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Organic Synteses vol 4 - Kamm O.

Organic Synteses vol 4

Author: Kamm O.
Other authors: Adams R.
Publishers: John Wiley & Sons
Year of publication: 1952
Number of pages: 48
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Download: organicsynthesesvol41925.pdf

+! ->
C6H5CH(0C0CH3)C02H+S0Cl2 ->
Prepared by F. . Thayer,
Checked by Roger Adams and E. E. Dreger.
1. Procedure
In a 500-cc. Claisen distilling flask with a low side-tube connected to a condenser, are placed 105 g, of mandelic acid (m.p. xx8) and 151 g. of acetyl chloride. A reaction sets in without the application of heat (Note 1). As soon as a clear solution results, the flask is warmed on a water bath and the excess acetyl chloride is distilled. The last trace of acetyl chloride may be removed by prolonged drying in a vacuum. The acetyl mandelic acid then crystallizes in large, round, white clusters after one or two days standing. The yield is 130-133 g. (97-99 per cent of the theoretical amount) (Note 2).
To the crude acetyl mandelic acid still containing some acetyl chloride obtained as described above, is added 250 g. of thionyl chloride. The reaction starts at once without warming but it is necessary to reflux for four hours to complete the reaction (Note 3). The excess thionyl chloride is then distilled
and the residue distilled in a vacuum (Note 4). The yield is 115-120 g. (79-83 per cent of the theoretical amount) of almost colorless liquid boiling at 125-1300/10 mm. (iSo-iS5/33 mm.).
2. Notes
1. Occasionally the application of a little heat is necessary to bring about a more rapid acetylation.
2. The melting points given in the literature range from 39 to 8o. The acetyl mandelic acid is difficult to crystallize but may be purified from benzene or chloroform, preferably the former. The product thus obtained melts at about 79-80.
3. Prolonged refluxing of the acetylated mandelic acid with the thionyl chloride tends to lower the yield.
4. Anschutz gives the boiling point of acetyl mandelyl chloride as i29/io mm. The vacuum used should be as low as possible, to avoid the formation of tar during the distillation.
3. Other Methods of Preparation
Acetyl mandelic acid was described by Naquet and Lougui-nine,1 but their product has been shown to be contaminated with the ethyl ester of acetyl mandelic acid. Dupont2 obtained the compound by the oxidation of diacetyl 1, 4-diphenylbutine-2-diol-i, 4. Anschutz and Bocker 3 prepared acetyl mandelic acid, and from it the acid chloride, by the use of phosphorus pentachloride, but with poor yields. Von Braun and Muller 4 state that acetyl mandelyl chloride can be made from acetylated mandelic acid and thionyl chloride, the resulting product being a viscous yellow oil.
1 Compt. rend. 62, 430 (1866); Ann. 139, 302 (1866).
2 Compt. rend. 150, 1525 (1910).
3 Ann. 368, 57, 59 (,1909).
4 Ber. 51, 244 (1918).
() -f 2NH3 -*
Prepared by . S. Marvel and V. du Vigneaud.
Checked by H. T. Clarke and E. R. Taylor.
1. Procedure
In a i-l. round-bottom flask is placed 760 g. of concentrated ammonium hydroxide (sp. gr. 0.9) and to this is slowly added 150 g. of a-bromocaproic acid (Note 1). The flask is well stoppered and allowed to stand in a warm place (50-55) for twenty to thirty hours. The amino acid separates and is filtered off with suction and washed with methyl alcohol (Note 2). This crop of crystals weighs 51-56 g. The aqueous filtrate is evaporated nearly to dryness on a steam bath and then treated with about 250 cc. of methyl alcohol. This precipitates a second crop of amino acid contaminated with ammonium bromide. On washing with methyl alcohol and recrystallizing from water, there is obtained 1015 g. more of pure product. The total yield is 63-68 g. (62-67 per cent of the theoretical amount).
2. Notes
1. The once-distilled bromocaproic acid (p. 9) is satisfactory.
2. If the amino acid is not carefully washed with alcohol, it contains ammonium bromide and may possess an objectionable
odor. Methyl alcohol is preferable to ethyl alcohol since it dissolves ammonium bromide more readily.
3. Other Methods of Preparation
a-Amino-w-caproic acid has been prepared by the action of ammonia on a-bromo-M-caproic acid.1
1J. prakt. Chem. (2) 1, 7 (1870); Ber. 33, 2381 (1900); Z. physiol. Chem. 86, 456 (1913); J. Am. Chem. Soc. 42, 320 (1920).
ClCmabNa+NasAsOs -> NaCl+CH2(C02Na)As03Na2 2CH2(C02H)As03H2+8H(H3P02) -> AsCH2C02H+6H20
Prepared by C. S. Palmer.
Checked by Oliver Kamm.
1. Procedure
One hundred grams of powdered arsenious oxide is added to the hot solution obtained by dissolving 160 g. of sodium hydroxide in 300 cc. of water. After the solution has cooled to 20, 48 g. of chloroacetic acid is added. The suspension is well stirred during about five minutes, when a strongly exothermic reaction begins, the temperature rises to 70-7 5 , and a clear solution results.
The reaction mixture is permitted to stand at room temperature during one hour, or longer if desired (Note 1). The solution is acidified with 160 cc. of glacial acetic acid and, after the temperature has been lowered to 40 by cooling, the precipitated arsenious oxide is filtered off by suction and washed with 50 cc. of water.
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