Facile Method for the Conversion of Semicarbazones/Thiosemicarbazones into Azines (Under Microwave Irradiation) and Oxadiazoles (by Grinding)

Green synthesis, characterizations, and in vitro biological evaluation of Cu (II) complexes of quercetin with N ^ N ligands

“…Solid-state synthesis is also known as green synthesis because there is no need for any additives for the completion of the reaction. This synthesis is more beneficial when compared to the current conventional organic reaction as it reacts faster, with fewer steps required for completion of the reaction, is cost-effective, and has a green impact on the environment [29].…”

Pyrolysis of hydrazine derivatives and related compounds with N N single bonds

“…The dialkylamino radicals, formed either thermally or photochemically in solution, can be used as initiators for radical polymerization [177] The reaction of the dimethylamino radical with toluene and substituted toluenes yielded a Hammett value of -1.08 for the abstraction reaction giving R 2 NH and a deuterium isotope effect of 4.0. The rate of the thermal decomposition of tetramethyl-2-tetrazene (TMT) in benzene solution at [126][127][128][129][130][131][132][133][134][135][136][137][138][139][140][141][142] o C were of the order 10 -5 -10 -4 s -1 with an approximate energy of activation of 45 kcal/mol -rather high compared with the gas-phase values given above. Importantly, however, at concentrations of TMT greater than 0.2 M, induced decomposition of the tetrazene becomes important [178].…”

“…However, the same azines are obtained on microwave irradiation of either semicarbazones or thiosemicarbazones, and a more reasonable mechanism involves elimination of HNCO or HNCS, as is common for (thio)semicarbazides (see Schemes 31,32 and 39). The resulting hydrazones X-Ar-CH=N-NH 2 are then the source of the azines [126]. …”

A Decade of Development of Ethylidenethiosemicarbazides as Building Blocks for Synthesis of Azoles and Azines (A Review)

“…The biological activity of ethylidenethiosemicarbazides is related to their chelating ability with metal ion through either thione or thiolate sulfur and one of the hydrazone-nitrogen atoms 12 . Furthermore, ethylidenethiosemicarbazides have been used as a reactive building blocks for synthesis of different azoles such as, bis-thiazoles 13 , [1,3,4]thiadiazoles 14 , [1,3,4]oxadiazoles 15 , thiazolidin-4-ones 16 , imidazolinones 17 , and thiazoles 18,19 . In this survey, we represent three approaches about ethylidenethiosemicarbazides, with different aryl or heterocyclic moieties, including synthesis, reactivity, and their biological activities.…”

“…Microwave irradiation of ethylidenehydrazine-1-carbothioamides3 or 5led to self-condensation and give3,4-diazahex-2,4-diene derivatives89 15 (Scheme 37).…”