首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
It has now been shown that Acetate A previously obtained by isomerizing ilexol acetate is nothing other than urs-13 (18)-en-3β-yl acetate prepared from α-amyrin, furnishing conclusive evidence for its conversion into one of the compounds of the ursane series.

Isoilexol, oxidized with chromium trioxide at room temperature, afforded a ketone named isoilexone, C30H48O, m.p. 194–195°, +75.90° (c, 0.527), and oxidized with the same oxidant at 70–80°, another ketone named isoilexenedione, C30H46O2, m.p. 221-223°, +16.28° (c, 0.307).

Huang-Milon reduction of these ketones afforded one and the same deoxy compound named isoilexene, C30H50, m.p. 183–185°, +48.34° (c, 0.290), which might well be assumed to constitute a pair of optical antipodes with olean-13 (18)-ene, C30H50, m.p. 184-185°, ?48.50° (c, 0.545).  相似文献   

2.
A sterol and a steryl glucoside were isolated from dried beet pulp. The sterol was identified with α-spinasterol, the glucoside possessed chemical and physical properties such as follows: The molecular formula C35H58O6, m.p. 292°, [ α]19D-34.1°, acetate; m.p. 168°, benzoate; m.p. 175-177°, and positive for Molish and Lieber-mann-Burchard reactions. When it was hydrolyzed with 1% sulfuric acid, the crystal of α-spinasterol and D-glucose detectable by paper chromatography were obtained. These results gave evidence that the glucoside was in question to be α-spinasteryl D-glucoside.  相似文献   

3.
From the mycelium of Ascochyta imperfecta decumbin, C16H24O4, mp 203°C, was obtained in one percent yield.

The absolute structure of decumbin was presented as [II] by the following evidences: The configuration about C4 was determined as (S) by the benzoate rule on the tetrahydromonoketone (21). The hydroxyl at C7 is α, because tetrahydrodecumbin (23) showed no intramolecular hydrogen bond, while its C7 epimer (24) did. Ring juncture was determined by ORD of a five membered ketone (16). Two double bonds were found to be trans from IR data. The stereochemistry of decumbin monoepoxide (7), tetrahydropyrans (12 and 13) was also studied. Plant tests of the twenty derivatives of decumbin on lucerne and rape revealed that the growth inhibition activity has close relation with the presence of double bond in the thirteen membered lactone ring.  相似文献   

4.
The purpose of this study is to find optimal conditions for pre-hydrolysis in the new wood saccharification process with strong sulfuric acid. In the experiment, the hydrolysis rate of resistant fraction of pentosan of white birch (Shirakamba, Betula platyphylla Sukatchev var. japonica Hara) wood and the decomposition rate of xylose are measured in acid concentrations ranging from 30 to 60% at temperatures ranging from 30 to 90°C. The hydrolysis of resistant pentosan of white birch and the decomposition of xylose are the first-order reactions. The first-order reaction constant of hydrolysis of resistant pentosan, kB min-1, is expressed by the following empirical equations as the function of percentage concentration of sulfuric acid, C, and reaction temperature described by absolute temperature, T°K, ranging from 40 to 80°C:

where sulfuric acid concentrations range from 30 to 50%;

where sulfuric acid concentration is 60%.

The first-order reaction constant of decomposition of xylose, k2 min-1, is expressed by the following empirical equation as the function of sulfuric acid strength described by acidity function, H0, and reaction temperature described by absolute temperature, T°K, in sulfuric acid concentrations ranging from 30 to 60% at temperatures within the range of 40 to 100°C.

where C is sulfuric acid strength described by acidity function, H0.  相似文献   

5.
The isolation of a new glycoside, named here as neocycasin A, with use of carbon chromatography, is described. It is one of a series of aliphatic azoxy glycosides, found in the seeds of Japanese cycad together with cycasin which is β-glucosyloxyazoxymethane as reported previously. The glycoside monohydrate gives m.p. 162° ~ 163° (decomp.), ? 35.1°; its heptaacetylate, m.p. 142° ~ 143°, ? 55.5°, from which octaacetyl-β-laminaribiose is isolated. On the basis of examination of the products obtained from partial or complete hydrolysis, and spectroscopic measurements, neocycasin A is concluded to be β-laminaribiosyloxyazoxymethane, i.e. 3-O-β-d-glucopyranosylcycasin.  相似文献   

6.
Four kinds of 4-substituted phenyl diethoxyphosphinyl disulfide (substitueras: H, CH3, C2H5, Cl) and phenyl diethoxyphosphinothioyl disulfide reacted readily with diazomethane. The phosphinyl disulfides produced diethyl (4-substituted phenylthio)methyl phosphorothionate and the isomer, diethyl S-(4-substituted phenylthio)methyl phosphorothiolate, as the main products, whereas the phosphinothioyl disulfide produced only diethyl S-(phenylthio)methyl phosphorodithioate.

