Iodosulfonation of alkenes with benzenesulfinic acid – N-iodosuccinimide — Facile preparation of α,β-unsaturated sulfones

2006 ◽  
Vol 84 (4) ◽  
pp. 667-675 ◽  
Author(s):  
Russell R Wolff ◽  
Vikram Basava ◽  
Robert M Giuliano ◽  
Walter J Boyko ◽  
J Herman Schauble
Keyword(s):  
Room Temperature ◽  
High Yield ◽  
Allylic Alcohols ◽  
Neutral Alumina ◽  
Silyl Ethers ◽  
Step Procedure ◽  
Ferrier Rearrangement ◽  
Facile Preparation ◽  
High Yields ◽  
Yield And Purity

Reaction of alkenes and alkenols with N-iodosuccinimide (NIS) and benzenesulfinic acid in dichloromethane at room temperature affords vic-iodophenylsulfonyl adducts in good to high yields. Treatment of the iodosulfones with neutral alumina in dichloromethane at room temperature results in dehydroiodination to give the corresponding vinyl sulfones in high yield and purity by this convenient two-step procedure. Application of the iodosulfonation–dehydroiodination sequence to allylic alcohols and silyl ethers gave γ-oxygenated, α,β-unsaturated phenylsulfones, while the attempted iodosulfonation of glycals, as intermediates to vinyl sulfones, resulted in addition of benzenesulfinic acid with double bond shift (Ferrier rearrangement). Key words: iodosulfonation, vinyl sulfones, benzenesulfinic acid, N-iodosuccinimide, dehydroiodination.

scholarly journals Epimerization-free C-term Activation of Peptide Fragments by Ball-Milling

2020 ◽  
Author(s):  
Yves Yeboue ◽  
Marion Jean ◽  
Gilles Subra ◽  
Jean Martinez ◽  
Frédéric Lamaty ◽  
...  
Keyword(s):  
Amino Acids ◽  
Ball Milling ◽  
High Yield ◽  
Coupling Agents ◽  
Peptide Fragment ◽  
Peptide Fragments ◽  
Solution Synthesis ◽  
High Yields ◽  
Synthesis Approach ◽  
Yield And Purity

Ball-milling enabled to perform [2+1], [2+2], and [2+3] peptide couplings with high yields and, if any, very low epimerization. Very good results were obtained with peptide fragments containing highly epimerization-prone and/or highly hindered amino acids at C-term such as phenylglycine, cysteine and valine. Ball-milling was clearly identified as the key element to obtain both high yield and purity along with low epimerization. Indeed, the ball-milling conditions proved to be superior to the classical solution synthesis approach on a various array of widely used coupling agents. These results open avenues for the development of highly efficient, convergent and flexible peptide synthesis strategies based on peptide fragment couplings mediated by ball-milling.

scholarly journals Epimerization-free C-term Activation of Peptide Fragments by Ball-Milling

2020 ◽  
Author(s):  
Yves Yeboue ◽  
Marion Jean ◽  
Gilles Subra ◽  
Jean Martinez ◽  
Frédéric Lamaty ◽  
...  
Keyword(s):  
Amino Acids ◽  
Ball Milling ◽  
High Yield ◽  
Coupling Agents ◽  
Peptide Fragment ◽  
Peptide Fragments ◽  
Solution Synthesis ◽  
High Yields ◽  
Synthesis Approach ◽  
Yield And Purity

Ball-milling enabled to perform [2+1], [2+2], and [2+3] peptide couplings with high yields and, if any, very low epimerization. Very good results were obtained with peptide fragments containing highly epimerization-prone and/or highly hindered amino acids at C-term such as phenylglycine, cysteine and valine. Ball-milling was clearly identified as the key element to obtain both high yield and purity along with low epimerization. Indeed, the ball-milling conditions proved to be superior to the classical solution synthesis approach on a various array of widely used coupling agents. These results open avenues for the development of highly efficient, convergent and flexible peptide synthesis strategies based on peptide fragment couplings mediated by ball-milling.

Reductions with sulfurated borohydrides. V. Reductions of ketones

1970 ◽  
Vol 48 (15) ◽  
pp. 2366-2371 ◽  
Author(s):  
J. M. Lalancette ◽  
A. Freche
Keyword(s):  
High Temperature ◽  
Carbonyl Group ◽  
Sodium Borohydride ◽  
Room Temperature ◽  
High Yield ◽  
High Yields ◽  
Very High

Ketones can be reduced with sulfurated sodium borohydride. Very high yield (≈90%) of the corresponding alcohol is obtained with the appropriate ratio of ketone and hydride at room temperature. The reaction is much influenced by the steric environment around the carbonyl group. At high temperature (65°) disulfides and tetrasulfides are produced. In some cases the structure of those sulfides have been established. Conjugated ketones can be reduced to the corresponding alcohols with very high yields.

