Reactions of primulagenin A. II. Acid-catalysed transformation

1971 ◽  
Vol 24 (10) ◽  
pp. 2117 ◽  
Author(s):  
OD Hensens ◽  
KG Lewis
Keyword(s):  
Double Bond ◽  
Hydrochloric Acid ◽  
Cyclopropane Ring ◽  
New Products ◽  
Complex Mixture ◽  
Hydroxy Ketone ◽  
Aromatic Alcohol ◽  
Methanolic Hydrochloric Acid ◽  
Bond Isomer

Treatment of primulagenin A with methanolic hydrochloric acid gave a complex mixture of products from which the known aegiceradiol (oleana- 12,15-diene-3β,28-dial) and aegiceradienol (28-noroleana-12,17(18)- dien-3β-ol) were obtained. In addition, three new products, a double- bond isomer of aegiceradiol, the structure of which has been established by synthesis, a C30 aromatic alcohol, and a hydroxy ketone containing a cyclopropane ring, have been isolated.

15N, 13C, and 1H NMR Spectra of Azo and Hydrazo Compounds Derived from 1,3,3-Trimethyl-2-methylidene-2,3-dihydroindole (Fischer Base)

1998 ◽  
Vol 63 (7) ◽  
pp. 1012-1020 ◽  
Author(s):  
Antonín Lyčka ◽  
Josef Jirman ◽  
Alois Koloničný
Keyword(s):  
Double Bond ◽  
Hydrochloric Acid ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Azo Compounds ◽  
Passive Component ◽  
Geometric Isomers ◽  
H Nmr ◽  
Fischer Base ◽  
Hydrazone Form

The 15N, 13C, and 1H NMR spectra were measured for azo and hydrazo compounds derived from 1,3,3-trimethyl-2-methylidene-2,3-dihydroindole (Fischer base), which is a passive component with a terminal methylidene group. Products prepared by coupling in hydrochloric acid exist in the corresponding hydrazone form as the E-isomers. Neutralization gives a mixture of two isomeric azo compounds which differ in the arrangement at the C(2)=C(10) double bond. This mixture was alkylated with methyl iodide to obtain the =N-N(CH3)- hydrazone derivatives. The geometric isomers were resolved based on the NOESY approach and the stereospecific behaviour of the 2J(15N,13C) coupling constants was studied for the 15N-labelled compounds.

scholarly journals An assessment of methanolysis and other factors used in the analysis of carbohydrate-containing materials

1971 ◽  
Vol 125 (4) ◽  
pp. 1009-1018 ◽  
Author(s):  
R. E. Chambers ◽  
J. R. Clamp
Keyword(s):  
Hydrochloric Acid ◽  
Analytical Procedure ◽  
Internal Standard ◽  
Inorganic Contaminants ◽  
Rotary Evaporation ◽  
Silver Salts ◽  
Methanolic Hydrochloric Acid ◽  
Different Temperatures ◽  
The Stability ◽  
Analytical System

The stability of monosaccharides in methanolic hydrochloric acid of different strengths and at different temperatures was determined. They are generally stable for 24h in methanolic 1m- and 2m-hydrochloric acid at both 85°C and 100°C, but undergo considerable destruction in methanolic 4m- and 6m-hydrochloric acid at 100°C. Analysis of glycopeptides and oligosaccharides of known composition showed that release of carbohydrate was complete within 3h in methanolic 1m-hydrochloric acid at 85°C. Removal of methanolic hydrochloric acid by rotary evaporation resulted in considerable losses of monosaccharides, which could be prevented by prior neutralization. Methanolysis caused extensive de-N-acetylation of acetamidohexoses, so that a re-N-acetylation step is necessary in the analytical procedure. The addition of acetic anhydride for this purpose also prevented loss of internal standard by adsorption on the insoluble silver salts used in neutralization. Several trimethylsilylating agents were studied and suitable conditions are recommended. The effects on the analytical system of water and some common organic and inorganic contaminants are assessed.

scholarly journals Phenolation of vegetable oils

2011 ◽  
Vol 76 (4) ◽  
pp. 591-606 ◽  
Author(s):  
Mihail Ionescu ◽  
Zoran Petrovic
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Double Bond ◽  
Vegetable Oils ◽  
Raw Materials ◽  
Complex Mixture ◽  
Double Bonds ◽  
Triflic Acid ◽  
Model Compounds ◽  
Phenol Alkylation

