Acid-mediated four-component tandem cyclization: Access to multifused 1,3-benzoxazine frameworks
摘要:
An acid-mediated multicomponent reaction has been developed for the direct synthesis of multifused 1,3-benzoxazine derivatives from simple and readily available arylglyoxal monohydrates and 2-aminobenzyl alcohols under mild conditions. This novel protocol is proposed to proceed through intramolecular poly-heterocyclizations, thus leading to the formation of three new rings and six new chemical bonds, including four C-N and two C-O bonds. (C) 2018 Published by Elsevier Ltd.
An I-2-promoted sp(3) C-H functionalization has been developed for the synthesis of 2,5-disubstituted oxazoles from easily available methyl ketones and benzylamines without any metal and peroxide catalyst. This domino oxidative cyclization process involves the cleavage of C H bond and the formation of C-N, C-O bonds. (C) 2012 Elsevier Ltd. All rights reserved.
An acid-promoted multicomponent reaction for the synthesis of diverse fully substituted oxazole derivatives from simple and readily available arylglyoxal monohydrates, nitriles, and various C-nucleophiles has been developed. This protocol features wide functional group diversity which is capable of installing 4-hydroxycoumarin, 2-naphthol, and 1,3-cyclohexanedione motifs to oxazoles. Mechanistic analysis
A simple and efficient one-pot construction of pyrazolo[3,4-e]indolizinederivatives via a diethylamine-catalyzed three-component domino reaction of arylglyoxals, cyclic 1,3-diones, and 5-aminopyrazoles under microwave irradiation is described. In this one-pot transformation, seven bonds and two new rings are efficiently formed. This synthesis was confirmed to follow the group-assisted-purification
描述了在微波辐射下通过芳基乙二醛,环状1,3-二酮和5-氨基吡唑的二乙胺催化的三组分多米诺反应,一种简单有效的一锅构建吡唑并[3,4- e ]吲哚嗪衍生物。在这种一锅转换中,有效地形成了七个键和两个新的环。确认该合成遵循组辅助纯化(GAP)化学过程,可以避免传统的重结晶或色谱纯化方法。
A C–H Oxidation/Two-Fold Cyclization Approach to Imidazopyridoindole Scaffold under Mild Oxidizing Conditions
An expeditious one-step synthesis of the imidazopyridoindole scaffold was achieved through the C–H oxidation/two-fold cyclization reaction of methyl ketone and tryptamine derivatives. Mild oxidizing conditions were employed to realize the efficientoxidation of C(sp3)–H bonds, while suppressing overoxidation of the intermediate and ensuring the cross-trapping of two in situ generated acylimine intermediates
An I-2/KOH synergistically promoted direct ring-opening aroylation of benzothiazoles with aryl ketones has been discovered. Aryl ketones were seen to act as carbonyl sources to construct 2-acylbenzothiazoles. This reaction could provide an example for the convergent integration of self-labor domino sequences based on an in situ cross-trapping strategy.
Reprint of: Acid-mediated four-component tandem cyclization: Access to multifused 1,3-benzoxazine frameworks
An acid-mediated multicomponent reaction has been developed for the direct synthesis of multifused 1,3-benzoxazine derivatives from simple and readily available arylglyoxal monohydrates and 2-aminobenzyl alcohols under mild conditions. This novel protocol is proposed to proceed through intramolecular poly-heterocyclizations, thus leading to the formation of three new rings and six new chemical bonds, including four C-N and two C-O bonds. (C) 2019 Published by Elsevier Ltd.