Lactone, hydroxy

Hydroxypentadecanoic acid lactone) (hydroxy fatty acid lactone) ... 

A15.1.1.2 Lactones. Hydroxy acids (HO—(CH2)s—CO—OH), are compounds that contain both a hydroxyl and a carboxylic acid function within the same molecule, and have the capacity to form cyclic esters called lactones (refer to Figures A15-1 and A15-2). Lactones are subject to general acid- or base-... 

Diols with primary and tertiary hydroxyls also give lactones on treatment with silver carbonate, but diols with primary and secondary hydroxyls yield, besides lactones, hydroxy ketones, resulting from preferential oxidation at the secondary center (equation 293) [377]. 

Gamma-lactones are quite prevalent in biolipids and in microbiological transformation products. Any of these may be the source of y-lactones. Hydroxy-acids and unsaturated acids may also be the source of y-lactones in Aleksinac shale. If y-lactones were found to be typical for certain class of sediments, they might shed more light on the source of the organic matter of these sediments. 

About 6,0001 of the animal feed additive calcium-D-pantothenate are produced annually via D-pantolactone (d-112) (Scheme 35, left side).D-Pantolactone itself is an important chiral intermediate for chemical synthesis and a chiral resolution agent for optically pure amines. Optically pure d-112 is for instance produced by Fuji Chemical Industries by using the D-specific 1,4-lactone hydroxy-acylhydrolase from Fusarium oxysporum [100-102], an enzyme that catalyzes the stereospecific hydrolysis of various kinds of lactones. Treatment of mc-112 leads to an exclusive hydrolysis of d-112 the hydroxy acid d-113 can be easily separated from the remaining lactone l-1 12 and is subsequently chemically con-... 

Reactions.—Asymmetric syntheses involving cr-sulphinyl carbanions have been described, including the preparation of /ff-methoxy-)ff-phenylacetaldehyde via a chiral dithioacetal mono-5-oxide anion " and of lactones, -hydroxy-lactones, and esters such as (i )-mevalonolactone. or-Sulphinyl carbanions are intermediates in the reaction of sulphines with carbanions (thiophilic addition) which can lead ultimately to ketones or olefins - (see also Chap. 3, Pt II, p. 162). 

Y Hydroxybutyric acid cyclic ester 4-Hydroxybutyric acid Y-lactone - Hydroxy-butyric acid lactone Y-Hydroxybutyrolactone. See Butyrolactone Hydroxycellulose. See Cellulose Hydroxyceteth-60... 

Scheme 44 Resolution of hydroxy lactones, hydroxy amides, and hydroxy phosphonamides.

For the preparation of 4-substituted coumarins, a phenol may be condensed with ethyl acetoacetate under the influence of sulphuric acid. Thus resorcinol (II) readily undergoes this condensation (which is represented diagrammatically above) to give 7-hydroxy-4-methyl-coumarin (III). Note that the coumarins, like all 2 pyrones, are systematically lactones. 

Basic catalysts other than alkali acetates have been employed in the Perkin reaction thus salicylaldehyde condenses with acetic anhydride in the presence of triethylamine to yield coumarin (tlie lactone of the cis form of o-hydroxy-cinnamio acid) together with some of the acetyl derivative of the trans form (o-acetoxycoumaric acid) ... 

Epoxides provide another useful a -synthon. Nucleophilic ring opening with dianions of carboxylic acids (P.L. Creger, 1972) leads to y-hydroxy carboxylic acids or y-lactones. Addition of imidoester anions to epoxides yields y-hydroxyaldehyde derivatives after reduction (H.W. Adickes, 1969). 

Cyclopentene derivatives with carboxylic acid side-chains can be stereoselectively hydroxy-lated by the iodolactonization procedure (E.J. Corey, 1969, 1970). To the trisubstituted cyclopentene described on p. 210 a large iodine cation is added stereoselectively to the less hindered -side of the 9,10 double bond. Lactone formation occurs on the intermediate iod-onium ion specifically at C-9ot. Later the iodine is reductively removed with tri-n-butyltin hydride. The cyclopentane ring now bears all oxygen and carbon substituents in the right stereochemistry, and the carbon chains can be built starting from the C-8 and C-12 substit""" ... 

