Reactions of enantiopure cyclic diols with sulfuryl chloride

2014 ◽  
Vol 12 (13) ◽  
pp. 2128-2136 ◽  
Author(s):  
Derek R. Boyd ◽  
Narain D. Sharma ◽  
Magdalena Kaik ◽  
Peter B. A. McIntyre ◽  
John F. Malone ◽  
...  
Keyword(s):  
Sulfuryl Chloride ◽  
Reaction Conditions ◽  
Cyclic Sulfates

Monocyclic allyliccis-1,2-diols on reaction with sulfuryl chloride can either give thetrans-2-chloro-1-sulfochloridates or the cyclic sulfates depending on the reaction conditions. The former compounds can be hydrolysed totrans-1,2 chlorohydrins.

REACTIONS OF SUGAR CHLOROSULFATES: VII. SOME CONFORMATIONAL ASPECTS

1966 ◽  
Vol 44 (13) ◽  
pp. 1483-1491 ◽  
Author(s):  
A. G. Cottrell ◽  
E. Buncel ◽  
J. K. N. Jones
Keyword(s):  
Transition State ◽  
Sulfuryl Chloride ◽  
Reaction Conditions ◽  
Steric Interactions

The reaction of sulfuryl chloride with several 1,6-anhydro-hexosans has yielded crystalline, fully chlorosulfated derivatives. Replacement of the chlorosulfate moieties by chlorodeoxy groups could not be achieved under the reaction conditions employed. This non-reactivity is discussed in terms of steric interactions in the transition state for substitution.An examination of some chloro-substituted sugar chlorosulfates confirmed that an axial chlorodeoxy group in a glycopyranoside deactivates a neighboring equatorial chlorosulfate group and thus prevents further chlorodeoxy groups being introduced into such positions. Methyl α-D-altropyranoside, methyl α-L-rhamnopyranoside, methyl α-D-lyxopyranoside, L-rhamnose, and D-lyxose were reacted with sulfuryl chloride. The resulting products were those expected if these sugars reacted primarily in the C1 conformation.

The preparation, spectral properties, structures, and base-induced cleavage reactions of some α-halo-β-ketosulfones

1984 ◽  
Vol 62 (4) ◽  
pp. 798-807 ◽  
Author(s):  
J. Stuart Grossert ◽  
Pramod K. Dubey ◽  
Glen H. Gill ◽  
T. Stanley Cameron ◽  
Patrick A. Gardner
Keyword(s):  
Spectral Properties ◽  
Mass Spectra ◽  
Sulfuryl Chloride ◽  
Substitution Reactions ◽  
Reaction Conditions ◽  
Pyridinium Bromide ◽  
X Ray ◽  
X Ray Crystallography ◽  
Cleavage Reactions ◽  
C Nmr

The halogenation of β-ketosulfones such as α-methylsulfonylacetophenone (1) and benzenesulfonylacetone (10) can be effected with sulfuryl chloride or pyridinium bromide perbromide. Regiochemical control can be achieved by control of stoichiometry and/or the reaction conditions. Detailed 1H and 13C nmr, and mass spectra are recorded for a series of halogenated β-ketosulfones, together with structures by X-ray crystallography for 1, 2-chloro-2-methylsulfonyl-1-phenylethanone (2), chloromethyl methyl sulfone (4), and α-chloroacetophenone (21). Results from these studies are used to suggest a reason for the difficulty associated with substitution reactions of α-halosulfones.

A Convenient Method for the Chlorination of P-Methoxybenzyl 2-(3-Phenylacetamido-4-Benzenesulfonylthio-2-Azetidinone-1-Yl)-3-Methyl-3-Butenate

2011 ◽  
Vol 233-235 ◽  
pp. 66-69
Author(s):  
Jun De Xing ◽  
Wen Long Wei ◽  
Hong Hong Chang ◽  
Xing Li
Keyword(s):  
Convenient Method ◽  
Feeding Rate ◽  
Penicillin G ◽  
Sulfuryl Chloride ◽  
Reaction Conditions ◽  
Cephalosporin Antibiotics

A convenient method for the chlorination of p-methoxybenzyl 2-(3- phenylacetamido-4- benzenesulfonylthio-2-azetidinone-1-yl)-3-methyl-3-butenate from penicillin G with sulfuryl chloride ( SO2Cl2) , which is subsequently converted to p-methoxybenzyl 2-(3- phenylacetamido-4- benzenesulfonylthio-2-azetidinone-1-yl)-3-chloromethyl-3-butenate, versatile intermediates for the synthesis of cephalosporin antibiotics was developed. The method has the advantage of cheap reagents, mild reaction conditions and convenient operation. The quantity and the feeding rate of the chlorination reagent can be controlled easily. The method is particularly suitable for the chlorination in an industral process.

