103492-33-7

A rapid and simple method for the preparation of 4-substituted 1-ethoxycarbonyl semi[0-9] carbazide is reported. The reaction is carried out under microwave irradiation by the reaction of five different isocyanates with ethyl carbazate.

A rapid and simple method for the preparation of 1-ethoxycarbonyl-4- substituted-semicarbazides has been developed. As examples the reaction of six different isocyanates with ethyl carbazate under solvent-free conditions are reported.

Cyclic azodicarbonyl derivatives, particularly 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD), commonly serve as arenophile, dienophile, enophile and electrophile. Perplexed by its instability in aqueous environment, there are few studies focused on the transient intermediate produced by hydrolysis of PTAD to achieve synthetic significance. Herein, we describe a “photo-click” method that involves nitrile imine (NI) from diarylsydnone to capture the diazenecarbonyl-phenyl-carbamic acid (DACPA) generated by water-promoted ring-opening of PTAD. DFT calculation reveal that H-bonding interactions between PTAD and water are vital to form DACPA which exhibited an umpolung effect during ligation by nature bond orbit (NBO) analysis. The ultra-fast ligation resulted in carbamoyl formazans, as a unique Z?E photo-switchable linker on target molecules, including peptide and drugs, with excellent anti-fatigue performance. This strategy is showcased to construct highly functionalized carbamoyl formazans in situ for photo-pharmacology and material studies, which also expands the chemistry of PTAD in aqueous media.

The efficient and one-pot synthesis of 4-substituted-1,2,4-triazolidin-3,5- dione derivatives (4-substituted urazoles) via combination of triphosgene, substituted anilines, and ethyl carbazate in the presence of cesium carbonate is presented.

To increase the effectiveness of cancer treatment, more effective anti-cancer drugs, as well as the new improved strategies of cancer treatment, are urgently needed. Our previous results have shown that various diazenes are cytotoxic to different tumor ce

Betulin, a naturally occurring abundant triterpene is converted in four steps to 3,28-di-O-acetyllupa-12,18-diene. When various 4-substituted urazoles were oxidized to the corresponding urazines with iodobenzene diacetate in the presence of 3,28-di-O-acetyllupa-12,18-diene, new heterocyclic betulin derivatives were produced. These betulin derivatives were examined in a microplate assay at 50 μM for their ability to inhibit the growth of Leishmania donovani axenic amastigotes, a species that causes the fatal visceral leishmaniasis. GI50 (concentration for 50% growth inhibition) values of the most effective compounds were determined and their cytotoxicity on the human macrophage cell line THP-1 evaluated. The anti-leishmanial activity on L. donovani amastigotes growing in macrophages was also examined. The heterocycloadduct between 3,28-di-O-acetyllupa-12,18-diene and 4-methylurazine was the most effective derivative with an GI50 = 8.9 μM against L. donovani amastigotes.

N,N-dialkyl-N′-chlorosulfonyl chloroformamidines 1 reacted with 4-substituted urazoles 2 to give [1,2,4]triazolo[1,2-b] [1,2,3,5]thiatriazoles 3 in a selective 1,2-NN dinucleophilic mode of reaction.The reaction of 1 with N1-substituted pyrazol-5-ones 4 afforded pyrazolo[4,3-e][1,4,3] oxathiazines 5 via selective 1,3-CCO dinucleophilic substitution. Compounds 3 and 5 were the sole products isolated from the respective reactions and both represent new ring systems. CSIRO 2010.

A simple and efficient three-step synthetic procedure for the preparation of 4-substituted phenyl derivatives of 1,2,4-triazolidindiones (urazoles), starting from anilines, has been developed. In this method, aniline derivatives were reacted with 4-nitrophenyl chloroformate to provide corresponding carbamate derivatives. In the second step, semicarbazide derivatives were prepared from these carbamates by reaction with ethyl carbazate. The cyclization reaction of corresponding semicarbazides furnished 1,2,4-triazolidindiones in high yields. Copyright Taylor & Francis Group, LLC.

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