Abstract: Novel didemnin compounds named didemnin X and didemnin Y have been isolated from the Caribbean tunicate Trididemnum solidum. These compounds have cytotoxic activity and, therefore, are useful as antitumor drugs.

Abstract: Novel antibiotics didemnins A, B and C (didemnins), and nordidemnins A, B and C (nordidemnins) which can be obtained from a marine organism. These antibiotics are active against a variety of DNA and RNA viruses; thus, they can be used in various environments to control or eradicate these viruses. Further, these antibiotics have demonstrated therapeutic value against two murine cancer types.

Abstract: Synthetically produced substantially pure biologically active compounds having the general formula ##STR1## wherein R.sub.1 is C.sub.1 -C.sub.20 alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, cycloalkenyl, alkylcycloalkenyl, or cycloalkenylalkyl;R.sub.2 is hydrogen, C.sub.1 -C.sub.10 alkyl or an amide-substituted alkyl having up to 10 carbon atoms;R.sub.3 is a cyclic, straight or branched chain hydrocarbon group having 2-12 carbon atoms, particularly --(CH.sub.2).sub.n --, wherein n is 2-12; orR.sub.2 and R.sub.3 are linked together to form an alkylene chain; andR.sub.4 is selected from ##STR2## (substituted or unsubstituted carbamimidoyl), ##STR3## (dimethylpyrimidyl), or ##STR4## (carbamyl) wherein each of R.sub.5, R.sub.6, and R.sub.7 is hydrogen or the same or different C.sub.1 -C.sub.8 alkyl group. The compounds are useful as bactericides for a wide variety of bacteria, including S.pyogenes, B.subtilis, K.pneumoniae, M.avium, B.fragilis, C.perfringens and C.albicans.

Abstract: Novel bioactive metabolites from the Caribbean sponge Agelas coniferin are disclosed. These compounds are generically referred to as halopyrroles. They exhibit antiviral and antibacterial properties, and, thus, are useful for various non-therapeutic and therapeutic purposes.

Abstract: The subject invention concerns novel and useful antiviral compounds referred to as eudistomins. These compounds are obtainable from well-known and available marine organisms. Their utility is as antiviral agents as well as antibacterial and antitumor agents in some cases.

Abstract: This invention relates to the hybridization of streptolydigin, tirandamycin and sorbic acid to penicillin and cephalosporin nuclei.

Abstract: Novel antibiotics didemnins A, B and C (didemnins), and nordidemnins A, B and C (nordidemnins) which can be obtained from a marine organism. These antibiotics are active against a variety of DNA and RNA viruses; thus, they can be used in various environments to control or eradicate these viruses. Further, these antibiotics can be used to treat animals and humans hosting a neoplastic disease.

Abstract: Novel antibiotics didemnins A, B, C, D, and E (didemnins), are obtained from a marine organism. These antibiotics, and derivatives thereof, are active against a variety of DNA and RNA viruses; thus, they can be used in various environments to control or eradicate these viruses.

Abstract: New biologically active compounds derived by acylation and/or oxidative degradation of streptovaricin ansamycin materials, pharmaceutical compositions and therapeutic methods involving the same.

Abstract: Compounds possessing anti-bacterial and anti-viral activity of the formula II, ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are the same or different and selected from hydrogen, hydroxy, halo, amino, and C.sub.1 to C.sub.20 alkyl, alkoxyl, alkoxycarbonyl, amide or N-alkyl substituted amide.

Abstract: A novel plate system for thin layer chromatography comprises a supporting plate coated over about 50-90% of its area with an adsorbent layer, the uncoated surface comprising at least one strip of uniform width along an end of the supporting plate. Two such plates grafted and clamped in a lap-joint so that the edges of the adsorbent layers are in intimate contact provide an assembly on which a chromatogram developed on the first plate can be transferred in whole or in part onto the second plate. The assembly and technique are particularly useful for preparative thin layer chromatography.

Abstract: Biologically active geldanamycin derivatives of Formula III, ##SPC1##wherein R.sub.5, R.sub.6, R.sub.7 and R.sub.8 are the same or different and selected from hydrogen, hydroxy, halo, alkyl, alkoxy, carboxyl, carboalkoxyl, amino, amido, or N-alkylsubstituted amido; pharmaceutical compositions and therapeutic methods involving the same.

Abstract: Biologically active stereoisomeric forms of ansa ring compounds are prepared by heat treatment of a reaction mixture comprising the compound dissolved or suspended in a selected reaction medium and subsequent isolation of the desired isomeric form from the reaction mixture.