A new site‐selective route for synthesis of functionalized imidazo[2,1‐c][1,2,4]triazoles

Abstract

Reactions of 4‐arylhydrazono‐2‐methylthio‐imidazolin‐5(1H)‐one 3 with various hydrazonoyl halides 1 proved to be site‐selective and yielded the respective imidazo[2,1‐c][1,2,4]triazole derivatives 8. The structure of the latter was elucidated by X‐ray analysis and the mechanism of the studied reactions was discussed.

Cyclocondensation Reactions of Hydrazonoyl Chlorides with Some Azines: Synthesis of New Fused Heterocycles of Expected Microbiological Activity

“…Elemental analyses were carried out at the Microanalytical Center of Cairo University, Cairo, Egypt. The starting compounds, N-phenyl benzenecarbohydrazonoylchloride (1a) [28] [29] [30], N-phenyl-2-phenylami-no-2-oxoethanehydrazonoyl chloride (1b), N-phenyl-2-oxopropanehydrazonoyl chloride (1c), ethyl N-phenylhydrazonochloroacetate (1d) and ethyl N-p-nitro-phenylhydrazonochloroacetate (1e) [20] [31] were prepared as previously reported.…”

Synthesis of a new triheterocycle. Bis-pyrazolo[1,5-a][4',3'-e]pyrimidine

“…In continuation of our studies dealing with the utility of hydrazonoyl halides for synthesis of various heterocyclic ring systems, [1][2][3][4][5][6][7][8][9][10][11] we wish to report herein a new facile synthesis of bispyrazolo [1,5-a][4',3'-e]pyrimidine ring system and its various functionalized derivatives that have not been reported hitherto. The earlier methods reported for synthesis of such ring system are multisteps.…”

Solvent and Substituent Effects on the Electronic Spectra of 3-Arylazo-Imidazo[1,2-b]pyrazolo[4,3-d]-pyridazines

“…Over the past five years, we have explored the utility of hydrazonoyl halides in the synthesis of aryl-and heteroarylazo derivatives of heterocyclic compounds and studied their azo-hydrazone tautomerism. [1][2][3][4][5][6][7][8] Many such colourants have found numerous applications including hair dyes, disperse dyes, ink-jet inks and laser materials. 9,10 In this work, a series of 10 3-arylazo-8H-imidazo [1,2-b]pyrazolo [4,3-d]pyridazine derivatives 5a-j were synthesised and their electronic absorption spectra have been recorded in the region 200-800 nm in five different solvents.…”