Natural musk owes its odor to a ketone, muscone, which is contained in the natural product to the extent of from 0,5 to 2°/o. As to its chemical composition only this much is known that either the formula C15H280 or C16H30O applies to it.2) Muscone is a dark, colorless oil, which is but sparingly soluble in water, soluble in alcohol in all proportions. It has a strong, very agreable, pure musk odor, which, in a concentrated condition, reminds of the fragrance of dried pine needles. In great dilution it is particularly agreable. Like ionone it possesses the property to fatigue the nerves very readily. Hence it is possible to recognize the musk odor of the muscone for a short time only. It boils at 142 to 143° (2 mm.) and at 327 to 330° (752 mm.). Under the latter conditions partial decomposition appears to take place. Of muscone derivatives there are known the oxime, which crystallizes in needles that melt at 46°, and the semicar-bazone, which crystallizes from alcohol in fine, white prisms that melt at 133 to 134°. Both compounds are odorless. From the semicarbazone the muscone can be liberated by means of dilute sulphuric acid.

The socalled artificial musk, however, is something very different. The only similarity between natural and socalled artificial musk is that of odor, such as is observed not infrequently, e. g. between nitrobenzene and bitter almond oil. In both instances the substitute is very different chemically from the original product and reproduces the odor only to a certain degree. At the present time there are found in the market a considerable number of "artificial musks". Most of these are highly nitrated tertiary butyl toluenes and tertiary butylxylenes or stand in close relation to these nitrocompounds. Characteristic for these compounds is the tertiary butyl group. If other alkyl radicles take its place, the compounds resulting have either only a faint musk-like odor, or none at all.1) Those compounds containing three nitro groups are characterized by a strong musk-like odor. However, the strength of the musk odor is not interfered with if one of these nitro groups is replaced by a cyanogen or aldehyde group or by halogen or an acid radicle. With reference to these groups the artificial musks are distinguished as cyanide musk, aldehyde musk, halogen musk and ketone musk. The most important of these compounds are here described briefly.

1) Kobert, Lehrbuch der Intoxikationen, vol. II, p. 799. Stuttgart 1906. 2) Walbaum, Journ. f. prakt. Chem. II. 73 (1906), 488; comp. also Report of Schimmel & Co. April 1906, 93.

Trinitro-tert-butyltoluene, C6HCH3C(CH3)3(N02)3, is of special interest since it is the first musk-like smelling-substance which was placed upon the market as "Tonquinol" and "Musc Baur". It is obtained by condensation of Isobutyl chloride and toluene with the aid of aluminium chloride and subsequent nitration of the butyl toluene. During the condensation a rearrangement of the Isobutyl to the tertiary butyl group takes place. It is adventageous to purify the hydrocarbon carefully before nitrating it. Trinitrobutyl benzene crystallizes from alcohol in yellowish-white needles, which melt at 96 to 97°.

Trinitro-tert.-butylxylene, C6(CH3)2-C(CH3)3-(N02)3, is prepared in like manner. It crystallizes in white needles that melt at at 110°.

Trinitro-tert.-butylethylbenzene, C6 H • C2 H5 • C(CH3)3 • (N02)3, is readily soluble in alcohol and hence cannot readily be obtained in a crystalline condition.

Dinitro-tert.-butylxylene iodide, C6I(CH3)2C(CH3)3(N02)2, results when tert.-butylxylene iodide is nitrated. It forms yellow crystals that melt at 105°.

Dinitro-tert.-butylxylene cyanide, C6(CH3)2CN • C(CH3)3 • (N02)2, cyanide musk. Prismatic crystals that melt at 110°.2)

1) Comp. Baur, Berl. Berichte 24(1891), 2832; 31 (1898), 1344; Baur and Bischler, Ibidem 32 (1899), 3647.

2) Baur-Thurgau, Berl. Berichte 33 (1900), 2567.

Dinitro-tert-butylxylene aldehyde, C6(CH3)2-C(CH3)3-(N02)2 ketone musk is obtained by condensation of the corresponding acid chloride with tert.-butyltoluene or xylene in the presence of aluminium chloride and subsequent nitration of the condensation product. Baur1) has prepared the following representatives of this class.

• CHO, aldehyde musk, is soluble in alcohol and benzene and crystallizes from ligroin in plate-like, faintly yellowish crystals that melt at 112°.

Dinitroaceto-tert-butyltoluene, C6 H • CH3 • C (CH3)3 • (N02)2CO •CH3, or methyldinitrobutyltolyl ketone, broad needles that melts at 131°.

Dinitroaceto-tert.-butylxylene, C6(CH3)2 • C(CH3)3 • (N02)2 • CO

• CH3, m. p. 136°; soluble in alcohol, ether, benzene, etc, more difficultly in ligroin and 60 p. c. acetic acid.

Dinitrobutyryl-tert.-butylxylene, C6 (CH3)2 • C (CH3)3 • (N02)2 •COC3H7, is the butyryl ketone of dinitro-tert.-butylxylene, and melts at 128°.

Dinitrovaleryl-tert-butylxylene, C6(CH3)2 • C(CH3)3 • (N02)2 •COC4H9, when crystallized from alcohol, is obtained as long, faintly yellowish needles that melt at 151°.

In addition to those enumerated above, other substances with a musk-like odor are to be found in the market. Moreover, mixtures of these are likewise found, for upon careful fractional crystallization compounds with different melting points are obtained.

Artificial musk is insoluble in water and, as a rule, is but difficultly soluble in alcohol. For the preparation of relatively concentrated solutions that are durable, cinnameine and benzyl benzoate have been recommended. According to Koehler,2) the latter solvent when gently heated dissolves as much as 20 p. c. of musk "Baur" and retains it in solution at + 10°. Neither does the addition of absolute alcohol cause precipitation. With cinnamein, Mannl) claims even to have obtained a 50 p. c. solution. According to Schimmel & Co.,2) both solvents possess much the same solvent capacity, but benzyl benzoate appears to be a somewhat better solvent than cinnamein. Much, naturally, depends on the musk product dissolved.

1) Baur-Thurgau, Berl. Berichte 31 (1898), 1344. 2) Pharm. Ztg. 49 (1904), 1083.

Artificial musk is frequently adulterated with acetanilide. Formerly products of "Musk Baur" were placed upon the market which according to statements of the manufacturer contained up to 90 p. c. of antifebrine. Adulterations with cinnamic acid have also been observed. These added substances can be separated from the musk by means of hot water. Others are recognized by means of their solubility in alcohol in which solvent most artificial musk preparations are rather difficultly soluble. Anti-febrine can be identified by means of the Isonitrile and acetic acid reactions.