Identification and synthesis of volatiles released by the myxobacterium Chondromyces crocatus

Cultures of the myxobacterium Chondromyces crocatus on agar plates were analysed by closed-loop-stripping analysis or solid phase micro extraction. The odour profiles consist mainly of pyrazines, sesquiterpenoids and some aromatic compounds, summing up to more than 50 components. Several new pyrazines as 2-(1-hydroxy-1-methylethyl)-3-methoxypyrazine (), 2-(1-hydroxy-1-methylpropyl)-3-methoxypyrazine (), and 2-(1-hydroxy-2-methylpropyl)-3-methoxypyrazine () were identified besides several known pyrazines. A major pyrazine occurring in most samples was 2,5-bis-(1-methylethyl)pyrazine (). While the well known sesquiterpenoid geosmin () was present in low amounts, the related compound (1(10)E,5E)-germacradien-11-ol () was identified in most samples in larger quantities. Other prominent sesquiterpenoids not reported before from microorganisms were (6S,10S)-6,10-dimethylbicyclo[4.4.0]dec-1-en-3-one (), which was accompanied by smaller amounts of several derivatives. The biosynthesis of these compounds is discussed in relation to the recently proposed biosynthetic pathways to and .