Marine carotenoids halocynthiaxanthin 2, mytiloxanthin 3 and crassostreaxanthin B 4 have characteristic structures, commonly possessing a monoacetylenic end group. The cyclopentyl end group of 3 is believed to be formed in nature from the epoxide end group of 5, 6-epoxy carotenoids such as 2 (Chart 1, route a). It is also conceivable that 4 including a novel tetrasubstituted olefinic end group arises from epoxy carotenoids by the opening of the C-6-oxygen bond of the oxirane ring and the subsequent migration of the methyl group at the C-1 position (route b). We found that treatment of the epoxide 6a having a partial structure of epoxy carotenoids with Lewis acids gave the cyclopentyl ethyl ketone 9 possessing the same configuration as 3, and the acyclic tetrasubstituted olefinic methyl ketone 11 including a partial structure of 4 (Chart2). It supported the proposed metabolic pathway of 5, 6-epoxy carotenoids. Toward the biomimetic synthesis of 4, we examined the reaction of epoxides having several substituents at C-6 position with Lewis acids. Among these epoxides, an epoxide 60 was found to provide a tetrasubstituted compound 61 as a major product. This could be converted into an aldehyde 73 in 8 steps which was transformed into a compound 75 through the coupling reaction with vinyllithium 63. Then, the first total synthesis of 4 was accomplished via the double Wittig condensation of 75 with phosphonium salts 76 and 77.
This review summarizes our efficient syntheses of novel bicyclic nucleoside analogues, 3'-O, 4'-C-methyleneribonucleosides (1) (4-BC type nucleoside analogue), 2'-O, 4'-C-methyleneribonucleosides (2) (5-BC), 3'-amino-3'-deoxy-3'-N, 4'-C-methyleneribonucleosides (3) (aza 4-BC), and 3'-azido- and 3'-amino-3'-deoxy-2'-O, 4'-C-methyleneribonucleosides (4, 5) (aza 5-BC). From 1H-NMR and X-ray crystallographic analyses, the 4-BC and aza 4-BC type nucleoside analogues (1, 3) were found to have a S-conformation predominantly, while the conformations of 5-BC and aza 5-BC type nucleoside analogues (2, 4, 5) were exclusively locked in N-form. The 4-BC and 5-BC type nucleoside analogues (1, 2) were effectively introduced into oligonucleotides using a DNA synthesizer. Furthermore, unprecedented hybridizing ability towards complementary RNA and DNA, RNA selectivity, potent triplex forming ability, and sufficient enzymatic stability of these modified oligonucleotides were also confirmed. These results should reveal a promising route to the development of antisense/antigene methodology.
Microcystins, produced by freshwater cyanobacteria, are cyclic peptide hepatotoxins and tumor promoters. An outbreak of human poisoning attributed to microcystins has been reported in Caruaru, Brazil in 1996, where exposure through renal dialysis led to the death of 50 patients. Although such severe acute effects on human health seem to be rare, microcystins poses problems to human health which could result from low-level, chronic exposure to microcystins in drinking water. It is therefore important to monitor the levels of microcystins in water reservoirs where cyanobacterial blooms occur. We have developed a total analysis system for microcystins using GC-MS and LC-MS. This comprises initial screening of samples to check for the presence of microcystins by detecting 2-methyl-3-methoxy-4-phenylbutyric acid as an ozonolysis product using thermospray interface LC-MS and electron ionization/GC-MS. If a sample is positive in a screening test, it will be necessary to follow through with identification and quantification. Frit-FAB interface LC-MS allowed the rapid identification of microcystins in cyanobacteria and lake water, and also enabled us to identify microcystins and their metabolites formed in vivo in mouse liver. Finally, Frit-FAB/LC-MS using selected ion monitoring could be used for quantitative analysis of microcystins in lake water in the low nanogram range. The total analysis system proposed in the present study should be applicable to studies of the metabolism of microcystins, of their detoxification, and those of the mechanism(s) of the accumulation in the food chain.
