Hexane-2,4-dione

Heptane-2-5-dione Sd (roasted Hexan-3-one Sd (roasted) Hexane-2-3 dione Sd (roasted) Hexane-2-5-dione Sd (roasted) Histidine Lf ... 

D.46) 2,3-Hexanedione, hexane-2,3-dione, methyl propyl diketone, acetyl-n-butyryl [3848-24-6] FEMA 2558... 

In British practice the locant (or locants) is placed immediately before the syllable that it qualifies (see p. 35), as in hexan-3-one, hexane-2,3-dione, 1-chloro-hexan-3-one, hex-3-en-l-yne, pyrazol-3-yl, carbazole-2-carboxylic acid. In USA, one locant (or one set of locants) for a suffix is placed in front of the stem name, as in 3-hexanone, 2,3-hexanedione, l-chloro-3-hexanone, 3-hexene, 3-pyrazolyl but only one numeral (or set of numerals) is so placed any others precede the syUable that they qualify, 3-hexen-l-yne, 3-cyclohexen-l-one (the 1 maybe omitted in the second name, giving 3-cyclohexenone, where the 3 refers to the unsaturation en ). There are, however, many cases where parent names carry locants in front of them, e.g., m-dioxan, 1,7-naphthyridine (where the heteroatoms in the ring are cited by the locants 1,7 or m) in such cases the additional locants for suffixes are all placed after the parent name, as in m-dioxan-4-carboxylic or l,7-naphthyridin-2(lfl )-one. The tendency in Chemical Abstracts is to place the locants after the parent name whenever ambiguity might arise it is matched by a tendency in Great Britain to place one numeral in front of the parent name when no ambiguity can arise. A compromise seems to be working itself out unofficially. 

In animal studies acetone has been found to potentiate the toxicity of other solvents by altering their metabolism through induction of microsomal enzymes, particularly cytochrome P-450. Reported effects include enhancement of the ethanol-induced loss of righting reflex in mice by reduction of the elimination rate of ethanol increased hepatotoxicity of compounds such as carbon tetrachloride and trichloroethylene in the rat potentiation of acrylonitrile toxicity by altering the rate at which it is metabolized to cyanide and potentiation of the neurotoxicity of -hexane by altering the toxicokinetics of its 2,4-hexane-dione metabolite.Because occupationally exposed workers are most often exposed to a mixmre of solvents, use of the rule of additivity may underestimate the effect of combined exposures. ... 

The photochemistry of a number of long chain aliphatic a-diketones has been reported.46 68 Included in the study were 2,3-pentanedione, 3,4-hexane-dione, 4,5-octanedione, 5,6-decanedione, 2,7-dimethyl-4,5-octanedione, and 1,2-cyclodecanedione. Without exception, irradiation of these compounds in cyclohexane or benzene yielded cyclobutanols, presumably by an internal abstraction-cyclization mechanism. The reaction is quite selective, producing... 

Zhu M, Spink DC, Yan B, Bank S, DeCaprio AP. 1994. Formation and structure of crosslinking and monomeric pyrrole autoxidation products in 2,5-hexane-dione-treated amino acids, peptides, and protein. Chem. Res. Toxicol. 7 551-58... 

Blanchard KT,Allard EK, Boekelheide K. 1996. Fate of germ cells in 2,5-hexane-dione-induced testicular injury. I. Apoptosis is the mechanism of germ cell death. Toxicol. Appl. Pharmacol. 137 141 —48... 

Allard EK, Hall SJ, Boekelheide K. 1995. Stem cell kinetics in rat testis after irreversible injury induced by 2,5-hexane-dione. Biol. Reprod. 53 186-92... 

Dixon et al. (2001) described a preliminary PB-PK model to predict JP-8 concentrations in Air Force fuel-cell maintenance workers. The model used data from PB-PK models of naphthalene inhalation in mice and rats and nonane inhalation in rats. In addition to inhalation, a pathway of dermal exposure and a skin compartment were included. For highly exposed people, the PB-PK model was generally in agreement with exhaled-air naphthalene concentrations however, predictions for the low-exposure scenarios were grossly underestimated, especially in female workers, by a factor of 10. The model did not predict blood and urinary concentrations. The major limitation of the Dixon et al. (2001) study was the lack of appropriate human data (e.g., metabolic measures, blood and tissue partition coefficients, and diffusion rates). The Dixon et al. (2001) model predicted a rapid decline in naphthalene concentrations in all compartments after exposure except liver, fat, and brain. The model predicted accumulation in liver, brain, and fat tissues for a 7-day period that included 4-hr exposures on 5 days. Competition for enzyme does not occur only from interactions of different inhaled compounds. Interactions can also occur between inhaled compounds and metabolites formed in the body that require similar enzymes for biotransformation. Detailed kinetic studies with both benzene and -hexane show inhibition of later metabolic steps, phenol to hydroquinone or methyl -butyl ketone to 2,5-hexane dione, by high concentrations of inhaled benzene or hexane, respectively (Medinsky et al. 1989 Andersen and Clewell 1984). 

