Natural muscone, traditionally harvested from the Asian musk deer (pictured, at right), is (R)-3- methylcyclopentadecanone. Found in nature with a small amount of muscopyridine, which completes the animalistic character of musk, muscone supplies a pyridinic, urinaceous undertone. In samples where muscopyridine was found, the muscone detected was most likely derived from male musk deer. However, muscopyridine was also identified in civet.
Muscopyridine is an unusual metapyridinophane, which was originally isolated by Prelog et al. from the ether extract of 2 kg of crude musk by exhaustive extraction with an aqueous solution of tartaric acid and 10% HCl. The filtered aqueous solutions were made alkali with KOH and extracted with ether. Distilling off the ether leaves a residue and oil. Distillation of the oil yields 0.75 g of muscopyridine (~0.04% of the crude musk). Convergent total synthesis of muscopyridine has been achieved in its enantiomerically natural form by ring closing metathesis strategy, enabling the determination of its absolute stereochemistry more than 50 years after its isolation by Prelog.
The presence of muscopyridine in natural musk established a method for differentiating natural and artificial musk. GC/MS was used to detect the extract of musk, and several characteristic components were qualitatively differentiated simultaneously. The results showed that two characteristic components—muscopyridine and 3-methylcyclotridecanone—could be used to differentiate natural and artificial musk. This method has the advantages of simple operation, less consumption of samples and reliable qualitative results.