2-Cyanopyridazin-3(2H)-ones: effective and chemoselective electrophilic cyanating agents

A Novel One-pot Synthesis of Isothiocyanates and Cyanamides from Dithiocarbamate Salts Using Environmentally Benign Reagent Tetrapropylammonium Tribromide

“…37 However, this method involves the use of po-tassium or sodium cyanide and bromine for the preparation of cyanogen halide (which is again highly toxic), making the protocol environmentally unacceptable. Literature reports on various other methods for the preparation of cyanamide using different synthetic strategies, such as cyanation of amines using CN + equivalents as synthons, [38][39][40][41][42][43][44] Tiemann rearrangement of amidoximes, 45 coupling reactions involving Pd isocyanides, allyl carbonates and trimethylsilyl azide, 46 and sodium bis(trimethylsilyl)amide as deoxygenating or desulfurizing agents. 47 Yet another method for the preparation of cyanamides involves the reaction of hypervalent iodine(V) species with N,N 1 -disubstituted glycylamide.…”

Characteristic Effects of 4,5-Disubstituted Pyridazin-3-one Derivatives with Various Functional Groups: Ab initio Study

“…Since pyridazine nucleosides were recognized as having biological activity 1,2 and as being useful as synthetic auxiliary materials, 3,4 many studies have focused on their synthesis [5][6][7][8][9][10][11][12][13][14][15] and applications. [16][17][18][19][20][21] Particularly, much effort has been made to develop convenient and efficient routes for their synthesis. Pyridazin-3(2H)-one derivatives are ambident anions under basic conditions, 3,4 acting as stable anions and good leaving groups.…”

“…In the synthesis of pyridazine derivatives by Yoon's group, [6][7][8][9][10][11][12][13][14][15][16] the nucleophilic substitution reactions of the pyridazine derivatives rely on both structural and electronic condition factors. The structural factors are the positions and numbers of the substituent groups.…”

“…[6][7][8][9][10][11][12][13][14][15][16][20][21][22][23] Multisubstituted pyridazin-3(2H)-one derivatives are also useful materials (as intermediates) for the synthesis of some bi-and tricyclic heterocycles and fused ring derivatives. [10][11][12][13][14][15][16] For N-nitration substitution reactions, 10 the N2-atom of 4,5-dihalopyridazin-3-one reacts well with N-nitrating reagents such as Cu(NO 3 ) 2 under neutral conditions, whereas the reaction does not take place under acidic conditions. 4-chloro-5-alkoxypyridazin-3-one does not react well with N-nitrating reagents such as Cu(NO 3 ) 2 .…”

C-Cyanation with 1-cyanobenzotriazole

“…Electrophilic reaction with NC + donors are more rare: most are electrophilic substitution reactions of organometallic reagents 1 with tosyl cyanide, 2a,b 2-chlorobenzyl thiocyanate, 3 thiocyanogen, 4 2-cyanopyridazin-3(2H)-ones, 5 cyanogen halides, 6 and 1-cyanoimidazole. 7 These show problems with stability, lack of reactivity, poor solubility, corrosiveness, availability, toxicity, cost, and/or complicated preparative procedures.…”