Novel bio-based compounds containing phenols suitable for the synthesis of polyurethanes were prepared. The direct alkylation of phenols with different vegetable oils in the presence of superacids (HBF4, triflic acid) as catalysts was studied. The reaction kinetics was followed by monitoring the decrease of the double bond content (iodine value) with time. In order to understand the mechanism of the reaction, phenol was alkylated with model compounds. The model compounds containing one internal double bond were 9-octadecene and methyl oleate and those with three double bonds were triolein and high oleic safflower oil (82% oleic acid). It was shown that the best structures for phenol alkylation are fatty acids with only one double bond (oleic acid). Fatty acids with two double bonds (linoleic acid) and three double bonds (linolenic acid) lead to polymerized oils by a Diels Alder reaction, and to a lesser extent to phenol alkylated products. The reaction product of direct alkylation of phenol with vegetable oils is a complex mixture of phenol alkylated with polymerized oil (30-60%), phenyl esters formed by transesterification of phenol with triglyceride ester bonds (<10 %) and unreacted oil (30%). The phenolated vegetable oils are new aromatic-aliphatic bio-based raw materials suitable for the preparation of polyols (by propoxylation, ethoxylation, Mannich reactions) for the preparation of polyurethanes, as intermediates for phenolic resins or as bio-based antioxidants.

scholarly journals Chemoselective and metal-free reduction of α,β-unsaturated ketones by in situ produced benzeneselenol from O-(tert-butyl) Se-phenyl selenocarbonate

RSC Advances ◽  
2020 ◽  
Vol 10 (56) ◽  
pp. 33706-33717
Author(s):  
Andrea Temperini ◽  
Marco Ballarotto ◽  
Carlo Siciliano
Keyword(s):  
Double Bond ◽  
Hydrochloric Acid ◽  
Unsaturated Ketones ◽  
Metal Free ◽  
Tert Butyl ◽  
Carbon Double Bond

The carbon–carbon double bond of arylidene acetones and chalcones can be selectively reduced with benzeneselenol generated in situ by reacting O-(tert-butyl) Se-phenyl selenocarbonate with hydrochloric acid in ethanol.

Reactions of primulagenin A. IV. Ring expansion in Oleana-12,15-diene-3b,28-diol and the related 13(18),15-diene isomer

1980 ◽  
Vol 33 (11) ◽  
pp. 2517 ◽  
Author(s):  
OD Hensens ◽  
KG Lewis ◽  
DJ Tucker
Keyword(s):  
Double Bond ◽  
Sulfonyl Chloride ◽  
Ring Expansion ◽  
Pyridine Solution ◽  
Bond Isomer

Treatment of oleana-12,15-diene-3β,28-diol 3-acetate with a cold pyridine solution of p-toluene-sulfonyl chloride leads to expansion of ring D with the formation of 28-nor-D(16a)-homo-oleana-12,15,17(18)- trien-3β-yl acetate (7). Under more vigorous conditions a mixture of the D-homo compound (7) and a double bond isomer (11) is obtained. Subjection of oleana-13(18),15-diene-3β,28- diol 3-acetate to similar reflux conditions also forms the D-homo compound (7).

scholarly journals Studies on Sesquiterpenoids. V. The Structure of a Double Bond Isomer of α-Dihydroguaiene.

1963 ◽  
Vol 11 (7) ◽  
pp. 867-871 ◽  
Author(s):  
Kenichi Takeda ◽  
Hitoshi Minato ◽  
Satoko Nosaka ◽  
Ichiro Ishizuka
Keyword(s):  
Double Bond ◽  
Bond Isomer

Synthesis of a novel cyclic sulfone dihydropyridine: An investigation of the isomerization reaction converting an exocyclic double bond isomer into a 1,4-dihydropyridine

1994 ◽  
Vol 31 (2) ◽  
pp. 351-355 ◽  
Author(s):  
Christopher J. Fenk ◽  
Richard A. Conley ◽  
Gregory C. Lindabery ◽  
Stephen M. Stefanick ◽  
Thomas E. Royster ◽  
...  
Keyword(s):  
Double Bond ◽  
Isomerization Reaction ◽  
Exocyclic Double Bond ◽  
Bond Isomer
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