Anodization of a glassy carbon (GC) in a 1-alkanol in a cycled or constant potential mode serves as a useful tool for preparing a chemically modified GC electrode. By this treatment, 1-alkanol molecules are fixed on the GC surface via ether linkage. As the 1-alkanol in the anodic modification, CH3(CH2)nOH (1 : n=0-7), HO(CH2)nOH (2 : n=1-5), and HO(CH2CH2O)nR (3 : n=1-4, R=H; 4 : n=1-3, R=CH3) are utilized. The surface of a GC electrode anodized in the 1-alkanol remarkably reflects the identities of the modifiers. Some of the modified GC electrodes exhibit surface characteristics useful for electroanalytical application as follows : (1) the surface of the GC electrode anodized in 3 or 4 is hydrophilic and resists protein adsorption. An HPLC system equipped with an electrochemical detector employing the GC plate anodized in triethylene glycol as a working electrode has proven to provide a useful analytical method for a protein-containing sample; (2) in the course of anodization of the GC electrode in 2, the diol molecules are first fixed on the surface via ether linkage with one of hydroxyl groups, and the remaining terminal hydroxyl groups in some of the fixed molecules are then oxidized to carboxyl groups. Thus, the GC electrode anodically modified with 2 has carboxyl groups on the surface, which allow dopamine to be voltammetrically discriminated from ascorbic acid in a large excess; (3) when the GC electrode is anodized in triethylene glycol containing HOCH2CH2SO3Na, carboxyl groups are effectively introduced on the surface. On the basis of the formation of an amide bond formation through chemical reaction between the functional groups and amino compounds, electrochemical catalysts such as 2, 2, 6, 6-tetramethylpiperidinyl-1-oxyl (TEMPO) and catechol are immobilized on the surface of the GC electrode. The obtained electrodes shows stable voltammetric and electrochemically catalytic performance probably because the catalytic molecules are confined on the electrode surfaces via a hydrophilic linker instead of a hydrophobic one.
As a new type of zincate, "highly coordinated" zincates, Me3Zn(R)Li2 (R=Me, CN, SCN) were designed. On the basis of their excellent chemical yields and chemoselectivities, these species were considered to be differentiated from ordinary triorganozincates, R3ZnLi. The structures of the newly designed zincates were discussed on their spectroscopic studies. All results strongly support the fact that these newly designed zincates are new category of zincate species. Various dialkylzinc hydride "ate" complexes were also designed and the reactivities of these zincates toward the carbonyl compounds investigated. The results clearly reveal that dimethylzinc hydrides are the most powerful and selective zincate for the reduction of the carbonyl group.
A general scheme for the efficient synthesis of Trp-containing cystine peptide by the successive treatment with methyltrichlorosilane-diphenylsulfoxide in trifluoroacetic acid (TFA) and trifluoromethanesulfonic acid (TFMSA)-thioanisole in TFA, is described. A disulfide bond-forming reaction by silyl chloride-sulfoxide system is completed within 10-15 min without modifications at sensitive residues (Tyr, His, Met) in peptide chain, except for a Trp residue. In order to synthesize a Trp-containing cystine peptide using silyl chloride, the indole moiety of Trp has to be protected since the chlorination of the indole ring proceeded predominantly. A formyl group has been the only protecting group employed for this purpose in practical syntheses of cystine peptides, although it was clarified that a side reaction derived from the formyl group migration was inevitable in the synthesis of somatostatin. Firstly, we examined the application of the following Nin-protecting groups, mesitylene-2-sulfonyl (Mts), cyclohexyloxycarbonyl(Hoc), and 2, 4-dimethylpent-3-yloxycarbonyl(Doc) for an efficient synthesis of the Trp-containing cystine peptide by the silyl chloride method. In order to find a feasible scheme of the successive treatment with CH3SiCl3-PhS(O)Ph/TFA and TFMSA-thioanisole in TFA, we synthesized somatostatin using Trp(Mts), Trp(Hoc) or Trp(Doc) derivative. The Doc group was found to be the most suitable as an indole protecting group, since the protecting group was cleaved under mild conditions (4°C, 30 min) via the corresponding Nin-carboxylic acid intermediate. We then applied the above procedure to the synthesis of endothelin-1(ET-1), a peptide containing 21-amino acid residues having a C-terminal Trp residue and two disulfide bonds, by regioselective disulfide formation. The combination of the silyl chloride method with iodine oxidation using S-acetamidomethyl (Acm) and S-tBu groups for the regioselective double disulfide formation was successfully applied to give a highly purified ET-1. These results also show that the Nin-Doc group would be useful for the efficient syntheses of complex cystine-peptides by the silyl chloride method.
