Tartaric acid recrystallization

The united filtrate is evaporated on the steam bath until the volume amounts to 200 cc., at which point crystals should have already begun to separate from the hot solution. After standing at room temperature for twenty-four hours or longer, the crystals are filtered by suction as free from mother liquor as possible and recrystallized from an equal weight of distilled water (Note 5). The filtrate from this recrystallization is evaporated on the steam bath and the second crop of /-tartaric acid filtered and recrystallized as before. The -yield is 65-75 (32-5-35-5 per cent of the theoretical amount). 

The residual solid in the mother liquors is repeatedly and systematically crystallized, yielding a further fraction of 1-a-methylphenethylamine d-tartrate which may be purified by recrystallization. d-a-Methylphenethylamine may be readily recovered from the mother liquors by the addition of tartaric acid thereto for the formation of acid tartrates and separation of d-a-methylphenethylamine d-bitartrate by crystallization. 

Stirring is carried out first for 3 hours at room temperature and then for 2 hours at boiling temperature, it is then cooled and poured into 300 ml of ice-cold 20% ammonium chloride solution. It is then shaken out with methylene chloride, the methylene chloride solution washed with water and shaken 3 times with 30 ml portions of aqueous 2N tartaric acid solution. The tartaric acid extract is rendered alkaline while cooling thoroughly and then extracted twice with methylene chloride. After washing with water, drying over potassium carbonate and reducing in volume by evaporation, the residue is recrystallized from ethanol. MP 197° to 199°C. 

Enantiopure (R)- and (S)-nipecotic acid (Nip) derivatives 64 were obtained following classical resolution of ethyl nipecotate with either enantiomer of tartaric acid and successive recrystallization of the corresponding salts [153, 154, 156] or by resolution of racemic nipecotic acid with enantiomerically pure camphorsul-fonic acid [154]. N-Boc protected pyrrolidine-3-carboxylic acid (PCA) 65 for the synthesis of homo-ohgomers [155] was prepared by GeUman from trans-4-hydroxy-L-prohne according to a known procedure [157]. 

C. (1S,2S)-(-)- and (1 R,2R)-(+)-1,2-Diphenyi-1,2-ethylenediamine (Note 11). A 1 -L, round-bottomed flask equipped with a mechanical stirrer is charged with 42.5 g (0.200 mol) of the racemic diamine and 230 mL of ethanol (Note 9). The solids are dissolved by heating the mixture to 70°C whereupon a hot (70°C), homogeneous solution, of 30.0 g (0.200 mol) of (L)-(+)-tartaric acid (Note 12) in 230 mL of ethanol is added (Note 13). The tartrate salts precipitate immediately, and after the mixture is cooled to ambient temperature, the crystals are collected by filtration, washed twice with 60 mL of ethanol, and dried under reduced pressure. The solids are dissolved in 230 mL of boiling water, 230 mL of ethanol is added and the homogeneous solution is allowed to cool slowly to room temperature. The crystals are collected by filtration, washed with 40 mL of ethanol and dried under reduced pressure. The recrystallization procedure is then repeated twice using the same volumes of solvents (230 mL of water and 230 mL of ethanol) to give 23-25 g (63-69%) of the tartrate salt... 

R)-(+)-1-(1-Naphthyl)ethylamine is purchased from Aldrich Chemical Company, Inc. The reagent is purified by recrystallization of its tartaric acid salt three times from 94% aqueous methanol followed by treatment with base and distillation of the free amine. 

In principle, separation of resonances of diastereomeric compounds (such as dl and meso isomers) may be increased simply through use of an appropriate achiral solvent. Chiral solvents may in some cases be especially effective in producing a separation, particularly if the diastereomers differ in configuration about a center that is amenable to analysis by the CSA method. Kaehler and Rehse (89) give a detailed account of conditions necessary for measurement of the ratio of meso- and dZ-tartaric acid employing A,N-dimethyl PEA. Bomyl acetate used as solvent for l,2-difluoro-l,2-dichloroethane (90) allows measurement of the diastereomeric composition. Paquette and co-workers (91,92), using TFAE, were able to determine the diastereomeric purity of the recrystallized adducts 47 of... 

Louis Pasteur" (Figure 7) was the first to suggest that molecules can be chiral. In 1848, he recrystallized a salt of tartaric acid and obtained two kinds of small crystals that were mirror images of each other. The discovery... 

