Feb 09, 2012 · Pioneers in this field, Bolm et al., reported that the asymmetric aldol reaction under solventfree conditions and alyzed by (S)proline (10 mol%) in a ball mill, employing a : 1 ketone/aldehyde ratio, proceeded efficiently to give selectively the antialdol diastereomeric products in high yields and with up to 99% enantiomeric excess ...
Green procedure for highly efficient, rapid synthesis of imidazo[1,2a]pyridine and its late stage functionalization ... Nanoparticles Catalyzed Regioselective Synthesis of Some Novel Substituted Spirooxindoles via One Pot Multicomponent Reaction in a Ball Mill: A Step Towards Green and Sustainable Chemistry: ... New and effective prolinebased ...
A Highly Efficient SolventFree Asymmetric Direct Aldol Reaction Organoalyzed by Recoverable (s)BinamLProlinamides. ... and ball mill technique. These procedures allow one to reduce not only the amount of required ketone to 2 equiv but also the reaction time to give the aldol products with regio, diastereo, and enantioselectivities ...
Dec 02, 2014 · (2011) Efficient ballmill procedure in the 'green' asymmetric aldol reaction organoalyzed by (S)prolinecontaining dipeptides in the presence of water. Tetrahedron 67 ( 36 ): 6953 – 6959 OpenUrl CrossRef
Dear Colleagues, This issue of the Annual Review of the Boreskov. Institute of Catalysis, BIC, is appearing at the very. important time for the Institute: the Institute celebrates at. the year 2008 its 50th anniversary. However, the issue. covers the BIC's activity in the main fields of its. academic and RD activities during the year 2007 and
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[23] Hernández, Juaristi E., Efficient ballmill procedure inthe 'green' asymmetric aldol reaction organoalyzed by(S)prolinecontaining dipeptides in the presence of water,Tetrahedron, 2011, 67, .
Dec 31, 2019 · A green method has been developed for the synthesis of N arylsulfonylhydrazones via a simple grindstone procedure. By grinding mixtures of benzensulfonyl hydrazides and a series of aryl aldehydes or ketones in the mortar using Ltyrosine as alyst, 24 N arylsulfonylhydrazones were synthesized in a few minutes with high .
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Mar 07, 2018 · Pioneering investigations of mechanochemical (S)prolinealyzed asymmetric aldol reactions were carried out by Bolm and coworkers, affording antialdol products in high yield and with up to 99% ee . 56 When comparing the reaction of 4nitrobenzaldehyde 21 with tetrahydrothiopyran4one 22 to analogous solution reactions, a higher yield was ...
Click Chemistry AzideAlkyne Cycloaddition "Click Chemistry" is a term that was introduced by K. B. Sharpless in 2001 to describe reactions that are high yielding, wide in scope, create only byproducts that can be removed without chromatography, are stereospecific, simple to perform, and can be conducted in easily removable or benign solvents.
The samples were used as basic alysts for aldol condensation of furfural and acetone studied in a batch reactor at 100°C, autogenous pressure and a reaction time of 2h. To establish a relationship between physicochemical properties and alytic behavior of BEA zeolites, the samples were characterized by XRD, N2 adsorption, FTIR ...
May 24, 2018 · Ball milling pretreatment of oil palm biomass for enhancing enzymatic hydrolysis.. PubMed. Zakaria, Mohd Rafein; Fujimoto, Shinji; Hirata, Satoshi; Hassan, Mohd Ali. . Oil palm biomass, namely empty fruit bunch and frond fiber, were pretreated using a planetary ball sizes and crystallinity index values of the oil palm biomass were significantly .
Chapter 5, 'Cross Dehydrogenative Coupling Reactions by Ball Milling' by Jingbo Yu, Zhijiang Jiang and Weike Su (Zhejiang University of Technology, China) confirms how ball milling can promote cross dehydrogenative coupling (CDC) and asymmetric CDC reactions. This method efficiently provides C–C bonds directly from C–H bonds.
Jul 04, 2008 · Three different methods are assayed: simple conventional magnetic stirring, magnetic stirring after previous dissolution in THF and evaporation, and ball mill technique. These procedures allow one to reduce not only the amount of required ketone to 2 equiv but also the reaction time to give the aldol products with regio, diastereo, and ...
50 General bromination experimental procedure: Substrate (1 mmol), NBS ( g) and MCM41SO 3 H ( g) were added to a ballmill jar. Reaction was conducted at a rotational frequency of 30 Hz at room temperature and the reaction was followed by TLC. After completion, the mixture was separated and MCM41SO 3 H was recovered.
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BINAMprolinamides are very efficient alyst for the synthesis of nonprotected and Nbenzyl isatin derivatives by using an aldol reaction between ketones and isatins under solventfree conditions. The results in terms of diastereo and enantioselectivities are good, up to 99% de and 97% ee, and higher to those previously reported in the literature under similar reaction .
Machuca, E.; Juaristi, E. Organoalytic activity of α,αdipeptide derivatives of (S)proline in the asymmetric aldol reaction in absence of solvent. Evidence for noncovalent p–p interactions in the transition state. Tetrahedron Lett., 2015, 56, .
Jan 01, 2015 · With the aim of developing sustainable enantioselective reactions, the organoalytic activity of three proline‐based α,β‐dipeptides was evaluated in the asymmetric aldol reaction between cyclohexanone and 4‐nitrobenzaldehyde according to three contrasting experimental protocols: (1) solvent‐free, under high‐speed ball milling (HSBM) activation, (2) .
Highyielding asymmetric synthesis of bioactive and natural products through mild alysis is an efficient approach in reaction engineering. In the early days, synthetic chemists mainly focused on the synthesis of complex molecules, with less attention on the reaction efficiency and ecofriendly conditions.
132. Hernández, Juaristi E. Efficient ballmill procedure in the 'green' asymmetric aldol reaction organoalyzed by (S)prolinecontaining dipeptides in the presence of water// Tetrahedron Lett., 2011, Vol. 67, № 36, P. 133.
The first example of the asymmetric direct aldol reaction alyzed by heterobimetallic complexes was reported by Shibasaki and coworkers (6, 7).Cited by. Polyleucines of various lengths act as enantioselective alysts in the aldol condensation between cyclohexanone and a series of aromatic aldehydes, a reaction which.
Feb 17, 2017 · The organoalytic activity of the methyl ester of (S)proline(S)phenylalanine, (S,S)2, in the asymmetric aldol reaction between cyclohexanone and acetone with various aromatic aldehydes under solventfree conditions in a ball mill has been evaluated. α,αDipeptide (S,S)2 alyzed the stereoselective formation of the expected aldol ...
The recent advances on green and sustainable organoalysis are revised in this chapter. An important focus on one of the 12 principles of green chemistry, organoalysis pursues to reduce energy consumption as well as to optimize the use of different resources, targeting to become a sustainable strategy in organic chemical transformations.
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