2-Hydroxy-3-methyl- -4-hexenoic acid

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 (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... 

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. ... 

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

Methyl-2-hydroxy-5-hexenoic acid with 85%-H3P04 slowly distilled at 30 mm. —2,5-epoxy-2-methylhexanoic acid. Y 75%. (Bl. 1949, 24.) —Cyelization of sec. alcohols is best effected by H3P04, which, however, forms diethylenic hydrocarbons from tert. alcohols (Bl. 1949, 17). (F. e., also via dibromo alcohols, s. J. Colonge and A. Lagier, Bl. 1949, 24, 17.)... 

CN ( )-6-(l,3-dihydro-4-hydroxy-6-methoxy-7-methyl-3-oxo-5-isobenzofuranyl)-4-methyl-4-hexenoic acid 2-(4-morpholinyl)ethyl ester... 

The Claisen rearrangement of (R)-l-methyl-(E)-2-butenyl hydroxy acetate (7) gives (2R,3S)-2-hydroxy-3-methyl-(E)-4-hexenoic acid (8) with complete 1,3-chirality transfer and with 98% syn-selectivity.4... 

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... 

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. 

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]... 

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... 

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... 

Mycophenolic acid (6-(4 hydroxy-6-methoxy-7-methyl-3-HDxo-5- pathalanyl)-4-methyl-4-hexenoic acid) also shown to inhibit IMP dehydrogenase (9) effectively interferred with the synthesis of guanosine nucleotides from IMP by PRBC (Table 1). The decrease (85%) in labelled GTP and total guanylates was significant (p <. 001). There was also a moderate (p <. 01) decrease in the concentration of GTP and in the level of the guanylate pool. 

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

Natsch, A., H. Gfeller, RGygax, J. Schmid and G. Acuna,/. Biol. Chem., 278, 2003, 5718-5727. (Enzyme release of 3-methyl-2-hexenoic acid and 3-hydroxy-3-methylhexanoic acid.)... 

R)-Hydroxy-4-pentenoic44,322 (R-94) and 3(R)-hydroxy-3(R)-methyl-4-hexenoic (R-99, R = H)4S acids were obtained from the racemic acids by recrystallization of their quinine salts. Compound R-94 served322 as the substrate for the synthesis of 2-deoxy-L-eri/t/iro-pen-tose as in 94 —> 98. The enantiomeric acid R-99 was employed46 for the preparation of D-everniicose (see 99 — 105). 

Mycophenolic acid may be obtained by the fermentation broth of Pennicillium brevicompactum. The synthesis of Mycophenolate mofetil (Patent U.S. 4,753,935). The mixture of Mycophenolic acid (32.0 g), thionyl chloride (25.0 ml) and DMF (0.3 ml) in dichloromethane (250 ml) was stirred at room temperature for 3 hours, after which the volatile components were removed under vacuum to afford mycophenolic acid chloride as an oil. The mycophenolic acid chloride oil was dissolved in dichloromethane (50.0 ml) and added to the chilled solution of morpholinoethanol (30.5 ml) in dichloromethane (250 ml). After stirring for 90 min at 4°C, the reaction mixture was washed with water and then with aqueous sodium bicarbonate. The organic solution was dried with sodium sulfate and evaporated to yield Mycophenolate mofetil morpholinoethyl E-6-(l,3-dihydro-4-hydroxy-6-methoxy-7-methyl-3-oxo-5-isobenzofuranyl)-4-methyl-4-hexenoate (melting point 93-94°C). 

Figure 1 shows part of a reconstructed ion chromatogram of a pineapple aroma extract isolated after incubation of pineapple slices with 3-hydroxyhexanoic acid-3-di. GC-MS detection of deuterated compounds showed that the following pathways are active (a) esterification leading to methyl and ethyl esters, (b) dehydration to (E)-2-and (E)-3-hexenoates, and (c) chain elongation to methyl 5-hydroxy octanoate followed by acetylation (methyl 5-acetoxyoctanoate) and cyclization ( 6-octalactone). 

R)-(-)-2,4-0-ETHYLIDENE-D-ERYTHR0SE AND ETHYL (E)-(-)-4,6-0-ETHYLIDENE-(4S,5R,1 R)-4,5,6-TRtHYDROXY-2-HEXENOATE (1,3-Dioxane-(R)-4-carboxaldehyde, 5-hydroxy-2-methyl-, [2R-(2a,4a,5p)]- and D-erythro-Hex-2-enonlc acid, 2,3-dideoxy-4,6-0-ethylidene-, ethyl ester [2E,4(S)]-)... 

E)- and (Z)-4-Benzyloxy-3-hydroxy-l-(4-methylphenyl)-l-butene gave, with triethyl orthoacetate in the presence of pivalic acid, the same, but enantiomeric, (R,E) and (.S , )-6-benzyloxy-3-(4-methylphenyl)-4-hexenoate [5 65%, 87% ee from the (E -butene R 78%, 90% ee from the (Z)-butene] (see p 3374)288. Similarly, (R,E)- and (S, )-6-benzyloxy-3-(4-methylphenyl)-4-hexenal are obtained by heating the (E)- and (Z)-butenes with excess methyl vinyl ether in the presence of mercury(II) acetate in a sealed tube [S 72 %, 90 % ee from the (E)-butene R 71 %, 85% ee from the (Z)-butcnc]288. Analogous strategies have been used to construct the phytyl side chain of tocopherol (see p 3370)289,290. 

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