The known methods for synthesis of thioxopyrimidines and their condensed analogs with exocyclic sulfur atom are summarized and discussed. The most popular approaches are based on [3+3], [4+2], [5+1] cyclization processes or domino reactions. The literature data analysis shows that the title compounds possess diverse biological activities, such as antioxidant, radioprotective, analgesic, antiinflammatory, antihypertensive, anxiolytic, anamnestic, anticonvulsant, antimicrobial, fungicidal, herbicidal, antiviral, and anticancer.

First synthesis and biological evaluation of indeno[2,1-e]pyrazolo[3,4-b]pyrazin-5-one and related derivatives

The synthesis of indeno[2,1-e]pyrazolo[3,4-b]pyrazin-5-one was achieved by intramolecular Friedel-Crafts reaction of the acid chloride 3-methyl-1,6-diphenyl-1H-pyrazolo[3,4-b] pyrazine-5-carboxylic acid chloride (4) using AlCl3 in boiling CS2. Compound 4 proved to be a versatile compound for the synthesis of several Indenopyrazolopyrazinone derivatives. The antibacterial and antifungal activities of selected derivatives were evaluated.

Pyridine-based heterocycles. Synthesis of new pyrido [4',3':4,5]thieno[2,3-d]pyrimidines and related heterocycles

The synthesis of the title compounds was achieved using ethyl 2-amino-6-methyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylate (1) as starting material. The reaction of the amino ester 1 with phenylisothiocyanate in boiling ethanol afforded the thiourea derivative 5. The cyclization reactions of 5 under different reaction conditions led to different pyridothienopyrimidine derivatives. Other reactions of the latter derivatives leading to pyrido[4',3':4,5]thieno[2,3-d]triazolo[1,5-a]pyrimidines are also presented.