scholarly journals Structure Determination of Two New Monocillin I Derivatives

2010 ◽  
Vol 5 (5) ◽  
pp. 1934578X1000500
Author(s):  
Jixun Zhan ◽  
E. M. Kithsiri Wijeratne ◽  
A. A. Leslie Gunatilaka
Keyword(s):  
Double Bond ◽  
Acid Solution ◽  
Beauveria Bassiana ◽  
Structure Determination ◽  
Spectroscopic Data ◽  
Enzymatic Process ◽  
Acid Catalyzed ◽  
Hydrolysis Of

Biotransformation of monocillin I (1) by Beauveria bassiana ATCC 7159 was investigated. Two new derivatives 2 and 3 were isolated and identified on the basis of the spectroscopic data. Compounds 2 and 3 are synthesized by hydration at 10,11-double bond and hydrolysis of 14,15-epoxide, respectively. The R configuration of 11-OH in 2 was established by the modified 2-methoxy-2-trifluoromethylphenylacetic acid (MTPA) method. The conversion of 1 to 2 and 3 was reconstituted in an acid solution, indicating that the formation of 2 and 3 is an acid-catalyzed instead of an enzymatic process.

Benzyl ethers of methyl α-D-glucopyranoside

1980 ◽  
Vol 45 (7) ◽  
pp. 1959-1963 ◽  
Author(s):  
Dušan Joniak ◽  
Božena Košíková ◽  
Ludmila Kosáková
Keyword(s):  
Kinetic Study ◽  
Spectrophotometric Determination ◽  
Reductive Cleavage ◽  
Ether Bond ◽  
Benzyl Ethers ◽  
Acid Catalyzed ◽  
Model Substances ◽  
Hydrolysis Of

Methyl 4-O-(3-methoxy-4-hydroxybenzyl) and methyl 4-O-(3,5-dimethoxy-4-hydroxybenzyl)-α-D-glucopyranoside and their 6-O-isomers were prepared as model substances for the ether lignin-saccharide bond by reductive cleavage of corresponding 4,6-O-benzylidene derivatives. Kinetic study of acid-catalyzed hydrolysis of the compounds prepared was carried out by spectrophotometric determination of the benzyl alcoholic groups set free, after their reaction with quinonemonochloroimide, and it showed the low stability of the p-hydroxybenzyl ether bond.

THE CHEMISTRY OF ETHYLENE OXIDE: V. THE REACTION OF ETHYLENE OXIDE WITH HALIDE IONS IN NEUTRAL AND ACID SOLUTION

1952 ◽  
Vol 30 (3) ◽  
pp. 169-176 ◽  
Author(s):  
A. M. Eastham ◽  
G. A. Latremouille
Keyword(s):  
Aqueous Solution ◽  
Ethylene Oxide ◽  
Acid Solution ◽  
Activation Energies ◽  
Hydrogen Halide ◽  
Halide Ions ◽  
Neutral Aqueous Solution ◽  
Rate Of Hydrolysis ◽  
Acid Catalyzed ◽  
Hydrolysis Of

The rates of reaction of halide ions with ethylene oxide in neutral aqueous solution and the rate of hydrolysis of ethylene oxide in acid solution have been measured and the activation energies determined. From these data and from the ratio of glycol to chlorohydrin formed when ethylene oxide reacts with excess aqueous hydrogen halide, the rates of the acid-catalyzed addition of halide ions to ethylene oxide at 25 °C. have been estimated.

Acid-catalyzed cyclization of 3,3',4,4'-tetrahydro-1,1'-binaphthyl and single-crystal x-ray structure determination of a polycyclic stable ozonide

1984 ◽  
Vol 49 (6) ◽  
pp. 1030-1033 ◽  
Author(s):  
Thomas K. Dobbs ◽  
Arnold R. Taylor ◽  
Julie A. Barnes ◽  
Belma D. Iscimenler ◽  
Elizabeth M. Holt ◽  
...  
Keyword(s):  
Single Crystal ◽  
Structure Determination ◽  
X Ray ◽  
Acid Catalyzed

Übergangsmetall-Carbin-Komplexe, LXXII [1]. Reaktionen von trans-Bromotetracarbonyl(phenylcarbin)chrom mit Lithiumthiokresolat und Lithiumselenophenolat / Transition Metal Carbyne Complexes, LXXII [1]. Reactions of trans-Bromotetracarbonyl(phenylcarbyne)chromium with Lithium Thiocresolate and Lithium Phenylselenolate

1982 ◽  
Vol 37 (10) ◽  
pp. 1274-1278 ◽  
Author(s):  
Werner Roll ◽  
Ernst Otto Fischer ◽  
Dietmar Neugebauer ◽  
Ulrich Schubert
Keyword(s):  
Hydrochloric Acid ◽  
Transition Metal ◽  
Structure Determination ◽  
Binuclear Complex ◽  
Spectroscopic Data ◽  
Reaction Conditions ◽  
X Ray ◽  
Carbyne Complexes ◽  
Ether Complex

The reaction of trans-bromotetracarbonyl(phenylcarbyne)chromium (1) with lithium phenylselenolate and subsequent protonation with aqueous hydrochloric acid leads to (CO)5Cr[Se2(C6H5)2] (3) and (CO)4Cr(μ-SeC6H5)2Cr(CO)4 (4). From 1 and lithium 4-methylphenylthiolate (CO)5CrC(C6H5)SC6H4CH3 (5) and (CO)5CrS(C2H5)(4-CH3C6H4) (6) are obtained, if triethyloxonium tetrafluoroborate is used instead of hydrochloric acid. The analoguous reaction of 1 with lithium phenylselenolate yields the seleno ether complex (7). Reaction conditions, properties, spectroscopic data and the results of an X-ray structure determination of the binuclear complex (4) are reported.

