Phosphorus in organic synthesis—XI Amino acids and peptides—XXI
作者:T. Shioiri、Y. Yokoyama、Y. Kasai、S. Yamada
DOI:10.1016/0040-4020(76)85134-4
日期:——
Diethyl phosphorocyanidate(DEPC) reacts with carboxylic acids in the presence of triethylamine leading to transient formation of acyl cyanides, but in presence of alcohols or amines, carboxylic esters or amides are produced. DEPC is especially effective for the synthesis of amides and peptides, and showed a satisfactory result on the Young racemization test.
Sulfated tungstate: a highly efficient catalyst for transamidation of carboxamides with amines
作者:Sagar P. Pathare、Ashish Kumar H. Jain、Krishnacharya G. Akamanchi
DOI:10.1039/c3ra00127j
日期:——
An environmentally benign protocol for the transamidation of carboxamides with amines using sulfated tungstate, as a heterogeneous catalyst, has been developed. The method has been successfully applied to the synthesis of a wide range of aromatic and aliphatic amides and phthalimides. Efficient transformation, mild reaction conditions, easy product isolation and the potential reusability of the catalyst
catalyst towards amidation of a wide range of alcohols with amines. Three newair-stable Ruthenium(II) complexes bearing bis-phenolate-N-heterocyclic carbene ligand were synthesized and characterized by FT-IR, NMR and ESI-Mass. The catalytic study of these complexes towards amidation of alcohol with amines was conducted. This new protocol is effective for many electronically diverse alcohols and amines
本贡献描述了由双酚盐-N-杂环卡宾[ t Bu(OCO)2- ](NHC)类型的三齿钳状配体支持的一族坚固的钌配合物的合成和表征。通过咪唑啉鎓配体(HL)与金属前体[RuHCl(CO)(EPh 3)2(B)的反应,以高收率合成了带有双酚盐-N-杂环卡宾配体的钌(II)配合物(1-3)。 ](E = P或As; B = PPh 3,AsPh 3或Py)从相应的银卡宾络合物中进行金属转移。所有的Ru(II)-NHC配合物均已通过元素分析,光谱方法以及ESI质谱进行了表征。根据光谱结果,为所有配合物分配了八面体几何形状。t Bu(OCO)2-配体的三齿性质以及t Bu基团提供的一定水平的空间保护可合理化本系统中Ru-C卡宾键的出色稳定性。此外,为了探索合成化合物的催化潜力,所有三种[Ru-NHC]配合物(1-3)被用作乙醇与胺酰胺化的催化剂。值得注意的是,发现配合物1对于将多种醇与胺酰胺化是非常有效和通用的催化剂。
<i>N</i>,<i>N</i>′-Carbonyldi[2(3<i>H</i>)-benzoxazolethione]: New, Reactive Condensing Agent for the Synthesis of Amides, Esters, Peptides, and Polyamides
作者:Mitsuru Ueda、Naomi Kawaharasaki、Yoshio Imai
DOI:10.1246/bcsj.57.85
日期:1984.1
N′-carbonyldi[2(3H)-benzoxazolethione] (3), was readily prepared by the reaction of 2-benzoxazolethiol and trichloromethyl chloroformate in benzene. The condensing agent 3 is shown to be useful for the preparation of amides, esters, and dipeptides under mild conditions. A successful polyamide synthesis by the polycondensation of isophthalic acid with diamines using 3 is also described.
C–N Coupling of Amides with Alcohols Catalyzed by N-Heterocyclic Carbene–Phosphine Iridium Complexes
作者:Sutthichat Kerdphon、Xu Quan、Vijay Singh Parihar、Pher G. Andersson
DOI:10.1021/acs.joc.5b01324
日期:2015.11.20
N-Heterocycliccarbene–phosphineiridiumcomplexes (NHC–Ir) were developed/found to be a highly reactive catalyst for N-monoalkylation of amides with alcohols via hydrogen transfer. The reaction produced the desired product in high isolated yields using a wide range of substrates with low catalyst loading and short reaction times.