Jervine. VIII. Δ13-Jervine, a New Double Bond Isomer of Jervine

1955 ◽  
Vol 77 (20) ◽  
pp. 5318-5323 ◽  
Author(s):  
B. M. Iselin ◽  
O. Wintersteiner
Keyword(s):  
Double Bond ◽  
Bond Isomer

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

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.

Synthetic Studies Concerning the Crinine Alkaloid Haemultine

2013 ◽  
Vol 66 (1) ◽  
pp. 30 ◽  
Author(s):  
Nadia (Yuqian) Gao ◽  
Xinghua Ma ◽  
Laurent Petit ◽  
Brett D. Schwartz ◽  
Martin G. Banwell ◽  
...  
Keyword(s):  
Double Bond ◽  
Natural Product ◽  
Trifluoroacetic Acid ◽  
Spectroscopic Data ◽  
Ene Reaction ◽  
Enantiomerically Pure ◽  
Racemic Form ◽  
Pure Compounds ◽  
First Time ◽  
Bond Isomer

The racemic form, (±)-1, of the structure originally assigned to the crinine alkaloid haemultine has been prepared for the first time. A key step involved the conversion of compound (±)-4 into the isomeric cis-C3a-arylhexahydroindole (±)-3 using a Pd0-catalysed intramolecular Alder-ene reaction. The amino-alcohol (±)-2 derived from the latter compound reacted with paraformaldehyde in the presence of trifluoroacetic acid to give, via a Pictet–Spengler reaction, the target (±)-1. The diastereoisomeric Mosher esters 15 and 16 obtained by coupling the racemate (±)-1 with the R-form, 14, of the Mosher acid could be separated chromatographically and then reductively cleaved to give the enantiomerically pure compounds (+)-1 and (–)-1, respectively. The physical and spectroscopic data derived from the former enantiomer are consistent with the proposition that the title natural product is, in fact, a mixture of (+)-1 and its Δ2,3-double bond isomer.

Preparation of Three Impurities in Cefoxitin

2018 ◽  
Vol 42 (11) ◽  
pp. 541-546
Author(s):  
Jun Yu ◽  
Luo-bing Jiang ◽  
Wei-dong Feng ◽  
Chuan-meng Zhao ◽  
Fu-li Zhang
Keyword(s):  
Quality Control ◽  
Double Bond ◽  
Side Chain ◽  
Bond Isomer

Three known impurities of cefoxitin have been prepared and characterised. One is a double-bond isomer of cefoxitin, Δ3-cefoxitin, which was easily prepared by base-catalysed isomerisation of cefoxitin. The second is a side-chain methoxylated derivative, methoxycefoxitin, which required a four-step synthesis from cephalothin. The last impurity is a lactone lacking the carbamyl grouping in cefoxitin, cefoxitin lactone, which was also prepared in four steps from cephalothin. The accessibility of these three impurities and methods for their analysis could be important for quality control in the manufacture of cefoxitin.

Studies on analogs of DAMASCENOLIDETM: Part 3. Synthesis and odor evaluation of dimethylated, cyclopropanated, and other analogs of DAMASCENOLIDETM

2020 ◽  
Vol 85 (4) ◽  
pp. 756-764 ◽  
Author(s):  
Yamato Miyazawa ◽  
Kenji Kawaguchi ◽  
Ryo Katsuta ◽  
Tomoo Nukada ◽  
Ken Ishigami
Keyword(s):  
Double Bond ◽  
Side Chain ◽  
Aroma Compound ◽  
Ring Size ◽  
Odor Evaluation ◽  
Bond Isomer

ABSTRACT DAMASCENOLIDETM [1, 4-(4-methylpent-3-en-1-yl)furan-2(5H)-one], which has a citrus-like odor, is an important aroma component of roses. We have previously reported on the synthesis and odor evaluation of 24 analogs of 1 as part of our new aroma compound developing project. To accumulate more information on structure–odor relationships, 10 more promising analogs such as dimethylated and cyclopropanated analogs were synthesized and subjected to odor evaluation. As a result, it was found that dimethylation of the furanone ring affected the odor. It was also found that cyclopropanation of 1 affected the odor, whereas cyclopropanation of the double bond isomer of 1 did not significantly affect the odor. The effects on the odor caused by ring size expansion and replacement of the side chain were also investigated.

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