Shtompel O. Search for plant growth regulators among five- and six-membered azaheterocycles

The effect of synthetic low molecular weight heterocyclic compounds derivatives of pyrimidine, pyrazolo[3,4-d][1,2,3]triazin-4-one, isoflavonoids, [1,3]oxazole[5,4-d]pyrimidine, N-sulfonyl substituted on plant growth regulation was studied for the first time. It was shown optimal physiologically active concentrations of tested synthetic compounds that were laid between 10-8 to 10-9 M. Among the tested classes of pyrimidines, dihydroimidazo[1,2-c]pyrimidine derivates have shown the highest plant growth regulating activity, that in most cases exceeds phytohormonal activity of IAA, NAA or Kinetin, used at the same concentrations. The correlation between the presence of substituents on the 8 (9) position of the pyrimidine cycle of pyrimido[1,6-a] pyrimidine and dihydroimidazo[1,2-c]pyrimidine, and their stimulating activity on tomato and pea plants was found. It has been established that the introduction of the methylsulfonyl group in this position increases the regulating activity of the compounds in relation to the morphometric and biochemical indices of the plants. According to specific auxin and cytokinin activity bioassays, which were carried out on isolated plant organs, it was revealed a similar to phytohormones activity of some tested compounds, which was equal to or exceeded the activity of phytohormones IAA, NAA or Kinetin. Based on the study of the activity of the derivatives of N-sulfonyl substituted 1,3-oxazole on soybean, wheat, linseed, cucumber and rape plants, the relationship between the chemical structure and their biological activity was established. This pattern can be used for the design of new synthetic plant growth regulators based on N-sulfonyl substituted 1,3-oxazoles. Scope – bioorganic chemistry.