Bridged Xanthenes. II. An Intramolecular Cycloaddition Route

1975 ◽  
Vol 53 (14) ◽  
pp. 2054-2063 ◽  
Author(s):  
D.J. Bichan ◽  
Peter Yates
Keyword(s):  
Carboxylic Acid ◽  
Acrylic Acid ◽  
Ethylene Glycol ◽  
Structural Features ◽  
Lead Tetraacetate ◽  
Gambogic Acid ◽  
Similar Treatment ◽  
Intramolecular Cycloaddition ◽  
Naturally Occurring ◽  
Acid Lactone

Oxidation of mesitol (8) with lead tetraacetate in acrylic acid followed by gentle heating gives 6-hydroxy-4,6,7-trimethyl-5-oxobicyclo[2.2.2]oct-7-ene-2-carboxylic acid lactone (13), which is considered to be formed via intramolecular cycloaddition of 6-acryloxy-2,4,6-trimethyl-2,4-cyclohexadienone (11). Similar treatment of 4-methylxanthen-3-o1 (7) gives the corresponding bridged xanthene keto lactone 5. Ketalization of this with ethylene glycol, followed by treatment with methylmagnesium iodide, hydrolysis, and pyrolysis gives the bridged xanthene keto ether 4, which possesses many of the structural features of the nucleus of the naturally occurring coloring matters morellin and gambogic acid.

scholarly journals Regioselective Base-induced Condensations of Acrylic Acid Derivatives

1999 ◽  
Vol 23 (3) ◽  
pp. 174-175
Author(s):  
E. Abdel-Ghani
Keyword(s):  
Carboxylic Acid ◽  
Acrylic Acid ◽  
Dicarboxylic Acid ◽  
Ethyl Acetoacetate ◽  
Tobacco Necrosis Virus ◽  
Necrosis Virus ◽  
Antiviral Activities

The orientation of cyclization of the reaction of methyl aroylacrylate (1) and aroylacrylic acid (8) with ethyl acetoacetate and/or thiourea leading to the formation of 4-aroylmethylcyclopentane-1,3-dione (2) 5-aryl-3-oxocyclohexene-1,2-dicarboxylic acid (9), 2-imino-5-aroylmethylthiazolidin-4-one (11) and 6-aryl-2-sulfonylpyrimidine-4-carboxylic acid (14) depends on the medium employed; some compounds show moderate antiviral activities against tobacco necrosis virus.

Dual-temperature and pH responsive (ethylene glycol)-based nanogels via structural design

2014 ◽  
Vol 5 (8) ◽  
pp. 3061-3070 ◽  
Author(s):  
Yohei Kotsuchibashi ◽  
Ravin Narain
Keyword(s):  
Carboxylic Acid ◽  
Ethylene Glycol ◽  
Salt Concentration ◽  
Structural Design ◽  
Solution Temperature ◽  
Ph Responsive ◽  
Solution Ph ◽  
Critical Solution Temperature ◽  
Carboxylic Acid Groups ◽  
The Core

Dual-temperature and pH responsive (ethylene glycol)-based nanogels were synthesized. Both the core and the shell of the nanogels showed a lower critical solution temperature (LCST) and the LCST of the shell was strongly affected by the solution pH and salt concentration due to the presence of carboxylic acid groups at the nanogel surface.

The synthesis of norbornanes with functionalized carbon substituents at a bridgehead. 1-(3-Oxonorborn-1-yl)ethanone and 1-(3-oxonorborn-1-yl)-2-propanone

1992 ◽  
Vol 70 (5) ◽  
pp. 1492-1505 ◽  
Author(s):  
Peter Yates ◽  
Magdy Kaldas
Keyword(s):  
Acetic Acid ◽  
Carboxylic Acid ◽  
Hydrogen Bromide ◽  
Tertiary Alcohol ◽  
Ethyl Bromoacetate ◽  
Second Molar ◽  
Molar Equivalent ◽  
Acid Lactone ◽  
Basic Hydrolysis ◽  
Hydrolysis Of

