Studies on gibberellin synthesis. Assembly of an ethanophenanthrenoid lactone and conversion into a gibbane derivative

1981 ◽  
Vol 34 (9) ◽  
pp. 1899 ◽  
Author(s):  
LN Mander ◽  
SG Pyne
Keyword(s):  
Sulfuric Acid ◽  
Carboxylic Acid ◽  
Total Synthesis ◽  
Dicarboxylic Acid ◽  
Aqueous Medium ◽  
Trifluoroacetic Acid ◽  
Conjugate Addition ◽  
New Approach ◽  
Standard Methods

Diazoketone (13), prepared by standard methods from 5-formyl-8-methoxy-1,2,3,4-tetrahydronaphthalene-2-carboxylic acid (7), was cyclized in trifluoroacetic acid to dienone (1) which under-went intramolecular 1,4-conjugate addition to afford the ethanophenanthrene derivative (15). Refunctionalization furnished dibenzoyloxy diacid (19) which cyclized in sulfuric acid specifically to the 8-carboxy-10,12-dibenzoyloxyperhydro-1H-2,10a-ethanophenanthrene-8,4b-carbolactone (2). Further refunctionalization to ketone (22), then formation of diazoketone (23) followed by photolysis in an aqueous medium, finally gave (1RS,4aRS,4bRS,7SR,8SR,9aSR,10SR,10aRS)-8-benzoyloxy-4a-hydroxy-1-methoxymethyloxymethylgibbane-1,10-dicarboxylic acid 1,4a-lactone (3) which may serve both as a model and intermediate for a radically new approach to the total synthesis of gibberellins.

Coupling of Steroid O-(Carboxymethyl)oxime Derivatives with Single-Protected α,ω-Diaminoalkanes

1999 ◽  
Vol 64 (12) ◽  
pp. 2035-2043 ◽  
Author(s):  
Vladimír Pouzar ◽  
Ivan Černý ◽  
Pavel Drašar
Keyword(s):  
Trifluoroacetic Acid ◽  
Protecting Groups ◽  
Oxime Group ◽  
Amino Groups ◽  
New Approach ◽  
Terminal Amino ◽  
Oxime Derivatives

New approach to the synthesis of steroid oximes bearing O-substituents with terminal amino groups was described. The easily accessible steroid O-(carboxymethyl)oximes were reacted with single-protected Boc-α,ω-diaminoalkanes to give corresponding amide intermediates. From them the Boc protecting groups were cleaved with trifluoroacetic acid to afford the desired steroid derivatives with terminal amino groups. The procedure was succesfully tested on steroids with O-(carboxymethyl)oxime group in positions 7 and 17. The decomposition of target products was observed during deprotection of substituted 19-oximes.

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.

Total syntheses and antiproliferative activities of prenostodione and its analogues

2021 ◽  
Author(s):  
Aldahir Ramos Orea ◽  
María Teresa Ramírez-Apan ◽  
Rosa M. Chávez-Santos ◽  
Rodrigo Aguayo-Ortiz ◽  
Clara I Espitia ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Total Synthesis ◽  
Indole Alkaloid ◽  
Total Syntheses ◽  
Antiproliferative Activities

A high-yielding total synthesis of the indole alkaloid prenostodione was completed in 4 steps and 44% overall yield from 1H-indole-3-carboxylic acid. The expedient syntheses of prenostodiones containing distinct substituents at...

ChemInform Abstract: Total Synthesis of the Marine Toxin Polycavernoside A (I) via Selective Macrolactonization of a Trihydroxy Carboxylic Acid.

ChemInform ◽  
2010 ◽  
Vol 32 (52) ◽  
pp. no-no
Author(s):  
James D. White ◽  
Paul R. Blakemore ◽  
Cindy C. Browder ◽  
Jian Hong ◽  
Christopher M. Lincoln ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Total Synthesis ◽  
Marine Toxin ◽  
Polycavernoside A

A new approach to the total synthesis of B-norsteroids

1969 ◽  
Vol 10 (15) ◽  
pp. 1207-1208 ◽  
Author(s):  
U.K. Pandit ◽  
K. de Jongen Mrs ◽  
K. Erhart ◽  
H.O. Huisman
Keyword(s):  
Total Synthesis ◽  
New Approach

Trifluoroacetic acid catalyzed highly regioselective bromocyclization of styrene-type carboxylic acid

2016 ◽  
Vol 14 (20) ◽  
pp. 4571-4575 ◽  
Author(s):  
Tao Chen ◽  
Ying-Yeung Yeung
Keyword(s):  
Carboxylic Acid ◽  
Trifluoroacetic Acid ◽  
Acid Catalyzed

A trifluoroacetic acid catalyzed highly 6-endo regioselective bromocyclization of styrene-type carboxylic acid has been developed.

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