Sodium mandelate

Problem 19.17 Phenylglyoxal, CftH COCHO, is converted by aqueous sodium hydroxide into sodium mandelate, Ct,H5CHOHCOONa. Suggest a likely mechanism fo this conversion. 

Sodium salt, C,H7NaOj, sodium mandelate. Cryst powder slight aromatic odor. Very sol in water sol in alcohol the aq soln Is neutral or slightly alkaline to litmus. 

Mandelic acid. This preparation is an example of the synthesis of an a-hydroxy acid by the cyanohydrin method. To avoid the use of the very volatile and extremely poisonous hquid hydrogen cyanide, the cyanohydrin (mandelonitrile) is prepared by treatment of the so um bisulphite addition compound of benzaldehj de (not isolated) with sodium cyanide ... 

Analyses of alloys or ores for hafnium by plasma emission atomic absorption spectroscopy, optical emission spectroscopy (qv), mass spectrometry (qv), x-ray spectroscopy (see X-ray technology), and neutron activation are possible without prior separation of hafnium (19). Alternatively, the combined hafnium and zirconium content can be separated from the sample by fusing the sample with sodium hydroxide, separating silica if present, and precipitating with mandelic acid from a dilute hydrochloric acid solution (20). The precipitate is ignited to oxide which is analy2ed by x-ray or emission spectroscopy to determine the relative proportion of each oxide. 

L-Menthol [2216-51-5] (75) and D-menthol [15356-70-4] have been used as chiral auxiharies in the synthesis of optically active mandehc acids. Reduction of (-)-menthol ben2oylfomiate (76) with a stericaHy bulky reducing agent, ie, sodium bis(2-methylethoxy)aluminum hydride (RED-Al), followed by saponification, yields (R)-mandelic acid (32) of 90% ee. 

Mandelic acid is best prepared by the hydrolysis of mandeloni-trile with hydrochloric acid. The mandelonitrile has been prepared from amygdalin, by the action of hydrocyanic acid on benzaldehyde, and by the action of sodium or potassium cyanide on the sodium bisulfite addition product of benzaldehyde. ... 

A. Ethyl mandelale. To 152 g. (1.0 mole) of mandelic acid and 200 ml. of absolute ethanol in a 1-1. round-bottomed flask f< ui[)ped with a reflux condenser, there is added 100 ml. of abso-liile ethanol containing about 10 g. of anhydrous hydrogen chlo-lidc (Note 1). The solution is heated under reflux on a steam bath for 5 hours, then poured into 11. of ice water in a 3-1. beaker (Note 2). A saturated aqueous solution of sodium bicarbonate is added until the mixture is faintly alkaline (Note 3). It is I lien extracted with two 300-ml. portions of ether in a 2-1. separatory funnel. The ether extracts are washed with a 200-ml. por-lioii of water and dried over 50 g. of anhydrous sodium sulfate. The dried ether solution is concentrated by distillation from a 25()-ml. Claisen flask, and the residue is distilled at reduced pressure. I here is obtained 147-154 g. (82-86%) of ethyl mandel-iilc, l).p. 144-145°/16 mm. The ester may crystallize upon standing for a prolonged period. It melts at 30.5-31.5°. 

Chlorophenylacetic acid has been prepared from mandeloni-trile and hydrochloric acid in a sealed tube, from mandelic acid and hydrochloric acid in a sealed tube/ from a-nitrostyrene and hydrochloric acid in a sealed tube, from phenylglycine, hydrochloric acid, and sodium nitrite, from mandelic acid and phosphorus pentachloride (to give the acid chloride which is then hydrolyzed), and, in poor yield, from mandelic acid and thionyl chloride. In the method described, ethyl mandelate is prepared according to Fischer and Speier. The conversion to the chloroester and the acid hydrolysis step are modifications of a preparation described by McKenzie and Barrow. ... 

A mixture of 42.5 grams (0.17 mol) of methyl a-cyclopentyl mandelate and 18 grams (0.175 mol) of 1-methyl-3-pyrrolidinol in 500 ml of heptane was refluxed under a Dean Stark moisture trap, with the addition of four 0.1 gram pieces of sodium at 1-hour intervals. After 5 hours refluxing the solution was concentrated to one-half volume, and extracted with cold 3N HCI. The acid extract was made alkaline with aqueous sodium hydroxide and extracted with ether which was washed, dried over sodium sulfate, filtered and concentrated. The residue was fractionated at reduced pressure. Yield 33 grams (64%) ... 

