New Water-Soluble Cytokinin Derivatives and Their Beneficial Impact on Barley Yield and Photosynthesis.

Solubility of growth regulators is essential for their use in agriculture. Four new cytokinin salts─6-benzylaminopurine mesylate (), 6-(2-hydroxybenzylamino)purine mesylate (), 6-(3-hydroxybenzylamino)purine mesylate (), and 6-(3-methoxybenzylamino)purine mesylate ()─were synthesized, and their crystal structures were determined to clarify structural influence on water solubility. The mesylates were several orders of magnitude more water-soluble than the parent CKs.