ChemInform Abstract: 1,3‐Dipolar Cycloaddition of Dipolar Reagents to Bifunctional Olefins with Chloramine‐T. Part 2.

Abstract

1,3-Dipolar Cycloaddition of Dipolar Reagents to Bifunctional Olefins with Chloramine-T. Part 2. -1,3-Dipolar cycloaddition of an activated olefin to nitrile imines or nitrile oxides, generated by action of chloramine-T on the corresponding hydrazones (II) or oximes (V), resp., provides an efficient one-pot route to pyrazoles or isoxazoles, respectively.-(PADMAVATHI, V.; SUMATHI, R. P.; VENUGOPAL REDDY, K.; SOMASEKHAR REDDY, A.; BHASKAR REDDY, D.; Synth.

One‐pot PTC synthesis of polyfused pyrazoles

“…Moreover, the reaction of compound 1 with CS 2 and the same halo compounds but in 1:1:2 molar ratio under the same PTC conditions afforded The reaction of compound 1 with CS 2 and alcoholic KOH in 2:1:1 molar ratio gave 5-hydroxy-4-mercapto-2,6-diphenyl-2,3,6,8-tetrahydrodipyrazolo-SCHEME 1 [3,4-b:4,3-e]pyridin-3-one (12), which was treated with ethyl chloroacetate under the proceeding PTC conditions to give ethoxy(8-hydroxy-3,7-diphenyl-5,7-dihydro-3H-1-thia-3,4,5,6,7-pentaazacyclopenta[cd]-s-indacen-2-yl)-1-methanone (14). On the other hand, 6-phenyl-2,4-dithioxo-2,6,7,8-tetrahydropyrazolo [1,5 -c] [ 1,3,5 ]-thiadiazin-7-one (13) was obtained by treating compound 1 with CS 2 and alcoholic KOH in 1:2:2 molar ratio, which was reacted with hydrazine hydrate [16,17] in refluxing ethanol, where H 2 S gas was evolved to afford 3-amino-6-phenyl-2,4-dithioxo-2,3,4,6,7,8-hexahydropyrazolo [1,5-a] [1,3,5]triazin-7-one (15) (Scheme 2). The structure of these compounds were confirmed using IR, 1 H-NMR, MS, and elemental analysis ( Table 1).…”

“…The precipitate was collected by filtration and crystallized from ethyl alcohol to give compound 15 as yellow needles. [3,4-b]pyridin-3-one (16) and 3a,4, [3,4-b]pyridin-5-yl Carbonitrile (17) A mixture of 1 (0.01 mol), anhydrous potassium carbonate (3 g), a catalytic amount of TBAB, dioxane (40 ml), carbon disulfide (0.01 mol) and ethyl cyanoacetate or malononitrile (0.01 mol) was stirred for 4 or 2 h at 60…”

“…The chemistry of pyrazoles has received much attention and many methods for their synthesis have been developed [12]. Various heterocyclic systems containing a pyrazole moiety have been prepared by 1,3-dipolar cycloaddition of iminonitriles to activated olefins [13][14][15][16]. This motivated us to synthesize some new fused and spiropyrazoles under PTC conditions.…”

1,3‐Dipolar cycloaddition of dipolar reagents to bis(styryl) sulfones

“…In recent times, we have been actively involved in 1,3-cycloaddition reactions of dipolar reagents with dipolarophiles for the development of manifold fivemembered heterocycles [1]. Prompted by the successful results on this front, we present in this article the utilization of E,E-bis(styryl) sulfones as dipolarophiles in the synthesis of sulfonyl bis pyrazolines and isoxazolines by the cycloaddition of dipoles nitrile imines and nitrile oxides, generated from araldehyde phenylhydrazones and araldoximes in the presence of chloramine-T (CAT).…”

Synthesis and Biological Activity of a New Class of Sulfone-Linked Pyrrolylpyrazoles and Pyrrolylisoxazoles from Methyl-3-aryl-2-(E-arylethenesulfonyl)acrylate

“…[13][14][15][16] Amongst different methods for the preparation of pyrazolines, isoxazolines, the 1,3-dipolar cycloaddition is the most important and versatile one. The dipolar reagents can be generated by the dehydrogenation of araldehyde hydrazones and araldoximes with lead tetracetate, 17) mercury acetate, 18) 1-chlorobenzotriazole, 19) chloramine-T (CAT) [20][21][22][23][24][25] etc. In fact, we have reported novel oxo-linked bis heterocycles by 1,3-dipolar cycloaddition of dipolar reagents viz., TosMIC, diazomethane, nitrile imines and nitrile oxides to symmetrical and unsymmetrical bischalcones.…”