The development of a large scale manufacturing route to Esomeprazole is described by Federsel and Larsson ° using the titanium catalyst originally described by Kagan and Luukas. Employment of a tartaric acid derived chiral auxiliary, with the addition of a base such as diisopropylethylamine to the reaction mixture, resulted in a full-scale catalytic process capable of delivering multi-ton quantities of product with optical yields well above 90 %, a figure which could be raised to 99.5 % ee by recrystallization from methyl isobutyl ketone. 

S-(—)-l-(2-Pyridyl)ethylamine.22 To a 1-L Erlenmeyer flask 34.5 g (0.230 mole) of L-(+)-tartaric acid in 220 mL of boiling 95% EtOH is added 23.6 g (0.193 mole) of racemic l-(2-pyridyl)ethylamine in 300 mL of hot 95% EtOH. As the solution cools to ambient temperature and is allowed to sit for several hours, a white precipitate forms. Four recrystallizations of this precipitate from 100 mL of 95% EtOH gives 12.9 g of the (+)-acid tartrate salt of S-( —) amine (> 99% ee). The salt is neutralized by dissolving in 250 mL of 2 NNaOH and extracting with four 150-mL portions of ether. The organic layer is dried over solid NaOH and then concentrated by rotary evaporation. 

S-Isomer was prepared the next way. To a solution of 160 parts of dibenzoyl d-tartaric acid in 1600 parts of anhydrous ethanol were added for 15 minutes 80 parts of dl-l-(3-trifluoromethylphenyl)-2-ethylaminopropane. After 15 additional minutes, 90.5 parts of crystalline solid were isolated. When this product was recrystallized from 1300 parts of anhydrous ethanol, there was obtained 70 parts of dibenzoyl d-tartarate acid salt of L-l-(3-trifluoromethylphenyl)-2-ethylaminopropane. This salt was treated with 500 parts of 4 N NaOH. The mixture was extracted with 2x200-part portions of diethyl ether and the ether extract was re-extracted with 100 parts of 4 N hydrodiboric acid. After treatment with 120 parts of 4 N NaOH, the free amine amounting to 25 parts distills at 105°-107°C (17.5 mm.). [a]D25 - 9.6° (c=8% in ethanol). 

A mixture of 96.5 g 2-methylsulfonylphenothiazine, 50 g 2-(2-chloroethyl)-l-methylpiperidine, 62 g diethyl carbonate and 2 g sodium methylate was heated at 135°C for 1 hour and then at 180-190°C for 2.5 hours. The product was dissolved in benzene (500 ml) and the solution was extracted with 700 ml of 15% aqueous solution tartaric acid. The extract was washed with benzene. After addition of sodium carbonate solution to the extract was obtained a precipitate which was dissolved in benzene. This solution was washed with water and concentrated. 2-Methylsulfonyl-10-(2-(l-methyl-2-piperidyl)ethyl)phenothiazin was recrystallized from acetone, melting point 121-123°C. 

Ethyl-l,2,3,6-tetrahydro-pyridine-3-carboxylic acid ethyl ester and (+)-tartaric acid were dissolved in hot 95% ethanol. The resulting solution was allowed to slowly cool to room temperature and refrigerated overnight. The crystals were filtered, washed with cold ethanol, and recrystallized from 95% ethanol, cooling as before to give the (+)-tartrate salt of (+)-5-ethyl-l,2,3,6-tetrahydro-pyridine-3-carboxylic acid ethyl ester. 

The d(—)-tartaric acid was recovered by decomposing the acid salt with excess ammonium hydroxide and removing the base by filtration. The filtrate was made barely acid with acetic acid and lead D-tartrate was precipitated with lead acetate solution. The filtered and washed lead D-tartrate was suspended in water and the lead removed by precipitation with hydrogen sulfide. The clear filtrate was evaporated to a small volume and allowed to crystallize in a desiccator. Recovery of 96.5% of d( — )-tartaric acid from the original acid salt was obtained after one recrystallization from water, it showed a specific rotation [< Pd of —14.2° (H20, l = 4, c = 4.05) and a melting point of 168-170° (corr.), which are the known values for pure d(—)-tartaric acid. 

The enantiomerically pure amines 82 and 84 are for example prepared by resolution of the racemic 8-benzyl-rfs-2,8-diazabicyclo[4.3.0]nonane 79 using natural R,R(+)-tartaric acid, whereupon the diastereomerically pure i ,i -tartrate of the R, /<-enantiomer is crystallized from dimethylformamide (DMF) and can be purified by recrystallization from methoxyethanol. The target S,S-enantiomer contained in the mother liquor is first converted into the free base, which is then, for the purpose of further purification, precipitated with S,S(-)-tartaric add to give the diastereomerically pure S,S-tartrate. The S,S-enantiomer 83 is then liberated with sodium hydroxide solution. The R,R-enantiomer 81 is obtained in the same way. Separation of the enantiomers can also be carried out with high optical yields in an aqueous/alcoholic solution [140]. The hydrogenolytic debenzylation of 81 and 83 produces the corresponding pure R,R- and, S, S —2,8-diazabicyclo[4.3,0]no-nanes 82 and 84 (Scheme 14.2) [129]. 

