Sodium 2-Cyanoethylene-1,1-dithiolate Tetrahydrate: a Stable Salt of Cyanodithioacetic Acid. A New Preparative Route to 2-Cyanoketene S,S-, S,N- and N,N-Acetals.
作者:Lars Henriksen、Sten C. Hj. Ljunggren、Gitte B. Vaaben、Ali A. El-Emam、Erik B. Pedersen、Claus Nielsen、Shu Hai Zhao、Mauro I. Ciglic、Monika Haugg、Nathalie Trabesinger-Rüf、Elmar G. Weinhold
DOI:10.3891/acta.chem.scand.50-0432
日期:——
2-Cyanoethylene-1,1-dithiolate, the dianion of cyanodithioacetic acid, is prepared from ethyl cyanoacetate by condensation with carbon disulfide followed by hydrolysis and decarboxylation with sodium hydroxide. The anion has been isolated and characterized as a stable, tetrahydrated sodium salt (2) and alkylated to give 3,3-bis(alkylthio)propenonitriles (3) in excellent yields. Alkylation of an intermediate, unstable trianion of 2-cyano-1,1-dithiomalonic acid (4) gives 3,3-bis(methylthio)-2-cyanopropenic acid (6a) which on treatment with mono- and di-alkylamines undergoes consecutive substitution and decarboxylation to 3-amino-3-(methylthio)propenonitriles (7). The application of 1,2-diamines or 2-aminoethanethiol leads to cyclized products, (imidazolidin-2-ylidene) acetonitriles(9) and (1,3-thiazolidin-2-ylidene)acetonitrile (10), respectively.
Efficient and Practical Route to α‐Aminocarbonylketene and α‐Cyanoketene Dithioacetals
作者:Yanbing Yin、Qian Zhang、Qun Liu、Yu Liu、Shaoguang Sun
DOI:10.1080/00397910601131379
日期:2007.3
A Practical Route to 2,3-Di-/1,2,3-Trisubstituted Indolizines from<b> α-</b>EWG Ketene <b><i>S</i></b>,<b><i>S</i></b>-Acetals and Their Application in Bis(1-indolizinyl)methane Synthesis
作者:Qun Liu、Shaoguang Sun、Mang Wang*、Hongxia Deng
DOI:10.1055/s-2008-1032144
日期:2008.2
An easy synthesis of 2,3-di-/1,2,3-trisubstituted indo-l-izines has been developed via a formal [3+2] annulation of α-EWG ketene S, S-acetals with 2-pyridine-/2-quinolinecarbaldehyde. The disubstituted products are formed via an intramolecular aza-Michael- addition and subsequent elimination of acetic acid, followed by desulfenylation- assisted by acetic acid, whereas the trisubstituted products are