A novel and efficient synthesis of 3-aminomethyl-N-tosyl-indazoles

Multicomponent Coupling Cyclization Access to Cinnolines via in Situ Generated Diazene with Arynes, and α-Bromo Ketones

“…To gain insight into the reaction process, control experiments were performed (Scheme 4). The reaction of benzyne precursor 1a with tosylhydrazone 5 16,17 did not afford the target product 4aa under standard conditions. This result identified that compound 5 may not be the intermediate for this reaction (eq 1).…”

Synthesis of indazole motifs and their medicinal importance: An overview

“…The 3-aminomethyl-N-tosyl-indazoles is synthesized by reacting amines with vinyl azines (Scheme-27) [41]. Thus, by the reaction of 1, 3-dinitrobenzene with 4-nitrobenzaldehyde hydrazone the cyclocondensation occurred by replacement of one of the nitro group, giving 5-nitro-3-(4-nitrophenyl) benzopyrazole as the main product (Scheme-28) [42].…”

Construction of bis-, tris- and tetrahydrazones by addition of azoalkenes to amines and ammonia

“…It has been demonstrated that amines react with azoalkenes A forming α-aminohydrazones (Scheme 1) [35–49], however, addition of several azoalkene molecules to amines is virtually unknown. To our knowledge, there is only one report on the formation of bishydrazones as undesirable products in reactions of some primary amines with N -tosylhydrazone of o -bromophenacyl bromide [50]. We suppose that extension of the scope of azoalkene–amine coupling to ammonia, primary amines and polyamines would open an easy access to various polyhydrazones of type I .…”