Chemical Preparations and Drugs. 71 



simple method is not directly applicable for the thymol synthesis, since in the sul- 

 phonation or nitration of the^-cymene the substituted radicle always takes the o-position 

 with respect to the methyl group. The authors succeeded by the following indirect 

 method: — They nitrated ^>-cymene, reduced the 2-nitrocymene produced to 2-amino- 

 cymene, sulphonated the latter by the baking process 1 ), used in the preparation of 

 sulphanilic acid, diazotised the 2-aminocymene-3- and -5-sulphonic acids obtained, 

 reduced the product of the reaction to the sulphonic acid of 3-cymene (only the latter 

 is produced) and obtained finally thymol-sodium, by means of fusing with sodium 

 hydroxide, and further thymol itself. 



The raw material in this reaction was the j9-cymene obtained in the manufacture 

 of the sulphite spruce pulp (m. p. 174 to 175°, ordinary pressure). By this method the 

 authors obtained 32 per cent, of the theoretically-possible yield of aminocymenesulphonic 

 acid and 40 per cent, (calculated as acid) of the theoretical quantity of pure thymol 

 (phenylurethane, m. p. 107°). 



As regards details it should be emphasised that the preparation of 3-cymene sulphonic 

 acid from 2-aminocymene-3-sulphonic acid was successful by the slightly-modified 

 Widman process 2 ) (addition of powdered copper in reducing the diazo-compound). 

 Without this addition, which may also consist of zinc dust, sodium ethylate, sodium 

 hydroxide, potassium carbonate or sodium methylate, the reduction of the diazo- 

 compound in boiling alcohol would yield an ethoxy-derivative 3 ). 



In order to determine the thymol in the oil of Mosla japonica, Maxim., T. Kariyone 

 and A. Katsumi 4 ) recommend a method which essentially corresponds to the method 

 of Kremers and Schreiner 5 ). The authors precipitate, from the alkaline solution in 

 phenol, the thymol by means of 15 per cent, hydrochloric acid, re-dissolve it in alkali 

 and titrate it in the known manner by means of iodine and sodium thiosulphate. The 

 errors of this method are said not to amount to more than 2 per cent, provided that 

 the total contents of phenols in the oil, as in the Mosla japonica, do not exceed 9 per cent. 



We have already reported at some length 6 ) on. the cultivation in Florida of Monarcla 

 punctata which is known in America as horse mint. According to an article by 

 G. A. Russell 7 ), which is essentially based upon the statements of Hood 6 ), the cultivation 

 of this plant has, even in the last years, not brought any better profits. In the year 

 1917 the harvest was much impaired by diseases; in 1918 and 1919 it was not possible 

 to manure the enlarged plantations sufficiently. 



In order to increase the yield of oil the author recommends to re-distil the 

 distillation water which still contains 9.5 per cent, of the total oil, consisting mainly 

 of portions very rich in phenols (above all thymol). The phenol contents of the monarda 

 oils which were obtained in the years 1914—1919 in Satsuma Heights, Putnam county, 

 Florida, and in Orlando, Florida, amounted to 65.3 to 70 per cent. 



The publication of an article on piperitone by Smith and Penf old — concerning the 

 preparation of thymol, menthol and menthone (compare page 23 of this Report) — 

 induced a London firm to offer larger quantities of peppermint ketone for the preparation 

 of thymol at a price of 4/6 d. to thirty chemical factories in England. Thymol being 



) The acid sulphate of the sulphanilic acid is baked in an oven to facilitate the conversion into sulph- 

 anilic acid. Zeitschr. f. angew. Chem. 9 (1896), I. 685. — 2 ) Berl. Berichte 15 (1882), 166. — 3 ) Cf. Berl. 

 Ihriehte 18 (1885), 65. — *) Yakugakuzasshi No. 457 (1920); from Journ. de Pharm. et Chim. VII. 23 (1921), 41. 

 — B ) Cf. Gildemeister and Hoffmann, The Volatile Oils, 2 nd ed., vol. I, p. 594. — «) Cf. Report 1916, 78; 1917, 

 100. — -■) Amerie. Perfumer 15 (1920), 365. 



