Abstract: Novel cyclic adenosine monophosphate derivatives represented by the following general formula: ##STR1## wherein A stands for --S-- or --NH-- and n is an integer of from 2 to 12, ARE SUPERIOR TO KNOWN CYCLIC ADENOSIENE DERIVATIVES IN BIOLOGICAL AND PHARMACOLOGICAL ACTIVITIES, ESPECIALLY PDE-inhibiting activity and membrane permeability. Accordingly, these derivatives are very effective for remedying and controlling diseases caused by disorder of the intracellular cyclic adenosine monophosphate level, such as asthma and scabies. These derivaives can readily be synthesized by reacting an 8-halogeno cyclic adenosine monophosphate of the following general formula ##STR2## wherein X is a halogen atom such as bromine, with an alkali metal salt of a linear alkylmercaptan having 3 to 13 carbon atoms in the alkyl group or a linear alkylamine having 3 to 13 carbon atoms in the alkyl group.