Synthesis of Secondary Amides from<i>N</i>-Substituted Amidines by Tandem Oxidative Rearrangement and Isocyanate Elimination
作者:Pradip Debnath、Mattijs Baeten、Nicolas Lefèvre、Stijn Van Daele、Bert U. W. Maes
DOI:10.1002/adsc.201400648
日期:2015.1.12
The periodinane reagents are obtained from the commercially available phenyliodine(III) diacetate [PhI(OAc)2, (PIDA)] by ligand exchange with carboxylic acids. The N‐substituted amidine substrates are easily synthesized from readily available nitriles. The method is applicable for secondary amide synthesis, based on both aliphatic and (hetero)aromatic amines, including challenging amides consisting
Chemoselective synthesis of 5,4′-imidazolinyl spirobarbiturates <i>via</i> NBS-promoted cyclization of unsaturated barbiturates and amidines
作者:Hui Xu、Rong-Lu Huang、Zhu Shu、Ran Hong、Ze Zhang
DOI:10.1039/d1ob00508a
日期:——
A selective cyclization of unsaturated barbiturates and amidines promoted by N-bromosuccinimide has been successfully developed to afford a vast variety of 5,4′-imidazolinyl spirobarbiturates in moderate to good yields. The present protocol features broad substrate scope, facile work-up procedure and mild reaction conditions, providing a novel strategy for the highly selective and efficient construction
Compounds of the invention, such as compounds of Formulae IIa, IIb, IIc or IId, and pharmaceutically acceptable salts, isomers, and prodrugs thereof, are useful as modulators of the activity of liver X receptors, where R
1
, R
2
, R
21
, R
3
and G are defined herein. Pharmaceutical compositions containing the compounds and methods of using the compounds are also disclosed.
Methods for the batch scale up of DABAL-Me-3 promoted direct ester to amide synthesis have been demonstrated at 10-100 g scales using a tert-amide model compound. Procedures for 20 g scale couplings in standard laboratory glassware and up to 0.1 kg in industry-standard jacketed glass reactors in near quantitative yields are given. A derivative of the anticancer agent Imatinib (Gleevec) has been synthesized on a 26 g scale (98% yield, >98% purity) establishing DABAL-Me-3 as a potential alternative for the synthesis of amides in API scale preparations. Continuous flow methodology provides a method for larger scales (productivities of >50 g h(-1)). In addition, nitriles were coupled to primary amines and hydrazines with DABAL-Me-3, resulting in the clean formation of free amidines (16 examples) and amidrazones.
Base-promoted formal [4 + 1+1] annulation of aldehyde, N -benzyl amidine and DMSO toward 2,4,6-triaryl pyrimidines
A base-promoted formal [4 + 1+1] annulation of aldehyde, N-benzyl amidine and DMSO was developed, leading to a series of 2,4,6-triaryl pyrimidines in moderate to good yields. Notably, DMSO served as a methine source, which was activated by base rather than either Lewis acid or electrophile. Molecular O-2 was the sole eco-friendly oxidant during this procedure. (C) 2017 Published by Elsevier Ltd.