THE SYNTHESIS OF 3-O-β-D-XYLOPYRANOSYL-D-XYLOSE AND THE RECHARACTERIZATION OF SOME BENZYLIDENE DERIVATIVES OF D-XYLOSE

1960 ◽  
Vol 38 (8) ◽  
pp. 1305-1315 ◽  
Author(s):  
E. J. C. Curtis ◽  
J. K. N. Jones
Keyword(s):  
Partial Hydrolysis ◽  
Benzylidene Derivative ◽  
Derivatives Of

The benzylidene groups of the di-O,O-benzylidene derivative of D-xylose diethyl dithioacetal have been located at the 2,4:3,5 positions, and not at the 2,3:4,5 positions suggested by Zinner, Rembarz, Linke, Ulbricht. Partial hydrolysis yielded the 2,4-O-benzylidene compound, from which 3-O-β-D-xylopyranosyl-D-xylose (rhodymenabiose) was prepared.

O-Benzylidene Derivatives of D-Arabinose Diethyl and Dipropyl Dithioacetal

1996 ◽  
Vol 49 (3) ◽  
pp. 273 ◽  
Author(s):  
J Kuszmann ◽  
E Gacsbaitz
Keyword(s):  
Hydrochloric Acid ◽  
Zinc Chloride ◽  
Partial Hydrolysis ◽  
Kinetic Control ◽  
Toluenesulfonic Acid ◽  
Thermodynamic Phase ◽  
Hydrolysis Of ◽  
Derivatives Of

Benzylidenation of D-arabinose diethyl and dipropyl dithioacetals with α,α-dimethoxytoluene in the presence of p-toluenesulfonic acid has been studied in detail. Under kinetic control the two terminal dioxolan -type 4,5-O-(R)- and 4,5-O-(S)-benzylidene diastereomers are formed first which are in equilibrium with each other In the thermodynamic phase of the reaction the corresponding dioxan -type 3,5-O-(R)- benzylidene isomer is formed too, but all three monobenzylidene isomers are gradually converted into the four possible dioxolan -type 2,3 : 4,5-di-O benzylidene diastereomers . The dioxan -type 2,4:3,5-di-O-benzylidene isomer was present only in trace amounts. When benzaldehyde was used as reagent in the presence of hydrochloric acid or zinc chloride only the 2,3: 4,5-di-O-benzylidene diastereomers were formed. Partial hydrolysis of the dibenzylidene derivatives yielded the corresponding 2,3-O-benzylidene diastereomers. Structures, including the chirality of the benzylidene groups, were determined by n.m.r. spectroscopy. A mechanism suggested for the reaction was partially supported by equilibration studies.

Hydrolytic products of 4-aryl-2,3-dicyano-1-naphthol derivatives

1981 ◽  
Vol 46 (9) ◽  
pp. 2207-2216 ◽  
Author(s):  
Jiří Křepelka ◽  
Iva Vančurová ◽  
Jiří Holubek ◽  
Jiří Roubík
Keyword(s):  
Dicarboxylic Acids ◽  
Ring Closure ◽  
Partial Hydrolysis ◽  
H Nmr ◽  
Antiviral Effects ◽  
Hydrolysis Of ◽  
Derivatives Of ◽  
Naphthol Derivatives ◽  
Intramolecular Ring

Depending on the conditions of hydrolysis, vicinal aromatic dicyano derivatives Ia-Ic gave anhydrides IIa-IIe and imides of 4-aryl-1-alkoxynaphthalene-2,3-dicarboxylic acids, IIIa,b, along with products of partial hydrolysis, decarboxylation and demethylation, IVa-IVd, IVf-IVg, and derivatives of benzo(c)fluorene, Va-Vc. The derivatives Va-Vc were also obtained by acid hydrolysis of dicyano derivatives Id-Ig. Methanolysis of the anhydride IId gave a mixture of positional isomers, IVh, which was esterified to the diester IVe. Intramolecular ring closure of the isomers IVh afforded derivatives of benzo(c)fluorene, VIa-VIb. The structures of the selected compounds were corroborated by IR and 1H NMR spectra. The compounds Va-Vc exhibited antiviral effects and interferonogenic activities in vivo.

