The reaction of organosulfur compounds with two or more equivalents of strong bases affords sulfur-containing dianions which are highly reactive toward a variety of electrophilic trapping agents. This review describes new synthetic reactions using the sulfur-containing dianions which have been recently developed in our laboratory.
The ecological role of secondary metabolites in plants is discussed with regard to coevolution between bioorganisms in nature. Several research works are described to explain the reason why there exists enormous diversity in bioorganisms and in secondary plant metabolites.
Highly sensitive methods established in our laboratories are outlined for the determination of bioactive substances including oligopeptides and related enzyme activities (i.e. aromatic aldehydes, their precursors and related amine-metabolizing enzymes, α-keto acids, sialic acids, catecholamines, their metabolites and biosynthetic enzymes, biogenic guanidines, arginine- and tyrosine-containing peptides, reducing sugars, fatty acids involving prostaglandines, nucleosides and nucleic acid bases with active imino hydrogen and biogenic alcoholic compounds) in biological materials, by means of conventional fluorometry and mostly pre- and postcolumn fluorescence derivatization high performance liquid chromatography. A series of mono- and bifunctional fluorogenic reagents has been developed for the selective derivatization of such bioactive substances and as enzyme substrates. Their use in the methods is briefly referred in the text.
Riboflavin tetrabutyrate of yellow powder (RTB C) was prepared from a methanol-H2O (45 : 55) solvent and various spectra were compared with those of RTB A. The emission spectra around 500-600 nm explained the color of RTB C; a maximum of RTB C was about 40 nm shorter than RTB A. Powder X-ray diffraction pattern of RTB C showed an aggregate of fine crystallites. The differences in infrared spectra between RTB A and C at 3430, 1380, 880-865 and 465-445 cm-1, assigned as NH on isoalloxazine ring, suggested a weak hydrogen-bond formation of RTB C. RTB A, B (a charge transfer type) and C changed their phase each other by treating them with solvents or by heating.
By taking notice of the fibrinolytic activity of urokinase (UK) which is a plasminogen activator, an antithrombogenic material was developed by immobilizing the UK on a material surface. That is, the immobilized UK possesses an action to transform catalytically the plasminogen in the blood into plasmin, and exhibits its antithrombotic action by dissolving constantly the fibrins produced on the material surface. The UK immobilized on nylon and ethylene vinyl acetate copolymer (EVA) surfaces showed stable activity both in vitro and in vivo. Thrombus formation time (TFT) of the UK immobilized materials was remarkably longer than that of non-treated materials. Since UK inhibiting substances were reported to be present in the blood, a nitrophthalic acid having an affinity for the UK inhibiting substances was co-immobilized with UK to see whether the inhibitory effect of UK could be prevented or not. The materials co-immobilized with UK and the nitrophthalic acid showed superior stability compared to that without the nitrophthalic acid. The UK immobilized material proved to be an adequate antithrombogenic material.
3-(Substituted benzenesulfonylamino)-5, 6-di(p-substituted phenyl)-1, 2, 4-triazines were synthesized and examined for their antimicrobial activities against influenza virus A2/Adachi strain and micro-organisms parasitic to animals and plants. 3-(Benzenesulfonylamino)-5, 6-di(p-chloro- and p-bromo-phenyl), 3-(4-fluorobenzenesulfonylamino)-5, 6-di(p-fluorophenyl), 3-(2, 5-dichlorobenzenesulfonylamino)-5, 6-di(p-butoxyphenyl), 3-(3-nitrobenzenesulfonylamino)-5, 6-di(p-chlorophenyl) and 3-(3-aminobenzenesulfonylamino)-5, 6-di(p-butoxyphenyl)-1, 2, 4-triazines were highly active against the influenza virus. Their 50% inhibitory concentrations were 4.4-19.8 μg/ml and 50% virucidal concentrations were 4.4-10 μg/ml. p-Substitution of halo group or alkoxy group having suitable chain length on 5- and 6-phenyl rings of 1, 2, 4-triazine enhanced especially the virucidal activity. Satisfactory quantitative structure-activity relationships were obtained for the inhibitory activity against the virus and for toxicity to chorio-allantoic membrane. About half of these compounds showed minimum inhibitory concentrations of 50-100 μg/ml against Mycoplasma gallisepticum and <6.3-100 μg/ml against Erwinia aroideae and Corynebacterium michiganense.
Dihydroergotoxin (DET)-bovine serum albumin (BSA) conjugate in which the hapten molecule is linked to BSA through the N-1 position on the DET, was prepared by means of the Mannich reaction. Antisera raised against DET-[N-1]-BSA immunogen in guinea pigs and rabbits possessed excellent specificity to DET, exhibiting no significant cross-reactions with dihydroergotamine and the metabolite of dihydroergocristine (<1%). The use of specific antiserum and radioactive tracer (3H-dihydro-α-ergocryptine, 42 Ci/mmol) allowed to assay DET in the plasma (detection limit ca. 10 pg/ml) directly without extraction. The proposed assay system was applied for measuring the plasma DET level in dogs after oral administration of a tablet of DET mesylate(2 mg).
The effects of various drugs on the metabolic reduction of acetohexamide were investigated by using the cytosols of the rabbit liver, kidney and heart. Most of nonsteroidal anti-inflammatory drugs inhibited the acetohexamide reduction in these three tissues. Especially, indomethacin, diclofenac, protizinic acid and flufenamic acid gave powerful inhibitions. Ketone-containing drugs including warfarin also inhibited the acetohexamide reduction in both the liver and kidney; acetohexamide reduction in the heart was inhibited by only warfarin. On the other hand, drugs which inhibited hepatic microsomal enzyme, and (-)-hydroxyhexamide, a major metabolite of acetohexamide, had no effect on acetohexamide reducing activities of these three tissues.
3-(E)-and-(Z)-Cyanomethylene-(5a), (5b), p-nitrophenylmethylene (6a), (6b), p-methoxyphenylmethylene (7a), (7b) and phenylmethylene (8a), (8b)-3-deoxy-1, 2;5, 6-di-O-isopropylidene-α-D-ribo-hexofuranose were prepared from 1, 2;5, 6-di-O-isopropylidene-α-D-ribo-hexofuranos-3-ulose (4) and the corresponding Wittig reagents. In deacetonylations of these 3-methylene derivatives by ion exchange resin (IR-120B), 5a, 5b and 6a, 6b gave rise to intramolecular cyclization products, 3, 6-anhydro-3α-cyanomethyl-1, 2-O-isopropylidene-α-D-glucofuranose (9) and 3, 6-anhydro-3α-p-nitrophenylmethyl-1, 2-O-isopropylidene-α-D-glucofuranose (11), respectively. While, 7a, 7b and 8a, 8b gave rise to the corresponding diol : 3-(E)-and-(Z)-p-methoxyphenylmethylene-3-deoxy-1, 2-O-isopropylidene-α-D-ribo-hexofuranose (12a), (12b) and 3-(E)- and-(Z)-phenylmethylene-3-deoxy-1, 2-O-isopropylidene-α-D-ribo-hexofuranose (13a), (13b).
Hot water extracts of green tea showed a prolonged hypotensive effect in anesthetized rabbits. The major active principle was purified by chromatography on Polyamide C-200 and Sephadex LH-20, and identified as (-)-gallocatechin gallate ((-)-GCG). (-)-GCG at a dose of 0.1 mg/kg (i.v.) effectively reduced blood pressure in anesthetized rabbits and at 0.5 mg/kg lowered it by 20-40 mmHg for an extended period of time. This compound seems to be an artifact by epimerization of (-)-epigallocatechin gallate during heating extraction.