18268-10-5Relevant academic research and scientific papers
Graphene oxide (GO)-catalyzed chemoselective thioacetalization of aldehydes under solvent-free conditions
Roy, Babli,Sengupta, Debasish,Basu, Basudeb
, p. 6596 - 6600 (2014)
An efficient method for the synthesis of open chain, cyclic, and unsymmetrical dithioacetals from aryl/hetero-aryl/aliphatic aldehydes is described. The reaction is performed using graphene oxide (GO) as the catalyst under solvent-free and aerobic conditions. High chemoselectivity is observed in the reaction as aryl/alkyl ketones do not give thioketals under the condition.
Facile construction of densely functionalized 4H-chromenes via three-component reactions catalyzed by l-proline
Li, Minghao,Zhang, Biao,Gu, Yanlong
supporting information, p. 2421 - 2428 (2013/02/21)
Three-component reactions of salicylaldehydes, 1,3-cyclohexanediones and a sulfur, carbon, or nitrogen-based nucleophile were developed, for the first time, by using l-proline as a catalyst, which generated various substituted 4H-chromene derivatives in good to excellent yields. The reactions were performed in ethanol under mild and metal-free conditions. In these reactions, the use of l-proline as a catalyst was proven to be key for rendering the reactions possible because replacing l-proline with other acids or bases resulted in the generation of many side products. Many nucleophiles, such as thiophenols, mercaptans, indoles, sulfinic acid, benzotriazole, 2-naphthol, 5-methyl-2-phenyl-1,2-dihydropyrazol-3-one, 6-aminouracil, 6-amino-1,3-dimethyl- 1,2,3,4-tetrahydropyrimidine-2,4-dione and some commonly used C-H acids including 4-hydroxycoumarin, 2-hydroxy-1,4-naphthoquinone and barbituric acid could be successively used to assemble with dimedone and salicylaldehyde. Particularly, the product generated from the reaction of benzotriazole, 3-methoxysalicylaldehyde and dimedone can also be used as a starting material, in which the fragment of benzotriazole acts as a leaving group, for the synthesis of some important compounds by reacting with many carbon-based nucleophiles, such as dibenzoylmethane, ethyl benzoylacetate, 1,3-cyclohexanedione, N,N-dimethylaniline, 2-methylfuran and sesamol in acidic conditions. This offers a complementary route to access some 4H-chromenes that cannot be attained with the above-mentioned three-component reactions.
Alkylidenation of esters on solid support and traceless synthesis of 2- substituted benzofurans
Guthrie, Emma J.,MacRitchie, Jackie,Hartley, Richard C.
, p. 4987 - 4990 (2007/10/03)
Polymer-supported esters are smoothly converted into enol ethers using a titanocene alkylidene prepared by treatment of 2-tert- butyldimethylsilyloxybenzaldehyde diphenyldithioacetal with the low valent titanium species Cp2Ti[P(OEt)3]2. Treatment of the enol ethers with acid leads to the release of ketones from the Wang resin in high yield. Traceless solid-phase synthesis of 2-substituted benzofurans is achieved in a three- step termination procedure. (C) 2000 Published by Elsevier Science Ltd.
