Rearrangement acetoacetates

Linalool can be converted to geranyl acetone (63) by the CarroU reaction (34). By transesterification with ethyl acetoacetate, the intermediate ester thermally rearranges with loss of carbon dioxide. Linalool can also be converted to geranyl acetone by reaction with methyl isopropenyl ether. The linalyl isopropenyl ether rearranges to give the geranyl acetone. 

An unusual reaction involving s-triazine (247) and ethyl acetoacetate with sodium ethoxide leads eventually to the pyrido[4,3-ring opening and Dimroth-type rearrangement of the intermediate (248) (80JHC389>. 

Leu to acetoacetate and acetyl-CoA through transamination, decarboxylation, and a bunch of rearrangements lie to propionyl-CoA through transamination, decarboxylation, and a bunch of rearrangements Phe to Tyr, then to acetoacetate and fumarate Tyr to acetoacetate and fumarate... 

The final product of the reaction, the sodium derivative of ethyl acetoacetate, is then formed by elimination of sodium ethoxide and salt formation with the ethyl acetoacetate, rearranged in the enol-form ... 

Constitution of the Esters of the (3-Ketocarboxylic Acids and of the P-Diketones.—Ethyl acetoacetate is taken as example. It reacts like a ketone with phenylhydrazine, bisulphite, and other ketone reagents on the other hand it shows an acid reaction, it dissolves in alkalis, and gives the colour reaction with ferric chloride characteristic of ends and also of phenols. From this double behaviour it was formerly concluded that it was either purely ketonic or purely enolic and that the reactions in the other form were to be attributed to a rearrangement caused by the reagents used. The true state of affairs was first disclosed by... 

However, if only two carbon atoms are present (15) they may be disconnected to give an allylic alcohol 16 and the acetoacetic ester, through a retro-Carroll rearrangement [6] (Scheme 7.6). 

The method of preparation of 5-dodecen-2-one presented here is a version of the literature procedure published earlier. It offers several advantages over existing methodology (1) The ester enolate modification of the Carroll rearrangement provides the allylic acetoacetates via a mild, fast, and high yield synthesis. This procedure represents a significant Improvement over... 

Carboni and co-workers have used 1,3-dicarbonyl compounds to cyclize a large variety of aminonaphthyridines (66G1443, 67G1262, 69G677). The use of ethyl acetoacetate on 2-aminonaphthyridines (390) followed by polyphosphoric acid or Dowtherm treatment produces oxopyrimidonaphthyridines (391) which can be rearranged to the isomeric 1,8,9-anthyridines (392). The products obtained from diethyl acetonedicarboxylate are very similar (69G677). 

Isodehydroacetic acid has been prepared by the action of sulfuric acid on acetoacetic ester 3 4 The ethyl ester has been prepared by the action of dry hydrogen chloride on acetoacetic ester 6 6 and by the sodium-catalyzed condensation of ethyl /3-chloroisocrotonate with ethyl acetoacetate3 The methyl ester of isodehydroacetic acid has been prepared by the thermal rearrangement of pyrazolines 7... 

Addition of acetylene to acetone results in the formation of 2-methyl-3-butyn-2-ol, which is hydrogenated to 2-methyl-3-buten-2-ol in the presence of a palladium catalyst. This product is converted into its acetoacetate derivative with diketene [38] or with ethyl acetoacetate [39]. The acetoacetate undergoes rearrangement when heated (Carroll reaction) to give 6-methyl-5-hepten-2-one ... 

No. Pinacolone has a trimethylated a C. Acetoacetic ester is used for preparing mono- or dialkylated methyl ketones. The compound is made by a pinacol-pinacolone rearrangement of (CH,)2COHCOH(CH,)2. 

Anomalous Fischer cyclizations are observed with certain o-substituted aryl-hydrazones, especially 2-alkoxy derivatives[l]. The products which are formed can generally be accounted for by an intermediate which would be formed by ( p.s o-substitution during the sigmatropic rearrangement step. Nucleophiles from the reaction medium, e.g. Cl or the solvent, are introduced at the 5-and/or 6-position of the indole ring. Even carbon nucleophiles, e.g. ethyl acetoacetate, can be incorporated if added to the reaction solution[2]. The use of 2-tosyloxy or 2-trifluoromethanesulfonyloxy derivatives has been found to avoid this complication and has proved useful in the preparation of 7-oxygen-ated indoles[3]. 

Rearrangement of triazolotriazepinones 174 (prepared by the action of ethyl acetoacetate on 4,5-diamino-s-triazoles) has been shown to take place in acetic anhydride to give pyrazolo[3,2-c]-s-triazoles (175). 62 The mechanism of this reaction is being investigated.163 It has been conclusively shown that compounds of structure 174 (not 173 as previously thought164) result from the action of ethyl acetoacetate on 3-substituted 4,5-diamino-s-triazoles.162... 

Hydroxythiocoumarins are, of course, enolic and react as acetoacetate analogues. Electrophiles such as Mannich reagents, aromatic aldehydes and enones react readily (Scheme 22), while acylation can be direct, or via a Fries-type rearrangement of 4-acyloxy precursors. 

TAFEL REARRANGEMENT. Rearrangement of the carbon skeleton of substituted acetoacetic esters to hydrocarbons with the same number of carbon atoms by electrolytic reduction to a lead cathode in alcoholic sulfuric acid. 

The Carroll rearrangement, a variation on the ester Claisen rearrangement, is a useful method for the preparation of y, 8-unsaturated ketones from allyl acetoacetates, and has been adapted to provide a method for the synthesis of a number of specific arylacetones. Thus, treatment of the p-quinol 1 with diketene and a catalytic amount of DMAP at room temperature gave a 72% yield of the arylacetone 2 together with 5% of the benzofuran 3. 

In fact, it isn t necessary to make 57 as, when R=Me, it is the natural alkaloid arecoline. However, when the synthesis was continued by attempted conjugate addition of the enolate of methyl acetoacetate to 57 only very low yields (12-18%) of products could be found. The problem turned out to be the base-catalysed rearrangement of 57 into the aromatic pyridone 71. 

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