Rosenmund reaction

Acetyl chlotide is reduced by vatious organometaUic compounds, eg, LiAlH (18). / fZ-Butyl alcohol lessens the activity of LiAlH to form lithium tti-/-butoxyalumium hydtide [17476-04-9] C22H2gA102Li, which can convert acetyl chlotide to acetaldehyde [75-07-0] (19). Triphenyl tin hydtide also reduces acetyl chlotide (20). Acetyl chlotide in the presence of Pt(II) or Rh(I) complexes, can cleave tetrahydrofuran [109-99-9] C HgO, to form chlorobutyl acetate [13398-04-4] in about 72% yield (21). Although catalytic hydrogenation of acetyl chlotide in the Rosenmund reaction is not very satisfactory, it is catalyticaHy possible to reduce acetic anhydride to ethylidene diacetate [542-10-9] in the presence of acetyl chlotide over palladium complexes (22). Rhodium trichloride, methyl iodide, and ttiphenylphosphine combine into a complex that is active in reducing acetyl chlotide (23). 

Rosenmund reaction is the action between acid chloride and hydrogen in the presence of palladium catalyst to produce aldehydes... 

As catalyst for the Rosenmund reaction palladium on a support, e.g. palladium on barium sulfate, is most often used. The palladium has to be made less active in order to avoid further reduction of the aldehyde to the corresponding alcohol. Such a poisoned catalyst is obtained for example by the addition of quinoline and sulfur. Recent reports state that the reactivity of the catalyst is determined by the morphology of the palladium surface." ... 

The procedure described is a modification of the general procedure of Angyal2 for the preparation of aldehydes from benzylamines by the Sommelet reaction. Isophthalaldehyde has been prepared from w-xylene by preparation of the tetrachloro derivative and hydrolysis,3 from isophthaloyl chloride by the Rosenmund reaction,4 from a,a -dibromo-m-xylene by the Sommelet reaction,5 and from isophthaloyl chloride by reduction with lithium tri-Cbutoxyaluminumhydride.6... 

Rosenmund reaction org chem Catalytic hydrogenation of an add chloride to form... 

Rosenmund reaction for synthesis of arsonic acids, 2, 10 Rosenmund reduction, 4, 7... 

Preparation of DL-erythrose succeeded,18 however, in a stepwise procedure. Lactone 12 was cleaved with alcoholic potassium hydroxide to potassium DL-erythronate (13a) which was next acetylated to 13b. The acid chloride 14, obtained from 13b, was then reduced under the conditions of the Rosenmund reaction to the desired DL-erythrose. 

Reduction of acid chlorides to aldehydes. Two laboratories12 have published details for this reduction. One difficulty is the large quantities of reagent needed for preparative-scale reactions. For large-scale reductions the Rosenmund reaction is preferable. 

When o-iodoaniline is subjected to the Bart reaction two products result, o-phenylenediarsonic add in 20% yield, together with a lesser amount of o-iodophenylarsonic acid.29 The o-iodophenylarsonic acid first formed reacts with another molecule of sodium arsenite (Rosenmund reaction) to produce the diarsonic acid. The conversion of 2,4-, 2,5-, and 3,4-dichloroaniline to the corresponding arsonic adds takes place in yields of 60-70%.88... 

In general, the Rosenmund reaction is carried out by heating one mole of trisodium or tripotassium arsenite with one mole of aromatic halide in boiling aqueous ethanol solution. Certain minor modifications of this procedure have been employed. If the aromatic halide contains an addic group (e.g., o-bromophenylarsonic add), no ethanol is necessary.82 Copper powder, as well as cuprous chloride, is sometimes employed as catalyst, but the value of either is uncertain.82- 86 Reactions of bromo-benzene and p-br omo acetophepo ne must be run in sealed tubes at temperatures of 150-2000.88 87 82... 

The Preparation op Aromatic Arsonic and Arsinic Acids by the Bart, Bechamp, and Rosenmund Reactions—Cliff S. Hamilton and Jack F. Morgan 415... 

Carboxylic acids can be reduced to aldehydes via their acyl chlorides using the Rosenmund reaction—see below. 

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