Synthesis and Enzymatic Activity of Adenosine 3', 5'-Cyclic Phosphate Analogs

2-Mono-and 2, 6-di-substituted cAMP (cAMP : adenosine 3', 5'-cyclic phosphate) were derived from the corresponding adenosine analogs via the 5'-phosphates. 2-Substituted cAMP and aristeromycin 3', 6'-cyclic phosphate were led to the 8-bromo derivatives. 8-(3, 5-Dimethylpyrazol-1-yl)-cAMP was derived from 8-hydrazinoadenosine. 8-(2-Hydroxypropyl-2)-cAMP was prepared by a γ-ray irradiation of cAMP in isopropanol. N6-Butyl-2-phenyl-cAMP was derived from 2-phenylinosine. 2-or 8-Substituted cAMP was led to its dibutyryl derivative. The activities of these new analogs were assessed with cAMP-dependent protein kinases (PK) and cAMP phosphodiesterases (PDE). 8-Bromo-2-chloro-, 2-chloro-, 2-bromo-, 2-phenylthio-, 8-carbamoyl- and 8-carboxy-cAMP were better activators of PK than cAMP, while 2-substituted analogs were significant substrates and inhibitors of PDE. 2-Phenyl-, benzyl-, phenoxy-, chloro- and bromo-cAMP or aristeromycin 3', 6'-cyclic phosphate had an inhibitory effect on the binding of cAMP to PK equal to or more than cAMP.