Partial hydrolysis of acyl 1,6-anhydro-β-D-glucopyranose

1984 ◽  
Vol 49 (8) ◽  
pp. 1780-1787 ◽  
Author(s):  
Štefan Kučár ◽  
Juraj Zámocký ◽  
Juraj Zemek ◽  
Dušan Anderle ◽  
Mária Matulová
Keyword(s):  
Acid Hydrolysis ◽  
Hydrazine Hydrate ◽  
Hydrogen Chloride ◽  
Ester Group ◽  
The Other ◽  
Hydroxyl Group ◽  
Partial Hydrolysis ◽  
Substantial Influence ◽  
Hydrolysis Of ◽  
Derivatives Of

Partial hydrolysis of per-O-acetyl- and per-O-benzoyl derivatives of 1,6-anhydro-β-D-glucopyranose with methanolic hydrogen chloride and hydrazine hydrate was investigated. The acyl group at C(3) is of substantial influence on the course of hydrolysis. The esterified hydroxyl group at C(3) was found to be most stable on acid hydrolysis with methanolic hydrogen chloride when compared with that at C(2), or C(4); on the other hand, this ester group is the most labile upon hydrolysis with hydrazine hydrate. Selectivity of the respective ester groups towards hydrolysis made it possible to prepare all variations of acetyl and benzoyl derivatives of 1,6-anhydro-β-D-glucopyranose.

Ketoximate Derivatives of Titanium Alkoxides and Partial Hydrolysis Products Thereof

2009 ◽  
Vol 2009 (22) ◽  
pp. 3333-3340 ◽  
Author(s):  
Stefan O. Baumann ◽  
Maria Bendova ◽  
Helmut Fric ◽  
Michael Puchberger ◽  
Claudia Visinescu ◽  
...  
Keyword(s):  
Partial Hydrolysis ◽  
Titanium Alkoxides ◽  
Hydrolysis Products ◽  
Derivatives Of

scholarly journals Studies of lipid A fractions from the lipopolysaccharides of Pseudomonas aeruginosa and Pseudomonas alcaligenes

1973 ◽  
Vol 133 (3) ◽  
pp. 563-572 ◽  
Author(s):  
David T. Drewry ◽  
James A. Lomax ◽  
George W. Gray ◽  
Stephen G. Wilkinson
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Lipid A ◽  
Gel Filtration ◽  
Structural Features ◽  
Partial Hydrolysis ◽  
Hexadecanoic Acid ◽  
Alkaline Methanolysis ◽  
Pseudomonas Alcaligenes ◽  
Hydrolysis Of ◽  
Derivatives Of

Lipid A fractions from Pseudomonas aeruginosa and Pseudomonas alcaligenes have similar compositions and structural features. By means of hydrazinolysis of the parent lipopolysaccharides and partial hydrolysis of the deacylation products, it was established that both lipids are derived from the β-(1→6)-linked disaccharide of glucosamine. Phosphorylated derivatives of the disaccharide from Ps. aeruginosa were also characterized. The lipids differ mainly in the absence of hexadecanoic acid and 2-hydroxydodecanoic acid from the lipid from Ps. alcaligenes. Evidence that in Ps. aeruginosa these acids are ester-linked to residues of 3-hydroxyalkanoic acids (including 3-hydroxydecanoic acid) was obtained. Heterogeneity of lipid A fractions was indicated by t.l.c., and by gel filtration of de-O-acylation products from mild alkaline methanolysis of the lipids.

Chemistry of the Podocarpaceae. XXI. Preparation of 3-oxo derivatives of 12-Methoxy-18,19-bisnorpodocarpa-4,8,11,13-tetraene and 18,19-Bisnorabieta-4,8,11,13-tetraene

1969 ◽  
Vol 22 (8) ◽  
pp. 1711 ◽  
Author(s):  
CR Bennett ◽  
RC Cambie ◽  
RA Franich ◽  
TJ Fullerton
Keyword(s):  
Benzylidene Derivative ◽  
Derivatives Of

12-Methoxypodocarpa-8,11,13-trien-19-oic acid (11) has been converted into the 3-oxo compound (XX) via the C 3 benzylidene derivative of 12- methoxy-18,19. bisnor-5β-podocarpa-8,11,13-trien-4-one (VIII). The route follows a modification of a sequence used by Zeiss and Martin to convert abieta-8,11,13-trien-18-oic acid (III) into a tricyclic steroid analogue. The latter conversion has been reinvestigated and modified to give a higher yield of 18,19-bisnorabieta-4,8,11,13-tetraen-3-one (XXI).

scholarly journals Metabolism of the diacetyl derivatives of stereoisomeric monoacyl-sn-glycerols by rat adipocytes in vitro