Hydrosilylation of alkenes and ketones catalyzed by nickel(II) indenyl complexes

2003 ◽  
Vol 81 (11) ◽  
pp. 1299-1306 ◽  
Author(s):  
Frédéric-Georges Fontaine ◽  
René-Viet Nguyen ◽  
Davit Zargarian
Keyword(s):  
Reaction Mechanism ◽  
Key Words ◽  
Room Temperature ◽  
Active Species ◽  
The Other ◽  
Silyl Ethers ◽  
Cationic Species ◽  
Catalytically Active ◽  
High Yields ◽  
Indenyl Complexes

Abstraction of Cl– from the complexes (indenyl)Ni(PPh3)Cl generates cationic species that are effective precatalysts for the hydrosilylation of some olefins and ketones. For instance, the mixture of (1-Me-indenyl)Ni(PPh3)Cl and NaBPh4 (or methylaluminoxane) reacts at room temperature with ca. 100 equiv. each of PhSiH3 and styrene to produce [1-phenyl-1-ethyl](phenyl)silane, PhCH(CH3)(SiPhH2), in 50%–80% yield. The same system can also catalyze the hydrosilylation of 1-hexene and norbornene, but the products arising from these substrates consist of mixtures of regio- and stereoisomers. On the other hand, ketone hydrosilylation is regiospecific, giving the corresponding silyl ethers in high yields. A number of experimental observations have indicated that the initially generated Ni-based cation is not the catalytically active species. Indeed, the cationic initiators may be replaced by LiAlH4 or AlMe3, which generate the corresponding Ni-H or Ni-Me derivatives, respectively. Moreover, the observed regioselectivity for the addition of PhSiH3 to styrene (i.e., predominant addition of the silyl fragment to the α-C) is opposite of what would be expected if the reaction mechanism involved carbocationic intermediates. A new mechanism is proposed in which the active species is a Ni-H species originating from the transfer of H– from PhSiH3 to the initially generated Ni cation. Key words: hydrosilylation, nickel indenyl complexes, cationic complexes, hydride intermediates.

scholarly journals Facile preparation and isolation of neutral organic electron donors based on 4-dimethylaminopyridine

2018 ◽  
Vol 96 (6) ◽  
pp. 522-525 ◽  
Author(s):  
Julien D. Martin ◽  
C. Adam Dyker
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Inert Atmosphere ◽  
Electron Donors ◽  
High Yield ◽  
Step Procedure ◽  
Organic Electron ◽  
Facile Preparation ◽  
Isolated Neutral

A number of new neutral bis-2-(4-dimethylamino)pyridinylidene electron donors featuring N-akyl groups of varying lengths (propyl, butyl, hexyl, dodecyl) have been prepared from 4-dimethylaminopyridine by means of a simple two-step procedure. Each derivative could be isolated in high yield and could be stored indefinitely under inert atmosphere. The electron donors were chemically oxidized to the corresponding bipyridinium ions, and all compounds were characterized by NMR spectroscopy and cyclic voltammetry. As an emerging class of electron transfer agents, the availability of the isolated neutral bispyridinylidenes should be beneficial for cases that are incompatible with generating the electron donor in situ.

scholarly journals Spectroscopic evaluation of chiral and achiral fluorescent ionic liquids

2010 ◽  
Vol 8 (4) ◽  
pp. 946-952 ◽  
Author(s):  
Hadi Marwani
Keyword(s):  
Ionic Liquids ◽  
Room Temperature ◽  
High Yield ◽  
Gravimetric Analysis ◽  
Chlorpromazine Hydrochloride ◽  
Good Thermal Stability ◽  
Chemical Structures ◽  
Phenanthroline Monohydrate ◽  
Yield And Purity ◽  
Good Agreement

AbstractIn this study, spectroscopic investigation of chiral and achiral room temperature ionic liquids is achieved. New ionic liquids were prepared via metathesis, accomplished by the reaction of either L-phenylalanine ethyl ester hydrochloride, chlorpromazine hydrochloride or 1,10-Phenanthroline monohydrate hydrochloride with lithium bis(trifluoromethane) sulfonamide in water. The resulting ionic liquids were produced in high yield and purity. The results obtained by use of 1H NMR and IR experiments were in very good agreement with the chemical structures of the synthesized ionic liquids. In addition, the results of thermal gravimetric analysis suggested that these ionic liquids have good thermal stability. UV-Vis and fluorescence spectroscopy measurements indicated that these ionic liquids are strongly optically absorbent and fluorescent. Lastly, time-based fluorescence steady-state measurements demonstrated the high photostability of these ionic liquids.