The possible mechanism involved is as follows: the S-S bond in (EtO)2P(X)-S-S-C6H4R (X = O or S) is cleaved by nucleophilic attack of diazomethane at the sulfur atom bonded to the phenyl group to produce and N2CH2–S–C6H4R; the latter reacts with the former with loss of nitrogen; therefore, when X is O, two compounds, (EtO)2P(S)–O–CH2–S–C6H4R and (EtO)2P(O)–S–CH2–S–C6H4R, are produced, when X is S, only (EtO)2P(S)–S–CH2 –S–C6H4R is obtained.  相似文献   

7.
A microorganism was isolated from the air of a patient-room and classified in the genus Oospora. This microorganism was cultured on a malt extract medium, and the mycellium was separated from the culture filtrate. A new compound (O-1), m.p. 129°C, C11H10O3, and eburicoic acid, m.p. 290°C, C31H50O3 were obtained from the dried mycellium. Another new compound (O-2), m.p. 176°C, C11H8O5 was obtained from the culture filtrate.  相似文献   

8.
From mycelia of Asp. niger and Asp. awamori aurasperones A, B and C along with related two yellow pigments have been isolated.

Aurasperone A, C32H26O10, is obtained in yellow prisms; m.p. 207°C; [α]d —136°; gives the diacetate and the dimethyl ether and is assumed to be a dimeric 2-methyl-5- hydroxy-6,8-dimethoxy-4H-naphtho [2,3-b] pyran-4-one (IV). Aurasperone B, [α]D +46.3°, is the main yellow metabolite, m.p. 186°C, and affords aurasperone A on hydrochloric acid-treatment. It has molecular formula C32H30O12 and is supposed to have the structure (V). The other yellow pigments have been found to be also congeners of aurasperone A.  相似文献   

9.
Three new pigments, named versicolorins A, Band C, as metabolites from the mycelium of Aspergillus versicolor have been isolated. Versicolorin A, C18H10O7, is fine orange yellow needles, m.p. 289°C (decomp.), [α]D-354°. It is an anthraquinoid pigment having three hydroxyl groups and a vinyl ether system contained in a five-membered ring. Versicolorin A trimethyl ether was hydrogenated to a dihydro-derivative, and by oxidation gave 3,5-dimethoxyphthalic acid and a hydroxy acid which may be 1,6,8-trirnethoxy-3-hydroxy anthraquinone-2-carboxylic acid. These chemical behavior and NMR data show that versicolorin A probably has the structure of (I). Versicolorin B, C18H12O7, is fine orange yellow needles, m.p., 298°C (decomp.), [α]D-223° Its trimethyl ether is identical with that of dihydroversicolorin A. Therefore, the structure (II) could be assigned to versicolorin B. Versicolorin C, C18H12O7, is orange red needles, m.p.>310°C, [α]D O° Comparison of optical properties, IR and NMR spectra of versicolorin B and its methyl ether with those of versicolorin C and its methyl ether indicates that versicolorin C is very probably a racemate of versicolorin B.  相似文献   

10.
Two moderately halophilic, facultatively aerobic, motile bacteria with flagella, designated strains 10-C-3T and 30-C-3, were isolated from jeotgal, a traditional Korean fermented seafood. Cells of the strains were observed to be ovoid-rods showing catalase- and oxidase-positive reactions and production of creamy-pink pigments. Growth of strain 10-C-3T was observed at 15–35 °C (optimum, 25–30 °C), at pH 5.5–9.0 (optimum, pH 7.0–7.5), and in the presence of 3–15 % (w/v) salts (optimum: 5–10 %). The two strains were found to contain C18:1 ω7c, C16:0, summed feature 3 (as defined by the MIDI system, comprising C16:1 ω7c and/or C16:1 ω6c), and C12:0 3-OH as the major cellular fatty acids. The G+C contents of the genomic DNA of strains 10-C-3T and 30-C-3 were determined to be 63.2 and 63.1 mol%, respectively and the respiratory quinone detected was ubiquinone 9 (Q-9) only. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strains 10-C-3Tand 30-C-3 formed a distinct phyletic lineage within the genus Halomonas and are most closely related to Halomonas fontilapidosi 5CRT with 95.2 % of 16S rRNA sequence similarity. Strains 10-C-3Tand 30-C-3 shared 99.2 % of 16S rRNA gene sequence similarity and their DNA–DNA relatedness value was 96.6 ± 0.9 %. On the basis of phenotypic, chemotaxonomic and molecular features, strains 10-C-3Tand 30-C-3 represent a novel species of the genus Halomonas, for which the name Halomonas cibimaris sp. nov. is proposed. The type strain is 10-C-3T (= KACC 14932T = JCM 16914T).  相似文献   