Southern corn rootworm. The structure of the southern corn rootworm has been defined as 10-methyl 2-tridecanone, XI (Figure 16) (5J3). Alkylation of undecanoic acid with n-propyl bromide was followed by conversion to the diastereomeric amides with either (S)- or (R)-a-methylbenzylamine that had been purified previously by recrystallization of D and L tartaric acid salts, respectively. Recrystallizations of these amides from ethanol (4 was sufficient) gave 32% yields of pure (>99.5%) diastereo-mers (Figure 16). Hydroxyethylation labilized the amides toward hydrolysis. It was convenient to intercept the aminoesters and reduce them with LAH. The resulting carbinols were than carried forward in standard manner to provide the ketones. 

A chiral object and its mirror image are enantiomorphous, and they are each other s enantiomorphs. Louis Pasteur (Figure 2-37) was the first who suggested that molecules can be chiral. In his famous experiment in 1848, he recrystallized a salt of tartaric acid and obtained two kinds of small crystals which were mirror images of each other as seen by Pasteur s models in Figure 2-38 preserved at Institut Pasteur at Paris. Originally Pasteur may have been motivated to make these large-scale models because Jean Baptiste Biot, the discoverer of optical activity had very poor vision by the time of Pasteur s discovery [42], Pasteur demonstrated chirality to Biot, who was visibly affected... 

Preparative Methods the most convenient preparation of (/ ,/ )-stilbenediamine is described in Organic Syntheses." Condensation of benzil and cyclohexanone in the presence of ammonium acetate and acetic acid (eq 1) produces a spirocyclic 2//-imidazole (mp 105-106 °C). Reduction with Lithium in THF/NH3 followed by an ethanol quench and hydrolysis with aqueous HCl (eq 2) affords the racemic diamine as a pale yellow solid (mp 81-82 °C). Resolution is achieved by multiple recrystallizations of the tartaric acid salts ifom water/ethanol. The sulfonamides are prepared by reaction of the enantiomeri-cally pure diamine with the appropriate anhydride or sulfonyl chloride in CH2CI2 in the presence of Triethylamine and a catalytic amount of 4-Dimethylaminopyridine (eq 3). 

Preparative Methods (i) preparation of racemic DPEN and its optical resolution Reaction of benzil and cyclohexanone in the presence of ammonium acetate and acetic acid at reflux temperature gives a cyclic bis-imine (1) (eq 1). Stereoselective reduction of the bis-imine with lithium in THF-liquid ammonia at —78 °C followed by addition of ethanol, then hydrolysis with hydrochloric acid and neutralization with sodium hydroxide produces the racemic diamine (2). Recrystallization of the l-tartaric acid salt from a 1 1 water-ethanol mixture followed by neutralization with sodium hydroxide, recrystallization from hexane results in (5,5)-DPEN (3) as colorless crystals. 

Dextro tartaric acid is the ordinary tartaric acid as it is found widely distributed in nature, in grapes, mountain ash berries, pineapples, potatoes and other plants. It crystallizes without water of crystallization in transparent, mono-clinic columns which are easily soluble in water or in alcohol. 100 parts of water at 15° dissolve 132 parts of the acid. It melts at i68°-i70°. In water solution it is dextro rotatory. The chief source of tartaric acid is the juice of the grape, where it is present as the free acid and as the acid potassium salt. In this source it is mostly the dextro variety that is found. It is obtained from the vinasse, or residue which settles out from the juice after it has been expressed. When grape juice ferments, in the formation of wine, the solubility of the acid potassium salt is lessened due to the presence of alcohol and it gradually separates and settles to the bottom iii the form of what is known as lees. These lees are dried or recrystallized once and the product is then known as crude tartar or argol. The crude tartar contains, in addition to the acid potassium tartrate, free tartaric... 

In the resolution procedure, racemic trans-dach (60 g) is dissolved in 200 mL of water along with 20 g of the appropriate (d or l) tartaric acid and 40 mL of acetic acid. The resulting dach-tartrate precipitate is collected and recrystallized two to three times from hot water. The resolved dach isomer is then liberated by treating the salt with excess 20% NaOH (aq) and extracting the free base into CHClj. 

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