Undecagold labeling of tRNA

1991 ◽  
Vol 49 ◽  
pp. 44-45
Author(s):  
James F. Hainfeld ◽  
Kyra M. Alford ◽  
Mathias Sprinzl ◽  
Valsan Mandiyan ◽  
Santa J. Tumminia ◽  
...  
Keyword(s):  
High Resolution ◽  
Transmission Electron Micrograph ◽  
Anticodon Loop ◽  
Electron Micrograph ◽  
Reaction Conditions ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

The undecagold (Au11) cluster was used to covalently label tRNA molecules at two specific ribonucleotides, one at position 75, and one at position 32 near the anticodon loop. Two different Au11 derivatives were used, one with a monomaleimide and one with a monoiodacetamide to effect efficient reactions.The first tRNA labeled was yeast tRNAphe which had a 2-thiocytidine (s2C) enzymatically introduced at position 75. This was found to react with the iodoacetamide-Aun derivative (Fig. 1) but not the maleimide-Aun (Fig. 2). Reaction conditions were 37° for 16 hours. Addition of dimethylformamide (DMF) up to 70% made no improvement in the labeling yield. A high resolution scanning transmission electron micrograph (STEM) taken using the darkfield elastically scattered electrons is shown in Fig. 3.

Dimensionally-Controlled Hydrothermal Tm3+-doped Oxidic Nanocrystals and Their Photoluminescence Properties

2010 ◽  
Vol 1247 ◽  
Author(s):  
Rocío Calderón-Villajos ◽  
Carlos Zaldo ◽  
Concepción Cascales
Keyword(s):  
Single Crystals ◽  
Fluorescence Lifetimes ◽  
Photoluminescence Properties ◽  
Reaction Conditions ◽  
Hydrothermal Processes ◽  
Bulk Single Crystals ◽  
Template Free ◽  
Reaction Media

AbstractControlled reaction conditions in simple, template-free hydrothermal processes yield Tm-Lu2O3 and Tm-GdVO4 nanocrystals with well-defined specific morphologies and sizes. In both oxide families, nanocrystals prepared at pH 7 reaction media exhibit photoluminescence in ∼1.95 μm similar to bulk single crystals. For the lowest Tm3+ concentration (0.2 % mol) in GdVO4 measured 3H4 and 3F4 fluorescence lifetimes τ are very near to τrad.

Urea-Catalyzed Functionalization of Unactivated C–H Bonds

2020 ◽  
Author(s):  
Alex L. Bagdasarian ◽  
Stasik Popov ◽  
Benjamin Wigman ◽  
Wenjing Wei ◽  
woojin lee ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Organic Synthesis ◽  
High Energy ◽  
Acid Catalysts ◽  
Potential Utility ◽  
New Paradigm ◽  
Lewis Acid Catalysts ◽  
Reaction Conditions ◽  
Highly Active ◽  
Acidic Nature

Herein we report the 3,5bistrifluoromethylphenyl urea-catalyzed functionalization of unactivated C–H bonds. In this system, the urea catalyst mediates the formation of high-energy vinyl carbocations that undergo facile C–H insertion and Friedel–Crafts reactions. We introduce a new paradigm for these privileged scaffolds where the combination of hydrogen bonding motifs and strong bases affords highly active Lewis acid catalysts capable of ionizing strong C–O bonds. Despite the highly Lewis acidic nature of these catalysts that enables triflate abstraction from sp<sup>2</sup> carbons, these newly found reaction conditions allow for the formation of heterocycles and tolerate highly Lewis basic heteroaromatic substrates. This strategy showcases the potential utility of dicoordinated vinyl carbocations in organic synthesis.<br>

Urea-Catalyzed Functionalization of Unactivated C–H Bonds

2020 ◽  
Author(s):  
Alex L. Bagdasarian ◽  
Stasik Popov ◽  
Benjamin Wigman ◽  
Wenjing Wei ◽  
woojin lee ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Organic Synthesis ◽  
High Energy ◽  
Acid Catalysts ◽  
Potential Utility ◽  
New Paradigm ◽  
Lewis Acid Catalysts ◽  
Reaction Conditions ◽  
Highly Active ◽  
Acidic Nature

Herein we report the 3,5bistrifluoromethylphenyl urea-catalyzed functionalization of unactivated C–H bonds. In this system, the urea catalyst mediates the formation of high-energy vinyl carbocations that undergo facile C–H insertion and Friedel–Crafts reactions. We introduce a new paradigm for these privileged scaffolds where the combination of hydrogen bonding motifs and strong bases affords highly active Lewis acid catalysts capable of ionizing strong C–O bonds. Despite the highly Lewis acidic nature of these catalysts that enables triflate abstraction from sp<sup>2</sup> carbons, these newly found reaction conditions allow for the formation of heterocycles and tolerate highly Lewis basic heteroaromatic substrates. This strategy showcases the potential utility of dicoordinated vinyl carbocations in organic synthesis.<br>

