Reduction with isopropyl alcohol

Hydrogenolysis of aryl chlorides can also be achieved by treatment with triethylsilane in the presence of palladium, and by reduction with isopropyl alcohol under UV irradiation (equation 53). ... 

The vapor-phase reduction of acrolein with isopropyl alcohol in the presence of a mixed metal oxide catalyst yields aHyl alcohol in a one-pass yield of 90.4%, with a selectivity (60) to the alcohol of 96.4%. Acrolein may also be selectively reduced to yield propionaldehyde by treatment with a variety of reducing reagents. 

An unusual reaction is used to form a KRe 4 HjO. The reduction of potassium perrhenate in en-H20 solutions by potassium metal yields a white solid containing the Rh ion mixed with KOH. Extraction with isopropyl alcohol gives a colloidal brown liquid containing a mixture of KOH, isopropyl alcohol and the rhenidc. Fractional extraction of the liquid gives a gray solid that contains 5.5-60% KRe 4 HjO... 

The pioneering work of Posner, on the reduction of carbonyl compounds with isopropyl alcohol and alumina [116], has now been adapted to an expeditious solvent-free reduction procedure that utilizes aluminum alkoxides under microwave irradiation conditions (Scheme 6.37) [117]. 

Several reagents reduce aldehydes preferentially to ketones in mixtures of both. Very high selectivity was found in reductions using dehydrated aluminum oxide soaked with isopropyl alcohol and especially diisopropylcarbinol [755], or silica gel and tributylstamane [756]. The best selectivity was achieved with lithium trialkoxyalumimm hydrides at —78°. In the system hexanal/ cyclohexanone the ratio of primary to secondary alcohol was 87 13 at 0° and 91.5 8.5 at —78° with lithium tris(/er/-butoxy)aluminum hydride [752], and 93.6 6.4 at 0° and 99.6 0.4 at —78° with lithium tris(3-ethyl-3-pentyl-oxy)aluminum hydride [752],... 

Reduction of unsaturated ketones to unsaturated alcohols is best carried out Nit v complex hydrides. a,/3-Unsaturated ketones may suifer reduction even at the conjugated double bond [764, 879]. Usually only the carbonyl group is reduced, especially if the inverse technique is applied. Such reductions are accomplished in high yields with lithium aluminum hydride [879, 880, 881, 882], with lithium trimethoxyaluminum hydride [764], with alane [879], with diisobutylalane [883], with lithium butylborohydride [884], with sodium boro-hydride [75/], with sodium cyanoborohydride [780, 885] with 9-borabicyclo [3.3.1]nonane (9-BBN) [764] and with isopropyl alcohol and aluminum isopro-... 

Although acetone is used widely as an industrial solvent, nevertheless it has become the by-product of the acetone-butanol fermentation and there is always the fear of overproduction. There is thus a need for an extension of the industrial utilization of acetone. A possibility in this direction may be in its conversion into pinacol, the preparation of which has recently been improved by McHenry, Drum and O Connor. It is obtained together with isopropyl alcohol by electrolytic reduction of acetone under controlled conditions. Pinacol (LXVI) may be dehydrated to 2,3-dimethylbutadiene which can be converted into a synthetic rubber, or converted through pinacolone (LXVII) into neohexane... 

Manchalk reaction. Some years ago Marschalk et al. found that leucoquinizarin (1), prepared in situ by reduction of quinizarin with alkaline dithionite, reacts with aldehydes to form 2-alkylquinizarins (2). It is not possible to obtain 2,3-disubstituted quinizarins in this way. Lewis found that pyridinium acetate with isopropyl alcohol as solvent is superior to a base or an acid catalyst for this reaction yields as high as 90% of 2 can be obtained. In addition, aromatic aldehydes can be used successfully. The leuco forms of 2 can be alkylated in this way to give 2,3-dialkylquinizarins in 40-70% yields. 

A novel preparation of benzopinacol, (CjHs)jC0HC0H(C H5)j, is by reduction of benzophenone with isopropyl alcohol in the presence of sunlight (95%). ... 

The discontinuous curves show the solubility extension at lower solubility parameters using certain solvents mixed with alcohol. For example, the maximum solute concentration with isopropyl alcohol (11.5 8) is 58%. By substituting increasing amounts of heptane until the mixed solvent contains only 10% alcohol, resin solubility extends to 7.9 8. The extension into lower delta values corresponds to a reduction in solids content. Solubility at lower than 11.5 8 is not successful above 58% resin concentration. 

In the presence of carbon tetrachloride, G(H2)t begins to fall rapidly at values of /p lower than 0.5. This is caused by reaction with H atoms in competition with their abstraction reaction from isopropyl alcohol. However, the values of G(H2)t at high values of /p indicate that the reduction in hydrogen yield owing to electron capture by CCl is similar to those in the presence of SF6 and C7Fi4. Any possibility that the effect of these additives is owing to reaction with H atoms may be excluded. SF6 reacts much too slowly with H atoms (13) to compete with isopropyl alcohol at the concentrations used, and since C7Fi4 has the same effect as SF6, it too must react too slowly with H atoms to compete with their abstraction reaction from isopropyl alcohol. 

The reduction of the glycosidulose derivative (439) with sodium borohydride proved to be particularly sensitive to the solvent used (see Scheme 148) exclusive formation of methyl 4,6-<7-benzylidene-a-D-allopyranoside could be ensured by the addition of a small proportion of water to a solution of the reductant in isopropyl alcohol. The reduction of (439) with sodium borodeuteride in dry isopropyl alcohol gave the 3- and 2-deuteriated compounds (440) and (441) after acetylation. The 2-deuteriated D-glucopyranoside derivative (441) presumably arises through attack of the reductant at C-2 of an intermediate 2,3-enolic species. 

This dihydride thermally or photochemically reductively eliminates hydrogen to complete the catalytic cycle. In a similar manner, [Pt2(pop)4] is a photochemical catalyst for the conversion of ethyl alcohol to acetaldehyde and hydrogen, and also for the transfer hydrogenation of cyclohexene and cyclopentene with isopropyl alcohol ... 

For many reductions it is not necessary to distil the reagent. Dilute the dark solution, prepared as above to the point marked with an asterisk, to 1 htre with dry isopropyl alcohol this gives an approximately one molar solution. Alternatively, prepare the quantity necessary for the reduction, using the appropriate proportions of the reagents. 

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