scholarly journals Cyanuric Chloride as an Efficient Catalyst for the Synthesis of 2,3-UnsaturatedO-Glycosides by Ferrier Rearrangement

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Xiaojuan Yang ◽  
Na Li
Keyword(s):  
Room Temperature ◽  
Cyanuric Chloride ◽  
Efficient Catalyst ◽  
Experimental Procedure ◽  
Wide Range ◽  
Ferrier Rearrangement ◽  
High Yields

Cyanuric chloride has been found to be an efficient catalyst for the synthesis of 2,3-unsaturatedO-glycosides from the reaction of 3,4,6-tri-O-acetyl-D-glucal and a wide range of alcohols in dichloromethane at room temperature. The experimental procedure is simple, and the products are obtained in high yields.

scholarly journals Iodination of industrially important aromatic compounds using N-iodosuccinimide by grinding method

2018 ◽  
Vol 7 (6) ◽  
pp. 477-486
Author(s):  
Vivek Sharma ◽  
Priyanka Srivastava ◽  
Santosh Kumar Bhardwaj ◽  
D.D. Agarwal
Keyword(s):  
Gas Chromatography ◽  
Reaction Time ◽  
Solid State ◽  
Aromatic Compounds ◽  
Room Temperature ◽  
High Yield ◽  
Short Reaction Time ◽  
Grinding Method ◽  
High Yields ◽  
Work Up

Abstract Iodination of various industrially and pharmaceutically important substituted aromatics has been achieved using N-iodosuccinimide (NIS) in solid state by grinding at room temperature. This method provides several advantages such as short reaction time (5–8 min), high yields (94–99%), and nonhazardous and simple work-up procedure. High gas chromatography (GC) purity (95–99.9%) suggests that the reaction is highly selective. Substrates which are sensitive to oxidation, viz aniline and phenols are iodinated smoothly in high yield.

Synthesis and Properties of 5-Hydroxymethyl-2′-deoxyuridine and its α-Anomer

1971 ◽  
Vol 49 (5) ◽  
pp. 719-724 ◽  
Author(s):  
V. S. Gupta ◽  
G. L. Bubbar
Keyword(s):  
Absorption Spectra ◽  
Elemental Analysis ◽  
Mercuric Chloride ◽  
Room Temperature ◽  
Major Product ◽  
High Yield ◽  
Crystalline Solid ◽  
Fusion Method ◽  
Excellent Yield ◽  
High Yields

The synthesis and properties of 5-hydroxymethyldeoxyuridine (6) and its α-anomer 7 are described. Treatment of 5-hydroxymethyluracil (2) with trimethylchlorosilane in the presence of triethylamine gave 2,4,5-tris(trimethylsilyl)-5-oxymethyluracil (3) in excellent yield (92%) which, upon condensation with 3,5-di-(O-p-toluoyl)-2-deoxy-D-ribofuranosyl chloride in acetonitrile at room temperature, furnished an anomeric mixture of substituted nucleosides β-anomer (4) and α-anomer (5) in high yield 90% (by a fusion method (12) yield of blocked nucleosides was 70%). Compound 4 was the major product formed by both methods and was recovered as a crystalline solid in high yield. However, condensation of 3 with chlorosugar in benezene with mercuric chloride as a catalyst at room temperature gave a mixture of protected nucleosides; the amount of 5 formed was appreciably higher (34%) and was isolated as a microcrystalline solid from mother liquors in low yield (without the catalyst nucleosides were formed in low yield 30%). Removal of the blocking groups by alcoholysis gave 6 and 7 in high yields. The structure was confirmed by n.m.r. studies, u.v. and i.r. absorption spectra, elemental analysis, and by conversion of 4 to β-thymidine (8).

scholarly journals An Efficient Oxidation of Benzoins to Benzils by Manganese(II) Schiff Base Complexes Using Green Oxidant

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Javad Safari ◽  
Zohre Zarnegar ◽  
Fatemeh Rahimi
Keyword(s):  
Schiff Base ◽  
Catalytic Oxidation ◽  
Room Temperature ◽  
Reaction Times ◽  
Schiff Base Complexes ◽  
High Yield ◽  
Reusable Catalyst ◽  
Simple Method ◽  
Convenient Procedure ◽  
Yield And Purity

A simple, highly efficient and mild catalytic oxidation of benzoins to the corresponding benzils was developed using manganese(II) Schiff base complexes as novel and reusable catalyst in the presence of acetonitrile as solvent and H2O2as green oxidant. This simple method affords benzil derivatives at room temperature in short reaction times with high yield and purity. This convenient procedure will allow a further increase of the diversity within the benzil family.

Sign in / Sign up

Export Citation Format

Share Document