11.
An Fe(III) oxide-reducing bacterium designated as SgZ-3T, which could couple glucose oxidation to Fe(III) oxide reduction for energy conservation, was isolated from an electrochemical biofilm. The isolate was Gram-negative, catalase-positive and oxidase-negative, and facultative anaerobic. NaCl was not required for growth, but NaCl concentrations up to 5 % (w/v) were tolerated. Growth occurred in TSB (tryptic soy broth) at 20–40 °C (optimum 30 °C) and at pH 6.0–7.5 (optimum 7.0). Phototrophic growth could not be demonstrated. No vesicular photosynthetic membrane was observed. Bacteriochlorophyll α and carotenoids were absent. Biotin and thiamine were required as growth factors for the isolate. Phylogenetic analysis of the 16S rRNA gene sequence placed strain SgZ-3T within the family Rhodobacteraceae and affiliated with an phototrophic genera Rhodobacter. The G+C content of the genomic DNA was 68.6 mol%. Strain SgZ-3T contained Q-10 as the predominant quinone. The major cellular fatty acids were C18:1 ω6c and/or C18:1 ω7c (66.9 %) and C16:0 (9.5 %). Based on its phenotypic and phylogenetic properties, chemotaxonomic analysis and the results of physiological and biochemical tests, strain SgZ-3T (=KACC 16603T = CCTCC AB2012026T) was designated as the type strain of a new genus and a novel species of the family Rhodobacteraceae, for which the name Sinorhodobacter ferrireducens sp. nov. was proposed.  相似文献   

12.
Justicidin A, C22H18O7, mp 263°C and B, C21H16O6, mp 240°C were isolated as fish-killing components from Justicia Hayatai var. decumbens. The piscicidal activities of both compounds were demonstrated to be as strong as rotenone and about ten times stronger than that of pentachlorophenol.  相似文献   

13.
Lipolytic activities of intracellular lipase obtained from Streptococcus lactis 527 cells grown at 30°C were determined using bacterial neutral lipids extracted from cells grown at 10 and 30°C. The amounts of free fatty acids liberated from lipids by lipase were in the order: 30°C neutral lipid > 10°C neutral lipid > triolein > intracellular membrane fraction. Glycerides hydrolyzed partially by lipase were detected on thin-layer plates and were composed of 1,3- and 1,2-diglycerides, fatty acids and unhydrolyzed triglycerides. Fatty acids liberated from neutral lipids by lipase were determined by gas chromatography. It was found that the major acid was cy-C10 and the minor among the acids liberated from 10°C neutral lipid, whereas the major acid was and the minors and cy-C10 from 30°C lipid.  相似文献   

14.
Malonogalactan, a malonylated polysaccharide (—74° (c=1.6, H2O)) produced by Penicillium citrinum, consisted of d-galactose and malonic acid in the approximate molar ratio of 3:1. Molecular weight of the demalonylated galactan (-99° (c=4.6, H2O)) was about 40,000. From the data regarding optical rotation, nuclear magnetic resonance spectrum, infrared spectrum, glycosidase susceptibility, periodate oxidation, Smith degradation, methylation and acid hydrolysis, the possible structure of the Penicillium malonogalactan is deduced as follows: A galactan, 1,5-β-galactofuranoside polymer esterified with malonic acid at the position of 2 or 3.  相似文献   

15.
The three-dimensional structure was determined by x-ray crystallography for d(T[p](CE)T), a uv photoproduct of the cyanoethyl (CE) derivative of d(TpT), having the cis-syn cyclobutane (CB) geometry and the S-configuration at the chiral phosphorus atom. The crystals of C23H30N5O12P · 2H2O belong to the orthorhombic space group P212121 (Z = 4), with cell dimensions a = 11.596 Å, b = 14.834 Å, and c = 15.946 Å, containing two water molecules per asymmetric unit. The CB ring is puckered with a dihedral angle of 151°. The two pyrimidine bases are rotated by –29° from the position of direct overlap of their corresponding atoms. This represents a major distortion of DNA, since in DNA adjacent thymines are rotated by +36°. The pyrimidine rings are puckered with Cremer–Pople parameters for T[p] and in parentheses [p]T: Q: 0.24 Å (0.31 Å); θ: 123° (120°); ?: 141° (86°). These represent half-chairs designated as 6H1 (T[p]) and 6H5 ([p]T). The CB and pyrimidine ring conformations are interrelated, and we postulate that they execute a coupled interconversion in solution. The T[p] segment has the syn glycosyl conformation, a 2T3 sugar pucker, and gauche? conformation at C4′-C5′; the [p]T segment is anti, 3T4, trans. The C5′-O5′ torsion of the [p]T unit is –124.5°, and the C3′-O3′ torsion of the T[p] unit is –152.9°. Bond angles and bond lengths involving the phosphorus atom are similar to those of other phosphotriesters. The P-O3′ and P-05′ torsion angles are –138.1° and 58.6°, respectively. Several intermolecular (but no intramolecular) hydrogen bonds are found in the crystal.  相似文献   

