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Organic syntheses vol 22 - Smith L.I.

Smith L.I., Adkins H. Organic syntheses vol 22 - John Willey, 1942. - 60 p.
Download (direct link): organicsynthesesvol221942.pdf
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»I. G. Farbenind. A-G., Brit. pat. 284,998 [Frdl. 16, 484 (1927-1929); C. A.
22, 4540 (1928)].
1 Henle and Lanz, U. S. pat. 1,871,990 [C. A. 26, 5971 (1932)].
6 Fierz and Tobler, Helv. Chim. Acta 5, 558 (1922).
6 Dutta, Ber. 67, 1321 (1934).
71. G. Farbenind. A-G., Brit. pat. 330,941 [Frdl. 16, 2999 (1927-1929); C. A. 24, 5768 (1930)].
«Schweitzer, U. S. pat. 1,806,714 [Frdl. 16, 2998 (1927-1929); C. A. 25, 4012 (1931)].
•I. G. Farbenind. A-G., Brit. pat. 282,450 [Frdl. 16, 487 (1927-1929); C. A. 22, 3669 (1928)].
Ilotz and Lanz, U. S. pat. 1,690,785 [Frdl. 16, 487 (1927-1929); C. A. 28, 397
(1929)].
<#-<*-AMINOPHENYLACETIC ACID
23
product is contaminated with considerable amounts of /3-naphthol and /3-naphthylamine.11
dZ-a-AMINOPHENYLACETIC ACID (c?Z-Phenylglycine; a-Toluic Acid, a-amino, dl-)
CgHsCHO + NaCN + NH4C1 -»
CoH5CH(NH2)CN + NaCl + H20
C«HfiCH(NH2)CN + 2HC1 + 2H20 -*
CoH5CH(NH2-HC1)C02H + nh4ci
C0H5CH(NH2-HCl)CO2H + NH3 -*•
C6H5CH(NH2)C02H + NH4CI Submitted by Robert E. Steiger.
Checked by R. L. Shriner, S. P. Rowland, and Ñ. H. Tilford.
1. Procedure
To a solution of 100 g. (2.0 moles) of 98 per cent sodium cyanide in 400 cc. of water, contained in a 3-1. round-bottomed llask fitted with a Hershberg stirrer (Org. Syn. 17, 31), is added IIX g. (2.2 moles) of ammonium chloride. The mixture is stirred :il room temperature under a properly ventilated hood. When the ammonium chloride has dissolved, a solution of 212 g. (2.0 moles) of benzaldehyde in 400 cc. methyl alcohol is added in one portion. The reaction begins rapidly, the temperature rising to about 45°. Stirring is continued for two hours. The heterogeneous mixture, after dilution with 1 1. of water, is extracted willi 1 1. of benzene, and the aqueous layer is discarded. The benzene layer is washed with three 50-cc. portions of water, and I lie aminonitrile is extracted, in the form of its hydrochloride, by shaking the benzene solution with 6 N hydrochloric acid, first willi one 600-cc. portion and then with two 300-cc. portions.
" Miililuii, Her. 2N, ,«Wi (1895).
24
ORGANIC SYNTHESES
The combined acid extracts are placed in a 3-1. round-bottomed flask and refluxed for two hours (Note 1). The hydrolysate is diluted with water to bring its volume to about 2 1. and is then subjected to distillation under reduced pressure (20-30 mm.) to remove all benzaldehyde and other volatile substances (Note 2). To remove some resinous matter deposited in the course of the hydrolysis, the mixture is treated with 10 g. of Norite and filtered through a Buchner funnel. The yellow filtrate is transferred to a 3-1. beaker. It is stirred by hand with a thick glass rod while ammonium hydroxide (sp. gr. 0.90) is added through a dropping funnel until the liquid is faintly alkaline to litmus (Note 3). The mixture becomes quite hot and acquires a strong odor of benzaldehyde. The amino acid separates in the form of yellow crystals. The mixture is cooled to room temperature, and the crystals are collected on a 15-cm. Buchner funnel. After washing with about 1 1. of water in small portions to remove the ammonium chloride, the solid is washed successively with 150 cc. of ethyl ether, three 50-cc. portions of hot 95 per cent ethyl alcohol, and finally with about 500 cc. of water. The crystals, when dried by suction, weigh 220 to 240 g. (Note 4). Drying is completed in a vacuum desiccator over phosphorus pentoxide. The yield of crude amino acid is 102-116 g. (34-39 per cent of the theoretical amount).
For purification, the product is dissolved in 800 cc. of 1 N sodium hydroxide, 500 cc. of ethyl alcohol is added, and the solution is filtered. The filtrate is transferred to a 2-1. beaker and is heated to the boiling point. Then 160 cc. of 5 N hydrochloric acid is slowly added, through a dropping funnel, while stirring by hand. The mixture is cooled to room temperature and is filtered with suction. The product is washed with 100 cc. of ethyl alcohol, then with 200 cc. of water, and is dried in a vacuum desiccator over phosphorus pentoxide. The nearly white, lustrous platelets have no definite melting point (Note 5). The yield of pure amino acid is 98-112 g. (33-37 per cent of the theoretical amount) (Note 6).
(é-a-AMINOPHENYLACETIC ACID
25
2. Notes
1. The hydrolysis of the aminonitrile should be carried out under a hood, since some hydrocyanic acid is liberated.
2. During this process, the volume of the solution must be maintained at about 2 1. by the frequent addition of water through a dropping funnel. Otherwise the hydrochloride of (//-phenylglycine, which is sparingly soluble in concentrated hydrochloric acid, may separate.
3. From 375 to 425 cc. of ammonium hydroxide of sp. gr.
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