5-Hydroxyhexanoic acid 6-lactone

Tertiary alcohols are oxidized in water-dioxane-NaOH to alkoxy radicals, wliich fragmentate to ketone and alkyl radicals R- (Eq. (216) ). The relative rate of cleavage decreases with R in the order sec -butyl > isopropyl > ethyl > propyl > pentyl > isobutyl > methyl 46 8). Likewise, the bisulfite adduct of cyclohexanone is converted in 20% yield to 4-hydroxyhexanoic acid lactone (160) and 3-hydroxycyclohexanoic acid lactone (161) by anodic fragmentation (Eq. (222) ) 469 ... 

In addition, n-hexanoic acid, methyl (X)-7-hexadecenoate and 4-hydroxyhexanoic acid lactone (T-caprolactone) (XV) have been identified as part of the sex attractant blend. All of these compounds are individually active. 

FEMA No. 2556 4-Hydroxyhexanoic Acid Lactone CH3CH2CHCH2CH2C=0 1 O herbaceous, sweet oils ins—water/ 220° mL 95% ale... 

Synonyms y-Caprolactone Ethyl butyrolactone y-Ethylbutyrolactone 2(3H)-Furanone, 5-ethyldihydro- y-Hexanolactone Hexanolide-1,4 Hexan-4-olide 4-Hydroxyhexanoic acid lactone 4-Hydroxyhexanoic acid y-lactone Tonkalide Classification Nonaromatic lactone Empirical C6H10O2... 

Hydroxyhexanoic acid lactone 4-Hydroxyhexanolc acid y-lactone. Seey-Hexalactone... 

Cinnamaldehyde — 3-phenylpropionaldehyde (98 % yield) Dimethyl maleate — dimethyl succinate (96 % yield) 5-Hydroxy-2-hexenoic acid <5-lactone — 5-hydroxyhexanoic acid -lactone... 

Hexan-6-olide 6-Hydroxyhexanoic acid lactone e-Lactone hexanoic acid 2-Oxepanone... 

Synonyms 5-Caprolactone 5-Hexanolactone 5-Hexanolide 5-Hydroxyhexanoic acid lactone 5-Methyl-5-valerolactone Tetrahydro-6-methyl-2H-pyran-2-one... 

Wheeler et al. (1976) showed that the secretions of Xylocopa hirsutissima (Xylocopinae) are dominated by c/5-2-methyl-5-hydroxyhexanoic acid lactone. In addition, traces of benzaldehyde, />-cresol, benzoic acid, and vanillin were detected. 

All four possible diastereomers of 2-methyl-5-hydroxyhexanoic acid lactone (628) have been synthesized by Pirkle and Adams (641) and await comparison with natural material to determine which is the pheromone of the carpenter bee. 

Caprolactam (5.68, Fig. 5.21) has a seven-membered lactam ring and is a major industrial compound in the production of Nylon , its polymer. This compound shows only moderate levels of toxicity in mice and rats when administered orally. The hydrolysis product 6-aminohexanoic acid (5.69) was a minor metabolite in rats [176]. Hydroxylation in the y-position to yield 5.70 without preliminary hydrolysis of the lactam linkage has been shown to be the major metabolic pathway. This metabolite hydrolyzes in urine to produce 6-amino-4-hydroxyhexanoic acid (5.71), which is in equilibrium with the corresponding lactone (5.72). 

Males of the carpenter bee, Xylocopa hirutissima, establish and defend territories that are located proximate to projecting trees on mountain tops (146). These territories are maintained by a mandibular gland secretion that contains, as a major constituent, the cis-lactone of 2-methyl-5-hydroxyhexanoic acid (XXXVIII) (147). 

CAS 502-44-3 EiNECS/ELiNCS 207-938-1 Synonyms Caproiactone e-Caproiactone 6-Caproiactone monomer 6-Hexanoiactone 1,6-Hexanoiide Hexan-6-oiide 6-Hydroxyhexanoic acid iactone e-Lactone hexanoic acid 2-Oxepanone Empirical CsHioO ... 

