scholarly journals ALKYL SUBSTITUENT EFFECTS ON C-13 NMR PARAMETERS FOR TRICHLORO-PLATINUM(II)-OLEFIN COMPLEXES AND β-METHOXYALKYLMERCURIC CHLORIDES

1973 ◽  
Vol 2 (12) ◽  
pp. 1255-1258 ◽  
Author(s):  
Takashi Ibusuki ◽  
Yasukazu Saito
Keyword(s):  
Substituent Effects ◽  
Alkyl Substituent ◽  
Nmr Parameters

Kinetic Study of Hydrolysis of Benzoates. Part XXVI. Variation of the Substituent Effect with Solvent in Alkaline Hydrolysis of Substituted Alkyl Benzoates

2006 ◽  
Vol 71 (11-12) ◽  
pp. 1557-1570 ◽  
Author(s):  
Vilve Nummert ◽  
Mare Piirsalu ◽  
Ilmar A. Koppel
Keyword(s):  
Kinetic Study ◽  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Substituent Effect ◽  
Substituent Effects ◽  
Alkyl Substituent ◽  
Solvent Parameters ◽  
Substituent Constants ◽  
Hydrolysis Of ◽  
Main Factor

The second-order rate constants k2 (dm3 mol-1 s-1) for the alkaline hydrolysis of substituted alkyl benzoates C6H5CO2R have been measured spectrophotometrically in aqueous 0.5 M Bu4NBr at 50 and 25 °C (R = CH3, CH2Cl, CH2CN, CH2C≡CH, CH2C6H5, CH2CH2Cl, CH2CH2OCH3, CH2CH3) and in aqueous 5.3 M NaClO4 at 25 °C (R = CH3, CH2Cl, CH2CN, CH2C≡CH). The dependence of the alkyl substituent effects on different solvent parameters was studied using the following equations:      ∆ log k = c0 + c1σI + c2EsB + c3∆E + c4∆Y + c5∆P + c6∆EσI + c7∆YσI + c8∆PσI     ∆ log k = c0 + c1σ* + c2EsB + c3∆E + c4∆Y + c5∆P + c6∆Eσ* + c7∆Yσ* + c8∆Pσ* .  ∆ log k = log kR - log kCH3. σI and σ* are the Taft inductive and polar substituent constants. E, Y and P are the solvent electrophilicity, polarity and polarizability parameters, respectively. In the data treatment ∆E = ES - EH2O , ∆Y = YS - YH2O , ∆P = PS - PH2O were used. The solvent electrophilicity, E, was found to be the main factor responsible for changes in alkyl substituent effects with medium. When σI constants were used, variation of the polar term of alkyl substituents with the solvent electrophilicity E was found to be similar to that observed earlier for meta and para substituents, but twice less when σ* constants were used. The steric term for alkyl substituents was approximately independent of the solvent parameters.

Alkyl Substituent effects on the stability of protonated benzene

1974 ◽  
Vol 96 (22) ◽  
pp. 7162-7163 ◽  
Author(s):  
Warren J. Hehre ◽  
Robert T. McIver ◽  
John A. Pople ◽  
Paul v. R. Schleyer
Keyword(s):  
Substituent Effects ◽  
Alkyl Substituent ◽  
The Stability

Alkyl Substituent Effects on the Conductivity of Polyaniline

2004 ◽  
Vol 14 (5) ◽  
pp. 479-486 ◽  
Author(s):  
N. A. Zaidi ◽  
J. P. Foreman ◽  
G. Tzamalis ◽  
S. C. Monkman ◽  
A. P. Monkman
Keyword(s):  
Substituent Effects ◽  
Alkyl Substituent

Electrophilic Substitution Reactions of [1]Benzothieno[3,2-b]furan

1996 ◽  
Vol 61 (6) ◽  
pp. 888-900 ◽  
Author(s):  
Jiří Svoboda ◽  
Pavel Pihera ◽  
Petr Sedmera ◽  
Jaroslav Paleček
Keyword(s):  
Electrophilic Substitution ◽  
Nmr Spectra ◽  
Substituent Effects ◽  
Substitution Reactions ◽  
Nmr Parameters ◽  
Elimination Mechanism ◽  
Electrophilic Substitution Reactions ◽  
C Nmr

In chlorination, bromination, iodination, nitration, sulfonation, formylation, and trifluoroacetylation of [1]benzothieno[3,2-b]furan (1) the substituent enters the 2-position. The said halogenations go by the addition-elimination mechanism. When the substitution is continued, the second substituent enters the 6-position of heterocycle 1. The 1H and 13C NMR spectra have been completely assigned. Substituent effects on NMR parameters are discussed.

Diastereoselective alkylations of chiral, phosphorus-stabilized carbanions: N-alkyl substituent effects in P-alkyl-1,3,2-diazaphosphorinane 2-oxides

2000 ◽  
Vol 78 (6) ◽  
pp. 673-688 ◽  
Author(s):  
Scott E Denmark ◽  
Jung-Ho Kim
Keyword(s):  
Systematic Study ◽  
Substituent Effects ◽  
Alkyl Substituent

A systematic study of the diastereoselective alkylation of anions derived from racemic N-substituted P-alkyl 1,3,2-diazaphosphorinane 2-oxides was carried out with variation of the N-substituent. High diastereoselectivity for the methylation of a P-benzyl anion has been achieved with N-neopentyl derivative 5d. Similarly, a P-ethyl anion derived from N-neopentyl derivative 6d showed high diastereoselectivity upon benzylation. The observed difference in alkylation diastereoselectivity between P-ethyl and P-benzyl anions for various N-alkyl substituents is discussed.Key words: phosphonamide-stabilized carbanions, alkylation, asymmetric, stereoselective, organolitihium.

Sign in / Sign up

Export Citation Format

Share Document