Abstract: Aphidicolin is produced with a high productivity by culturing microorganisms belonging to the genus Verticillium, for example, Verticillium sp FERM BP-3430, in a culture medium, thereby forming and accumulating aphidicolin therein and recovering the aphidicolin therefrom.

Abstract: A (trans 1-propenyl)disulfide derivative having a distinguished anti-tumor effect, represented by the following general formula: ##STR1## , wherein R is a lower alkylene group and R' is a hydrogen atom or a carboxyl protective group, is prepared by allowing a carboxylic acid thiol derivative, represented by the following general formula:AS--R--COOR', wherein R and R' have the same meanings as defined above and A is a thiol protective group releasable by a halogenating agent, to react with a trans 1-propenethiol derivative represented by the following general formula: ##STR2## , wherein A has the same meanings as defined above, in the presence of a halogenating agent.

Abstract: Pyrido[1,2,3-de][1,4]benzoxazine derivatives are described having the formula (I) ##STR1## wherein X is a halogen atom, R is a hydrogen atom or an alkyl group of 1 to 6 carbon atoms and Z represents mono-substituted, di-substituted or cyclic-substituted amino group which may contain a hetero atom and may have a substituent such as hydroxyl, alkyl having 1 to 6 carbon atoms, amino, hydroxyalkyl having 1 to 6 carbon atoms or mono- or di-alkylamino having 1 to 6 carbon atoms in each alkyl moiety and the pharmaceutically acceptable salt thereof, having antibacterial activity.