16.
Alkaline degradation of Aurasperone A, C32H26O10, gave a binaphthyl (IIa), m.p. 255°C and acetone. (IIa) afforded a tetraacetate (IIb), C32H30O12 m.p. 219°C and a tetramethyl ether (IId), C28H30O8, m.p. 188°C. These facts along with the NMR spectra of aurasperone A and (IIb) confirm that aurasperone A is a dimeric 2-methyl-5-hydroxy-6,8-dimethoxy-4H-naphtho[2,3-b]pyran-4-one with asymmetric C-C linkage (7-10′ or 9-10′). The ether (IId) is not identical with 1,1′ ,3,3′ ?6,6′ ,8,8′-octamethoxy-4,4′-binaphthyl. Thus, it follows that (IId) is a 2,4′-binaphthyl and hence aurasperone A is 2,2′-dimethyl-5,5′- dihydroxy-6,6′,8,8′-tetrahydroxy-7,10′-bi[4H-naphtho[2,3-b]pyran-4-one] (I).  相似文献   

17.
Protein-containing polysaccharides extracted from fruiting bodies of a Chinese fungus named Feng Wei Gu, were fractionated and purified, and their antitumor activities were tested, out of which the following active fractions were obtained.

FIo-a: A protein-containing xyloglucan, MW 280,000, polysaccharide: protein=76: 24 (w/w), polysaccharide consisting of Man: Gal: Xyl: Glc = 2: 12: 42: 42 (molar ratio). + 25.3°.

FA-2: A protein-containing mannogalactan, MW 120,000, polysaccharide: protein = 76 : 16 (w/w), consisting of Xyl : Man: Gal = 9 : 35 : 56 (molar ratio), + 98.5°.

FII-1: A Protein-containing xylan (62: 21 w/w). MW 200,000, +8.7°.

FIII-1a: A protein-containing glucoxylan (15: 71 w/w), +30.7°, MW 90,000, consisting of Glc : Xyl = 40 : 44 (molar ratio).

FIII-2a: A protein-containing xyloglucan, MW 70,000, polysaccharide: protein = 69: 3 (w /w), polysaccharide consisting of Xyl: Glc = 36 : 62 (molar ratio). + 38.6°.  相似文献   

18.
A new inhibitor of dopamine β-hydroxylase, dopastin, has been isolated. The dopastin-producing strain was found in a mushroom culture, and after being separated, it was confirmed to be a member of Pseudomonas. Dopastin was obtained as colorless needles, mp 116~119°C, (c=0.5, С2Н5ОН), C9H17N3O3. The catalytic hydrogenation afforded dihydro-dopastin which also inhibits dopamine β-hydroxylase.  相似文献   

19.
A Gram-negative, aerobic, motile rod strain, designated Ma-20T, was isolated from a pool of marine Spirulina platensis cultivation, Sanya, China, and was subjected to a polyphasic taxonomy study. Strain Ma-20T can grow in the presence of 0.5–11 % (w/v) NaCl, 10–43 °C and pH 6–10, and grew optimally at 30 °C, pH 7.5–9.0 in natural seawater medium. The polar lipids were composed of phosphatidylethanolamine, three unidentified phospholipids and three unidentified polar lipids. The respiratory quinone was ubiquinone 8 (Q-8) and the major fatty acids were C18:1ω6c/C18:1ω7c (summed feature 8, 32.84 %), C16:1ω6c/C16:1ω7c (summed feature 3, 30.76 %), C16:0 (13.54 %), C12:03-OH (4.63 %), and C12:0 (4.09 %). The DNA G+C content of strain Ma-20T was 58 mol %. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain Ma-20T belonging to Gammaproteobacteria, it shared 88.46–91.55 and 89.21–91.26 % 16S rRNA gene sequence similarity to the type strains in genus Hahella and Marinobacter, respectively. In addition to the large 16S rRNA gene sequence difference, Ma-20T can also be distinguished from the reference type strains Hahella ganghwensis FR1050T and Marinobacter hydrocarbonoclasticus sp. 17T by several phenotypic characteristics and chemotaxonomic properties. On the basis of phenotypic, chemotaxonomic and phylogenetic properties, strain Ma-20T is suggested to represent a novel species of a new genus in Gammaproteobacteria, for which the name Nonhongiella spirulinensis gen. nov., sp. nov. is proposed. The type strain is Ma-20T (=KCTC 32221T=LMG 27470T).  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号