Reduction of acids to alcohols

Synthesis of Compound I. As shown in Scheme II, 3-(thiophene-3-yl)propyl bromide can be prepared by a two-carbon homologation(2 ) of 3-thenyl bromide via reaction with diethyl malonate to form diethyl 3-thenylmalonate. This is followed by saponification, decarboxylation, reduction of acid to alcohol, (2 ) and replacement of the hydroxyl group with bromide by reacting with PBr3.(22) Compound 2 is synthesized by mono-quaternization of an excess of 4,4 -bipyridine with 3-(thiophene-3-yl)propyl bromide followed by N-methylation with CH3I. All the intermediates in Scheme II have been identified by NMR spectroscopy. 2 has been characterized by NMR and high resolution mass spectroscopy and by electrochemistry. 

Straight-chain acids from fats are more available than are the corresponding alcohols, and here the reverse process becomes important reduction of acids to alcohols. 

BHj-McjS or amine-boranes induce the same reductions of acids to alcohols linear anhydrides are reduced by Ph2NH BH3 in THF to alcohols, while succinic and phthalic anhydrides remain intact [CUl]. 

Reduction of carboxylic acids with 1 mole of LiAlH4 consumes three of the four hydrides that are available,25 and the reduction product is an alcohol. The acid has the acidic hydrogen of the OH unit, and this reacts first. Subsequent reduction of the carbonyl unit leads to the usual alkoxyaluminate, which is hydrolyzed to the alcohol. Reduction of acid 20 to alcohol 21 in 87% yield is a useful example.26 Reduction of acids to alcohols bearing a heteroatom at the a-position is also possible. 

Tetrahydrofuran, butanediol, y-butyrolactone family (family 1 Reduction) Selective reductions controlling the reduction of acids to alcohols, lactones, and furans Operation at mild conditions (pressure, temperature, etc.) Catalyst tolerance to inhibitory compounds and catalyst lifetime Solvents, fibers such as lycra... 

Promotion by Acid. In principle, the reduction of aldehydes to alcohols and alcohol derivatives by organosilicon hydrides should occur upon exposure to either Lewis or lirwnsted acids, as represented in Eq. 2. In practice, although... 

Peroxidases are heme iron-containing proteins similar in structure to that of cytochromes P450. The major difference is that peroxidases have histidine as the axial ligand instead of cysteine, and there are also other polar amino acids close to the heme iron that help to catalyze the peroxidase function of the enzyme (41). The result is that the peroxidases very rapidly catalyze the reduction of hydroperoxides to alcohols (or water in the case of... 

More abundant are reductions with sodium sulfite which is applied in aqueous solutions (solubility 24%). Its specialties are reduction of peroxides to alcohols [257], of sulfonyl chlorides to sulfinic acids [252], of aromatic diazonium compounds to hydrazines [253], and partial reduction of geminal polyhalides [254] Procedure 43, p. 216). 

Countless reductions of esters to alcohols have been accomplished using lithium aluminum hydride. One half of a mol of this hydride is needed for reduction of 1 mol of the ester. Ester or its solution in ether is added to a solution of lithium aluminum hydride in ether. The heat of reaction brings the mixture to boiling. The reaction mixture is decomposed by ice-water and acidified with mineral acid to dissolve lithium and aluminum salts. Less frequently sodium hydroxide is used for this purpose. Yields of alcohols are frequently quantitative [83,1059]. Lactones afford glycols (diols) [575]. 

Iron and acetic or dilute hydrochloric acid can be safely used for the reduction of nitro group to an amino group in nitro esters. The problem arises when a nitro ester is to be reduced to a nitro alcohol. Nitro groups are not inert toward the best reagents for the reduction of esters to alcohols, complex hydrides. However the rate of reduction of a nitro group by lithium... 

The procedure as given is generally applicable for the reduction of esters to alcohols in excellent yields. When preparing the solid normal saturated alcohols, the procedure may be modified, if desired, to permit the recovery of the acid from the unreduced ester. After the alkali is removed the alcohol layer is washed with two successive portions of 20 per cent salt solution which are discarded. Neither the strong alkali nor the salt solutions remove an appreciable amount of organic acid. A solution of 50 g. of calcium chloride in 150 cc. of water is added to the butyl alcohol solution, the mixture is steam-distilled until the butyl alcohol is removed, and the flask and contents are allowed to cool. A hole is made in the cake of solid alcohol and the water layer removed. Two liters of toluene is added and the flask warmed and shaken until the alcohol dissolves and only fine crystals of the calcium salt of the unreduced acid remain. The solution is cooled to 350 and filtered with suction. The calcium soap is removed from the filter, warmed with about 500 cc. of toluene, cooled, filtered, and washed with a little more toluene. The combined toluene solutions may be concentrated and the alcohol crystallized, or the toluene may be completely distilled and the residue vacuum distilled. The insoluble calcium... 

Periodate lignin may be another type of lignin preparation representative of whole lignin in wood [46]. Wood meal suspending in water with a small amount of acetic acid is treated with sodium metaperiodate at room temperature, by which vic-glycol structures in carbohydrates are cleaved to give aldehydes. After the subsequent reduction of aldehydes to alcohols, carbohydrates are readily hydrolyzed even at room temperature in a mild acid condi-... 

TiCl4 is used extensively as a Lewis acid in numerous organic transformations, forming adducts that mediate reactivity. Such reactions include Diels Alder, 54,355 hetero Diels Alder,356 cyclization of olefinic aldehydes,357 Flosomi Sakurai allylic coupling reactions,358 cyclopropanations,359 chal-cogen-Baylis Flillman,360 Mukaiyama Aldol reactions,36 363 reductions of ketones to alcohols 364 and stereoselective nucleophilic additions to aldehydes.365... 

Methods for performing the reduction of acids to the corresponding alcohols use an excess of BHj-THF or catecholborane [BK5, KB7, PSl]. These reagents react more rapidly with aliphatic acids than with aromatic ones. The reaction process... 

Reduction of acids to aldehydes one step from the acid, how to avoid the Rosenmund reaction or the reduction to alcohol followed by oxidation Aldehydes are very important reagent for fine organics, the access to those compounds is always multistep. Development of a catalyst for the reduction of an acid function to the aldehyde without reduction of a double bond in the framework of the molecule will be presented and discussed. 

Reduction of CO to alcohols using DIBAH (/-BU2AIH) and Cp2ZrCl2 occurs and makes use of both the acidic properties of aluminum alkyls and the hydridic nature of Zr hydrides. The reaction proceeds as in equation (b) via the intermediate II hydrolysis after CO uptake yields a mixture of C1-C4 alcohols. The observation of isobutylene suggests that each AlH(i-Bu)2 donates more than one H to the ROH products. 

The localization of branching is achieved by careful comparison of the MS fragmentation of normal and branched fatty acids. The intensity of some fragments is a useful diagnostic tool. However, a reduction of esters to alcohols can improve the interpretation. 

Thiol esters are reduced to primary alcohols by sodium borohydride in ethanol without significant transesterification.These conditions do not affect oxygen esters whereas sodium borohydride used either in polyethylene glycols such as PEG-400 at 65 or in DMSO containing methanesulphonic acid, has been shown to reduce esters to primary alcohols the borohydride-acidic DMSO system also reduces carboxylic acids, other than conjugated aromatic acids, to alcohols. An improved procedure for rapid reduction of esters to alcohols with borane-dimethylsulphide involves using THF as solvent at reflux, with an aqueous alkaline work-up. 

Reduction of acid chlorides, acid azides and anhydrides to alcohols 77 Degradation of acids to alcohols and phenols. 77-78... 

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