First Synthetic Method for the Preparation of 6-Unsubstituted-2,3-dihydro-1,3-oxazin-4-ones
摘要:
The first synthetic pathway to synthesize 6-unsubstituted-2,3-dihydro-1,3-oxazin-4-ones is described. The alpha-formylation of the starting amide and the cyclization of the alpha-formylamide with a desired aldehyde under acidic conditions gave compounds 5a-h (R = nPr, iPr, cPr, cHex, Ph, CH(2)Ph, nHex, and R(1) = H, Me). This strategy was used with little modification for the preparation of new monocyclic organic nitrates such as 2a-c (2a (R = Ph, R(1) = H, and R(2) = H), 2b (R = Ph, R(1) = H, and R(2) = Me), and 2c (R = H, R(1) = Ph, and R(2) = H).
已开发出一种铜 (II)/HOBt 催化合成二肽和“一般”酰胺的方法,使用微波辐射可显着加速反应。作为使用传统羧酸活化的替代方法,该方法依赖于使用 N-酰基咪唑作为活化的氨基伙伴。通过这样做,通过具有挑战性且研究较少的 N → C 方向合成,提出了一种非常规的方法来获得二肽和酰胺。已成功合成了一系列二肽和“通用”酰胺,并且该方法的适用性已在克级合成中得到说明。所提出的温和反应条件完全适合在敏感氨基酸存在下进行偶联,从而提供没有可检测到的外消旋作用的产物。此外,
Synthesis of Carboxamides by LDA-Catalyzed Haller−Bauer and Cannizzaro Reactions
作者:Kazuaki Ishihara、Takayuki Yano
DOI:10.1021/ol0494459
日期:2004.6.1
direct synthesis of N-alkylcarboxamides and N,N-dialkylcarboxamides by Haller-Bauer (HB) and Cannizzaro-type reactions has been realized. LithiumN,N-diisopropylamide (LDA) catalyst was successfully used in not only the HB reaction of benzylic ketones with lithium N-alkylamides to give the corresponding carboxamides and hydrocarbons but also in the Cannizzaro-type reaction of aldehydes with lithium N-alkylamides
N-Heterocyclic carbene-based well-defined ruthenium hydride complexes for direct amide synthesis from alcohols and amines under base-free conditions
作者:Kunsoon Kim、Byungjoon Kang、Soon Hyeok Hong
DOI:10.1016/j.tet.2015.02.016
日期:2015.7
carbene-based ruthenium(II) hydride complexes were developed for amidesynthesisfromalcohols and amines under base-free conditions. Diverse amides were synthesized in fair-to-excellent yields. In the case of secondary amines, where direct dehydrogenative amidation is not feasible, a catalytic amount of a base was required to promote the transamidation of esters, which are byproducts of alcohol dimerization
Catalytic Chemical Amide Synthesis at Room Temperature: One More Step Toward Peptide Synthesis
作者:Tharwat Mohy El Dine、William Erb、Yohann Berhault、Jacques Rouden、Jérôme Blanchet
DOI:10.1021/acs.joc.5b00378
日期:2015.5.1
An efficient method has been developed for direct amide bond synthesis between carboxylic acids and amines via (2-(thiophen-2-ylmethyl)phenyl)boronic acid as a highly active bench-stable catalyst. This catalyst was found to be very effective at room temperature for a large range of substrates with slightly higher temperatures required for challenging ones. This methodology can be applied to aliphatic
The formation of amides through the in situactivation of carboxylicacids with [Et2NSF2]BF4 is presented. A wide range of carboxylicacids and amines were used to produce the corresponding amides in up to 99 % yield. The reaction of hindered amines was also possible in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) under slightly modified conditions. An enantiopure carboxylicacid and amine