Synthesis of highly functionalized 2,2'-bipyridines by cyclocondensation of β-ketoenamides – scope and limitations
作者:Paul Hommes、Hans-Ulrich Reissig
DOI:10.3762/bjoc.12.112
日期:——
The scope of a flexible route to unsymmetrically functionalized bipyridines is described. Starting from 1,3-diketones 1a-e, the corresponding beta-ketoenamines 2a-e were converted into different beta-ketoenamides 3a-g by N-acylation with 2-pyridinecarboxylic acid derivatives. These beta-ketoenamides were treated with a mixture of TMSOTf and Hunig's base to promote the cyclocondensation to 4-hydroxypyridine
<i>N</i>-Acylbenzotriazoles: Neutral Acylating Reagents for the Preparation of Primary, Secondary, and Tertiary Amides
作者:Alan R. Katritzky、Hai-Ying He、Kazuyuki Suzuki
DOI:10.1021/jo000792f
日期:2000.12.1
Readily available N-acylbenzotriazoles 2a-q efficiently acylate aqueous ammonia and primary and secondaryamines to give primary, secondary, and tertiary amides in good to excellent yields. The wide applicability of the procedure is illustrated by the preparation of (i) alpha-hydroxyamides from alpha-hydroxy acids and of (ii) perfluoroalkylated amides.
Efficient Conversions of Carboxylic Acids into<i>O</i>-Alkyl,<i>N</i>-Alkyl and<i>O</i>,<i>N</i>-Dialkylhydroxamic Acids
作者:Alan R. Katritzky、Nataliya Kirichenko、Boris V. Rogovoy
DOI:10.1055/s-2003-42488
日期:——
Carboxylic acids were conveniently converted into unsubstituted, N-alkyl-, O-alkyl-, and O,N-dialkylhydroxamic acids via acylbenzotriazole intermediates. The ready availability of the reagents, mild conditions, and easy handling of the intermediates are advantageous.
Preparation of <i>β</i>-Keto Esters and <i>β</i>-Diketones by C-Acylation/Deacetylation of Acetoacetic Esters and Acetonyl Ketones with 1-Acylbenzotriazoles
作者:Alan R. Katritzky、Zuoquan Wang、Mingyi Wang、Chavon R. Wilkerson、C. Dennis Hall、Novruz G. Akhmedov
DOI:10.1021/jo049274l
日期:2004.10.1
Acyl-, aroyl-, and heteroaroyl-acetic esters 6a−f and 8a−l are prepared by reactions of 1-acylbenzotriazoles 1a−k with acetoacetic esters 5 or 7a,b in the presence of sodium hydride followed by regioselective deacetylation. Similar C-acylation/deacetylation of acetylacetone and benzoylacetone affords β-diketones 10a−d and 13a−c, respectively.