Organic Synthesis International by Dr Anthony Melvin Crasto Ph.D, Worlddrugtracker, Million hits on google on all sites, One lakh connections worldwide. Pushing boundaries.Interaction site for Organic chemists worldwide, Mail me at firstname.lastname@example.org if you like me
Green Chem., 2016, Advance Article DOI: 10.1039/C6GC02656G, Communication
Qingshan Tian, Bin Chen, Guozhu Zhang
A stereoselective synthesis of [small beta]-halogenated 2-methylenecyclopentanones via silver-catalyzed formal ring expansion using water as the cosolvent is described.
Silver-initiated radical ring expansion/fluorination of ethynyl cyclobutanols: efficient synthesis of monofluoroethenyl cyclopentanones
State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. China E-mail: email@example.com
Green Chem., 2016, Advance Article
A stereoselective synthesis of β-halogenated 2-methylenecyclopentanones via silver-catalyzed formal ring expansion using water as the cosolvent is described. A variety of 2-methylenecyclopentanones with fluoro, chloro and bromo functionalities are efficiently prepared from 1-alkynyl cyclobutanols. This method offers facile access to halogenated complex molecules which are not only useful chemicals but also valuable building blocks for further derivatizations.
Green Chem., 2016, 18,5769-5772 DOI: 10.1039/C6GC02448C, Communication
Zhichao Lu, Zofia Hetman, Gerald B. Hammond, Bo Xu
By combining reaction work-up and catalyst recovery into a simple filtration procedure we have developed a substantially faster technique for organic synthesis.
By combining reaction work-up and catalyst recovery into a simple filtration procedure we have developed a substantially faster technique for organic synthesis. Our protocol eliminates the time-consuming conventional liquid–liquid extraction and is capable of parallelization and automation. Additionally, it requires only minimal amounts of solvent.
Simultaneous rapid reaction workup and catalyst recovery
. General procedure for a reaction
Step 1. Reaction setup. The reaction is conducted in the
usual way with the supported catalyst. Porelite® (typically 1
mL for every 0.1 gram of product) is added to the reaction
mixture under stirring,
Step 2. Reaction quench and rigid solvent extraction. If
needed, the reaction is quenched with a suitable aqueous
solution (e.g. NaHCO3 solution).
• If the solvent used in the reaction is water-miscible
(eg., DMF, methanol, etc.), a minimum amount of
water immiscible solvent (e.g. 3 mL ether for every
1 g of product) is added to help organic material
become entrenched in Porelite.
• If the reaction is conducted in a water immiscible
solvent (e.g. toluene, DCM), no extra solvent is
needed in most cases.
The excess amount of solvent is removed by rotavapor or by
nitrogen/air purging (no need to remove the water from the
mixture). The reaction mixture is filtered to remove
aqueous-soluble components (starting materials, by-products,
etc.) and washed with water (or HCl or Na2CO3 solution to
remove basic or acidic byproducts. Vacuum is applied to dry
the filtrate for 2 minutes to remove any remaining aqueous
and volatile solvents. (For automatic flash chromatographic
separation, an empty loading cartridge can be used, which
can be directly attached to the commercial system. For
manual chromatographic separation, a regular Büchner
filter can be used).
Step 3. Sample loading to chromatographic system.
• The loading cartridge can be directly attached to the
commercial flash chromatographic system (e.g.,
CombiFlash Rf series).
• For manual chromatographic separation, the
polymer powder is loaded directly onto a manual
flash silica gel column (dry loading).
Because the polymer pad may contain some trapped air, it is recommended to start with the least
polar solvent (e.g., hexane) during chromatographic separation to remove the trapped air.
School of Life Sciences, Institute of Biochemistry and Molecular Biology, Lanzhou University, Lanzhou 730000, P. R. China E-mail: firstname.lastname@example.org
State Key Laboratory of Chiroscience, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, P. R. China E-mail: email@example.com
Green Chem., 2016, Advance Article
We have reported herein a catalyst-free 1,3-dipolar cycloaddition of C,N-cyclic azomethine imines and 3-nitroindoles by which a series of five-ring-fused tetrahydroisoquinolines featuring an indoline scaffold were obtained as single diastereomers in moderate to high yields without any additives under mild conditions. Moreover, the current method provides a novel and convenient approach for the efficient incorporation of two biologically important scaffolds (tetrahydroisoquinoline and indoline).
