Multicomponent synthesis of novel thiazolo[3,2-a]pyridin-8-yl-phosphonates as a model of plant growth regulator

Abstract

A series of thiazolo[3,2-a]pyridin-8-yl-phosphonate derivatives have been obtained by the reaction of diethyl (E)-((4-oxothiazolidin-2-ylidene)methyl)phospohonate, malononitrile and two equivalent of various aromatic aldehydes in a multicomponent reaction with good yields. The structures of the new compounds are confirmed by spectroscopic methods (IR, ¹H, ¹³C, ³¹P NMR and HRMS). Compound diethyl-(Z)-(5-amino-6-cyano-2-(4-nitrobenzylidene)-7-(4-nitrophenyl)-3-oxo-3,7-dihydro-2H-thiazolo[3,2-a]pyridin -8-yl)phosphonate (4k) at 1 mM concentration enhanced biomass plant height, number of branches and leaf area of tomato plants of at least two-fold compared to the control plants. In common bean plants, this compound enhanced the chlorophyl content and delayed senescence in comparison to the control plants. Therefore, in future studies, the compound(s) would be further tested to evaluate deeply their mode of action at physiological, biochemical and molecular level to finally enhance crop productivity of various plants.

GRAPHICAL ABSTRACT

Keywords:

• Multi-component Reactions
• Knoevenagel reaction
• alkylidene thiazolidin-4-one
• thiazolopyridine
• phosphonate
• plant growth
• chlorophyll content

Acknowledgement

This work was supported by grants from Scientific and Technological Research Council of Turkey (TÜBİTAK 114Z181- Grant for authors LYS and HG) and AİBÜ-BAP (project number is 2013.3.3.667). I would like to thank Layla Filiciotto for fruitful discussion about this work.