Heterogeneous biomimetic aerobic synthesis of 3-iodoimidazo[1,2-a]pyridines via CuO_x/OMS-2-catalyzed tandem cyclization/iodination and their late-stage functionalization

Abstract

Heterogeneous catalysis performs well in biomimetic oxidation to generate a low-energy pathway for the synthesis of 3-iodoimidazo[1,2-a]pyridines.

Heterogeneous Cu/OMS-2 as an efficient catalyst for the synthesis of tetrasubstituted 1,4-enediones and 4H-pyrido[1,2-a]-pyrimidin-4-ones

“…OMS-2 is microporous material with a composition of KMn 8 O 16 ·nH 2 O. 5 Based on the previous reports, it is believed that the catalytic ability of Cu/OMS-2 can be significantly improved by the electronic interaction, which might facilitate organic transformations and make them proceed under a low-energy pathway. 3 Consequently, the mixed valent, crystalline and semi-conductive properties make OMS-2 have a wide range of applications.…”

Precise Cu Localization‐Dependent Catalytic Degradation of Organic Pollutants in Water

“…OMS‐2 not only plays a decisive role on the stabilizing catalytic Cu species to be used in water with great stability, but also combines with Cu species to produce a low‐energy pathway for reduction by efficient electron‐transfer mediation. The catalyst CuO x /OMS‐2 is synthesized as previously reported by wet‐impregnation of OMS‐2 in Cu(NO 3 ) 2 solution followed by filtration, washing, drying and calcination (Figure ) . Copper‐doped manganese oxide‐based octahedral molecular sieves (Cu‐OMS‐2) is synthesized by the pre‐incorporation from KMnO 4 , Cu(NO 3 ) 2 , MnSO 4 and HNO 3 , followed by filtration, washing, drying and calcination, based on Yu's method .…”

“…Some of us have long term interest in the synthesis of OMS‐2 or modified OMS‐2 and their applications . In a previous work, we first reported copper loaded‐manganese oxide‐based octahedral molecular sieves (CuO x /OMS‐2) as an efficient heterogeneous and recyclable catalyst for aerobic synthesis of 3‐iodoimidazo[1,2‐a] pyridines by tandem cyclization/iodination of I 2 , acetophenones and 2‐aminopyridines . Hence we now report the comparison of the catalytic activities of CuO x /OMS‐2, Cu‐OMS‐2 and OMS‐2 for the degradation of organic pollutants in aqueous solutions and in particular the high catalytic activity and high recyclability of CuO x /OMS‐2 for pollutant degradation reactions.…”

“…[16] In a previous work, we first reported copper loaded-manganese oxide-based octahedral molecular sieves (CuO x /OMS-2) as an efficient heterogeneous and recyclable catalyst for aerobic synthesis of 3-iodoimidazo[1,2-a] pyridines by tandem cyclization/iodination of I 2 , acetophenones and 2-aminopyridines. [17] Hence we now report the comparison of the catalytic activities of CuO x /OMS-2, Cu-OMS-2 and OMS-2 for the degradation of organic pollutants in aqueous solutions and in particular the…”

Electrochemical Synthesis of 3‐Bromoimidazo[1,2‐a]pyridines Directly from 2‐Aminopyridines and alpha‐Bromoketones

“…To date, the preparation of these halogenated compounds has been generally accomplished in two steps: the build‐up of the imidazo[1,2‐a]pyridine core and the halogenation . Nevertheless, the existing few methods for one pot direct synthesis of 3‐halogen‐substituted imidazo[1,2‐a]pyridines suffered from one or more disadvantages, such as limited substrate scope, the involvement of transition‐metal,, elevated temperature– or microwave conditions . From the viewpoint of green and step‐economic strategy, development of direct synthesis of 3‐halogen‐substituted imidazo[1,2‐a]pyridines under mild conditions is still desirable.…”