Abstract
Alkaline hydrolysis rates coefficients for the series of methyl 3-(7-substituted-1-naphthyl) propynoate was calculated in 70%v/v dimethylsulphoxide-water at various temperatures (25,30,40, and 50̊ C). The pKa values of 3-(7-substituted-1-naphthyl) propynoic acid and (E)- 3-(7-substituted-1-naphthyl) propenoic acid calculated in 80%w/w 2-methoxyethanol-water at room temperature (25.0̊ C). logk2 of esterification rate coefficients for 3-(7-substituted-1-naphthyl) propynioc acid and (E)-3(7-substituted-1-naphthyl) propenioc acid with DDM have been measured at 30.0̊ C. Reversed substituent dipolar effects were found in the ionization reaction. In the esterification reaction with DDM the result show similar but reduced substituted effects. Rate retardations was found in the alkaline hydrolysis. It could be result from steric effect or reversal of substituent dipolar effect with a combination of steric effect.
Highlights
The objective of this study was to determine the reverse transmission of dipolar substituent effects
Studies [ 1, 4, 11, 12] explained the substituent dipolar effects reverse by using the right design circumstances which is currently in the molecular reliable model, such a model (3substituted propiolic acid) has been suggested 1st time by Roberts and carbon [13]
In the present study was found, the transmission of substituent dipolar effect shows best understood to explain the transmission of direct field effects, Ϭ- inductive and π–inductive effects
Summary
The objective of this study was to determine the reverse transmission of dipolar substituent effects. Studies [ 1, 4, 11, 12] explained the substituent dipolar effects reverse by using the right design circumstances which is currently in the molecular reliable model, such a model (3substituted propiolic acid) has been suggested 1st time by Roberts and carbon [13]. This “Jshaped “molecule is an excellence design and perfect for dipolar substituent transmission effects study as shown in systems below: ecule (1) (2). The pka values of the acids and their rates of esterification with DDM (diazodiphenylmethane) has been measured to assess their reactivity
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