Methyl propyl ketone, reduction

This is prepared by the general method of reduction of the dichloride using aqueous potassium metabisulphite. It crystallises from hot water or benzene-petroleum as yellow needles, melting without decomposition at 110° to 112° C., very soluble in cold acetone or hot benzene. It possesses residual acidity, dissolving in cold 5N sodium hydroxide to give an intensely yellow solution which blackens rapidly and then has an odour of methyl n-propyl ketone. 

Preparation of secondary (or tertiary) carbinols from pyridines and an aldehyde (or a ketone) in the presence of magnesium or aluminum and mercuric chloride is known in pyridine chemistry as the Emmert reaction. 7 70 For example, dimethyl-2-pyridylcarbinol is obtained in this way from pyridine and acetone. When a mixture of pyridine and acetone is subjected to an electrolytic reduction in dilute sulfuric acid at lead electrodes, a mixture of two main products results, namely, 2-(2-hydroxy-2-propyl)-3-piperideine and 4-(2-hydroxy-2-propyl)piperidine. Analogous compounds are obtained with the use of methyl ethyl ketone as the reactant. The mixed electrolytic reduction of 2-methylpyridine and acetone affords 2-(2-hydroxy-2-propyl)-6-methyl-3-piper ideine (74) and 2-methyl-4-(2-hydroxy-2-propyl)-piperidine.71... 

The use of ethyl alcohol for the selective reduction of the carbonyl group in unsaturated aldehydes and ketones other than acrolein is illustrated in Table V. Here also, the data listed are the best obtained in a limited number of runs with each compound and do not necessarily represent optimum conditions. As previously stated, in the acrolein-allyl alcohol reaction a small amount of propyl alcohol is found in the products. This side reaction appears to be considerably more important with crotonaldehyde, since the C4 alcohol fraction here contained 27 % butyl alcohol. The relatively high conversion to saturated alcohol is believed to be due in part to unfavorable reaction conditions. With methacrolein and with methyl isopropenyl ketone the saturated alcohol amounted to 5 % of the imsaturated alcohol produced. 

Using our standard conditions (19,20), the anti aldol reaction ( 1) of the propyl ketone 19 (available in 3 steps from methyl (/ )-3-hydroxy-2-methylpropionate) with methacrolein proceeded via the preferred chair TS 23 (Figure 4). The in situ reduction (40) of the resulting boron aldolate 24 with LiBH4 proceeds by axial delivery of hydride through the TS 25 to produce the, 3-syn diol 26 (>95% ds for the introduction of 3 stereocenters). Protection of the hydroxyl groups in 26 followed by diastereoselective hydroboration of the... 

Reductive amination of methyl ketoreserpate was studied in detail. The use of re-propylamine in the presence of a palladium-charcoal catalyst led not only to the expected mixture of a- and /3-amino derivatives (X), but also to a methyl 17-demethoxy-18-deoxy-l 8-re-propyl -aminoreserpate (XII). In the last case, no attempt was made to define the stereochemistry at C-16 and C-18. Similar eliminations of the C-17 methoxyl under basic conditions were also encountered with other ketone derivative. Reductive aminations were also effected with secondary amines. Piperidine yielded as the sole insolable product the... 

The sex pheromone structure, 10-methyl-2-tridecanone, was synthesized using the carboxyl group as the source of the methyl branch (lA) (Figure 6). Undecylenic acid was a-propylated and resolved via amides. The procedure followed allowed us to obtain the alcohols,(R)- and (S)-2-propyl-10-undecenol (>99.6% ee). The corresponding bromide was reduced with lithium triethylborohydride (15) then the double bond was converted to a methyl ketone by a) oxymercuration, b) reduction of the C-Hg bond with sodium borohy-dride, and c) oxidation with dichromate. The male southern corn rootworm responds only to the (R)-configuration no biological activity was noted for the (S)-enantiomer. Therefore, in this instance the racemic compound would be predicted to monitor this species adequately. 

Reduction of a-ketocyclopropanes. Cyclopropyl methyl ketone (1) is reduced by the reagent in methanol under the influence of radical initiators [hi/, azobisiso-butyronitrile, 1,45] to propyl methyl ketone as the only product of reduction (51 % yield). In the absence of an initiator the reaction is slow and results in reduction of the carbonyl group. ... 

Simple aliphatic ketones are reduced by baker s yeast predominantly to the (S)-configurated alcohols, often with high enantioselectivity. As in other cases, a large difference in the size of the two residues in the substrate is advantageous. Compounds with two larger residues (e.g., propyl butyl ketone) are not accepted, but if one residue is methyl then compounds with many different groups as the second are accepted for reduction. For example, 6-heptyn-2-one is reduced to (S)-6-heptyn-2-ol in >99% ee235. 

Treatment with dichloroacetyl chloride, followed by dechlorination of the resulting bicycloheptenone (177), produced the bicyclic ketone (178). Conversion into lactone (179) and reduction to (180) followed by Wittig reaction with propyl ylide produced cw-(181) selectively. The synthesis of (175) from (181) was then completed (- 0% overall yield) by oxidation to (182), isomerization to (183), followed by methylation and oxidation (Scheme 17). 

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