- Synthesis and characterization of N-acylaniline derivatives as potential chemical hybridizing agents (CHAs) for wheat (Triticum aestivum L.)
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Induction of male sterility by deployment of chemical hybridizing agents (CHAs) are important in heterosis breeding of self-pollinated crops like wheat, wherein the male and female organs are in the same flower. Taking a lead from the earlier work on rice, a total of 25 N-acylanilines comprising of malonanilates, acetoacetanilides, and acetanilides (including halogenated acetanilides) were synthesized and screened as CHAs on three genotypes of wheat, viz., PBW 343, HD 2046, and HD 2733 at 1500 ppm in the winter of 2001-2002. The N-acylanilines containing variations at the acyl and aromatic domain were synthesized by condensation of substituted anilines with appropriate diesters, acid chlorides, or monoesters. The test compounds with highly electronegative groups such as F/Br at the para position of the aryl ring were identified as the most potent CHAs, causing higher induction of male sterility. A variation of N-substitution at the side chain generally furnished analogues like 4′-fluoroacetoacetanilide (7) and ethyl 4′-fluoromalonanilate (1), which induced 89.12 and 84.66% male sterility, respectively, in PBW 343. Among halogenated acetanilides, the increasing number of chlorine atoms in the side chain led to an increase in the activity of 4′-fluoro (23) and 4′-bromo (24) derivatives of trichoroacetanilides, which induced >87% male sterility. Quantitative structure-activity relationship (QSAR) models indicated the positive contributions of the field effect exemplified by the Swain-Lupton constant (Fp) and negative contributions of the Swain-Lupton resonance constant (R) for the aromatic substitution. The positive influences of parachor (P) for the acyl domain have been underlined. These leads will be significant in explaining the CHA fit in the macromolecular receptor site. The CHAs appeared to act by causing an imbalance in the acid-base equilibrium in pollen mother cells resulting in dissolution of the callose wall by premature callase secretion.
- Chakraborty, Kajal,Devakumar
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p. 6800 - 6808
(2007/10/03)
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- Photochemical Bromination of Anilides by Benzenehexabromide
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Benzenehexabromide was found to afford photochemical bromination of substituted acetanilide in the p-position.The rates of bromination were found to follow the order predicted on the basis of inductive effect of the substituents and similar to the sequence of reactivities observed for bromination of acetanilides with N-bromosuccinimide.Similar results were obtained in the case of p-substituted benzanilides and the reaction shows a good Hammett correlation with the ?+ values for the substituents with a ρ value -0.266.
- Aly, M. M.,Awad, I. M. A.,Fahmy, A. M.
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- Formation of N-Substituted Trichloroacetamides from Amines and Hexachloroacetone
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Procedures are described for converting primary amines into their well-crystalline trichloroacetyl-derivatives by treatment with hexachloroacetone under mild conditions.Although secondary aromatic N-methylamines are unaffected by hexachloroacetone, saturated heterocyclic amines react vigorously.A mechanistic study using 2-amino-4-t-butylthiazole showed that the reaction is first order in hexachloroacetone, second order in amine, and base-catalysed; there is no appreciable kinetic isotope (H/D) effect nor accumulation of intermediates during the reaction.A sequence which accommodates these results is suggested.
- Bew, Clive,Joshi, Virginia Otero de,Gray, Jim,Kaye, Perry T.,Meakins, G. Denis
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p. 945 - 948
(2007/10/02)
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