Bases derived from some substituted propenylbenzenes with a note on the preparation of pure methylamine / by T.M. Sharp and W. Solomon.

  • Sharp, Thomas Marvel.
Date:
[1931.]
Catalogue details

Licence: Public Domain Mark

Credit: Bases derived from some substituted propenylbenzenes with a note on the preparation of pure methylamine / by T.M. Sharp and W. Solomon. Source: Wellcome Collection.

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    phenol were adopted, and the crude product (4*85 g.), obtained by the latter method, which probably consists mainly of ethyl-p- hydroxyphenylcarbinol, HO*C6H4*CH(OH)*C2H5, was heated in a sealed tube at 130° for 3J hours with a mixture of acetic anhydride (10 c.c.) and acetyl chloride (10 c.c.). The cold solution was then treated with bromine, the absorption, owing to incomplete dehydr¬ ation, being 0-9 c.c. (calc., T6 c.c.). The liquid was poured into water (200 c.c.) and shaken, the precipitate being dissolved in ether and dried over anhydrous sodium sulphate. The dry solid (9T g.) so obtained was substantially freed from unbrominated material by one recrystallisation from petroleum (b. p. 90—120°). Yield, 3-3 g.; m. p. 112—122°. This product, which can be used for the next stage, is purified by recrystallisation from petroleum, p-acetoxy- propenylbenzene dibromide separating in short white needles, m. p. 125—129° (corr.) (Found : C, 395; H, 3-6; Br, 47-5. C11H1202Br2 requires C, 39-3; H, 3-6; Br, 47-6%). The dibromide (2-64 g.), acetic acid (15 c.c.), and silver acetate (T31 g.) yielded fi-bromo- cc-acetoxy-cc-p-acetoxyphenylpropane (2-4 g.), which did not crystallise (Found : Br, 25*4. C13H1504Br requires Br, 25*4%). The acetoxybromide (5 g.) with methylamine (4-0 g.) in dry alcohol (20 c.c.) furnished non-basic material (TO g.), which was not examined, and crude base (2-35 g.). The latter was converted into sulphate (T5 g.), which was almost insoluble in alcohol, and was purified by solution in water (1 vol.) and addition of alcohol (15 vols.); the sulphate of ccfi-di(methylamino)-cc--p-hydroxyphenyl- propane (VI) then separated in white needles, m. p. 211—213° (corr.) (Found in air-dried salt : loss at 110° in a vacuum, 8-4. CiiHi80N2,H2S04,T5H20 requires H20, 8-5%. Found in salt dried at 110°: C, 45-4; H, 71; N, 9-35; S, 10-8; NMe, 200. CnHi80N2,H2S04 requires C, 45-2 ; H, 6-9; N, 9-6; S, 11*0; 2NMe, 19*9%). The anhydrous salt absorbs the equivalent of T5 mols. of water on exposure to air. The Preparation of Pure Methylamine. Methylamine hydrochloride of commerce usually contains ammon¬ ium chloride, which cannot easily be eliminated. As it was desirable to use pure methylamine for the preparation of the bases described above, and since standard methods, for example, that described in “ Organic Syntheses,” Vol. Ill, p. 67, gave an impure product, the following process of purification was devised, based on the fact that when a mixture of methylamine and ammonia reacts with an insufficient quantity of hydrochloric acid the methylamine is preferentially neutralised and the ammonia left free. The most practicable method of applying this principle is one
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