Facile Syntheses of 2,2-Dimethyl-6-(2-oxoalkyl)-1,3-dioxin-4-ones and the Corresponding 6-Substituted 4-Hydroxy-2-pyrones
作者:Alan R. Katritzky、Zuoquan Wang、Mingyi Wang、C. Dennis Hall、Kazuyuki Suzuki
DOI:10.1021/jo050307m
日期:2005.6.1
A variety of 2,2-dimethyl-6-(2-oxoalkyl)-1,3-dioxin-4-ones 5a-l and the corresponding 6-substituted 4-hydroxy-2-pyrones 3a-l were prepared in high yields under mild reaction conditions by the reaction of 2,2,6-trimethyl-1,3-dioxin-4-one 4 with 1-acylbenzotriazoles 9 in the presence of LDA followed by thermal cyclization of 5a-l to 3a-1. Synthesis of novel 6-(1-benzoylalkyl)-2,2-dimethyl-1,3-dioxin-4-ones 12a-c was achieved by alkylation of dioxinone 5a and their subsequent cyclization gave 5-alkyl-4-hydroxy-2-pyrones 13a-c.
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.
Efficient Conversion of Carboxylic Acids into<i>N</i>-Acylbenzotriazoles<b />
作者:Alan R. Katritzky、Yuming Zhang、Sandeep K. Singh
DOI:10.1055/s-2003-42462
日期:——
An improved one-pot procedure for the preparation of N-acylbenzotriazoles involves mild reaction conditions and allows the preparation of several derivatives not accessible by the previously reported methods.