Preparation of Organometallic and Silyl Complexes of Palladium(II) via [PdCl(SnCl3)L2], where L = PPh3, P(p-Tol)3

2004 ◽  
Vol 69 (7) ◽  
pp. 1464-1471 ◽  
Author(s):  
Małgorzata Noskowska ◽  
Wojciech Duczmal
Keyword(s):  
Reaction Mechanism ◽  
Good Yield ◽  
New Method ◽  
Organohalogen Compound ◽  
Silyl Complexes

A new method for preparing organometallic and monosilyl complexes of Pd(II), based on the interaction between [PdCl(SnCl3)L2] (L = PPh3 or P(p-Tol)3) and appropriate organohalogen compound or chlorosilane has been developed. The products without tin have been obtained with good yield (85-97%). The reaction mechanism has been proposed on the basis of kinetic and chemometric investigations of the reaction between [PdCl(SnCl3)(PPh3)2] and Me2SiCl2.

scholarly journals Synthetic routes to 1,3-divinyl cyclobutanes

1987 ◽  
Author(s):  
Σωτήριος Ιερόπουλος
Keyword(s):  
Metal Complexes ◽  
Good Yield ◽  
Room Temperature ◽  
Wittig Reaction ◽  
Organic Reactions ◽  
New Method ◽  
Cycloaddition Reactions ◽  
Facile Synthesis ◽  
Synthetic Routes ◽  
Ketone Ester

The chemistry of the cyclobutadiene metal complexes of the last decade is reviewed. Emphasis is given to the organic reactions involving the cyclobutadiene ligand. Dichoro, dimethyl, and diphenyl ketenes were used in [2+21-cycloaddition reactions with 1,3-dienes, which included 1-vinyl cyclohexene, 2-triethylsilylbuta-l,3-diene and 1- and 2- trimethylsilyloxybuta-1,3-dienes. Thecycloadditions were rarely found to be regiospecific and nearly always low yielding. The produced cyclobutanones were very often unstable. 2,2-Diphenyl-3-(1'-triethylsilyl-1'-ethenyl) cyclobutanone was prepared but it was found not to produce the expected 1,3-divinyl cyclobutan-l-ol when treated with vinylmagnesium bromide. 2,2-Dimethyl and 2,2-diphenyl-3-ethoxy cyclobutanones were prepared and their reactions with vinylmagnesium bromide and methyl lithium were investigated. Ethyl 4,4-diphenylbut-3-enoate was formed when 2,2-diphenyl-3-ethoxy cyclobutanone was treated with vinylmagnesium bromide. As well as the above ester, the same cyclobutanone gave 5,5-diphenylpent4-en-2-one when treated with methyl lithium. 2,2-Dimethyl3-ethoxy cyclobutanone gave the expected alcohols when reacted with the same two reagents. 1-(11-Phenyl-2'-propenyl)-2,2-dimethyl-3-vinyl cyclobutane was synthesised starting from a-pinene. The best route was found to involve the preparation of pinonic aldehyde by ozonolysis of q-pinene. The aldehyde was reduced to pinonic alcohol which was then converted to pinonic iodide by treatment with triphenylphosphine and iodine. The iodide was dehydrohalogenated by a new method, described in chapter six of the thesis, to givel-acetyl-2,2-dimethy1-3-vinyl cyclobutane. A subsequent Wittig reaction gave the desired divinyl cyclobutane. Finally, the development of a new methodology is described for the dehydrohalogenation of primary bromides and iodides. It involves a novel, facile synthesis of tetrakis(triphenylphosphine) nickel. The primary halide is mixed with 1,8-diazabicyclo[5.4.0lundec-7-ene and the mixture added to the low valent nickel reagent. The alkene was formed in good yield after twelve hours of stirring at room temperature under argon. The reaction was applied to a few halides and it was found to be compatible with alcohol, ketone, ester, and ether groups.

