Some observations relating to substituent effects in halogenation. Part V. Reaction of t-butylbenzene with chlorine acetate in aqueous acetic acid

1969 ◽  
pp. 591
Author(s):  
M. Hassan ◽  
G. Yousif
Keyword(s):  
Acetic Acid ◽  
Substituent Effects ◽  
Aqueous Acetic Acid

Chlorination of 2-Phenoxypropanoic Acid with NCP in Aqueous Acetic Acid:  Using a Novel Ortho−Para Relationship and the Para/Meta Ratio of Substituent Effects for Mechanism Elucidation

2007 ◽  
Vol 72 (14) ◽  
pp. 5327-5336 ◽  
Author(s):  
Manuel A. P. Segurado ◽  
João Carlos R. Reis ◽  
Jaime D. Gomes de Oliveira ◽  
Senthamaraikannan Kabilan ◽  
Manohar Shanthi
Keyword(s):  
Acetic Acid ◽  
Substituent Effects ◽  
Aqueous Acetic Acid

Chlorination of N-Phenylbenzenesulfonamides with NCP in Aqueous Acetic Acid. Using the para/meta Ratio of Substituent Effects for Mechanism Elucidation

2004 ◽  
Vol 69 (12) ◽  
pp. 2253-2275 ◽  
Author(s):  
João Carlos R. Reis ◽  
Manuel A. P. Segurado ◽  
Jaime D. Gomes de Oliveira ◽  
Senthamaraikannan Kabilan ◽  
Krishnasamy Suganya
Keyword(s):  
Acetic Acid ◽  
Nitrogen Atom ◽  
Rate Constants ◽  
Substituent Effects ◽  
Aqueous Acetic Acid ◽  
Isokinetic Temperature ◽  
Isokinetic Relationship ◽  
Rate Determining Step ◽  
Different Temperatures ◽  
Energy Ratios

Rate constants were measured for the oxidative chlorination reaction of N-phenylbenzenesulfonamide 2 and twelve ortho-, nine meta- and twelve para-substituted derivatives in the aniline moiety, using 1-chloro-3-methyl-2,6-diphenylpiperidin-4-one (1) as chlorinating agent. The kinetics was run in 50% (v/v) aqueous acetic acid acidified with perchloric acid under pseudo-first-order conditions with respect to 1 at five different temperatures between 298 and 318 K. The dependence of rate constants on temperature was analysed in terms of the isokinetic relationship (IKR). The resulting isokinetic temperature was estimated to be 513 K. Using the Linert's theory of the IKR, the experimental isokinetic temperature was interpreted as evidence for the preferential involvement of water molecules in the formation of activated complexes. The dependence of the rate constants on the substituents was analysed using the tetralinear extension of the Yukawa-Tsuno equation for the effects of meta and para substituents. A positively charged transition state was suggested by an experimental value r+ = 0.39 for the resonance demand, which was found to be insensitive to temperature variation. The parameter λ for the para/meta ratio of substituent effects was estimated to be 0.952. The electrostatic modelling of λ values was re-examined in the light of the recent calculations of the energies of interaction between charged and/or dipolar groups by Exner and Böhm. Based on energy ratios, the electrostatic method was shown to remain valid for the purpose of modelling λ values. The experimental λ value for the reaction indicates the formation of an activated complex possessing an electric charge in the vicinity of the nitrogen atom of the substrate. The electrophilic attack on the substrate nitrogen atom by the protonated chlorinating reagent has been proposed as the rate-determining step, with the last step being the fast rearrangement of the intermediate N-chloro-N-phenylbenzenesulfonamidium cation into the products.

Novel Compound from Flowers of Moringa oleifera Active Against Multi- Drug Resistant Gram-negative Bacilli

2020 ◽  
Vol 20 (1) ◽  
pp. 69-75
Author(s):  
Santi M. Mandal ◽  
Subhanil Chakraborty ◽  
Santanu Sahoo ◽  
Smritikona Pyne ◽  
Samaresh Ghosh ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Moringa Oleifera ◽  
Aqueous Acetic Acid ◽  
Phytochemical Analysis ◽  
Hydroxyl Groups ◽  
Drug Resistant ◽  
Gram Negative ◽  
Isolated Compound ◽  
Conventional Antibiotics

Background: The need for suitable antibacterial agents effective against Multi-drug resistant Gram-negative bacteria is acknowledged globally. The present study was designed to evaluate the possible antibacterial potential of an extracted compound from edible flowers of Moringa oleifera. Methods: Five different solvents were used for preparing dried flower extracts. The most effective extract was subjected to fractionation and further isolation of the active compound with the highest antibacterial effect was obtained using TLC, Column Chromatography and reverse phase- HPLC. Approaches were made for characterization of the isolated compound using FTIR, NMR and Mass spectrometry. Antibacterial activity was evaluated according to the CLSI guidelines. Results: One fraction of aqueous acetic acid extract of M. oleifera flower was found highly effective and more potent than conventional antibiotics of different classes against Multi-drug resistant Gram-negative bacilli (MDR-GNB) when compared. The phytochemical analysis of the isolated compound revealed the presence of hydrogen-bonded amine and hydroxyl groups attributable to unsaturated amides. Conclusion: The present study provided data indicating a potential for use of the flowers extract of M. oleifera in the fight against infections caused by lethal MDR-GNB. Recommendations: Aqueous acetic acid flower extract of M. oleifera is effective, in-vitro, against Gram-negative bacilli. This finding may open a scope in pharmaceutics for the development of new classes of antibiotics.

Compatibility studies of chitosan/PVA blend in 2% aqueous acetic acid solution at 30°C

2010 ◽  
Vol 82 (2) ◽  
pp. 251-255 ◽  
Author(s):  
H.M.P. Naveen Kumar ◽  
M.N. Prabhakar ◽  
C. Venkata Prasad ◽  
K. Madhusudhan Rao ◽  
T.V. Ashok Kumar Reddy ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Acid Solution ◽  
Acetic Acid Solution ◽  
Aqueous Acetic Acid ◽  
Compatibility Studies ◽  
Aqueous Acetic Acid Solution
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