Tripod-shaped trithiols 1-3, containing CH2SH groups at the three bridgehead positions of the adamantane framework and a halogen-containing group [Br (1), p-BrC6H4 (2), or p-IC6H4 (3)] at the fourth bridgehead, were synthesized, and self-assembled monolayers (SAMs) were prepared on atomically flat Au111 surfaces. The three-point chemisorption of these tripods was confirmed by polarization modulation infrared reflection absorption spectroscopy, which showed the absence of a S-H stretching band. Scanning tunneling microscopy of the SAM of 1 exhibited a hexagonal arrangement of the adsorbed molecule with a lattice constant of 8.7 angstroms. A unidirectionally oriented, head-to-tail array of 1, which allows the close approach of neighboring molecules, is proposed as a reasonable model of the two-dimensional crystal, where the adsorbed sulfur atoms form a quasi-(radical3 x radical3)R30 degrees lattice. The charge of the electrochemical reductive desorption of the SAM of 1 was in good agreement with the expected surface coverage, while the SAMs of 2 and 3 showed somewhat less (ca. 70%) charge. The large negative reduction peak potentials, observed for the SAM of 1, are taken to indicate a tight anchoring of this tripod by three sulfur atoms.

Hydantocidin1, a new compoundwith potent non-selective herbicidal activity, was found in a submerged culture of Streptomyces hygroscopicus SANK63584. It was isolated from the culture filtrate by the following successive treatments comprised of activated carbon, Diaion HP-20, Dowex 50WX4,and Avicel column chromatographies. Finally it was crystallized as colorless needles from acetone.The molecular formula, C7H10N2O6, was determined by analyses of HRFABmass spectrum in conjunction with 13C NMRspectrometry. The structural elucidation revealed that it has a unique structure with a spiro-bond between ribose and hydantoin moieties in the molecule. The characteristic herbicidal activities against annuals as well as perennials, including monocotyledonous and dicotyledonous weeds, were observed. 293 In the course of screening for new herbicidal substances from culture broths of microorganisms, we found a new compound, hydantocidin, produced by a streptomycete identified as Streptomyces hygroscopicus SANK63584, which was isolated from a soil sample collected in Annaka, GunmaPrefecture, Japan.In this paper, we report the taxonomy, fermentation of the producing strain, isolation, physico-chemical and biological properties of hydantocidin. The detailed herbicidal activity and the structural elucidation of the compoundwill be reported elsewhere (under preparation).

A dyad consisting of a tripod-shaped trithiol with an adamantane core and a terminal ferrocenyl group linked through ap-phenyleneethynylene bridge was synthesized. The trithiol formed a stable self-assembled monolayer (SAM) on Au(111), wherein each molecule is bound to the surface by three-point adsorption using all sulfur atoms, with confirmation by PM-IRRAS and XPS analyses. Cyclic voltammetry of the SAM showed a line shape typical of an ideal adsorbed system, that is, a monolayer with negligible electrostatic interaction among the terminal ferrocenyl groups. Thus, a rare SAM was achieved, in which the component molecules were isolated from adjacent molecules without the coadsorption of nonelectroactive molecules.

During the course of our screening program for natural product drugs effective against multidrug resistant cells by using adriamycin resistant HL-60 cells, we have discovered a new 12 membered macrolide FD-895 in the fermentation broth of Streptomyces hygroscopicus A-9561 isolated from a soil sample collected at Iriomote Island, Okinawa prefecture, Japan. FD-895 showed stronger cytocidal activities against in vitro tumor cell lines than adriamycin. FD-895 had the same IC50values against parent and adriamycin resistant HL-60 cells.A major drawback to cancer chemotherapy is that many tumors are either intrinsically resistant to the compoundor develop resistance over the course of treatment. Treatment with chemotherapeutic agents generally results only in temporary remission of tumor disease in the clinic.It is also well knownexperimentally1 '2) that mammalian cells selected for resistance to a single cytotoxic natural product drug can becomenot only resistant to the agent used but also cross-resistant to a wide range of structurally and functionally unrelated antibiotics and alkaloids. For these reasons the developmentof chemotherapeutic agents equally effective against malignant and resistant cells has been desired world wide for overcoming tumor disease. From this standpoint, we have explored natural product drugs effective against multidrug resistant cells.In the course of our screening program using adriamycin resistant HL-60cells to discover low molecular compoundsproduced in microbial fermentation broths and capable of circumventing multidrug resistance, we have discovered a new 12-membered macrolide FD-895 (Fig. 1)