In principle, many intramolecular aldol reactions can lead to a mixture) products, depending on which enolate ion is formed. For example, 2,5-hexan dione might yield either the five-membered-ring product 3-methyl-2-cyclopee tenone or the three-membered-ring product (2-methylcyclopropenyl)ethan (Figure 23.4). In practice, though, only the cyclopentenone is formed. 

The metabolites of n-hexane injected in guinea pigs were reported as 2,5- hexane-dione and 5-hydroxy-2-hexanone, which are also metabolites of methyl butyl ketone (DiVincenzo et al. 1976). Thus methyl butyl ketone and n- hexane should have similar toxicities. The neurotoxic metabolite, 2,5-hexanedione, however, is produced considerably less in n-hexane. However, in the case of hexane, the neurotoxic metabolite 2,5-hexanedione is produced to a much lesser extent. Continuous exposure to 250 ppm n-hexane produced neurotoxic effects in... 

The polymer formed from a compound with molecular formula C H (, undergoes ozonolysis to give 2,5-hexane-dione. What is the structure of C Hj ... 

Thus the ozonide of the tail-to-tail 1,4 configuration upon ozonisation and hydrolysis yields succinaldehyde (CHO-CH2-CH2-CHO). Similarly, the ozonides of the head-to-tail and head-to-head configurations yield laevulinaldehyde (CHO-CH2-CH2-CO-CH3) and 2,5-hexane dione (-CH3-CO-CH2-CH2-CO-CH3), respectively. 

Finally, 4-aminopyrimidine-5-carbaldehydes with cyclic jS-diketones, such as cyclo-hexane-l,3-dione, give partially reduced pyrimido[4,5-f>]quinolones (239) (76JOC1058). 

Prednisolone acetate (21-acetoxypregna-l,4-diene-ll3-17a-diol-3,20-dione) [52-21-1] M 402.5, m 237-239 , 240-242°, 240-243 , 244 , [a]], +116° (c 1, dioxane). Recrystd from EtOH, Mc2CO, Me2CO-hexane, and has UV 243nm in EtOH. [Joly et al. Bull Soc Chim Fr 366... 

A solution of 16jS-methyl-l la,17a,21-trihydroxy-5j5-pregnane-3,20-dione 21-acetate (52), 45 g, in dioxane (297 ml) is cooled to 15° and treated over a 5 min period with a solution of bromine (34.2 g) in dioxane (594 ml) precooled to 18°. After 2 min a solution of sodium acetate (60 g) in water (600 ml) is added and the mixture poured into ice water (8 liters). The precipitate is filtered off, washed to neutrality with water, and dried to give the crude dibromide (53), 55.7 g mp 125-126° (dec.) [aJu 58°. A mixture of dibromide (53), 55.5 g, lithium bromide (27.8 g), lithium carbonate (27.8 g) and DMF (1.11 liters) is refluxed under rapid stirring for 6 hr. The mixture is concentrated under vacuum to about 250 ml, poured into ice water (8 liters) containing hydrochloric acid (250 ml), and extracted with methylene dichloride. The extracts are washed to neutrality with water and evaporated to dryness. The residue is dissolved in acetone, evaporated to dryness under reduced pressure, redissolved in acetone and crystallized by the additon of hexane. This gives the dienone (54) 24.4 g, mp 236-239°. 

A suspension of 17a,21-dihydroxypregna-4,9(ll)-diene-3,20-dione 21-acetate (0.77 g) and iV-bromoacetamide (0.3 g) in anhydrous methylene dichloride (40 ml) is added over 2-3 min with stirring to a mixture of anhydrous hydrogen fluoride (10.19 g), and anhydrous tetrahydrofuran (18 g) in a polyethylene bottle at —80° (acetone-dry ice). After 1 hr at —80° the reaction mixture is kept for a further 1 hr at 0° and then added cautiously to an excess of an ice-cold solution of sodium carbonate. Extraction with methylene dichloride and crystallization from acetone-hexane furnish 9a-bromo-ll -fluoro-17a,21-dihydroxypregn-4-ene-3,20-dione 21-acetate (0.69 g), mp 205-208°, raised by several crystallizations from acetone-hexane to 215-217° [aju 142° (CHCI3) max 240-242 mju (e 15,500). 

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