Abstract: A mitotic kinesin Eg5 inhibitor which comprises a thiadiazoline derivative represented by the general formula (I) or a pharmacologically acceptable salt thereof as an active ingredient: [wherein R1 represents a hydrogen atom and the like, R2 represents a hydrogen atom, —C(?W)R6 (wherein W represents an oxygen atom or a sulfur atom, and R6 represents substituted or unsubstituted lower alkyl and the like) and the like, R3 represents —C(?Z)R19 (wherein Z represents an oxygen atom or a sulfur atom, and R19 represents substituted or unsubstituted lower alkyl and the like) and the like, R4 represents substituted or unsubstituted lower alkyl and the like, and R5 represents substituted or unsubstituted aryl and the like] and the like are provided.

Abstract: A mitotic kinesin Eg5 inhibitor which comprises a thiadiazoline derivative represented by the general formula (I) or a pharmacologically acceptable salt thereof as an active ingredient: [wherein R1 represents a hydrogen atom and the like, R2 represents a hydrogen atom, —C(?W)R6 (wherein W represents an oxygen atom or a sulfur atom, and R6 represents substituted or unsubstituted lower alkyl and the like) and the like, R3 represents —C(?Z)R19 (wherein Z represents an oxygen atom or a sulfur atom, and R19 represents substituted or unsubstituted lower alkyl and the like) and the like, R4 represents substituted or unsubstituted lower alkyl and the like, and R5 represents substituted or unsubstituted aryl and the like] and the like are provided.

Abstract: The present invention relates to radicicol derivatives represented by the following formula (I) or pharmacologically acceptable salts thereof: ##STR1## wherein R.sup.1 and R.sup.2 are the same or different and each represents hydrogen, alkanoyl, alkenoyl or tert-butyldimethylsilyl; (1) when X represents halogen, Y represents an oxygen atom or R.sup.4 --O--N (wherein R.sup.4 represents hydrogen or substituted or unsubstituted lower alkyl); and R.sup.3 represents hydrogen, alkanoyl, alkenoyl or the like; and (2) when X and R.sup.3 are combined with each other to represent a single bond; Y represents R.sup.4B --O--N (wherein R.sup.4B has the same meaning as R.sup.4). The radicicol derivatives of the present invention demonstrate tyrosine kinase inhibition activity and pharmacological activities such as antitumor, antimicrobial or immunosuppression effects.

Abstract: The present invention relates to a farnesyltransferase inhibitor and an antitumor agent comprising, as an active ingredient, a piperazinedione derivative represented by formula (I): ##STR1## wherein R.sup.1 and R.sup.2 independently represent lower alkyl, lower alkoxyalkyl, substituted or unsubstituted aryl, or aralkyl; R.sup.3 and R.sup.4 independently represent mercapto, lower alkanoylthio, aroylthio, lower alkoxycarbonylthio, or aryloxycarbonylthio, or alternatively R.sup.3 and R.sup.4 are combined together to form disulfide; and R.sup.5 and R.sup.6 independently represent hydrogen, lower alkyl, lower alkoxyalkyl, hydroxyalkyl, lower alkanoyloxyalkyl, aroyloxyalkyl, aralkyloxyalkyl, or aralkyl.

Abstract: The present invention relates to a farnesyltransferase inhibitor and an antitumor agent comprising, as an active ingredient, a piperazinedione derivative represented by formula (I): ##STR1## wherein R.sup.1 and R.sup.2 independently represent lower alkyl, lower alkoxyalkyl, substituted or unsubstituted aryl, or aralkyl; R.sup.3 and R.sup.4 independently represent mercapto, lower alkanoylthio, aroylthio, lower alkoxycarbonylthio, or aryloxycarbonylthio, or alternatively R.sup.3 and R.sup.4 are combined together to form disulfide; and R.sup.5 and R.sup.6 independently represent hydrogen, lower alkyl, lower alkoxyalkyl, hydroxyalkyl, lower alkanoyloxyalkyl, aroyloxyalkyl, aralkyloxyalkyl, or aralkyl.

Abstract: The present invention relates to an epoxycyclohexenedione derivative represented by formula (I): ##STR1## wherein R is a straight-chain or branched alkanoyl group having 10 to 25 carbon atoms, a straight-chain alkenoyl group having 10 to 25 carbon atoms, or a group represented by formula (A): ##STR2## wherein n is an integer of 1 to 4; or a pharmaceutically acceptable salt thereof.The compounds exhibit antimicrobial activity and antitumor activity.