Treatment of 2-norobornene-1-carboxylic acid (7) with one equivalent of methyllithium in ether followed by a second molar equivalent after dilution with tetrahydrofuran gave 1-(norborn-2-en-lyl)ethanone (10) and only a trace of the tertiary alcohol 11. Reaction of 7 with formic acid followed by hydrolysis gave a 4:3 mixture of exo-3- and exo-2-hydroxynorbornane-1-carboxylic acid (16 and 17), whereas oxymercuration–demercuration gave only the exo-3-hydroxy isomer 16. Oxidation of 16 and 17 gave 3- and 2-oxonorbornane-1-carboxylic acid (27 and 29), respectively. Oxymercuration–demercuration of 10 gave exclusively 1-(exo-3-hydroxynorborn-1-yl)ethanone (30), which was also prepared by treatment of 16 with methyllithium in analogous fashion to that used for the conversion of 7 to 10. Oxidation of 30 gave 1-(3-oxonorborn-1-yl)ethanone (1). Dehydrobromination of exo-2-bromonorbornane-1-acetic acid and dehydration of 2-hydroxy-norbornane-2-acetic acid derivatives gave 1-(norborn-2-ylidene) acetic acid derivatives to the exclusion of norborn-2-ene-1 -acetic acid derivatives. Treatment of exo-5-acetyloxy-2-norobornanone (52) with ethyl bromoacetate and zinc gave ethyl exo-5-acetyloxy-2-hydroxynorbornane-(exo- and endo-2-acetate (53 and 54). Reaction of 53 with hydrogen bromide gave initially ethyl endo-3-acetyloxy-exo-6-bromonorbornane-1-acetate (59), which was subsequently converted to a mixture of 59 and its exo-3-acetyloxy epimer 61. Catalytic hydrogenation of this mixture gave a mixture of ethyl endo- and exo-3-acetyloxynorbornane-1 -acetate (62 and 63). Basic hydrolysis of this gave a mixture of the corresponding hydroxy acids, 70 and 71; the former was slowly converted to the latter at pH 5. Oxidation of the mixture of 70 and 71 gave 3-oxonorbornane-1-acetic acid (72). Treatment of the mixture with methyllithium as for 16 gave a mixture of 1-(endo- and exo-3-hydroxynorborn-1-yl)-2-propanone (73 and 74), which was oxidized to 1-(3-oxo-norborn-1-yl)-2-propanone (2). Reaction of exo-2-hydroxynorbornane-1-acetic acid lactone (75) with methyllithium in ether gave (1-(exo-2-hydroxynorborn-1-yl)-2-propanone (76), which on oxidation gave the 2-oxo isomer 78 of 2.

Improved synthesis of anti-sesquinorbornene

1984 ◽  
Vol 62 (9) ◽  
pp. 1840-1844 ◽  
Author(s):  
Karl R. Kopecky ◽  
Alan J. Miller
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Carboxylic Acid ◽  
Lead Tetraacetate ◽  
Carboxyl Group ◽  
Silver Acetate ◽  
Benzenesulfonyl Chloride ◽  
Methoxide Ion ◽  
Hydrolysis Of ◽  
Monomethyl Ester

Treatment of methyl hydrogen decahydro-1,4:5,8-exo,endo-dimethanonaphthalene-4a,8a-dicarboxylate with lead tetraacetate in benzene – acetic acid replaces the carboxyl group by an acetoxy group. Hydrolysis of this product with 25% sulfuric acid at 130 °C forms 8a-hydroxydecahydro-1,4:5,8-exo,endo-dimethanonaphthalene-4a-carboxylic acid 10. The reaction between 10 and benzenesulfonyl chloride in pyridine containing triethylamine at 95 °C produces anti-sesquinorbornene 1 in 34% yield. In the absence of triethylamine 1 is converted to the hydrochloride. The iodohydroperoxide of 1 is converted by silver acetate at 0 °C to the diketone in a luminescent reaction. The 1,2-dioxetane could not be isolated. Decahydro-1,4:5,8-exo,exo-dimethanonaphthalene-4a,8a-dicarboxylic anhydride is converted slowly by methoxide ion in methanol at 150 °C to the monomethyl ester which then undergoes demethylation. The isomeric exo,endo anhydride undergoes reaction readily with methoxide ion at 80 °C.

