Some oxidation products of lycoctonine revisited

2006 ◽  
Vol 84 (9) ◽  
pp. 1167-1173 ◽  
Author(s):  
Doaa Abdelrahman ◽  
Michael Benn ◽  
Ryan Hellyer ◽  
Masood Parvez ◽  
Oliver E Edwards
Keyword(s):  
Oxidation Product ◽  
Chromic Acid ◽  
Oxidation Products ◽  
Acid Oxidation ◽  
Lithium Aluminium Hydride ◽  
X Ray ◽  
X Ray Crystallography ◽  
Chromic Acid Oxidation ◽  
Lithium Aluminium ◽  
Norditerpenoid Alkaloid

The structure of a chromic acid oxidation product of the norditerpenoid alkaloid lycoctonine (1) was established as hydroxylycoctonal (3) by spectrometric analyses and X-ray crystallography of its reduction product, hydroxylycoctonine (5); the structure of lycoxonine, a chromic acid oxidation product of the lactam, lycoctonam (7), was similarly confirmed as N-ethyl-4,7,8-trihydroxy-1α,6β,14α,16β-tetramethoxy-19-oxoaconitane (8). Reduction of lycoxonine with lithium aluminium hydride gave the 1,14-di-O-methyl ether (12) of the bisnorditerpenoid alkaloid delbine (9).Key words: norditerpenoid, bisnorditerpenoid, alkaloids, lycoctonine, lycoctonam, hydroxylycoctonal, lycoxonine. 1,14-di-O-methyldelbine, semisynthesis.

Selective O-Methyloxime Formation From 6-Methoxy-2-[(1'-methyl-2',5'-dioxocyclopentyl)-methyl]-3,4-dihydronaphthalen-1(2H)-one

1994 ◽  
Vol 47 (4) ◽  
pp. 649 ◽  
Author(s):  
DJ Collins ◽  
GD Fallon ◽  
CE Skene
Keyword(s):  
Lithium Aluminium Hydride ◽  
X Ray ◽  
X Ray Crystallography ◽  
Lithium Aluminium ◽  
Major Isomer ◽  
Toluenesulfonic Acid ◽  
Ester Formation ◽  
Diastereomeric Mixture ◽  
A Minor

Reaction of 6-methoxy-2-[(1′-methyl-2′,5′-dioxocyclopentyl)methyl]-3,4-dihydronaphthalen-1(2H)-one (4a) with 1 or 2 moles of O- methylhydroxylamine hydrochloride in pyridine gave (1′SR,2RS)-6-methoxy-2-[(1′-methyl-2′,5′-dioxocyclopentyl)methyl]-3,4-dihydronaphthalen-1(2H)-one (E)-2′-O-methyloxime (5a), or the corresponding 2′,5′-bis(O-methyloxime ) (6), respectively. A minor product from the formation of the bis (O- methyloxime ) (6) was the (Z) isomer (5b) of the mono(O- methyloxime ) (5a); the structure and stereochemistry of (5a) and (5b) were established by X-ray crystallography. Reduction of the keto bis (O-methyloxime ) (6) with 0.25 mole of lithium aluminium hydride gave a diastereomeric mixture of the corresponding alcohols (7a), of which the major isomer was characterized by ester formation. The bis (O-methyloxime ) (6) could be hydrolysed to the parent triketone (4a), but it resisted deprotection with cetyltrimethylammonium permanganate. Reaction of the triketone (4a) with 1 mole of 4-anisidine in the presence of 4-toluenesulfonic acid resulted in retro Michael cleavage with formation of 3-(4′-methoxyphenyl)amino-2-methylcyclopent-2-en-1-one (1).

THE RUBBER HYDROCARBON OF ASCLEPIAS SYRIACA L.

1943 ◽  
Vol 21b (10) ◽  
pp. 219-223 ◽  
Author(s):  
E. B. Paul ◽  
A. L. Blakers ◽  
R. W. Watson
Keyword(s):  
Molecular Weight ◽  
Chromic Acid ◽  
Acid Oxidation ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
Asclepias Syriaca ◽  
X Ray ◽  
Chromic Acid Oxidation ◽  
Gutta Percha ◽  
Diffraction Diagram

Milkweed latex collected in mid-July was coagulated in acetone, the coagulum purified, and the rubber examined by chemical and X-ray diffraction methods. Chromic acid oxidation analyses indicate that the monomer is isoprene. The X-ray evidence verifies these results and, further, fixes the polymer as the cis-configuration (rubber) as opposed to the trans-configuration (gutta-percha) of polyisoprene.The solvent-extracted rubber from the leaves appears from the chromic acid oxidation results to be isoprene, but so far no polyisoprene diffraction diagram has been obtained. It is therefore likely that the solvent-extracted leaf rubber is an isoprene polymer of low molecular weight.

scholarly journals Chromic Acid Oxidation of Coal (II) Oxidation Products

1972 ◽  
Vol 51 (6) ◽  
pp. 344-353
Author(s):  
Nobuaki Fujiwara ◽  
Futoru Yoshimura
Keyword(s):  
Chromic Acid ◽  
Oxidation Products ◽  
Acid Oxidation ◽  
Chromic Acid Oxidation

STUDIES ON CHLOROBIUM CHLOROPHYLLS: II. THE RESOLUTION OF OXIDATION PRODUCTS OF CHLOROBIUM PHEOPHORBIDE (660) BY GAS–LIQUID PARTITION CHROMATOGRAPHY

1961 ◽  
Vol 39 (4) ◽  
pp. 755-760 ◽  
Author(s):  
H. V. Morley ◽  
A. S. Holt
Keyword(s):  
Chromic Acid ◽  
Oxidation Products ◽  
Acid Oxidation ◽  
Partition Chromatography ◽  
Chromic Acid Oxidation

Methylethylmaleimide, methyl-n-propyl maleimide, and dihydrohematinic acid imide are obtained from Chlorobium pheophorbide (660) on chromic acid oxidation. The separation and isolation of these products and of other imides and pyrroles by gas–liquid partition chromatography is described.

The Chemistry of Laurenene. VI. An Investigation of the Widely Differing Reactivity of a Pair of Epimeric Keto Esters

1987 ◽  
Vol 40 (9) ◽  
pp. 1591
Author(s):  
LR Hanton ◽  
SD Lorimer ◽  
RT Weavers
Keyword(s):  
Lithium Aluminium Hydride ◽  
Two Dimensional ◽  
X Ray ◽  
X Ray Crystallography ◽  
Keto Esters ◽  
Lithium Aluminium

X-ray crystallography and two-dimensional n.m.r. techniques have been used to establish the conformations of the epimeric keto esters (1) and (3), derived from cleavage of ring A of lauren-1-ene (2). This information has been used to rationalize the disparate reactivity of the keto functions of (1) and (3) in acid-catalysed carbocation rearrangements and with lithium aluminium hydride. The structures of two new rearranged ethers derived from (1) are also discussed.

The kinetics of the chromic acid oxidation of diphenylmethane

Tetrahedron ◽  
1960 ◽  
Vol 8 (3-4) ◽  
pp. 313-335 ◽  
Author(s):  
K.B. Wiberg ◽  
R.J. Evans
Keyword(s):  
Chromic Acid ◽  
Acid Oxidation ◽  
Chromic Acid Oxidation ◽  
Kinetics Of
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