Abstract: This invention relates to cyclobutane derivatives represented by the following general formula (1) and physiologically acceptable salts thereof: ##STR1## wherein B represents a nucleic acid base derivative, R.sup.1 and R.sup.2 independently represent hydrogen atom, dialkylaminoacyl group, 1,4-dihydro-1-methylnicotinoyl group or substituted phosphoric acid group, provided that either one of R.sup.1 and R.sup.2 is a group other than hydrogen atom.The compounds of this invention exhibit a high oral absorbability and are metabolized in vivo into the compounds of formula (1a). Accordingly, the compounds of this invention are expectedly useful as antiviral agent.

Abstract: This invention relates to forskolin derivatives, their physiologically acceptable salts, and a process for producing these compounds. The forskolin derivative is represented by the general formula ##STR1## wherein; I. when R.sup.1 is hydrogen and R.sup.4 is vinyl, ethyl, or cyclopropyl,(1) either of R.sup.2 and R.sup.3 denotes a residue represented by the formula ##STR2## wherein each of R.sup.5 and R.sup.6 denotes hydrogen or lower alkyl or R.sup.5 and R.sup.6 combine with each other to form a lower alkylene chain which may or may not contain an oxygen or nitrogen atom and m is an integer of 1 to 5, and the other one of R.sup.2 and R.sup.3 denotes hydrogen or a residue represented by the formula CO(CH.sub.2).sub.n X, X being hydrogen or ##STR3## wherein, each of R.sup.7 and R.sup.8 denotes hydrogen or lower alkyl or R.sup.7 and R.sup.8 combine with each other to form a lower alkylene chain which may or may not contain an oxygen or nitrogen atom, and n being an integer of 1 to 5, or(2) R.sup.