Register now for the inaugural ACS Industry Symposium, 11-12 November 2016 in Hyderabad, India. Be sure to secure your seat today as rates will increase on 27 October! The theme of the Symposium is Recent Advances in Drug Development. The event will feature lectures by the world's leading researchers and experts in the pharma industry, including:
Dr. Peter Senter of Seattle Genetics
Dr. Jagath Reddy Junutula of Cellerant Therapeutics, Inc.
Dr. Ming-Wei Wang of the Shanghai Institute of Materia Medica, Chinese Academy of Sciences
I am happy to share with you our laboratory recent publication on asymmetric catalysis. This communication deals with the understanding and development of Brønsted Acid-Primary Amine as a Synergistic-catalyst for Stereoselective Asymmetric Barbas [4+2]-cycloaddition reaction by using 2-aminobuta-1,3-diene-catalysis under ambient conditions. I believe this reaction can become good tool for chemists.
I congratulate my co-workers for their hard work to make this work more successful.
(1R,3S,5S)-5-hydroxy-3-methyl-2'-oxospiro[cyclohexane-1,3'-indoline]-2,2-dicarbonitrile (7ag): Prepared by following the
procedure E and purified by column chromatography using EtOAc/hexane and isolated as solid.
Dr. D. B. Ramchary, Ph.D. Associate Professor School of Chemistry University of Hyderabad Prof. C. R. Rao Road, Gachibowli Hyderabad, 500046, India Tel: 0091-40-23134816 Email: firstname.lastname@example.org
Ramachary obtained his Masters degree (General Chemistry) at the University of Hyderabad in 1996. There as part of curricula he studied and actively involved in the project, entitled Synthesis and Utilization of Aromatic Radical Anions for Reduction of Carbon Monoxide (with Prof. M. Periasamy).
Ramachary obtained his Doctoral degree (Organic Synthesis) at the Indian Institute of Science, Bangalore for his research work on Total Synthesis of Sesquiterpenes Containing Three Contiguous Quaternary Carbon Atoms (with Prof. A. Srikrishna).
In January 2002, he moved to Prof. Carlos F. Barabas III research group as Skaggs Post Doctoral fellow at The Scripps Research Institute, San Diego. After three year post doctoral studies at TSRI, he then joined as Faculty member in School of Chemistry, University of Hyderabad in Jan 2005, where at present he is a Reader.
Dr Ramachary has been awarded the INSA Medal for Young Scientists in Chemical Sciences for the year 2006 for his outstanding contributions to the emerging area of asymmetric organocatalysis.
The main focus of his research group is to engineer the novel and green asymmetric cascade and multi-component reactions (MCRs) to generate the biologically important molecules and natural products in a single step via emerging chiral amines or amino acid-catalysis.
His research group is actively engaged in the design and synthesis of novel enzyme mimetic small organic amines and amino acids to catalyze the fundamental organic reactions in enantioselective manner.
His interest about inquisitive questions like how small can be highly active and stereo-selective catalysts and what are the minimal functional and structural features required in a chiral catalyst had made him to venture in the most advanced versions of synthetic chemistry.
Significant Publications: D. B. Ramachary, M. Kishor and Y. Vijayendar Reddy, Development of Pharmaceutical Drugs, Drug Intermediates and Ingredients by Using Direct Organo-Click Reactions, Eur. J. Org. Chem., 2007, xxxx-xxxx (DOI: 10.1002/ejoc.200701014).
D. B. Ramachary, G. Babul Reddy and Rumpa Mondal, New Organocatalyst for Friedel-Crafts Alkylation of 2-Naphthols with Isatins: Application of an Organo-Click Strategy for the Cascade Synthesis of Highly Functionalized Molecules, Tetrahedron Lett., 2007, 48, 7618-7623.
D. B. Ramachary and M. Kishor, Organocatalytic Sequential One-Pot Double Cascade Asymmetric Synthesis of Wieland-Miescher Ketone Analogs from a Knoevenagel/Hydrogenation/Robinson Annulation Sequence: Scope and Applications of Organocatalytic Bio-Mimetic Reductions, J. Org. Chem., 2007, 72, 5056-5068.