scholarly journals Crystal structure of betulinic acid methanol monosolvate

2014 ◽  
Vol 70 (12) ◽  
pp. o1242-o1243 ◽  
Author(s):  
Wei Tang ◽  
Neng-Hua Chen ◽  
Guo-Qiang Li ◽  
Guo-Cai Wang ◽  
Yao-Lan Li
Keyword(s):  
Carboxylic Acid ◽  
Solvent Molecule ◽  
Acid Group ◽  
Carboxylic Acid Group ◽  
Syzygium Jambos ◽  
Carboxylic Acid Groups ◽  
Pentacyclic Triterpenoid ◽  
Naturally Occurring ◽  
Dimensional Network ◽  
Chinese Medicinal Plant

The title compound [systematic name: 3β-hydroxylup-20(29)-en-28-oic acid methanol monosolvate], C30H48O3·CH3OH, is a solvent pseudopolymorph of a naturally occurring plant-derived lupane-type pentacyclic triterpenoid, which was isolated from the traditional Chinese medicinal plantSyzygium jambos(L.) Alston. The dihedral angle between the planes of the carboxylic acid group and the olefinic group is 12.17 (18)°. TheA/B,B/C,C/DandD/Ering junctions are alltrans-fused. In the crystal, O—H...O hydrogen bonds involving the hydroxy and carboxylic acid groups and the methanol solvent molecule give rise to a two-dimensional network structure lying parallel to (001).

α-CYANO-β-ARYLACRYLIC ACIDS

1945 ◽  
Vol 23b (2) ◽  
pp. 84-87 ◽  
Author(s):  
C. Y. Hopkins ◽  
Mary Chisholm ◽  
Ruth Michael
Keyword(s):  
Carboxylic Acid ◽  
Acrylic Acid

α-Cyano-β-arylacrylic acids have been prepared by condensing the following aldehydes with sodium cyanoacetate: 1-naphthaldehyde, 2,3-dimethoxybenzaldehyde, 3,4-diethoxybenzaldehyde, 6-chloropiperonal, 4-isopropylbenzaldehyde, 2-acetoxy-3-methoxybenzaldehyde, 2-hydroxy-3-methoxybenzaldehyde. The last-named gave α-cyano-β (2-hydroxy-3-methoxyphenyl) acrylic acid, which was readily converted to 8-methoxycoumarin-3-carboxylic acid.

scholarly journals Total Syntheses of Pladienolide-Derived Spliceosome Modulators

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5938
Author(s):  
Jaehoon Sim ◽  
Eunbin Jang ◽  
Hyun Jin Kim ◽  
Hongjun Jeon
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Structural Features ◽  
Synthetic Approach ◽  
Synthetic Analog ◽  
Phase I Clinical Trials ◽  
Total Syntheses ◽  
Naturally Occurring ◽  
Anti Cancer ◽  
Synthetic Approaches

Pladienolides, an emerging class of naturally occurring spliceosome modulators, exhibit interesting structural features, such as highly substituted 12-membered macrocycles and epoxide-containing diene side chains. The potential of pladienolides as anti-cancer agents is confirmed by H3B-8800, a synthetic analog of this natural product class, which is currently under Phase I clinical trials. Since its isolation in 2004 and the first total synthesis in 2007, a dozen total syntheses and synthetic approaches toward the pladienolide class have been reported to date. This review focuses on the eight completed total syntheses of naturally occurring pladienolides or their synthetic analogs, in addition to a synthetic approach to the main framework of the natural product.

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