Preparation of 4-anilino-6-aryl-2H-pyran-2-ones from trilithiated acetoacetanilides and aromatic esters

2004 ◽  
Vol 82 (5) ◽  
pp. 659-664 ◽  
Author(s):  
Jennifer R Downs ◽  
Sally P Grant ◽  
Jessica D Townsend ◽  
Deborah A Schady ◽  
Stefan J Pastine ◽  
...  
Keyword(s):  
Lithium Diisopropylamide ◽  
Aromatic Esters ◽  
Acid Cyclization

Acetoacetanilide and 4′-chloroacetoacetanilide were trilithiated with excess lithium diisopropylamide and condensed with several aromatic esters, followed by neutralization, separate acid cyclization, and rearrangements. After C-acylation of trilithiated acetoacetanilides and cyclization to 4H-pyran-4-ones, these compounds underwent multistep rearrangements to 4-anilino-6-aryl-2H-pyran-2-ones.Key words: pyranones, trianions, Claisen-type condensations, rearrangements.

Preparation of N-aryl-4-oxo-4H-1-benzothiopyran-2-acetamides from trilithiated acetoacetanilides and lithiated methyl thiosalicylate

1999 ◽  
Vol 77 (1) ◽  
pp. 94-97 ◽  
Author(s):  
April J Angel ◽  
Anne E Finefrock ◽  
Kristen L French ◽  
Douglas R Hurst ◽  
Angela R Williams ◽  
...  
Keyword(s):  
Key Words ◽  
Lithium Diisopropylamide ◽  
Strong Base ◽  
Multiple Anion Synthesis ◽  
Acid Cyclization

Acetoacetanilide and substituted acetoacetanilides were trilithiated in excess lithium diisopropylamide, and the polylithiated intermediates were regioselectively condensed with lithiated methyl thiosalicylate, followed by acid cyclization to afford substituted N-aryl-4-oxo-4H-1-benzothiopyran-2-acetamides (thiochromone-2-acetamides).Key words: thiochromones, strong-base multiple anion synthesis, Claisen-type condensation.

Cytotoxicity Study on Some Synthetic Aromatic Esters of 4-Demethyl-4-deoxypodophyllotoxin

2011 ◽  
Vol 8 (9) ◽  
pp. 857-860
Author(s):  
Juan-Juan Wang/snm ◽  
> ◽  
Hong-Jin Han ◽  
Guang-Zhi Zeng ◽  
Hui Xu ◽  
...  
Keyword(s):  
Aromatic Esters

Excited states of aromatic esters

1979 ◽  
Vol 11 (2) ◽  
pp. 109-119 ◽  
Author(s):  
Sílvia M. de B. Costa ◽  
António L. Maçanita ◽  
M.J. Prieto
Keyword(s):  
Excited States ◽  
Aromatic Esters

Electrochemical screening for electron acceptors: aromatic esters

1986 ◽  
Vol 207 (1-2) ◽  
pp. 161-175 ◽  
Author(s):  
Carlo de Luca ◽  
Claudio Giomini ◽  
Liliana Rampazzo
Keyword(s):  
Electron Acceptors ◽  
Aromatic Esters

Cyclization of 2-(2-bromoethoxy)-acetophenones and 5-(ω-haloalkoxy)-1,5-dihydro-2H-pyrrol-2-ones – Formation of five- to eight-membered oxygen-containing heterocycles via intramolecular alkylation

2004 ◽  
Vol 82 (5) ◽  
pp. 571-578 ◽  
Author(s):  
Kirill V Nikitin ◽  
Nonna P Andryukhova
Keyword(s):  
Sodium Hydride ◽  
Spiro Compounds ◽  
Lithium Diisopropylamide ◽  
Intramolecular Alkylation ◽  
High Yields

Under basic conditions (lithium diisopropylamide or sodium hydride in THF) 2-(2-bromoethoxy)-acetophenones were transformed to 3,4-dihydro[1]benzoxepin-5(2H)-ones (homochromanones) in high yields. The preparation of novel tetrahydropyrano[2,3-b]pyrrol-6(2H)-ones and 3,4-dihydro-2H-pyrrolo[2,1-b][1,3]oxazin-6(8aH)-ones and spiro compounds was performed using similar cyclization in moderate to good yields.Key words: cyclization, lithiation, spiro heterocycles.

Stereoselective deprotonation of tropinone and reactions of tropinone lithium enolate

1992 ◽  
Vol 70 (10) ◽  
pp. 2618-2626 ◽  
Author(s):  
Marek Majewski ◽  
Guo-Zhu Zheng
Keyword(s):  
Acetic Acid ◽  
Ring Opening ◽  
Aldol Reaction ◽  
Ethyl Chloroformate ◽  
Lithium Diisopropylamide ◽  
Silver Acetate ◽  
Lithium Amides ◽  
Lithium Enolate ◽  
The Absolute ◽  
Absolute Stereochemistry

Tropinone (6) was deprotonated with lithium diisopropylamide and with chiral lithium amides (18–24) and the resulting enolates (two enantiomers) were treated with electrophiles. The aldol reaction with benzaldehyde and deuteration were both diastereoselective. The former yielded only one isomer (exo, anti) of the aldol 8a; the latter proceeded from the exo face. This selectivity permitted us to probe the deprotonation of tropinone with lithium amides; it was concluded that the reaction involves predominantly the exo axial protons. The reaction of tropinone enolate with ethyl chloroformate led, via a ring opening, to the cycloheptenone derivative 9. The reaction with methyl cyanoformate yielded, in the presence of silver acetate and acetic acid, the β-ketoester 8b; however, in the absence of these additives, and especially when 12-crown-4 was added to the enolate, a ring opening leading to the pyrrolidine derivative 10 occurred instead. Deprotonation of tropinone with chiral lithium amides proceeded with modest enantioselectivity. A synthesis of non-racemic anhydroecgonine via this strategy allowed establishing the absolute stereochemistry of deprotonation.

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