1986 ◽  
Vol 235 (3) ◽  
pp. 833-838 ◽  
Author(s):  
W W Christie ◽  
M L Hunter
Keyword(s):  
Oleic Acid ◽  
Significant Degree ◽  
Partial Hydrolysis ◽  
Unesterified Fatty Acid ◽  
Triacylglycerol Biosynthesis ◽  
Bonded Phase ◽  
High Degree ◽  
Hydrolysis Of ◽  
Derivatives Of

Diacetyl long-chain 1(3)- and 2-acyl-sn-glycerols containing either [9,10-3H]oleic acid or [1-14C]palmitic acid were synthesized by partial hydrolysis of the corresponding labelled triacylglycerols and acetylation. They were obtained in a high degree of stereochemical purity by preparative h.p.l.c. on a column containing a diol bonded phase. Each compound was rapidly metabolized by adipocyte preparations in vitro, and a high proportion of the label was recovered in the unesterified fatty acid and triacylglycerol fractions. Negligible amounts of intermediate products of hydrolysis were detected. Triacylglycerols were formed from [9,10-3H]oleic acid and from diacetyl-1(3)-[9,10-3H]oleoyl glycerol precursors at about the same rate, but the 2-isomer was metabolized rather more slowly. The results were consistent with the hypothesis that essentially complete hydrolysis occurred in the medium or at the plasma membrane, through the actions of lipoprotein lipase and monoacylglycerol lipase, and that subsequent esterification took place within the cell. To confirm that no putative intermediate monoacylglycerols were utilized for triacylglycerol biosynthesis via the monacylglycerol pathway, the positional distributions of fatty acids in triacylglycerols from each substrate were determined. No positional selectivity was observed. It was concluded that monoacylglycerols, of an origin exogenous to the tissue, e.g. those derived from plasma triacylglycerols, were not utilized to a significant degree for triacylglycerol biosynthesis in adipose tissue. The diacetyl derivatives of monoacylglycerols may serve as useful stereochemical probes in studies of triacylglycerol biosynthesis via the monoacylglycerol pathway in other tissues.

Selective Suecinylation of Adenosine Catalyzed by 4-Morpholine-N,N′ -dicyclohexylcarboxamidine

1981 ◽  
Vol 36 (6) ◽  
pp. 750-754 ◽  
Author(s):  
C. Sauer ◽  
U. Schwabe
Keyword(s):  
Anion Exchange ◽  
Succinic Anhydride ◽  
Partial Hydrolysis ◽  
Direct Reaction ◽  
Thermodynamic Conditions ◽  
Derivatives Of

Abstract Succinyl derivatives of adenosine are synthesized by direct reaction with succinic anhydride catalyzed by 4-morpholine N,N′-dicyclohexylcarboxamidine under kinetic or thermodynamic conditions and partial hydrolysis. Derivatives obtained were N6 -succinyl adenosine, N6 ,5′-O-disuccinyl adenosine, 3′(2′)-O-succinyl adenosine, N6, 3′(2′)-O-di-succinyl adenosine and 3′(2′),5′-O-disuccinyl adenosine. The last three derivatives were crystallized and gave equilibrium mixtures of 2′-O-and 3′-O-isomers in aqueous solvents with the 3′-O-isomer prevailing. Differentiation of isomers was done by PMR. A mechanism for isomerisation is proposed. The products were purified by anion exchange chromato-graphy and desalting. The procedures are useful for pharmacological applications because of the purity and yield of products.

Antiandrogenic A-homo-B,19-dinor-analogues of androgens from 6β-chloro-5-methyl-19-nor-5β-androst-9-enes

1989 ◽  
Vol 54 (5) ◽  
pp. 1318-1326 ◽  
Author(s):  
Alexander Kasal
Keyword(s):  
Partial Hydrolysis ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium ◽  
Selective Acylation ◽  
Chloro Derivatives ◽  
Hydrolysis Of ◽  
Derivatives Of ◽  
Antiandrogenic Activity

6β-Chloro derivatives of 5-methyl-19-nor-5β-androst-9-enes (Westphalen diol type) with oxygen functionalities in positions 3 and 17 were converted into diene VI by treatment with lithium aluminium hydride. The lipophilic product of hydrogenation of VI was shown to be 4aα-methyl-A-homo-B,19-dinor-5β,10α-androstane-3β,17β-diol (IX). Various paths leading to dihydrotestosteron analogues, e.g. selective acylation or oxidation of diol IX and partial hydrolysis of diacetate X, have been realized. 17β-Hydroxy-4aα-methyl-A-homo-B,19-dinor-5β,10α-androstan-3-one (XVI) has been found to exhibit antiandrogenic activity.

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