The Structure of the Novel Lichen Xanthone Thiomelin and Its Cogenors

1987 ◽  
Vol 40 (7) ◽  
pp. 1169 ◽  
Author(s):  
JA Elix ◽  
KL Gaul ◽  
M Sterns ◽  
MW Binsamsudin
Keyword(s):  
Crystal Structure ◽  
Structure Determination ◽  
Ring Opening ◽  
Spectroscopic Data ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lichen Metabolite

The structure determination of thiomelin (2,4-dichloro-1,8-dihydroxy-5-methoxy-6-methyl-9H-xanthen-9-one) (3), an unusual lichen metabolite probably derived biosynthetically by oxidative ring opening of a precursor anthraquinone, is reported. The crystal structure of thiomelin diacetate (4) was determined by X-ray diffraction, while that of the cogenors 8-O-methylthiomelin (5), 4-dechlorothiomelin (7), 4-dechloro-8- O- methylthiomelin (9), 2-dechloro-8- O- methylthiomelin (10) and 2,4-dichloro-l-hydroxy-7-methoxy-6,8-dimethyl-9H-xanthen-9-one (12) were deduced from spectroscopic data.

scholarly journals Structure Determination of a Natural Juvenile Hormone Isolated from a Heteropteran Insect

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Toyomi Kotaki ◽  
Tetsuro Shinada ◽  
Hideharu Numata
Keyword(s):  
Double Bond ◽  
Juvenile Hormone ◽  
Structure Determination ◽  
Stink Bug ◽  
Juvenile Hormone Iii ◽  
Experimental Animals ◽  
Insect Hormones ◽  
Plautia Stali

Juvenile hormone (JH), which occurs in several forms in different insects, is one of the most important insect hormones. The structure of JH in Heteroptera has not been elucidated until recently, although insects in this suborder have long been used as experimental animals for JH research. Here we review the structure determination of a novel JH in a stink bug,Plautia stali, which was named juvenile hormone III skipped bisepoxide [JHSB3: methyl (2R,3S,10R)-2,3;10,11-bisepoxyfarnesoate], based on the arrangement of two epoxides at C2,3 and C10,11 with a skipped double bond at C6,7.

scholarly journals The reaction of phosphoglycolipids and other lipids with hydrofluoric acid

1974 ◽  
Vol 143 (2) ◽  
pp. 461-464 ◽  
Author(s):  
N. Shaw ◽  
A. Stead
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Structure Determination ◽  
Hydrofluoric Acid ◽  
Good Yield ◽  
Glycosidic Linkage ◽  
Cyclopropane Fatty Acids ◽  
Hydrolysis Of

1. The use of HF as a dephosphorylating reagent for phospholipids was examined. 2. Hydrolysis of phosphatidylethanolamine at 0°C for 24h with 60% HF gives a good yield of diglyceride. Under similar conditions phosphatidyldiglucosyl diglyceride gives diglyceride and diglucosyl diglyceride. 3. The glycolipid is also obtained from hydrolysis of glycerylphosphoryldiglucosyl diglyceride. No lyso derivative of the glycolipid could be detected and the glycosidic linkage was also stable. 4. Triglycerides, unsaturated and cyclopropane fatty acids were unaffected by the reagent. 5. 1,2-Diglycerides and 1,3-diglycerides were partially isomerized and also gave small amounts of free fatty acid and monoglyceride. 6. Monoglycerides underwent extensive rearrangement to form 1,2- and 1,3-diglycerides. 7. Lysophosphatidylethanolamine also gave 1,2- and 1,3-diglycerides as well as monoglycerides. 8. The application of this procedure to the structure determination of various phosphoglycolipids is discussed.

5,10,15,20-Tetrakis(diphenylmethyl)porphyrin - A Nonplanar Porphyrin with Intermediate Degree of Ruffling

1999 ◽  
Vol 54 (5) ◽  
pp. 662-666 ◽  
Author(s):  
Steffen Runge ◽  
Mathias O. Senge ◽  
Karin Ruhlandt-Senge
Keyword(s):  
Crystal Structure ◽  
Structure Determination ◽  
Title Compound ◽  
Spectroscopic Data ◽  
Crystal Structure Determination ◽  
Free Base ◽  
Out Of Plane ◽  
Intermediate Degree ◽  
Plane Displacement

The title compound was prepared by condensation of pyrrole and diphenylacetaldehyde in 16% yield. Based on spectroscopic data, the free base porphyrin exhibits a nonplanar macrocycle in solution with a degree of distortion between that of 5,10,15,20-tetracyclohexylporphyrin and 5,10,15,20-tetra(t-butyl)porphyrin. A crystal structure determination of the cobalt(II) complex reveals a ruffled macrocycle conformation with an average out-of-plane displacement of the meso carbon atoms by 0.55 Å.

Structure Determination of the Products from the Acid-Catalyzed Condensation of Indole with Acetone†

1996 ◽  
Vol 61 (2) ◽  
pp. 451-454 ◽  
Author(s):  
Wayland E. Noland ◽  
Michael J. Konkel ◽  
Lisa M. C. Konkel ◽  
Bradley C. Pearce ◽  
Charles L. Barnes ◽  
...  
Keyword(s):  
Structure Determination ◽  
Acid Catalyzed
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