A copper/iodine cocatalyzed decarboxylative cyclization of α-amino acids is described. Starting from the readily available amino acids and either 2-benzoylpyridines or 2-benzoylquinolines, 1,3-disubstituted imidazo[1,5-a]pyridines and 1,3-disubstituted imidazo[1,5-a]quinolines were prepared in excellent yields.
描述了铜/碘共催化的α-氨基酸的脱羧环化。从容易获得的氨基酸和2-苯甲酰基吡啶或2-苯甲酰基喹啉开始,以优异的条件制备了1,3-二取代的咪唑并[1,5- a ]吡啶和1,3-二取代的咪唑并[1,5- a ]喹啉产量。
Heterogeneous copper-catalyzed decarboxylative cyclization of 2-benzoylpyridines with α-amino acids leading to imidazo[1,5-a]pyridines
作者:Yang Liao、Chenyu Yan、Rongli Zhang、Mingzhong Cai
DOI:10.1016/j.jorganchem.2018.11.030
日期:2019.2
The heterogeneous decarboxylative cyclization reaction between 2-benzoylpyridines and α-aminoacids was achieved in toluene at 120 °C in the presence of 15 mol% of l-proline-functionalized MCM-41-supported copper(II) complex [l-Proline-MCM-41-Cu(OTf)2] and iodine with di-tert-butyl peroxide (DTBP) as oxidant, yielding a variety of 1,3-disubstituted imidazo[1,5-a]pyridines in good to excellent yields
2- benzoylpyridines和α-氨基酸之间的非均相脱羧环化反应在甲苯中于120℃下在15%(摩尔)的存在下实现的升-脯氨酸官能MCM-41支持的铜(II)配合物[升-Proline- MCM-41-Cu(OTf)2 ]和碘与二叔丁基过氧化物(DTBP)作氧化剂,可产生各种1,3-二取代的咪唑并[1,5- a ]吡啶,产率高至优异。新的负载型铜催化剂可以用市售的廉价试剂制备,并通过简单的过滤从反应混合物中回收,并以几乎一致的活性回收至八次。
Copper-Catalyzed Oxidative Amination of sp<sup>3</sup> C–H Bonds under Air: Synthesis of 1,3-Diarylated Imidazo[1,5-<i>a</i>]pyridines
A copper(II)-catalyzed tandem reaction between pyridine ketone and benzylamine was developed by using clean O2 as an oxidant. This transformation proceeded via an efficient condensation–amination–oxidative dehydrogenation process, affording 1,3-diarylated imidazo[1,5-a]pyridines in excellent yields.
通过使用纯净的O 2作为氧化剂,进行了吡啶酮和苄胺之间的铜(II)催化串联反应。该转化过程通过有效的缩合-胺化-氧化脱氢过程进行,从而以优异的收率得到了1,3-二芳基咪唑并[1,5- a ]吡啶。
Synthesis of Fluorescent 1,3-Diarylated Imidazo[1,5-<i>a</i>]pyridines: Oxidative Condensation−Cyclization of Aryl-2-Pyridylmethylamines and Aldehydes with Elemental Sulfur as an Oxidant
Oxidative condensation−cyclization of aldehydes and aryl-2-pyridylmethylamines proceeded in the presence of a stoichiometric amount of elemental sulfur as an oxidant in the absence of catalyst. The reaction gave a variety of 1,3-diarylated imidazo[1,5-a]pyridines in good to high yields. The products showed fluorescence emission in a wavelength range of 454−524 nm. The quantum yields of 1,3-diarylated
醛和芳基-2-吡啶基甲胺的氧化缩合环化反应在存在化学计算量的元素硫作为氧化剂且没有催化剂的情况下进行。反应以良好至高收率得到各种1,3-二芳基咪唑并[1,5- a ]吡啶。产品显示出在454-524 nm波长范围内的荧光发射。与母体3-单取代的化合物相比,1,3-二芳基咪唑并吡啶的量子产率大大提高。