The influence of (1H-1,2,3-triazol-1-yl)-1,2,5-oxadiazole derivatives: 4-amino-3-(5-methyl-4-ethoxycarbonyl-(1H-1,2,3-triazol-1-yl)-1,2,5-oxadiazole (TF4CH3) and 4,4′-bis(5-methyl-4-ethoxycarbo-nyl-1H-1,2,3-triazol-1-yl)-3,3′-azo-1,2,5-oxadiazole (2TF4CH3) on stimulation of human platelet soluble guanylate cyclase by YC-1, NO donors (sodium nitroprusside, SNP, and spermine NONO) and on a synergistic increase of NO-dependent activation of the enzyme in the presence of YC-1 has been investigated. Both compounds increased guanylate cyclase activation by YC-1, potentiated guanylate cyclase stimulation by NO donors and increased the synergistic effect of YC-1 on the NO-dependent activation of soluble guanylate cyclase. The similarity in the properties of the examined 1,2,3-triazol-1-yl-1,2,5-oxadiazole derivatives with that of YC-1 and a possible mechanism underlying the recognized properties of compounds used are discussed.

First representatives of dichloroamino- and chloroaminofurazans, viz. , 4,4′-bis(dichloroamino)- and 4,4′-bis(chloroamino)-3,3′-azofurazans, were synthesized by the chlorination of 4,4′-diamino-3,3′-azofurazan with sodium hypochlorite in the CH 2 Cl 2 —H 2 O mixture.

[3+2] Cycloaddition of azide groups of N,N′-bis(4-azidofurazan-3-yl)methylenediamine to 1,3-dicarbonyl compounds and malonodinitrile was shown to proceed regioselectively with the formation of the corresponding N,N′-bis[4-(1H-1,2,3-triazol-1-yl)furazan-3-yl]methylenediamine derivatives. The reactions of N,N′-bis(4-azidofurazan-3-yl)methylenediamine with cyanoacetic acid ethyl ester and amide led to the formation of the product of transformation of the azide group in the starting compound to the amino groups.

A method of 3-amino-4-[5-aryl(heteroaryl)-1 H -1,2,3-triazol-1-yl)]furazan synthesis was optimized. Condensation of these compounds with 2,5-dimethoxytetrahydrofuran resulted in a series of previously unknown 4-[5-aryl(heteroaryl)-1 H -1,2,3-triazol-1-yl)]-3-(pyrrol-1-yl)furazans. All target compounds were evaluated for both antimitotic microtubule destabilizing effect in a phenotypic sea urchin embryo assay and cytotoxicity in a panel of 60 human cancer cell lines. Pyrrolyl derivatives of triazolylfurazans were determined as antiproliferative compounds. The most potent microtubule targeting compounds 7a and 7e are of interest for further trials as antineoplastic agents.

Nitration of 3-amino-4-(1H-1,2,3-triazol-1-yl)-1,2,5-oxadiazoles (3-amino-4-triazolylfurazans) with a mixture of NaNO3 and conc. H2SO4 gave for the first time triazolylfurazans with a primary nitramino group attached to the furazan ring. If the starting amino(triazolyl)-furazan contains an aromatic substituent, the latter also undergoes nitration under the conditions studied. Some of these nitramines were converted into salts (K, Na, and NH4).

Methods for the synthesis of 4-amino-4′-R-3,3′-(NNO)-azoxy-1,2,5-oxadiazoles (amino-azoxyfurazans) with 4-nitro-1,2,3-triazol-1-yl and 1,2,3-triazolo[4,5-c]furazan-5-yl substituents (R) by cycloaddition of morpholinonitroethylene to 4′-amino-4-azido-3,3′-(ONN)-azoxyfurazan or oxidative condensation of 3-R-4-aminofurazans with 4-trifluoroacetylamino-3-nitrosofurazan were elaborated. Related polycyclic azo derivatives were also synthesized.

Methods for the synthesis of amino(1,2,3-triazol-1-yl)-1,2,5-oxadiazoles (amino-triazolylfurazans) with CH 2 Cl and COCH 2 Br substituents in the triazole ring were developed and nucleophilic substitution for their halogen atom in reactions with N-, O-, and S-nucleophiles were studied. The possibility of displacing the NO 2 group from the furazan and triazole rings in triazolylfurazans by an azido group was investigated. Novel compounds of this series were synthesized; the reaction rate and pathway were found to depend on the nature of the substrate and the reagent and the position of the substituent in isomers.

Nitro-, nitroso-, and azo-1,2,5-oxadiazoles with 4-R1-5-R2-1,2,3-triazol-1-yl substituents were synthesized by oxidation of amino-(1,2,3-triazol-1-yl)-1,2,5-oxadiazoles (aminotriazolylfurazans). Azido-1,2,5-oxadiazole was prepared by diazotization of amino(triazolyl)furazan followed by treatment of the diazonium salt with sodium azide. Depending on the nature of the substituents and the reagent, triazolylfurazans can undergo destruction to give amino-R-furazans (R = NO2, N3, aminofurazanylazo), the amino group being formed from the triazole ring.

We have studied the 1,3-dipolar cycloaddition of azidofurazans to morpholinonitroethene and prepared 1,2,3-triazoles with furazan ring in position 1 and NO 2 group at position 4.

The 1,3-dipolar cycloaddition of azidofurazans to substituted acetylenes has been studied and substituted 3-(1,2,3-triazol-l-yl)furazans have been synthesized.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

We have established the formation of a tetradiazenofurazan macrocycle as a result of intramolecular oxidative cyclization of 4,4′-bis(4-aminofurazanyl-3-azo)-3,3′-azofurazan and have studied its crystal structure.

The oxidative cyclocondensation of 3,4-diaminofurazan and 4,4′-diamino-3,3′-azofurazan with dibromoisocyanurate afforded macrocyclec polydiazenofurazans. The reaction can be directed towards the formation of both the four-membered cycle alone or the three-, six-, and eight-membered macrocycles.

4,4′-Diamino-3,3′-azofurazane undergoes intramolecular oxidative cyclization to give 5-[4-amino(1,2,5)oxadiazolyl]-5H-[1,2,3]triazolo[4,5-c][1,2,5]oxadiazole upon heating with Pb(OAc)4 in chlorobenzene oro-dichlorobenzene or with thionyl chloride.

The thermodynamic stability of a number of tricyclic conjugated compounds has been evaluated on the basis of the composition of the occupied molecular orbitals and Hueckel molecular orbital calculations. The relative stability of the compounds under study depends on the number and location of the nitrogen and oxygen atoms in their structures.