Human Prothrombin: A New Method of Preparation from a Single Individual

1973 ◽  
Vol 30 (03) ◽  
pp. 425-436 ◽  
Author(s):  
Richard Benarous ◽  
Dominique Labie ◽  
François Josso
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
Good Yield ◽  
New Method ◽  
Single Individual ◽  
Single Chain ◽  
Simple Method ◽  
Terminal Residue ◽  
Sds Electrophoresis

SummaryA simple method for purification of human prothrombin from ACT) plasma of one single individual is described. This method is based on three steps :1. isolation of crude prothrombin complex by barium citrate adsorption;2. first purification by hydroxyapatite chromatography;3. further purification by DEAE Sephadex chromatography.The final product was obtained with a good yield and exhibited less than 5 p. cent contamination. The human purified prothrombin obtained in this way displays :– one single chain by SDS electrophoresis,– a molecular weight of 75,000-80,000 daltons,– a pi value pH 4.4 by electrofocusing,– Alanine as थ terminal residue.Amino-acid analysis is reported.

A new method to discover the reaction mechanism of perovskite nanocrystals

2018 ◽  
Vol 47 (45) ◽  
pp. 16218-16224 ◽  
Author(s):  
Chun Sun ◽  
Zhiyuan Gao ◽  
Hanxin Liu ◽  
Chong Geng ◽  
Hua Wu ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
New Method ◽  
Simple Method ◽  
Perovskite Nanocrystals

A novel and simple method for revealing the reaction mechanism of perovskite nanocrystals is reported.

scholarly journals C-Acetylation of Ketones

1974 ◽  
Vol 52 (8) ◽  
pp. 1379-1380 ◽  
Author(s):  
Stuart Nicholas Huckin ◽  
Larry Weiler
Keyword(s):  
Good Yield ◽  
New Method ◽  
Keto Esters

The action of 2 equiv. of methyllithium on the monoanion of simple β-keto esters gives the β-diketone in good yield. This represents a facile and new method to achieve the C-acylation of a ketone.

Direct electrochemical synthesis of neutral and anionic chloro- and bromo-complexes of titanium, zirconium, and hafnium

1977 ◽  
Vol 55 (22) ◽  
pp. 3882-3886 ◽  
Author(s):  
Jacob J. Habeeb ◽  
Farouq F. Said ◽  
Dennis G. Tuck
Keyword(s):  
Reaction Mechanism ◽  
Electrochemical Oxidation ◽  
Electrochemical Synthesis ◽  
Good Yield ◽  
Direct Synthesis ◽  
Solution Phase ◽  
Tetraalkylammonium Salts ◽  
Titanium Zirconium

Electrochemical oxidation of titanium, zirconium, or hafnium(IV) in the presence of a solution of chlorine or bromine (X) in acetonitrile (L) leads to direct synthesis of MX4L2 species in good yield. These compounds are easily transformed into other neutral adducts. On addition of tetraalkylammonium salts to the solution phase, the products are the salts (R4N)MCl5 or (R4N)2MBr6, except that with titanium Et4NTiBr4 was also formed under some conditions. The advantages of this method are discussed, and a possible reaction mechanism proposed.

scholarly journals Preparation, proteolysis and reversible oxidation of highly purified Azotobacter vinelandii polynucleotide phosphorylase

1970 ◽  
Vol 120 (4) ◽  
pp. 753-761 ◽  
Author(s):  
A. T. Gajda ◽  
G. Zaror de Behrens ◽  
P. S. Fitt
Keyword(s):  
Electrophoretic Mobility ◽  
Good Yield ◽  
Azotobacter Vinelandii ◽  
New Method ◽  
Reduced Form ◽  
Polyacrylamide Gels ◽  
Polynucleotide Phosphorylase ◽  
Oligonucleotide Primers ◽  
Aerial Oxidation

1. A new method has been developed for the preparation in good yield of highly purified Azotobacter vinelandii polynucleotide phosphorylase in its reduced form. 2. Aging or digestion with trypsin causes the enzyme to develop a primer requirement that is not eliminated by β-mercaptoethanol. 3. The development of a primer requirement is accompanied by marked changes of the electrophoretic mobility of the enzyme in polyacrylamide gels. 4. The enzyme is inactivated by aerial oxidation or thiol-specific reagents. The lost activity is restored by β-mercaptoethanol, but not by oligonucleotide primers.