The carbonylation of COD PdCl2 complex in aqueous sodium acetate produces /rui7x-2-hydroxy-5-cyclooctenecarboxylic acid /i-lactone (240). The lactone is obtained in 79% yield directly by the carbonylation of the COD complex in aqueous sodium acetate solution[220]. /i-Propiolactone (241) is obtained in 72% yield by the reaction of the PdCC complex of ethylene with CO and water in MeCN at —20 " C. /3-Propiolactone synthesis can be carried out with a catalytic amount of PdCC and a stoichiometric amount of CuCl2[221]. 

The reaction of vinyloxiranes with malonate proceeds regio- and stereose-lectively. The reaction has been utilized for the introduction of a 15-hydroxy group in a steroid related to oogoniol (265)(156]. The oxirane 264 is the J-form and the attack of Pd(0) takes place from the o-side by inversion. Then the nucleophile comes from the /i-side. Thus overall reaction is sT -StM2 type, in the intramolecular reaction, the stereochemical information is transmitted to the newly formed stereogenic center. Thus the formation of the six-membered ring lactone 267 from 266 proceeded with overall retention of the stereochemistry, and was employed to control the stereochemistry of C-15 in the prostaglandin 268[157]. The method has also been employed to create the butenolide... 

The telomer 145 of nitroethane was used for the synthesis of recifeiolide (148)[121], The nitro group was converted into a hydroxy group via the ketone and the terminal double bond was converted into iodide to give 146. The ester 147 of phenythioacetic acid was prepared and its intramolecular alkylation afforded the 12-membered lactone, which was converted into recifeiolide (148),... 

Alkynyl)oxiranes also react with carbon nucleophiles to afford furan derivatives. Furanes of different types are obtained depending on the structure of the substrates. 7-Methyl-2-ethynyloxirane (95) reacts with acetoacetate to give the furan 97 by the elimination of formaldehyde from the cyclized product 96. The hydroxy ester of the alkylidenefuran 98 and the corresponding lactone 99 are obtained by the reaction of i-methyl-2-(2-propynyI)oxirane[40, 42]. 

Lactones, l xictides, iMciams, and Lactims. When the hydroxy acid from which water may be considered to have been eliminated has a trivial name, the lactone is designated by substituting -olactone for -ic acid. Locants for a carbonyl group are numbered as low as possible, even before that of a hydroxyl group. 

P-Hydroxy acids lose water, especially in the presence of an acid catalyst, to give a,P-unsaturated acids, and frequendy P,y-unsaturated acids. P-Hydroxy acids do not form lactones readily because of the difficulty of four-membered ring formation. The simplest P-lactone, P-propiolactone, can be made from ketene and formaldehyde in the presence of methyl borate but not from P-hydroxypropionic acid. P-Propiolactone [57-57-8] is a usehil intermediate for organic synthesis but caution should be exercised when handling this lactone because it is a known carcinogen. 

Composition. Shellac is primarily a mixture of aUphatic polyhydroxy acids in the form of lactones and esters. It has an acid number of ca 70, a saponification number of ca 230, a hydroxyl number of ca 260, and an iodine number of ca 15. Its average molecular weight is ca 1000. Shellac is a complex mixture, but some of its constituents have been identified. Aleuritic acid, an optically inactive 9,10,16-trihydroxypalmitic acid, has been isolated by saponification. Related carboxyflc acids such as 16-hydroxy- and 9,10-dihydroxypalmitic acids, also have been identified after saponification. These acids may not be primary products of hydrolysis, but may have been produced by the treatment. Studies show that shellac contains carboxyflc acids with long methylene chains, unsaturated esters, probably an aliphatic aldehyde, a saturated aliphatic ester, a primary alcohol, and isolated or unconjugated double bonds. 

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). 

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