5- Hydroxy-2-hexenoic acid 6-lactone

SYNS (S)-(+)-5,6-DIHYDRO-6-METHYL-2H-PYRAN-2-ONE Y-HEXENOLACTONE 2-HEXEN-5.1-OUDE D"-HEXENOLLACTONE 5-HYDROXY-2-HEXENOIC ACID LACTONE PARASORBIC ACID (+) PARASORBINSAEURE (GERMAN) SORBIC OIL... 

Benzalacetone Methyl vinyl ketone A -Cholestenone Cinnamaldehyde Dimethyl maleate 5-Hydroxy-2-hexenoic acid -lactone... 

Parasorbic Acid, S-5,6-Dihydro-6-methyi -2H-py-mn-2-one 5-hydroxy-2-hexenoic acid lactone 5 -A" -hex -endactone 2-hexcn-5,l-olide sorbic oil. C.H.O, mol wt 112.12. C 64.27%, H 7,19%, O 28.54%. The sole constituent of "Vogel beerof , an oil obtained by steam distillation of the acidified juice of the ripe berries of the mountain ash, Sorbus nucupario L Rosaceae Hofmann, Ann. 110, 129 (1859) Doebner, Ber. 27, 344 (1894) Kuhn, Jerchel. Ber. 76, 413 (1943). Structure eidem, ibid. Synthesis Haynes, Jones, J. Chem. Soc. 1946, 954 Lamberti el al, Rec. Trav. Chim. Pays-BttS 86, 504 (1967). 

Other methods include ring opening of parasorbic acid [108-54-3] (5-lactone of 5-hydroxy-2-hexenoic acid) in hydrochloric acid or in alkaline solutions (43,44), the ring opening of y-vinyl- y-butyrolactone in various catalysts (45,46), or isomerization of 2,5-hexadienoic acid esters (47,48). Other methods are described in thehterature (6,49,50). 

Examples of 1,3-asymmetric induction in cyclizations to 8-lactones have been observed. Iodolactonization of 3-methyl-5-hexenoic acid to a 8-lactone under equilibrating conditions showed reasonable stereoselectivity (6 1 cis trans).l20b Recent studies have examined the formation of 8-lactones from cyclization of 5-hexenoic acids with a homoallylic oxygen substituent at C-3.135 Selenolactonization of 3-hydroxy-5-hexenoic acid under conditions of kinetic control provided the trans lactone in modest yield (40%) and high stereoselectivity.13515 Equilibrating conditions led to a slight preponderance of the cis... 

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... 

ACETYL-5-HYDROXY-3-OXO-4-HEXENOIC ACID A-LACTONE see MFW500... 

HEXENOIC ACID, 2-ACETYL-5-HYDROXY-3-OXO, A-LACTONE, SODIUM derivative see SGDOOO... 

High cis selectivity has been observed in the halolactonization of 2-amino-5-substituted (Z)- and ( )-4-pentenoie acids. Treatment of (S)-(Z)-2-/m-butoxycarbonylamino-6-hydroxy-4-hexenoic acid [(S)-(Z)-8] with A -bromosuccinitrude in tetrahydrofuran at 0 °C for 5 minutes gives a 90 10 mixture of the cisjtrans-y-lactone 9 in 95% yield41. The major n.s-isomer can be purified by crystallization from chloroform/hexane. 

The lactonization of 3-hydroxy-5-methyl-4-hexenoic acid (3) is an example of regio- and stereoselective cyclization under kinetic conditions which predominantly leads to six-membered rings, i.e., the. 5-lactones 45a. 

The a-bromine atom is stable during lactone formation from a,y-dibromo-butyryl bromide the yield of a-bromo lactone is 94%. Under similar conditions the /3-bromine atom of /3,y-dibromohexanoic acid is eliminated as hydrogen bromide to give the lactone of 4-hydroxy-2-hexenoic acid. Cyclization of alkali salts of 15-bromopentadecanoic acid has been studied using various solvents and concentrations. Best yields of the O)-lactone are obtained from the potassium salt in methyl ethyl ketone. ... 

Formation of 2-Ethyl-2(5H) Furanone. The presence of artifacts with increased retention times suggests the formation of components of increased polarity and/or the formation of higher molecular weight constituents from condensation or addition reactions. The acids, aldehydes and alcohols present can undergo oxidation to form y- and 6-lactones (14, 15). The formation of the lactone, 5-ethyl-2(5H)-furanone, probably occurs by the steps outlined in Figure 4. A plausible sequence would be reaction of 2-hexenoic acid to form a peroxy radical at the y-position followed by production of the hydroperoxide. Cleavage of the 0-0 bond with the subsequent addition of H could lead to 4-hydroxy-2-hexenoic acid. Intramolecular esterification would then produce the identified lactone. 

G.13) 2(5/f)-Furanone, 5-ethyl-3-hydroxy-4-methyl-, 2-hydroxy-3-methylhex-2-eno-4-lactone, 5-ethyl-2,5-dihydro-3-hydroxy-4-methylfuran-2-one, 4-ethyl-2-hydroxy-3-methyl-2-buten-4-olide, 2,4-dihydroxy-3-methyl-2-hexenoic acid, 7-lactone, a-hydroxy-p-methyl-Aa,p-7-hexenolactone, abhexone 698-10-2] FEMA 3153 ( )- 1144810-13-9] (/ )- 144831-60-7J (5)- 14483l-61-8]... 

Dehydroacetic Acid. 3-A cctyl-b-melhyl 2H-py-ran-2,4(3H)-dione 2-acetyl-5-hydroxy-3-oxo-4-hexenoic acid i-lactone methylacetopyronone DHA. CjHjO mol wt 168.]4. C 57.14%, H 4.80%, O 38.06%. Polymerization product of ketene Steele er al. J. Org. Chem. 14, 460 0949)- From ethyl acetoacetate Arndt, Org. Syn. coll, vol. Ill, 231 (1955). Series of articles on toxicity studies, pharmacology, mechanism of action, absorption, distribution, renal action J. Pharmacol. Exp Ther. 99, 57-111 (1950). 

Acetyl-5-hydroxy-3-oxo-4-hexenoic acid A-lactone. See Dehydroacetic acid... 

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... 

Hexenoic acid, 2-acetyl-5-hydroxy-3-oxo-, A-lactone, sodium deriv.. See Sodium dehydroacetate... 

Synonyms Dehydroacetic acid sodium salt DHA-Na 4-Hexenoic acid, 2-acetyl-5-hydroxy-3-OXO-, A-lactone, sodium deriv. 3-(1-Hydroxyethylidene)-6-methyl-2H-pyran-2,4(3H)-dione sodium salt 2H-Pyran-2,4(3H)-dione, 3-acetyl-6-methyl-, monosodium salt Sodium dehydroacetic acid Sodium dehydroxyacetate Sodium 1-(3,4-dihydro-6-methyl-2,4-dioxo-2H-pyran-3-ylidene) ethanolate... 

Dehyracetic acid 2-Acetyl-5hydroxy-3-oxo-4-hexenoic acid delta-lactone 3-Acetyl-4-hydroxy-6-methyl-pyron... 

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