scholarly journals X-Ray Crystallographic Analysis of Methyl (1S,2R,5R,6S,7R)-5,6-Dimethyl-2-(ω-camphanoyloxy)bicyclo[4.3.0]nonane-7-carboxylate. Revision of the Absolute Configurations of the Liverwort Sesquiterpenoids (−)-Chiloscyphone and (+)-Chiloscypholone

1991 ◽  
Vol 64 (7) ◽  
pp. 2303-2305 ◽  
Author(s):  
Motoo Tori ◽  
Takeshi Hasebe ◽  
Yoshinori Asakawa ◽  
Keiichiro Ogawa ◽  
Shin Yoshimura
Keyword(s):  
Crystallographic Analysis ◽  
X Ray ◽  
The Absolute

THE REACTION OF UNSATURATED CARBOHYDRATES WITH CARBON MONOXIDE AND HYDROGEN: V. ABSOLUTE STEREOCHEMISTRY OF ANHYDRODEOXYHEPTITOLS FROM 3,4,6-TRI-O-ACETYL-D-GLUCAL. STEREOCHEMISTRY OF HYDROFORMYLATION. CONFORMATIONAL ANALYSIS

1965 ◽  
Vol 43 (5) ◽  
pp. 1375-1381 ◽  
Author(s):  
Alex Rosenthal ◽  
Hans J. Koch
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Carbon Monoxide ◽  
Absolute Configuration ◽  
Sodium Iodide ◽  
Crystallographic Analysis ◽  
X Ray ◽  
Dicobalt Octacarbonyl ◽  
The Absolute ◽  
Compound Ii ◽  
Absolute Stereochemistry

3,4,6-Tri-O-acetyl-D-glucal reacted with carbon monoxide and hydrogen in the presence of dicobalt octacarbonyl to yield a mixture of two epimeric anhydrodeoxyheptitols, namely, 4,5,7-tri-O-acetyl-2,6-anhydro-3-deoxy-D-manno-heptitol (I) and 4,5,7-tri-O-acetyl-2,6-anhydro-3-deoxy-D-gluco-heptitol (II). De-O-acetylation of the mixture, followed by chromatographic separation, yielded crystalline 2,6-anhydro-3-deoxy-D-manno-heptitol (III) and 2,6-anhydro-3-deoxy-D-gluco-heptitol (IV). Reaction of the mixture of heptitols (I) and (II) with p-bromobenzenesulfonyl chloride, followed by fractional crystallization of the brosylates, gave pure 4,5,7-tri-O-acetyl-2,6-anhydro-1-O-(p-bromophenylsulfonyl)-3-deoxy-D-gluco-heptitol (VII). The absolute configuration of (VII) has been previously established by X-ray crystallographic analysis. The absolute configuration of (III) was established by correlation with that of (VII). The conversion of compound (II) into various derivatives is described.Reaction of 3,4,6-tri-O-acetyl-D-glucal with carbon monoxide and deuterium afforded 2,6-anhydro-3-deoxy-D-manno-heptitol-1,1,3-2H3 (XIII) and 2,6-anhydro-3-deoxy-D-gluco-heptitol-1,1,3-2H3 (XIV). Examination of the nuclear magnetic resonance (n.m.r.) spectra of the normal and deuterated anhydrodeoxyheptitols confirmed the structural assignments and showed that cis addition to the double bond took place to give (XIV).Comparison of the exchange reaction of sodium iodide with 4,5,7-tri-O-acetyl-2,6-anhydro-3-deoxy-1-O-tosyl-D-gluco-heptitol (VIII) and with 4,5,7-tri-O-acetyl-2,6-anhydro-3-deoxy-1-O-tosyl-D-manno-heptitol (XV) revealed that the equatorial primary tosyloxy group of (VIII) was exchanged by iodine twice as readily as the axial primary tosyloxy group of (XV).

scholarly journals Cytotoxic Thiodiketopiperazine Derivatives from the Deep Sea-Derived Fungus Epicoccum nigrum SD-388

Marine Drugs ◽  
2020 ◽  
Vol 18 (3) ◽  
pp. 160 ◽  
Author(s):  
Lu-Ping Chi ◽  
Xiao-Ming Li ◽  
Li Li ◽  
Xin Li ◽  
Bin-Gui Wang
Keyword(s):  
Deep Sea ◽  
Disulfide Bridge ◽  
Positive Control ◽  
Crystallographic Analysis ◽  
X Ray ◽  
Spectrometric Data ◽  
Epicoccum Nigrum ◽  
Culture Extract ◽  
The Absolute ◽  
Detailed Interpretation