Direct Cyclization of Alkenyl Thioester via Transition Metal‐hydrogen Atom Transfer/radical‐polar Crossover Mechanism

2019 ◽  
Author(s):  
Shiori Date ◽  
Kensei Hamasaki ◽  
Karen Sunagawa ◽  
Hiroki Koyama ◽  
Chikayoshi Sebe ◽  
...  
Keyword(s):  
Natural Products ◽  
Hydrogen Atom ◽  
Transition Metal ◽  
Hydrogen Atom Transfer ◽  
Synthetic Method ◽  
Atom Transfer ◽  
Reaction Conditions ◽  
Hydride Hydrogen ◽  
Sulfur Heterocycles ◽  
One Step

<div>We report here a catalytic, Markovnikov selective, and scalable synthetic method for the synthesis of saturated sulfur heterocycles, which are found in the structures of pharmaceuticals and natural products, in one step from an alkenyl thioester. Unlike a potentially labile alkenyl thiol, an alkenyl thioester is stable and easy to prepare. The powerful Co catalysis via a cobalt hydride hydrogen atom transfer and radical-polar crossover mechanism enabled simultaneous cyclization and deprotection. The substrate scope was expanded by the extensive optimization of the reaction conditions and tuning of the thioester unit.</div>

Iterative Supervised Principal Component Analysis-Driven Ligand Design for Regioselective Ti-Catalyzed Pyrrole Synthesis

2020 ◽  
Author(s):  
Xin Yi See ◽  
Benjamin Reiner ◽  
Xuelan Wen ◽  
T. Alexander Wheeler ◽  
Channing Klein ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
De Novo ◽  
Principal Component ◽  
Component Analysis ◽  
Catalyst Design ◽  
Data Driven ◽  
Initial Reaction ◽  
Training Set ◽  
Reaction Conditions ◽  
Component Loadings

<div> <div> <div> <p>Herein, we describe the use of iterative supervised principal component analysis (ISPCA) in de novo catalyst design. The regioselective synthesis of 2,5-dimethyl-1,3,4-triphenyl-1H- pyrrole (C) via Ti- catalyzed formal [2+2+1] cycloaddition of phenyl propyne and azobenzene was targeted as a proof of principle. The initial reaction conditions led to an unselective mixture of all possible pyrrole regioisomers. ISPCA was conducted on a training set of catalysts, and their performance was regressed against the scores from the top three principal components. Component loadings from this PCA space along with k-means clustering were used to inform the design of new test catalysts. The selectivity of a prospective test set was predicted in silico using the ISPCA model, and only optimal candidates were synthesized and tested experimentally. This data-driven predictive-modeling workflow was iterated, and after only three generations the catalytic selectivity was improved from 0.5 (statistical mixture of products) to over 11 (> 90% C) by incorporating 2,6-dimethyl- 4-(pyrrolidin-1-yl)pyridine as a ligand. The successful development of a highly selective catalyst without resorting to long, stochastic screening processes demonstrates the inherent power of ISPCA in de novo catalyst design and should motivate the general use of ISPCA in reaction development. </p> </div> </div> </div>

Suzuki–Miyaura cross-coupling for chemoproteomic applications

2020 ◽  
Author(s):  
Jian Cao ◽  
Ernest Armenta ◽  
Lisa Boatner ◽  
Heta Desai ◽  
Neil Chan ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Cross Coupling ◽  
Protein Profiling ◽  
Protein Labeling ◽  
Caspase 8 ◽  
Complex Cell ◽  
Bioorthogonal Chemistry ◽  
Reaction Conditions ◽  
Target Deconvolution ◽  
Palladium Catalyzed

Bioorthogonal chemistry is a mainstay of chemoproteomic sample preparation workflows. While numerous transformations are now available, chemoproteomic studies still rely overwhelmingly on copper-catalyzed azide –alkyne cycloaddition (CuAAC) or 'click' chemistry. Here we demonstrate that gel-based activity-based protein profiling (ABPP) and mass-spectrometry-based chemoproteomic profiling can be conducted using Suzuki–Miyaura cross-coupling. We identify reaction conditions that proceed in complex cell lysates and find that Suzuki –Miyaura cross-coupling and CuAAC yield comparable chemoproteomic coverage. Importantly, Suzuki–Miyaura is also compatible with chemoproteomic target deconvolution, as demonstrated using structurally matched probes tailored to react with the cysteine protease caspase-8. Uniquely enabled by the observed orthogonality of palladium-catalyzed cross-coupling and CuAAC, we combine both reactions to achieve dual protein labeling.

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