1, X-Naphthyridines (X=5, 6, and 8) (1-3) were synthesized in a high yield by the Skraup reactions of 4-, 3-, and 2-aminopyridines with glycerol, in the presence of ferrous sulfate and boric acid. The improved syntheses were applied to the syntheses of 1, 5-, 1, 6-, and 1, 8-naphthyridines (4-28), pyridonaphthyridines (31, 32), benzonaphthyridines (38-42), naphthonaphthyridines (44, 48, 49, 59). New synthetic methods of naphtho [1, 2-b or 2, 1-b][1, 8]naphthyridine (62, 63), benzo[b][1, 8]naphthyridine (41) and benzo[g]quinoline (67) were developed and their compounds obtained conveniently. Reissert reaction of 1, 6-naphthyridine (2) using triethylbenzylammonium chloride (TEBA) produced Reissert compounds and ring-opened compounds. Reissert reaction of 1, 7-naphthyridine (29), 4, 7- (87), 4, 6-phenanthroline (38) gave the Reissert compounds, and the compounds (2, 38) gave their pseudo bases (79, 90). Reissert-type reactions of benzo[f]quinoline (68), and 1, 7-phenanthroline (105) with acyl chloride and phosphite, gave α-and γ-phosphonate, and 87 produced α, α'-(108a-c) and α, γ'-diphosphonates (109a-c). The structure of 108c-1 was determined to be trans-type by an X-ray analysis. Compounds 1-3, 29, and benzo[f or h]quinoline were treated with dimetyl sulfoxide in the presence of sodium hydride to give mainly methylated compounds at the position para to the ring-nitrogen. When benzo[f or h]quinoline N-oxide was treated with methylsulfinylmethyl carbanion in the usual procedure, a new reaction took place to produce phenanthrene in an excellent yield. The same reaction of 1, 10-, 1, 7-, or 4, 7-phenanthroline N-oxides (143-145) resulted in the liberation of the N-oxide group to form benzo [f or h]quinoline, but isoquinoline N-oxide afforded to benzazepine derivatives (161). Reaction of quinaldine with methylsulfinylmethyl carbanion gave novel tricyclic compound (121a). The oxidation of 41, 62, and 63 with peroxy acids afforded novel products such as seven-membered 1, 4-oxazepine derivatives.
The failure of patients to comply with treatment regimens recommended by their physicians is a significant clinical problem. Researches on the assessment of compliance have, however, been precluded by methodological difficulties such as lack of adequate measures. The purpose of this study was to develop a self-administered questionnaire to evaluate drug compliance. First, questionnaire containing a 52-items complied by two doctors, a pharmacist and a nurse, was tested on 81 outpatients, all volunteers, attending the departments of psychosomatic medicine and internal medicine. Four items were temporarily removed for later analysis because they directly inquired about drug compliance (drug compliance items). The other 48 items were analyzed and three factors consisting of 26 items were further studied : expectation on taking medicine, rejection to taking medicine and seeking knowledge of drugs. Chronback's alpha coefficients representing internal consistency of the three factors were sufficiently high (ranging from .75 to .84). Furthermore, we preformed a simplified pill count to validate the 4 drug compliance items. There was a weak to moderate correlation between the result of pill count and each of 4 drug compliance items. A new self-administered questionnaire of 30 items was thus developed and named the Drug Compliance Scale.
The purpose of this study was to investigate psychological factors affecting drug compliance in the department of psychosomatic medicine. Seventy-four outpatients were asked to answer a battery of self-administered questionnaire including the Drug Compliance Scale (DCS) that we had recently developed and other questionnaire evaluating psychological and vegetative symptoms, self-efficacy and attributional styles on the promotion of health and personality closely related to interpersonal relationships. Results of path analysis indicated that attributional styles and self-efficacy mainly affected three factors of DCS such as expectation on taking medicine, rejection to taking medicine and seeking knowledge of drugs, through which they influenced drug compliance, and also indicated that personality and self-efficacy mainly affected the stability of mood state, suggesting a further influence on drug compliance.
There are few reports about marker substances for the identification of Cistanchis Herba in formulations. First, constituent analysis was performed by HPLC for screening of a marker substance, using several lots of Cistanchis Herba and its fluid extract. As a result, two components were clearly detected, which were thought to be good marker substances and identified to be echinacoside and acteoside by structural analysis. Stability testing of these two marker substances in various pH and temperature conditions was carried out, which suggested that they are stable and suitable enough for the identification. Therefore, the identification methods of Cistanchis Herba and its fluid extract in formulations were investigated using five different kinds of commercial drinkable preparations with authentic standard of echinacoside and acteoside as marker substances. Consequently, echinacoside and acteoside were clearly detected in all formulations investigated, using an HPLC-photodiode array detector system. Echinacoside and acteoside will be successfully used as marker substances for the identification of Cistanchis Herba and its fluid extract in formulations.