6- Hydroxy-2-hexanone

Additional aldehydes and ketones were also included in the U.S. Nationwide Occurrence Study dimethylglyoxal (2,3-butanedione), cyanoformaldehyde, 2-butanone (methyl ethyl ketone), trans-2-hexanal, 5-keto-l-hexanal, and 6-hydroxy-2-hexanone [11, 13]. Dimethylglyoxal was the most consistently detected of these carbonyl compounds (up to 3.5 pg/L) and was found at higher levels in plants using ozone. Maximum levels of 0.3, 5.0, and 0.7 pg/L were observed for cyanoformaldehyde, 2-butanone, and trans-2-hexenal, respectively 6-hydroxy-2-hexanone and 5-keto-1 -hexanal were only detected in early stages of treatment, and not in finished waters. 

Methyl ethyl ketone (2-butanone) 6-Hydroxy-2-hexanone Dimethylglyoxal (2,3-butanedione)... 

It is well known, however, that substituents favor cyclic as against acyclic forms,76 and electron-attracting substituents on the a-carbon atom increase the tendency of carbonyl groups to react with hydroxyl groups (for example, the ratio of aldehydrol to aldehyde in aqueous solution is —1.2 1 for acetaldehyde77 at 25°, and 17.5 1 for glycolalde-hyde78 at 35°). Hence, whereas 6-hydroxy-2-hexanone is found only in the acyclic form, aqueous solutions of the 1-deoxyhexuloses contain only 5% of this form at equilibrium, and those of the hexuloses contain less than 1% (see Table IV). 

Suppose a starting material A contains both a ketone and an ester, and it is necessary to selectively reduce the ester to an alcohol (6-hydroxy-2-hexanone), leaving the ketone untouched. Such a selective reduction is not possible in one step. Because ketones are more readily reduced, methyl 5-hydroxyhexanoate is formed instead. 

Syn 3-(EthyltHloniethyl)-4-hydroxy-6-pt)enyl-2-hexanone (4) and anti (5) To ethanethiol (10 0 mg 0 17 mmol) in THF (2 mL) was added 1 54 M n butyltittnum m hexane (0 11 mL) at 0 C under Ar Stannous triflate (69 0 mg 017 nvnol) was added and alter 20 mm the mocture was cooled to 4S°C Methyl vinyl Ketone 1 (118 mg 1 98 mmol) m THF (1 5 mL) was added followed by 3 phenyiptopanal 3 350 mg 2 61 mmol) m THF (1 S mL) Alter 12 h aq cilnc acid was added and the organic material extracted with OHjClj The resxlue after evaporation was dissolved in MeOH and treated with citric acxt After 30 min stimng, the mixture was quenched with pH 7 phosphate buffer extracted with CH2CI2, the solvent evaporated and the residue chromatographed to afford 336 mg ot 4 (75%), syn anti (90 10)... 

J)-4-Hydroxy-6-phenyl-2-hexanone (8, R1 =CH, R2 = (CH2)2C6H5) Typical Procedure for Enantioselective Aldol Reaction via Chiral Oxazolidines4 ... 

Fermenting baker s yeast also catalyzes the 1,4-addition of a formal trifluoroethanol-d1-synthon to a,/i-unsaturated aldehydes, to give optically active l,l,l-trifluoro-2-hydroxy-5-alka-nones52. Presumably, the mechanism involves oxidation of the alcohol to the corresponding aldehyde followed by an umpolung step with thiamine pyrophosphate and Michael addition to the a,/i-unsaturated aldehyde. For example, l,l,l-trifluoro-2-hydroxy-5-hexanone (yield 26%, ee 93%) is thus obtained from trifluoroethanol and l-bnten-3-one. 

The metabolism of 77-hexane takes place in the liver. The initial reaction is oxidation by cytochrome P-450 isozymes to hexanols, predominantly 2-hexanol. Further reactions convert 2-hexanol to 2-hexanone, 2,5-hexanediol, 5-hydroxy-2-hexanone, 4,5-dihydroxy-2-hexanone and the neurotoxicant 2,5-hexanedione. Hydroxylation at the 1- and 3- positions can be considered detoxification pathways hydroxylation at the 2- position is a bioactivation pathway. A diagram of the proposed pathway for mammalian metabolism of -hexane is presented in Figure 2-3. 

ACETATE AND ALDEHYDES OR KETONES ETHYL 1-HYDROXYCYCLO-HEXYLACETATE, 53, 66 2- (Hydroxymethylene)cyclohexanone with p-toluenesulfonyl azide to give 2-diazocyclo-hexanone, 51, 86 y-HYDROXY-ct, (3-UNSATURATED ALDEHYDES VIA 1,3-BIS(METHYL-THIO) ALLYLLITHIUM trans-4-HYDROXY-2-HEXENAL, 54, 19... 

Generation and Use of Lithium Pentafluoropropen-2-olate 4-Hydroxy-1,1,1,3,3-pentafluoro-2-hexanone Hydrate. 

We now turn to the remaining two hydroxylamines that are N-hydroxylated derivatives of 2,2,6,6-tetramethyl-4-piperidone and -4-piperidinol. The enthalpies of formation of some simple 4-piperidones and their corresponding 4-piperidinols have recently been determined. The values of gaseous N-methyl-4-piperidone and Af-methyl-4-piperidinol are —160.7 1.7 and —226.8 1.8 kJmol (also see Reference 18). The difference between these contemporary values is — 66.1 2.5 kJmol while for the hydroxylated and methylated counterpart species the difference is —47.0 4.8 kJmoH. For comparison, the formal enthalpy of reduction of 3-hexanone to 3-hexanol is ca —54 kJmoH. As has been discussed earlier, reduction enthalpies are not necessarily constant . Relatedly, reaction 8 that exchanges N-methyl and N-hydroxy and parent and tetramethylpiperidines is endothermic by 19.1 5.4 kJmol . The deviation from thermoneutrality is more... 

Moreover, a reaction of the Mannich type has been observed with heterocyclic enamines, e.g. in the treatment of 1,2-dimethyl-A2-piperideine with formaldehyde as described by Lipp and Widn-mann.350 In the condensation, the ring-opened form, viz. 1-methyl-amino-5-hexanone, is presumably involved. Recrystallization of the intermediate Y-hydroxy methyl derivative then gives the final 1-methyl-3-acetylpiperidine (121). 

Hexanone, 2-heptanone, 2-octanone, 2-nonanone, 6-methyl-5-hepten-2-one, fenchone, carvone, acetophenone, 2-hydroxy-4,6-dimethoxy-5-methylacetophenone... 

Subsequently, TOFs of 3900 h-1 have been reported12 for the hydration of 3-hexyne at 343 K in aqueous methanol using Ph3PAuI0C(0)C2Fs as catalyst with BF3 -Et20 as co-catalyst to give 3-hydroxy-3-hexene and 3-hexanone ... 

Ar-PdCl) E21b, 2058 (Cyclo-hexanon + Ar —MgX) Cyclohexen 6-Hydroxy-1-phenyl-Vl/la, 1, 50 Cyclopentan... 

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