Synthesis, characterization, and C—N bond cleavage of tungsten(VI)arylimido-calix[4]arene complexes

2001 ◽  
Vol 79 (5-6) ◽  
pp. 463-471
Author(s):  
Martyn Brown ◽  
Chet Jablonski
Keyword(s):  
Reaction Mechanism ◽  
Good Yield ◽  
Bond Cleavage ◽  
Aliphatic Amines ◽  
Arene Complexes ◽  
Cone Conformation ◽  
Arene Derivative ◽  
Tert Butyl ◽  
Arene Complex

The tetradentate, partially flattened cone tungsten(VI) imido-calix[4]arene derivative [W(NC6H5)(t-BucalixH)]+Cl–, (4), is formed in good yield from reaction of p-tert-butyl-calix[4]arene (t-BucalixH4), and W(NC6H5)Cl4. A reaction mechanism involving a putative, bidentate calixarene intermediate W(NC6H5)(t-BucalixH2)Cl2 (3), which partitions by reversible cleavage of the imido group to give the known tetradentate calixarene complex W(t-Bucalix)Cl2 (2), and elimination of HCl to form the thermodynamic imido product 4 is proposed. A series of iso structural [W(NAr)(t-BucalixH)]+Cl– (Ar = C6H5 or o,m,p-C6H4CH3) imido derivatives (4–7), which adopt a partially flattened cone conformation in solution has been prepared by reaction of dichloride 2 with H2NAr (Ar = C6H5, o,m,p-C6H4CH3). Reaction of W(t-Bucalix)Cl2 with aliphatic amines affords a red product formulated as the nitrido complex, 9, which results from facile cleavage of the imido C—N bond.Key words: calix[4]arene complex, imido complex, nitrido complex, C—N bond cleavage, conformation, metallocalixarene.

Selective Sampling and Orientation of Non-Homogeneous Tissues

1968 ◽  
Vol 26 ◽  
pp. 98-99
Author(s):  
C. C. Clawson ◽  
L. W. Anderson ◽  
R. A. Good
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Light Microscopy ◽  
Random Sampling ◽  
New Method ◽  
Microscope Examination ◽  
Small Areas ◽  
Selective Sampling ◽  
Large Numbers ◽  
Specific Orientation

Investigations which require electron microscope examination of a few specific areas of non-homogeneous tissues make random sampling of small blocks an inefficient and unrewarding procedure. Therefore, several investigators have devised methods which allow obtaining sample blocks for electron microscopy from region of tissue previously identified by light microscopy of present here techniques which make possible: 1) sampling tissue for electron microscopy from selected areas previously identified by light microscopy of relatively large pieces of tissue; 2) dehydration and embedding large numbers of individually identified blocks while keeping each one separate; 3) a new method of maintaining specific orientation of blocks during embedding; 4) special light microscopic staining or fluorescent procedures and electron microscopy on immediately adjacent small areas of tissue.

Arylation of enelactams using TIPSOTf: reaction scope and mechanistic insight

2021 ◽  
Author(s):  
Tomasz J. Idzik ◽  
Zofia M. Myk ◽  
Łukasz Struk ◽  
Magdalena Perużyńska ◽  
Gabriela Maciejewska ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Multinuclear Nmr ◽  
Mechanistic Insight ◽  
Nmr Study ◽  
Wide Range

Triisopropylsilyltrifluoromethanesulfonate can be effectively used for the arylation of a wide range of enelactams. The multinuclear NMR study provided deep insights into the reaction mechanism.

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