Musk Baur

The natural musks were always very expensive and their macrocyclic structures presented synthetic challenges which were not conquered, even on laboratory scale, until the pioneering work of Ruzicka in 1926. It was therefore of major importance to the fragrance industry when, in 1888, Baur discovered the nitromusks. He had actually been working on explosives and noticed that the product of t-butylation of trinitrotoluene (TNT) had a pleasant, sweet, musky odour. The compound was named Musk Baur (38), although the alternative name, Musk Toluene , eventually became more common. For a while it was also known as Tonkinol because of the similarity of its odour to that of musk Tonkin. Baur then searched for analogues of this material and... 

B.p 186-8 (191-3 ). HNOj —> trinitro deriv (artificial musk. Musk Baur). 

In 1888, Albert Baur, while experimenting with explosives, stumbled onto some synthetic compounds that smelled like musk. Two of these compounds are shown below. (Note the similarity between the structure of musk Baur and that of TNT.) Musk ketone, the molecule that smelled closest to muscone, was far cheaper than natural musk, but it was toxic and hazardous to prepare. In the 1950s, it was replaced with a series of synthetic musk compounds without the NOi groups. These new compounds are widely used in the fragrance industry. 

In 1888, a German chemist named Albert Baur decided to introduce a butyl group into TNT to try to make it more explosive. He synthesized a variation of TNT with a tertiary butyl group replacing a hydrogen atom. Baur was disappointed when this did not have explosive properties, but things turned out well, as it had a marvelous musk smell, and was adopted by the perfume industry. In the ultimate compliment to a chemist, the compound came to be known as Musk Baur. 

Musk Baur Musk Xylene Musk Ketone Musk Ambrette... 

The artificial musk which was the first to achieve marked success was that manufactured under the patent of Albert Baur (English patent No. 4963 of 1889). The provisional and complete specifications of this patent are as follows —... 

Still later Baur has shown that if an acetyl group is introduced into the butyl toluene molecule, and the methyl ketone thus formed is nitrated, artificial musk (ketone musk) is produced. One part of butyl toluene, 10 parts of carbon disulphide, and 6 parts of aluminium chloride are cooled in a flask and 6 parts of acetyl chloride are run in quickly. After distillation on a water-bath, the residue is poured on to ice and treated in the usual manner. The acetyl derivative is obtained as an oil with a pleasant aromatic odour, boiling at 255° to 258°, of the formula—... 

T rinitro-5-( tert-hutyl)-2-methoxy- toluene, yel ndls, having an odor of musk, mp 69 70° was prepd from the Ag salt of butyltrinitro-ortho -cresol as described in Ref 2, or by nitrating butyl-ortho-methoxytoluene(Ref 2). The expl props of these trinitro-derivs were not detd Refs l)Beil 6,[507-8] 2)A.Baur, Ber 27,... 

Nitro musk (first artificial fragrance compound) A. Baur... 

In 1889, a turning point in perfume preparation had come, when Aime Guerlain introduced his perfume /icfcy , in which, for the first time, only synthetically generated vanillin, coumarin and heliotropin (3,4-methylenedioxy-benzaldehyde also known as piperonal) were used. In the course of his work on highly nitrated benzene derivatives, which would become very important as explosives, the French chemist Albert Baur found by chance a group of compounds with a musk odour. Ferdinand Tiemann in Berlin, looking for a syn-... 

The nitro musks, which are characterized by a nitro-aromatic moiety, were accidentally discovered by Baur in 1888 [51]. This group is basically formed by five compounds, that is, musk ambrette (MA), musk xylene (MX), musk moskene (MM), musk tibetene (MT), and musk ketmie (MK). Figure 107.2 shows the chemical structure of these compounds. 

Baur went on to synthesize even better nitromusks, notably Musk Xylene, Musk Ketone and Musk Ambrette. These and similar molecules e.g. Musk Moskene and Musk Tibetine) became widely used in the perfume industry. The famous French perfumer Ernest Beaux reportedly used over 10% nitromusks, especially Musk Ketone, in Chanel No. 5 (1921), which reports indicate is still used in No. 5 today (see p333). Musk Ambrette s additional floral note was used to advantage... 

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