Adamus et al. [26] studied copolymers with units of beta-butyrolactone (HB) and2-hydroxyhexanoic acid (2HHA) with ESI. The mixture of HB and 2HHA was stirred and heated at 70°C. The heating was continued until the racemic beta-butyrolactone was consumed, as determined by infrared (IR) spectroscopy (disappearance of beta-lactone carbonyl absorption band at 1815/cm).The copolymer yield was higher than 80%. The subsequent SEC analysis allowed to estabhsh that the polydispersity index is reasonably large ( I =1.6). 

Identification of volatile lactones by NMR. I. Synthesis of y- and 6-lactones and assignments in the carbon-13 NMR spectra of 4-hydroxyhexanoic and 5-hydroxyheptanoic acid lactones, Finn. Chem. Lett. 1975 129 Chem. Abstr. 84 ... 

Hydroxyhexanoic acid ethylester (E,E)-2,4-Decadienal trans-4,5-Epoxy-(E)-2-decenal Wine lactone Vanillin... 

Lipase CA also polymerized hydrophobic oxyacids efficiently [88]. The DP value was beyond 100 in the polymerization of l6-hydroxyhexadecanoic acid, 12-hydroxydodecanoic acid, or 10-hydroxydecanoic acid under vacuum at high temperature (90 °C) for 24 h, whereas a polyester with a lower molecular weight was formed from 6-hydroxyhexanoic acid under similar reaction conditions. This difference may be due to the lipase-substrate interaction. Similar behaviors were reported in the lipase-catalyzed ring-opening polymerization of lactones in different ring sizes [24,25]. 

Figure VIII shows the enantiomeric composition of various hydroxy- and acetoxyacid esters and of if -hexa-and -octalactone isolated from pineapple. Methyl 3-hydroxyhexanoate and methyl 3-acetoxyhexanoate are mainly of the (S)-configuration corresponding to intermediates of B-oxidation. The optical purity of the 5-acetoxy esters is lower than of the 3-acetoxy derivatives. The lactones were mainly of the (R)-configuration. Figure IX presents a possible pathway to explain the formation of these compounds. Methyl (S)-(+)-3-hydroxyhexanoate and methyl (S)-3-acetoxyhexanoate may be derived from (S)-3-hydroxyhexanoyl-CoA by transacylation with methanol and acetyl-CoA, respectively. The biosynthesis of 5-hydroxyacids is still unknown, but they may be formed by elongation of 3-hydroxyacids with malonyl-ACP. This hypothesis could explain their varying enantiomeric composition relative to the 3-hydroxyacids. However, hydration of unsaturated acids and/or the reduction of 5-oxoacids may be involved.

The action of peroxyacids, such as Caro s acid, on cyclic ketones affords co-hydroxy carboxylic acids or their lactones, the latter being convertible into co-hydroxy carboxylic esters by the action of an alcohol and an acid cyclohexanone, for instance, gives a 6-hydroxyhexanoic ester in this way 126,127... 

Esters constituted the largest family and included acetates (ethyl, propyl, isobutyl, butyl, isoamyl, and phenethyl), ethyl esters of fatty acids (propanoate, isobutanoate, butanoate, hexanoate, octanoate, 3-hydroxybutanoate, 3-hydroxyhexanoate and furcate), ethyl esters of organic acids (pyruvate, lactate, ethyl myristate, diethyl malate and, mono- and diethyl succinate) and various other esters, such as methyl butanoate, isobutyl lactate and phenylethyl octanoate. The acids quantified included isobutanoic, butanoic, hexanoic, octanoic, decanoic, lauiic and 3-methylbutanoic. The lactones included y-butyrolactone, pantolactone, y-decalactone and E- and Z-oak lactone and the terpenes included neral d-terpineol, P-dtronellol and Z-nerolidol. The aldehyde family comprised acetaldehyde, benzaldehyde, furfural, 5-methylfurfural and octanal, and the phenol family included eugenol, 4-ethylphenol and 4-ethylguaiacol. Finally, 1,1-diethoxyethane, acetoin, sotolon, 2, 3-butanedione, p-cymene and methionol were also determined. 

---