Synthesis and Screening of Anilides Having Olefinic and Alkyl Moiety in the Side Chain as Chemical Hybridizing Agents for Wheat (Triticum aestivum L.)

Induction of male sterility by deployment of chemical hybridizing agents (CHAs) holds immense potential in heterosis breeding of wheat. A total of 21 anilides having different aromatic substitutions and side-chain variation were synthesized and screened as CHAs on three genotypes of wheat viz., PBW 343, HW 2046, and HD 2733, at winter season. Various anilides having vinyl moiety in the acyl side chain were synthesized by condensation between substituted anilines with different esters or acid chlorides. Another lead in the form of N-alkyl anilines also became evident. The percent male sterility data caused by CHAs revealed the significant contribution of anilides containing vinyl double bond incorporated in the form of closed ring structure viz., furyl moiety as the side chain. 4‘-Fluoro-furyl anilide (1) and 4‘-bromo-furyl anilide (2) are found to be promising lead CHAs for the design of highly active molecules. QSAR analysis revealed a direct relationship of field effect exemplified by the Swain−Lupton constant F p for the aromatic substitution but an inverse relationship of molar refractivity MR for the side chain. The negative influences of parachor for the acyl domain have been underlined. The real guiding principle for selectivity of CHA action was found to be the π value. The CHAs act by mimicking UDP-glucose, the key substrate in the synthesis of callose, or lead to an imbalance in acid−base equilibrium in pollen mother cells resulting in dissolution of callose wall by premature callase secretion. Keywords: Anilides; chemical hybridizing agents (CHAs); QSAR; wheat