Triazolines X. Organic Synthesis via 1,2,3-Triazoline Intermediates. A Unique Synthesis of 4-Anilinopyridazine

Syntheses of 1-(4-methylsulfonylphenyl)-5-aryl-1,2,3-triazoles and -(4-aminosulfonylphenyl)-5-aryl-1,2,3-triazoles

“…The organic layer was dried (Na 2 SO 4 ), filtered and evaporated. The residue was purified by column chromatography (silica gel, EtOAc/hexane 40:60) [7].…”

“…Potassium permanganate oxidation of 4 in an acetone solution gave low yield of the desired product 1-(4-methylsulfonylphenyl)-5-aryl-1,2,3-triazole 5 [6]. However, compound 5 could be obtained in moderate to good yield using potassium permanganate in a two phase system in the presence of a phase transfer catalyst, namely tetrabutylammonium chloride [7] (Table 3). Cycloadition of diazomethane in dioxane with the imino compound 6 did not give the desired compound 14.…”

Triazolines. XII. Permanganate Oxidation of 1,2,3,‐Triazolines Using Phase‐Transfer Catalysis. Electronic and steric effects

“…Elekt,ronische und sterisehe Effekt.e Heterocydes are assuming growing importance in recent years as intermediates in organic synthesis [2]. The decomposition react.ions of differently substituted 1, 'I, 3-triazolines (1H-4.5-dihydro-1,2,3-triazoles) make them useful in the synthesis of a host of organic compounds such as azomethines [2-41, uiridines [2-4], ketones [2--5], oxazolinrs [ 2 , 41. ninidines [2,4], ennniines [4-.j] and aminopyridazines [C], the product formed being largely dependent on t'he nature of the substituent groups.R'eceiit>ly we found t)liitt the oxidative dehydrogenation of 1, <>-subst itiited-1, ?,3-triazolines (1 ) bearing a pyridyl substituent In-p (R1, R2 see Table 1) 2a-p (R'), using phase-transfer c:~t:~lysis, provided a convenient route to thc synthesis of T)-hetero substituted lH-l,2,3-t~ri;izoles [7] (2).With the objective of evaluating the scope of triazoline oxidation in trinzole synthesis, we have now investigated t,he osida.tion of triszolines bearing 5-qninolyl and 6-t)hienyI groups as well as i~ number of 1, . :,-diary1 substituted triazolines and the electronic and steric effects of substituent groups on the plienyl rings.…”

“…R'eceiit>ly we found t)liitt the oxidative dehydrogenation of 1, <>-subst itiited-1, ?,3-triazolines (1 ) bearing a pyridyl substituent In-p (R1, R2 see Table 1) 2a-p (R'), using phase-transfer c:~t:~lysis, provided a convenient route to thc synthesis of T)-hetero substituted lH-l,2,3-t~ri;izoles [7] (2).…”