P. Giori

A new general and efficient synthesis of imidazo[4,5-c]pyrazole derivatives

Abstract A new general and efficient synthesis of imidazo[4,5-c]pyrazoles ( 5 ) is reported. The key step of this synthetic procedure is the intramolecular cyclodehydration of 5 -alkylamino- 4 -nitrosopyrazoles ( 4 ), which affords the title compounds ( 5 ) in good yields.

A new route to the synthesis of imidazo [4,5-c]pyrazoles

Abstract A new synthesis of imidazo [4,5-c] pyrazoles, obtained through cyclisation of 4-nitroso-5-alkylamino-pyrazoles, is described.

An Efficient Procedure for the Synthesis of Pyrazolo]3,4-d][1,3]thiazine-4-ones

Trichloromethyl chloroformate reacts with N-(1-alkyl/aryl-5-pyrazolyl) thiocarboxamides (2a-j) to give pyrazolo[3,4-d][1,3]thiazin-4-ones (3) while it reacts with N-(3-methyl-5-pyrazolyl)thiobenzamide (2m) to give the pyrazolo[1,5-c] [1,3,5]thiadiazine-4-one (4). Heating under reflux in formic acid of homologues (3g-i) bearing a tert-butyl group linked to pyrazole N-1 atom afforded the dealkylated derivatives (3k-m)

A New Synthesis of Pyrazolo[3,4-d]thiazoles

An efficient synthesis of pyrazolo[3,4-d]thiazoles (6) was achieved by treatment of N-(4-amino-5-pyrazolyl)thiocarboxamides (4) with sodium nitrite in acidic medium followed by irradiation with uv light

Antifungal properties of some pyrazolyl-alkyl-sulfides

Four 5-amino-4-alkylthio-pyrazoles were synthesized and their antifungal activity was evaluated in vitro in Trichophyton mentagrophytes, Microsporum cookei and Candida albicans. The compounds slightly influenced the growth kinetics of the yeast, but at concentrations ranging from 20 to 40 μg/ml completely prevented the mycelial growth of the two dermatophytes cultivated on Sabourauds agar medium. An electron microscopic study, undertaken by using the most active compound, showed that in C. albicans mitochondria were the only cell targets affected whereas in the dermatophytes cell wall, plasmalemma and the main cytoplasmic organelles were damaged in various degrees. Since the most remarkable alterations were connected with membrane abnormalities, the cytological changes observed were tentatively interpreted as a consequence of the compound intrusion into the lipid bilayer of the membranes, since the drug is lipophilic in nature.

Synthesis of 6,7-disubstituted pteridine-2,4-diones

The reaction of pyrimido[5,4-c][1,2,5]oxadiazin-3(5H)-one with carbon nucleophiles afforded pteridine-2,4-diones bearing a variety of substituents unequivocally positioned in the pyrazine ring