Four new thiodiketopiperazine alkaloids, namely, 5’-hydroxy-6’-ene-epicoccin G (1), 7-methoxy-7’-hydroxyepicoccin G (2), 8’-acetoxyepicoccin D (3), and 7’-demethoxyrostratin C (4), as well as a pair of new enantiomeric diketopiperazines, (±)-5-hydroxydiphenylalazine A (5), along with five known analogues (6–10), were isolated and identified from the culture extract of Epicoccum nigrum SD-388, a fungus obtained from deep-sea sediments (−4500 m). Their structures were established on the basis of detailed interpretation of the NMR spectroscopic and mass spectrometric data. X-ray crystallographic analysis confirmed the structures and established the absolute configurations of compounds 1–3, while the absolute configurations for compounds 4 and 5 were determined by ECD calculations. Compounds 4 and 10 showed potent activity against Huh7.5 liver tumor cells, which were comparable to that of the positive control, sorafenib, and the disulfide bridge at C-2/C-2’ is likely essential for the activity.

scholarly journals 2,4-Dimethyl-3,4-O-isopropylidene-L-arabinono-1,5-lactone

2007 ◽  
Vol 63 (3) ◽  
pp. o1128-o1130 ◽  
Author(s):  
Kathrine V. Booth ◽  
David J. Watkin ◽  
Sarah F. Jenkinson ◽  
George W. J. Fleet
Keyword(s):  
Absolute Configuration ◽  
Crystallographic Analysis ◽  
Starting Material ◽  
Relative Configuration ◽  
X Ray ◽  
Boat Form ◽  
The Absolute

The relative configuration at C-2 of 2,4-dimethyl-3,4-O-isopropylidene-L-arabinono lactone, C10H16O5, which exists in the boat form, was unequivocally established by X-ray crystallographic analysis. The absolute configuration was determined by the use of 2-C-methyl-D-ribonolactone as a starting material.

Crystallization and X-ray crystallographic analysis of m-calpain, a Ca2+-dependent protease

1999 ◽  
Vol 55 (8) ◽  
pp. 1484-1486 ◽  
Author(s):  
Christopher M. Hosfield ◽  
Qilu Ye ◽  
J. Simon C. Arthur ◽  
Carol Hegadorn ◽  
Dorothy E. Croall ◽  
...  
Keyword(s):  
Proteolytic Activity ◽  
Cysteine Proteases ◽  
Crystallographic Analysis ◽  
Crystal Forms ◽  
X Ray ◽  
Anomalous Data ◽  
Absolute Requirement ◽  
The Absolute

The absolute requirement of Ca2+ for proteolytic activity is a feature unique to the calpains, a family of heterodimeric cysteine proteases. Conditions are described which give rise to diffraction-quality crystals of m-calpain in two crystal forms, P1 and P21. Data have been collected from native crystals of m-calpain in both P1 and P21 forms, to 2.6 and 2.15 Å, respectively. Selenomethionine-containing crystals have been grown in both forms, and anomalous data from the P21 selenomethionine enzyme provided the location of 17 of the 19 Se atoms in the protein.

Revised Absolute Configurations of Latifolic Acid and the Pyrrolizidine Alkaloid Latifoline

1988 ◽  
Vol 41 (11) ◽  
pp. 1781 ◽  
Author(s):  
JN Roitman ◽  
RY Wong
Keyword(s):  
Carboxylic Acid ◽  
Single Crystal ◽  
Pyrrolizidine Alkaloid ◽  
Crystallographic Analysis ◽  
Side Chain ◽  
X Ray ◽  
The Absolute ◽  
Absolute Stereochemistry

The absolute stereochemistry of (+)- latifolk acid has been determined by single-crystal X-ray crystallographic analysis to be (2S,3R,4R)-3- hydroxy-2,4-dimethyl-5-oxotetrahydrofuran-3-carboxylic acid. The configuration of the three chiral centres is opposite to that presently recorded in the literature. Accordingly, the configuration of the pyrrolizidine alkaloid, latifoline, which includes a latifolic acid side chain, must be revised.

The Absolute Configurations of Haliclonacyclamines A and B Determined by X-Ray Crystallographic Analysis

2009 ◽  
Vol 62 (7) ◽  
pp. 667 ◽  
Author(s):  
I. Wayan Mudianta ◽  
Mary J. Garson ◽  
Paul V. Bernhardt
Keyword(s):  
Biosynthetic Pathway ◽  
Crystallographic Analysis ◽  
Marine Alkaloids ◽  
Enantiomerically Pure ◽  
X Ray ◽  
X Ray Crystallography ◽  
The Absolute ◽  
Insight Into

X-Ray crystallography establishes that the marine alkaloids (–)-haliclonacyclamine A 1 and (+)-haliclonacyclamine B 2 each have the configuration C2 (R), C3 (R), C7 (R), and C9 (R). The alkaloids appear to be enantiomerically pure; this provides an insight into the stereochemical consequences of the biosynthetic pathway leading to these bioactive 3-alkylpiperidine alkaloids.

scholarly journals Punctaporonins N–S, New Caryophyllene Sesquiterpenoids from Cytospora sp.

