Adenylate anticytokinins

The optimum B4 value for N4-substituents, 4.5 A coincides very well not only with that for N substituents of adenylate cytokinins, 5.2 A, shown in the previous section, but also with the value of 4.7 A observed for another class of compounds, N4-substituted 4-amino-2-methylpyrrolo[2,3-d]pyrimidines (24)47) which show either cytokinin or anticytokinin activity depending upon the structure of N4-substituents. These results in combination may help to think of the size of structure which should sterically fit well the cytokinin receptor cavity. 

Since the discovery of cytokinins, different adenylate and non-adenylate compounds have been synthesized and classified as potent anticytokinins based on the reduction of cytokinin effects, i.e. chlorophyll retention, radish leaf expansion and callus growth. 

The anticytokinins hitherto developed were adenylate compounds. Anticytokinins with a structural resemblance to DPUs, or a non-adenylate structure, were not yet known. 

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