Dehydracetic acid

Dehydracetic acid, which was mentioned on p. 252, is formed from ethyl acetoacetate by intermolecular condensation. On boiling with acids the lactone ring is broken and a triketocarboxylic add is produced. This acid loses C02 and H20 and is thus transformed into dimethylpyrone O O... 

C8H9NO4 3-Acetyl-6-methyl-2//-pyran-2,4(3//)-dione oxime (Dehydracetic acid oxime) Spectrophotometric Co, Cu 83, 84... 

Very exciting is the reaction specificity with dehydracetic acid 334 in the stoichiometric milling reaction. Only 335c,d is obtained. Also, a rather good... 

By prolonged boiling of acetoacetic ester under a reflux condenser at ordinary pressures, condensation occurs, and dehydracetic acid is formed. The parent acid, a 8-hydroxy-acid, is unstable, and has not yet been isolated. 

Dehydracetic acid, triace tic add lacton, and related pyrones 92AHC(53)1. 

Propionic acid, crotonic acid, benzoic acid, succinic acid, maleic and fumaric acid, phthalic acid, camphoric acid, glycollic acid, lactic acid, malic acid, tartaric acid, the oxybenzoic acids, pyroracemic acid, laevulinic acid, dehydracetic acid, and aceto-acetic acid (or its esters). 

SYNS 2-ACETYL-5-HYDROXY-3-OXO-4-HEXENOIC ACID A-LACTONE 3-ACETYL-6-METHYL-2.4-PYRANDIONE 3-ACETYL-6-METHYLPYRANDIONE-2,4 3-ACETYL-6-METHYL-2H-PYRAN-2,4(3H)-DIONE DEHYDRACETIC ACID DEHYDROACETIC ACID (FCC) DHA DHS... 

Arndt, F., Eistert, B., Scholz, H., Aron, E. Synthesis of dehydracetic acid from acetoacetic ester. Ber. 1936, 69B, 2373-2380. 

Kaupp et al. described that the 1,3-dicarbonyl compounds such as 1,3-cyclohex-anedione, dimedone, and dehydracetic acid reacted in the solid state with aniline derivatives to obtain enamine ketones 250 and 252 in quantitative yields (Scheme 3.66) [18]. Advantages over the solvent synthesis were identified it is unnecessary to use acid catalysis, solvents, or liquid phases. A further benefit of avoiding iminiiim salt intermediates in such synthesis is the lack of workup requirements. 

Arndt, F., Org. Synth., Coll. Vol. Ill, 1955, 231 Dehydracetic acid, triacetic acid lactone, and related pyrones , Moreno-Manas, M. and Pleixats, R., Adv. Heterocycl. Chem., 1993,55,1. 

Dehydol PTA 40. See Talloweth-40 Dehydol PTA 80/E. See Talloweth-80 Dehydol PTA 114. See Talloweth-11 Dehydol TA 5. See Talloweth-5 Dehydol TA 11. See Talloweth-11 Dehydol TA 12. See Talloweth-12 Dehydol TA 14. See Talloweth-14 Dehydol TA 20. See Talloweth-20 Dehydol TA 30. See Talloweth-30 Dehydol WM 90. See Laureth-9 Dehydracetic acid. See Dehydroacetic acid Dehydran 150. See Silicone emulsion Dehydran 1767 A. See Mineral oil Dehydran 3273] Dehydran 4005] Dehydran 401 O, Dehydran 4015] Dehydran 4025]... 

Synonyms 3-Acetyl-5-hydroxy-3-oxo-4-hexenoic acid A-lactone 3-Acetyl-6-methyl-1,2-pyran-2,4(3H)-dione 3-Acetyl-6-methyl-2,4-pyrandione 3-Acetyl-6-methylpyrandione-2,4 3-Acetyl-6-methyl-2H-pyran-2,4(3H)-dione Dehydracetic acid DHA DHS Methylacetopyronone... 

The first indication that phenols might be derived from C units stemmed from chemical studies performed by Collie (1907), who synthesized them from acetate via a Q intermediate he neuned dehydracetic acid. This view... 

Methyl-l-phenyl-4-benzoylpyrazolone ( 27 14 2 2 3-Acetyl-2-hydroxy-6-raethyl-4-pyrone (dehydracetic acid) (CgH3E>3) 6-Ethyl-2-hydroxy-3-propionyl-4-pyrone... 

This correlation does not apply to lactones with two carbonyl groups in the same six-membered ring. Wasserman and Zimmerman [23] have examined mesolactide and benzilide in which the carbonyl frequencies occur between 1767 cm" and 1757 cm" and Randall et al [17] quote a value of 1721 cm" for dehydracetic acid. There are compounds in which interaction effects might well be expected and are too complex for any interpretation of these shifts to be attempted. 

In the laboratory preparation of diketene the mixture of ketene, unchanged acetone, and methane from a ketene generator is passed into a condensing system which is cooled initially in Dry Ice, and the condensate is allowed to warm to room temperature over a period of about twenty-four hours. The resulting mixture of acetone, diketene, and dehydracetic acid is separated by distillation under reduced pressure (50-55% of diketene). More exact control of the concentration and... 

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