The chemistry of α,β-ditosyloxyketones: new and convenient route for the synthesis of 1,4,5-trisubstituted pyrazoles from α,β-chalcone ditosylates

Oxidative Rearrangement via 1,2-Aryl Migration using Hydroxy(tosyloxy)iodobenzene in a Polar Aprotic Solvent

“…As a result, in many previous investigations, our research group assumed that the structure of the ditosyloxy ketones corresponded to that of the vicinal ,-ditosyloxy ketone 3 (Scheme 3). [42][43][44] Scheme 3 Reported syntheses of pyrazoles 4, isoxazoles 5, -aryl -keto dialkylacetals 6, and desoxybenzoins 7, assuming that the structure of the ditosyloxy ketone was that of the vicinal ,-ditosyloxy ketone 3…”

Chalcones as Versatile Synthons for the Synthesis of 5- and 6-membered Nitrogen Heterocycles

“…A series of bispyrazoles can be accomplished through the reaction of bischalcones tetrabromo derivatives with hydrazine hydrate in refluxing methanol [189]. [190]. At the same time Aggarwal and co-workers used iodobenzene diacetate for the oxidation of the intermediates Nsubstituted hydrazones from chalcones to afford 1,3,5-trisubstituted pyrazoles under mild conditions in high yields [191].…”

Synthesis of 1,4,5-Triarylpyrazoles from the Addition Products ofα,β-Chalcones with New Ion-Supported [Hydrox-yl(tosyloxy)iodo]benzenes

“…如果氟化物中心原 子属于不同周期、 不同族的, 熔点次序是 6 PF -＞ 4 BF - [18] . [20] . 对甲苯磺酰氧基是非常好的离去基团, 1,3-二芳 基-2,3-二对甲苯磺酰氧基-1-丙酮和苯肼发生环合反应 生成 1-苯基-4,5-二芳基吡唑 [20] .…”

“…[20] . 对甲苯磺酰氧基是非常好的离去基团, 1,3-二芳 基-2,3-二对甲苯磺酰氧基-1-丙酮和苯肼发生环合反应 生成 1-苯基-4,5-二芳基吡唑 [20] . 本文尝试了离子负载 HTIB 试剂 10, 11, 4 和查尔酮及其衍生物中的碳碳双键 加成, 成功地得到了 1,3-二芳基-2,3-二对甲苯磺酰氧基-1-丙酮, 随后和苯肼发生环合, 制备了 1-苯基-4,5-二芳 基吡唑(Scheme 2).…”