The basal medium of Mandels (Mandels et al., 1976) was used with the following modifications it was buffered with 3 g/1 of sodium nitrate to pH 5.5 and supplemented with 1% w/v citrus pectin " Sigma" or other carbon sources. For enzyme production, 50 ml medium in 250 ml erlemneyer flasks were inoculatedwith spores (10 spores /ml ) exept for the non sporulating Pol 6 strain, where mycelium was used. The culture were incubated at 30° C on a rotary shaker (150 rev mn -1) for 5 days. The culture broth was filtered (Millipore 0.45 pm ) and the supernatant was analysed for pectinolytic activities, reducing sugars and proteins. 

Boron zirconimn chelates from ammonium hydroxide water-soluble amines sodium or potassimn zirconium and organic acid salts such as lactates, citrates, tartrates, glycolates, malates, gluconates, glycerates, and mandelates with polyols such as glycerol, erythritol, arabitol, xylitol, sorbitol, dulcitol, mannitol, inositol, monosaccharides, and disaccharides [463,464,1592,1593]... 

Chorionic gonadotropin. Follicle stimulating hormone Urea, Uric add. Bilirubin, Cortisol, n-Maimitol. n-Glucose, Sodium pyruvate, 4-hydroxy-3-methoxy mandelic add, 4-Nitro-phenol, 17 Amino adds in HQ, Angiotensin-I, Tripahnitin, Bone meal (8 elements), Bone ash (8 elements), lithium carbonate Luteinizing hormone. Thyroid stimulating hormone... 

If the reaction mixture is cooled at this point, some of the mandelic acid may crystallize. If this happens, the precipitate should not be filtered, as it is contaminated with sodium chloride. 

B) Mandelic Acid,.—In a 2-1. three-necked round-bottomed flask, fitted with an efficient mechanical stirrer, a dropping funnel, and a thermometer, is placed 156 g. (3.9 moles) of sodium hydrox-... 

Mandelic acid has been prepared by hydrolysis of mandeloni-trile (prepared in turn from benzaldehyde and hydrogen cyanide or from benzaldehyde, sodium bisulfite, and sodium cyanide) 3 by action of water at 180° upon trichloromethylphenylcarbinol by action of potassium carbonate upon a heated mixture of benzaldehyde and chloroform 7 by action of warm, dilute alkali upon dibromoacetophenone 8 and by action of warm, dilute sodium hydroxide upon phenylglyoxal. ... 

Mandelic Nitrile.—Freshly distilled benzaldehyde (15 g.) is stirred with a glass rod in a cylinder with about 50 c.c. of a concentrated solution of sodium bisulphite until a paste of the addition compound /H... 

If cinchonine d-mandelate is not available a specimen suitable for the inoculation in the first experiment is prepared as follows To a few cubic centimetres of the solution (a) saturated aqueous sodium chloride solution is added drop by drop until slight precipitation occurs. The mixture is then heated until the precipitated material has dissolved, after which the solution is allowed to stand until crystals have been deposited, which may require a day. The crystals consist of cinchonine hydrochloride on which a small amount of cinchonine d-mandelate is deposited, enough, however, to induce the separation of further quantities of the d-salt. 

The crude product contains varying quantities of sodium carbonate and sodium sulfate, which are difficult to remove. These impurities are insoluble in liquid ammonia consequently the crude compound can be ammonolyzed without further purification. The mandelic acid-acetone condensation product may be purified by recrystallization from absolute alcohol it then melts at 45°. 

Methenamine mandelate is a salt of mandelic acid and methenamine and both of these possess property of urinary antiseptic. It is rapidly absorbed in gastrointestinal tract and excreted unchanged in urine, where it broken down in acidic pH (< 5) of urine and formaldehyde is released, which inhibits most of the bacteria. It is administered with sodium biphosphate, mandelic acid or ascorbic acid to keep the urinary pH below 6. Its use is restricted to chronic, resistant type of UTI. 

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