Aza-Wittig Reaction of N-Vinylic Phosphazenes with Carbonyl Compounds. Azadiene-Mediated Synthesis of Isoquinolines and 5,6-Dihydro-2H-1,3-oxazines
摘要:
N-Vinylic phosphazenes 4 are obtained by reaction of phosphorus ylide 5 and nitriles 6. Aza-Wittig reaction of phosphazenes 4 with aldehydes leads to the formation of 2-azadienes 1, which are easily converted into isoquinolines 2. Reaction of conjugated phosphazenes 4 with ethyl glyoxalate affords 5,6-dihydro-2H-1,3-oxazines 9 in a regio- and stereoselective fashion, while heterodienes 1 react with ethyl glyoxalate and diethyl ketomalonate giving 1,3-oxazines 11 and 12.
Preparation of 3-(Fluoroalkyl)-2-azadienes and Its Application in the Synthesis of (Fluoroalkyl)isoquinoline and -pyridine Derivatives
作者:Francisco Palacios、Concepción Alonso、Marta Rodríguez、Eduardo Martínez de Marigorta、Gloria Rubiales
DOI:10.1002/ejoc.200400770
日期:2005.5
A method for the preparation of 3-(fluoroalkyl)-substituted 2-azabutadienes 5 by aza-Wittig reaction of N-vinylic 3-(fluoroalkyl)phosphazenes 4 and aldehydes is reported. Thermal 6π-electrocyclization of these azadienes gives 3-(fluoroalkyl)-substituted isoquinolines 6. Also [4+2] cycloaddition of these heterodienes 5 with enamine 8 gives fluoroalkyl-substituted pyridine derivatives 10–16. However,
Aza-Wittig reaction of fluoroalkylated N-vinylic phosphazenes with carbonyl compounds. Usefulness of 2-azadienes for the preparation of fluoroalkyl pyridine derivatives
A method for the preparation of 3-fluoroalkyl substituted 2-aza-butadienes 6 by aza-Wittig reaction of 3-fluoroalkyl-N-vinylic phosphazenes 4 and aldehydes 5 is reported. [4+2] Cycloaddition reaction of these heterodienes 6 with enamines 9 gives fluoroalkyl substituted pyridine 15, 16, 24–27 and isoquinoline 12–14, 20 derivatives.
CN-assisted oxidative cyclization of cyano cinnamates and styrene derivatives: a facile entry to 3-substituted chiral phthalides
作者:R. Santhosh Reddy、I. N. Chaithanya Kiran、Arumugam Sudalai
DOI:10.1039/c2ob25409c
日期:——
of o-cyano cinnamates and styrene derivatives leads to efficient construction of chiralphthalide frameworks in high optical purities. This unique reaction is characterized by unusual synergism between CN and osmate groups resulting in rate enhancement of the AD process. The method is amply demonstrated by the synthesis and the structural/stereochemical assignment of the natural products.
[EN] IMPROVED PROCESS FOR THE MANUFACTURE OF 1,2-DISUBSTITUTED HEXAHYDROPYRIDAZINE-3-CARBOXYLIC ACIDS AND ESTERS THEREOF<br/>[FR] PROCEDE AMELIORE DE FABRICATION D'ACIDES HEXAHYDROPYRIDAZINE-3-CARBOXYLIQUES 1,2-DISUBSTITUES ET LEURS ESTERS
申请人:HONEYWELL SPECIALTY CHEMICALS
公开号:WO2005028449A1
公开(公告)日:2005-03-31
The invention relates to an improved process for the manufacture of 1,2-disubstituted hexahydro-pyridazine-3-carboxylic acids and esters thereof by reacting N,N’-disubstituted hydrazine with 2,5-dihalogenated valeric acids and thereof by means of phase transfer catalysis. Said pyridazine carboxylic acids and esters thereof can be used as intermediates for the production of pharmaceutical products
Process for the preparation cyano carboxylic acid esters
申请人:Lonza Ltd
公开号:EP2455365A1
公开(公告)日:2012-05-23
The present invention relates to a process for the preparation of a cyano carboxylic acid ester of the formula
wherein
R1 is a linear or branched C1-8 alkanediyl group; and R2 is a linear or branched alkyl group, a cycloalkyl group, or an aryl or arylalkyl group, wherein aryl is optionally substituted with one or more C1-8 alkyl groups; comprising reacting a halo carboxylic acid ester of the formula
wherein R1 and R2 are as defined above; and Hal is fluorine, chlorine, bromine or iodine;
in a reaction mixture comprising a homogeneous liquid phase, wherein the liquid phase consists of water and an organic solvent,
with an alkali metal cyanide in the presence of hydrogen cyanide, optionally in the presence of a catalyst, to obtain the cyano carboxylic acid ester of the formula (I).