Analogues Furaniques des Chalcones Synthèse et Réaction Avec L'Ester Acetyl‐Acétique

Hanson, G. A.

doi:10.1002/bscb.19580670302

Cited by 7 publications

References 4 publications

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The Aldol Condensation

Nielsen

Houlihan²

2011

Organic Reactions

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The aldol condensation takes its name from aldol (3‐hydroxybutanal) a name introduced by Wurtz who first prepared the beta‐hydroxy aldehyde from acetaldehdye in 1872. The aldol condensation includes reactions producing beta‐hydroxy aldehydes or beta‐hydroxy ketones by self condensations or mixed condensations of aldehydes and ketones as well as reactions leading to alpha, beta‐unsaturated aldehydes or alpha,beta‐unsaturated ketones formed by dehydration of intermediate beta‐aldols or beta‐ketals. The Claisen‐Schmidt condensation is most often taken to be the condensation of an aromatic aldehyde or ketone usually in the presence of a basic catalyst. The term aldol condensation has also been applied to many other condensations involving the reaction of an aldehyde or ketone. These condenations are discussed. The present review includes examples that are solely condensation reactions of aldehydes and ketones.

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The Aldol Condensation

Nielsen

Houlihan²

2011

Organic Reactions

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1,4‐pentandien‐3‐ones, XXXII: Reaction of 2‐acetylthiophene and 2‐acetylfuran with malononitrile and aldehydes, and synthesis and properties of phenylene‐bis [(thienyl/furyl)nicotinonitrile] derivative

Greiner-Bechert

Otto

1991

Archiv der Pharmazie

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The (E}-I-hetaryl-2-propen-I-ones 3 and 4 are prepared by condensation of 2-acetylthiophenes (1a,1c:.ld)or 2-acetylfuran (Ib) with aldehydes. The Michael addUC\S 5/6 areobtained from 3/4 by reactionwith malononitrile/1..DA in TIIF at -78OC. or in OMSOwith NaH at room temp.Reactionof 3/4 with malononitrile and methylate in methanol yielded the substituted nicotinonitriles 7/8. From terephthalaldehyde. the diketones 9 are prepared,whichyield with malononitrile the phenylene-bis[(thienyVfuryl)nicotinonitrilel derivatives 10 undersimiliarconditions. StruetUrat and spectraldata are discussed.2-Acetylated thiophenes and furans 1 are versatile starting materials for many classes of heterocyclesi', We are especially interested in the construction of highly substituted pyridines and related heterocycles starting from 1,4-pentadien-3-ones and other substituted C1,~unsaturated ketones by Michael and similiar reactions 3 ). Here, we report about the reactions of 1 with aromaticaldehydes2 and malononitrile.Referring to a prescription given by Murphy and Watta· nasin 4 ) la was reacted with the aldehydes 2a-i in absol. methanol in the presence of NaOH. The (l,l3-unsaturated ketones 3a-i (Scheme 1) were obtained in yields between 80 and 90%5). 3y was prepared from Ic, and 3z from Id, By a similiar procedure, from Ib the unsaturated ketones 4a-i were obtained.According to spectroscopic data, all compounds 3/4 exist in the E-configuration. Their IR-spectra show a strong carbonyl absorption around 1640 em", and the C=C absorption appears between 1590 and 1600 em", The out-of-plane vibration bond at 980 cm' is a characteristic of trans alkenes. form", a.13-Unsaturated ketones with E-configuration usually prefer the s-trans conformatlonv", As the propenones 3 and 4 contain the l,4-pentadien-3-one system -one double bond of the system is included in the heteroaromatic ring -it might be of interest to know, whether these compounds exist in different conformers as shown in Scheme 2. The system is flexible, and, therefore. an equilibrium of at least four conformations should be possible in solution, and it was of special interest to see if 3 and 4 even prefer one conformation. Perhaps, the i.r, spectra suggest a preferred sods conformation as indicated by the ratio Ico/Ic-e, and by the difference of 50-60 em" between both bands. Using the ASIS effect lO ) (deuterochloroforrn/deuterobenzene), we demonstrated that the s-transls-cis conformation A is the preferred one in solution. The differences in the shifts of the l3-protons, Sc6D6 -SCDC13' vary between +0.05 and +0.3 ppm ll ) (Table 1).

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Analogues Thieniques des Chalcones Synthèse et Réaction Avec L'ester Acétylacétique

Hanson

1958

Bulletin des Soc Chimique

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Analogues Furaniques des Chalcones Synthèse et Réaction Avec L'Ester Acetyl‐Acétique

Cited by 7 publications

References 4 publications

The Aldol Condensation

The Aldol Condensation

1,4‐pentandien‐3‐ones, XXXII: Reaction of 2‐acetylthiophene and 2‐acetylfuran with malononitrile and aldehydes, and synthesis and properties of phenylene‐bis [(thienyl/furyl)nicotinonitrile] derivative

Analogues Thieniques des Chalcones Synthèse et Réaction Avec L'ester Acétylacétique

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