D. B. Ramachary, K. Ramakumar and V. V. Narayana, Organocatalytic Cascade Reactions Based on Push-Pull Dienamine Platform: Synthesis of Highly Substituted Anilines, J. Org. Chem., 2007, 72, 1458-1463.
D. B. Ramachary and G. Babul Reddy, Towards Organo-Click Reactions: Development of Pharmaceutical Ingredients by Using Direct Organocatalytic Bio-Mimetic Reductions, Org. Biomol. Chem., 2006, 4, 4463-4468.
D. B. Ramachary and Rumpa Mondal, Direct Organocatalytic Hydroalkoxylation of a,b-Unsaturated Ketones, Tetrahedron Lett., 2006, 47, 7689-7693.
Jorly Joseph, D. B. Ramachary, Eluvathingal D. Jemmis, Electrostatic Repulsion as an additional Selectivity Factor in Asymmetric Proline Catalysis, Org. Biomol. Chem., 2006, 4, 2685-2689.
D. B. Ramachary, M. Kishor and G. Babul Reddy, Development of Drug Intermediates by Using Direct Organocatalytic Multi-Component Reactions, Org. Biomol. Chem., 2006, 4, 1641-1646.
D. B. Ramachary, M. Kishor and K. Ramakumar, A Novel and Green Protocol for Two-Carbon Homologation: A Direct Amino Acid/K2CO3-Catalyzed Four-Component Reaction of Aldehydes, Active Methylenes, Hantzsch Esters and Alkyl Halides, Tetrahedron Lett., 2006, 47, 651-656.
D. B. Ramachary, K. Ramakumar and M. Kishor, Direct Organocatalytic in situ Generation of Novel Push-Pull Dienamines: Application in Tandem Claisen-Schmidt/Iso-Aromatization Reactions, Tetrahedron Lett., 2005, 46, 7037-7042.
D. B. Ramachary and Carlos F. Barbas III, Direct Amino Acid-Catalyzed Asymmetric Desymmetrization of meso-Compounds: Tandem Aminoxylation/O-N Bond Heterolysis Reactions, Org. Lett., 2005, 7, 1577-1580.
D. B. Ramachary, Naidu S. Chowdari and Carlos F. Barbas III, Organocatalytic Asymmetric Domino Knoevenagel/Diels-Alder Reactions: A Bioorganic Approach to the Diastereospecific and Enantioselective Construction of Highly Substituted Spiro[5,5]undecane-1,5,9-triones, Angew. Chem. Int. Ed., 2003, 42, 4233-4237.
Molybdenum- and tungsten-based olefin metathesis catalysts have demonstrated excellent results in the control of cis (Z-) selectivity as well as enantioselectivity. However, their air and moisture sensitivity, which requires the use of a glovebox, has prevented their more widespread use by organic chemists. Now we report on developed, preweighed Mo catalysts formulated in paraffin tablets. The significantly improved air stability, high homogeneity, and uniformity of the pellets allow researchers to carry out reactions on the bench avoiding the need of a glovebox. The two different Mo-based complexes which were packed into tablets are XiMoPac-Mo001 (1) that can be used to achieve endo-selective enyne ring-closing metathesis (RCM) reactions, interalia; and XiMoPac-Mo003 (2) which was reported among the best catalysts to promote Z-selective cross-metathesis. For the evaluation of the wax-protected catalysts commonly used, highly reproducible robust model reactions were chosen: homo cross-metathesis (HCM) of functionalized (e.g., methyl 9-decenoate) and unfunctionalized (allylbenzene) terminal olefins, and ring closing metathesis (RCM) of diethyl diallylmalonate. The yields and conversions were comparable with those which can be achieved in glovebox with nonformulated catalysts. Exposure to air did not cause any significant reduction in conversion while the product selectivity (targeted product vs homologues derived from double bond isomerization) remained high. In contrast, exposure to air caused a measurable drop in the conversion with the nonprotected catalyst. Furthermore, the formulated catalysts remained unaffected even after 4 h of exposure to air, showing its enhanced air stability. In conclusion, these commercially available air-stable Mo-catalyst tablets allow the reactions to be accomplished using ordinary Schlenk techniques, and hence simplify catalyst handling in pilot laboratories and plants.
From Box to Bench: Air-Stable Molybdenum Catalyst Tablets for Everyday Use in Olefin Metathesis