Pentanol oxidation

Now let s draw the forward scheme. Ethylene oxide is treated with methyl magnesium bromide, followed by water work-up to give 1-propanol. This alcohol is then oxidized to an aldehyde with PCC, and the resulting aldehyde is then treated with ethyl magnesium bromide, followed by water work-up, to give 3-pentanol. Oxidation with chromic acid gives 3-pentanone, which is then converted to the corresponding enamine upon treatment with dimethylamine and acid catalysis (with removal of water) ... 

Trimethyl aluminum and propylene oxide form a mixture of 2-methyl-1-propanol and 2-butanol (105). Triethyl aluminum yields products of 2-methyl-1-butanol and 2-pentanol (106). The ratio of products is determined by the ratio of reactants. Hydrolysis of the products of methyl aluminum dichloride and propylene oxide results ia 2-methylpropeae and 2-butene, with elimination of methane (105). Numerous other nucleophilic (107) and electrophilic (108) reactions of propylene oxide have been described ia the Hterature. 

The reaction of lead tetraacetate (LTA) with monohydric alcohols produces functionalization at a remote site yielding derivatives of tetrahydrofuran (THF) 12). An example is the reaction of 1-pentanol with LTA in nonpolar solvents which produces 30% THF. The reaction, which is believed to proceed through free-radical intermediates, gives a variable distribution of oxidation products depending on solvent polarity, temperature, reaction time, reagent ratios, and potential angle strain in the product. 

The trialkylborane is oxidized by the addition to the stirred reaction mixture of 32 ml of a 3 solution of sodium hydroxide, followed by the dropwise addition of 32 ml of 30 % hydrogen peroxide at a temperature of 30-32° (water bath). The reaction mixture is saturated with sodium chloride and the tetrahydrofuran layer formed is separated and washed with saturated sodium chloride solution. The organic solution is dried over anhydrous magnesium sulfate and the THF is removed. Distillation affords 24.5 g (80%) of 4-methyl-1-pentanol, bp I51-153°/735 mm. 

Hydroboration of 2-methyl-2-pentene at 25 °C followed by oxidation with alkaline H202 yields 2-methyl-3-pentanol/ but hydroboration at 160 °C followed by oxidation yields 4-methyl-l-pentanol. Suggest a mechanism. 

Write the balanced equation for the production of pentanone from pentanol, using dichromate ion as the oxidizing agent. 

Reaction temperature is one of the parameters affecting the enantioselectivity of a reaction [16]. For the oxidation of an alcohol, the values of kcat/fQn were determined for the (R)- and (S)-stereodefining enantiomers E is the ratio between them. From the transition state theory, the free energy difference at the transition state between (R) and (S) enantiomers can be calculated from E (Equation 2), and AAG is in turn the function of temperature (Equation 3). The racemic temperature (% ) can be calculated as shown in (Equation 4). Using these equations, % for 2-butanol and 2-pentanol of the Thermoanaerobacter ethanolicus alcohol dehydrogenase were determined to be 26 and 77 °C, respectively. 

The reactions can also be effected by phenyliodonium diacetate.377 A mechanistic prototype can be found in the conversion of pentanol to 2-methyltetrahydrofuran. The secondary radical is most likely captured by iodine or oxidized to the carbocation prior to cyclization.378... 

Methyloctane. see 4-Methyloctane Methylol. see Methanol Methylolpropane. see 1 -Butanol Methyloxirane. see Propylene oxide Methyl oxitol, see Methyl cellosolve 4-Methyl-2-pentanol acetate, see sec-Hexyl acetate 2-Methyl-2-pentanol-4-one, see Diacetone alcohol... 

Taylor and Flood could show that polystyrene-bound phenylselenic acid in the presence of TBHP can catalyze the oxidation of benzylic alcohols to ketones or aldehydes in a biphasic system (polymer-TBHP/alcohol in CCI4) in good yields (69-100%) (Scheme 117) °. No overoxidation of aldehydes to carboxylic acids was observed and unactivated allylic alcohols or aliphatic alcohols were unreactive under these conditions. In 1999, Berkessel and Sklorz presented a manganese-catalyzed method for the oxidation of primary and secondary alcohols to the corresponding carboxylic acids and ketones (Scheme 118). The authors employed the Mn-tmtacn complex (Mn/168a) in the presence of sodium ascorbate as very efficient cocatalyst and 30% H2O2 as oxidant to oxidize 1-butanol to butyric acid and 2-pentanol to 2-pentanone in yields of 90% and 97%, respectively. This catalytic system shows very good catalytic activity, as can be seen from the fact that for the oxidation of 2-pentanol as little as 0.03% of the catalyst is necessary to obtain the ketone in excellent yield. 

Die Photolyse von 4-Azido-3-phenyl-furazan-2-oxid in Dichlormethan/Ethanol fiihrt in einer stereoselektiven Reaktion zum (thermodynamisch weniger stabilen) (E)-2-Hydroximino-2-phenyl-acetonitril, bei der Pyrolyse (in Pentanol) entstehen sowohl das (E)- als auch das (Z)-Oxim426. 

Raw potato possesses little aroma. Approximately 50 compounds have been reported to contribute to raw potato aroma. Raw potatoes have a high content of LOX, which catalyses the oxidation of unsaturated fatty acids into volatile degradation products (Scheme 7.2) [187]. These reactions occur as the cells are disrupted, e.g. during peeling or cutting. Freshly cut, raw potatoes contain ( ,Z)-2,4-decadienal, ( ,Z)-2,6-nonadienal, ( )-2-octenal and hexanal, which are all products of LOX-initiated reactions of unsaturated fatty acids [188,189]. It is reported that two compounds represent typical potato aroma in raw potato methional and ( ,Z)-2,6-nonadienal [189]. Other important volatiles in raw potatoes produced via the LOX pathway are l-penten-3-one, heptanal, 2-pen-tyl furan, 1-pentanol and ( , )-2,4-heptadienal [189]. Pyrazines such as 3-iso-propyl-2-methoxypyrazine could be responsible for the earthy aroma of potato [35]. Some of the most important character-impact compounds of raw potatoes are summarised in Table 7.8. Aroma compounds from cooked, fried and baked potatoes have previously been reviewed [35]. 

Pentanol was first used m conjunction with eodium reduction of epoxides in 1306 by Klinger and Lonnes,94 who converted tetruplu-ml ethylene oxide into tetraphenylethane (Eq. 323). The known facility... 

Treatment of tt-methylstyrene oxide with f ri-butylmagnemuii chloride or phenylmagneaium bromide has been reported 24 171 p. yield 4,4-dimethyl 2phemyl-S-pentanol and 1.2-diphenyl-1-propanol respectively (Eq. 843). Both products presumably arise from methyl-phenylsoetsldehyde, formed by preliminary isomerization of a-mcthyl-styrene oxide. 

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