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Yan Li ◽  
Qingbin Wang ◽  
Xingzhong Liu ◽  
Yongsheng Che
Keyword(s):  
Nmr Spectroscopy ◽  
Absolute Configuration ◽  
Hela Cells ◽  
Crystallographic Analysis ◽  
X Ray ◽  
The Absolute

Six new caryophyllene sesquiterpenoids, punctaporonins N–S (1–6), and three known ones, 6-hydroxypunctaporonins B (7), A (8), and E (9), have been isolated from solid cultures of Cytospora sp. The structures of 1–6 were elucidated primarily by NMR spectroscopy. The absolute configuration of 1 was assigned by X-ray crystallographic analysis of its S-MTPA ester. Compounds 2, 5, and 6 showed modest cytotoxicity against HeLa cells.

scholarly journals Antimicrobial Sesquiterpenoid Derivatives and Monoterpenoids from the Deep-Sea Sediment-Derived Fungus Aspergillus versicolor SD-330

Marine Drugs ◽  
2019 ◽  
Vol 17 (10) ◽  
pp. 563 ◽  
Author(s):  
Xiao-Dong Li ◽  
Xiao-Ming Li ◽  
Xiu-Li Yin ◽  
Xin Li ◽  
Bin-Gui Wang
Keyword(s):  
Deep Sea ◽  
Pathogenic Bacteria ◽  
Vibrio Anguillarum ◽  
Antimicrobial Activities ◽  
Crystallographic Analysis ◽  
Edwardsiella Tarda ◽  
Aspergillus Versicolor ◽  
Deep Sea Sediment ◽  
X Ray ◽  
The Absolute

Two new antimicrobial bisabolane-type sesquiterpenoid derivatives, ent-aspergoterpenin C (compound 1) and 7-O-methylhydroxysydonic acid (2), and two new butyrolactone-type monoterpenoids, pestalotiolactones C (3) and D (4), along with a known monoterpenoid pestalotiolactone A (5) and four known bisabolane sesquiterpenoids (6−9), were isolated and identified from the deep-sea sediment-derived fungus Aspergillus versicolor SD-330. The structures of these compounds were elucidated on the basis of spectroscopic analysis, and the absolute configurations of the new compounds 1−4 were determined by the combination of NOESY and TDDFT-ECD calculations and X-ray crystallographic analysis. Additionally, we first determined and reported the absolute configuration of the known monoterpenoid pestalotiolactone A (5) through the X-ray crystallographic experiment. All of these isolated compounds were evaluated for antimicrobial activities against human and aquatic pathogenic bacteria. Compounds 1, 2, 6 and 9 exhibited selective inhibitory activities against zoonotic pathogenic bacteria such as Escherichia coli, Edwardsiella tarda, Vibrio anguillarum and V. harveyi, with MIC values ranging from 1.0 to 8.0 μg/mL.

scholarly journals 5-Amino-5-deoxy-2-C-hydroxymethyl-2,3-O-isopropylidene-L-lyxono-1,5-lactam

2007 ◽  
Vol 63 (3) ◽  
pp. o1409-o1411
Author(s):  
Michela Simone ◽  
George W. J. Fleet ◽  
Richard Bream ◽  
David J. Watkin
Keyword(s):  
Absolute Configuration ◽  
Catalytic Hydrogenation ◽  
Title Compound ◽  
Crystallographic Analysis ◽  
Starting Material ◽  
Relative Configuration ◽  
X Ray ◽  
Compound C ◽  
The Absolute

The relative configuration of the title compound, C9H14NO5, formed by catalytic hydrogenation of an azidolactone, has been established by X-ray crystallographic analysis. The absolute configuration was determined by the use of 2,3-O-isopropylidene-L-lyxono-1,4-lactone as the carbohydrate starting material.

The Absolute Structure of Latifoline

1992 ◽  
Vol 45 (2) ◽  
pp. 451 ◽  
Author(s):  
CCJ Culvenor ◽  
MF Mackay
Keyword(s):  
Single Crystal ◽  
Absolute Configuration ◽  
Crystallographic Analysis ◽  
Salt Hydrate ◽  
Space Group ◽  
X Ray ◽  
Orthorhombic Crystals ◽  
The Absolute ◽  
Absolute Structure

The absolute structure of latifoline, a pyrrolizidine diester alkaloid of retronecine and latifolic and angelic acids, has been defined by single-crystal X-ray crystallographic analysis of the hydrobromide salt hydrate. Orthorhombic crystals of C20H27NO7.HBr.H2O belong to the space group P 2′2′2′ with a 7.279(1), b 17.898(3), c 17.922(2) � and V 2334-9(8) � 3 . The structure has been refined to an R index of 0.054 for 1725 observed terms. The absolute configuration has been assigned by comparison with that of retronecine and also determined independently by X-ray examination of selected Bijvoet pairs. Our results have shown that the absolute structure of latifolic acid is 13S,14R,19S (2R,3S,4S in latifolic acid numbering), and not the stereoisomer reported recently by Roitman and Wong.

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