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Synthesis and Olfactory Characterization of Novel Silicon‐Containing Acyclic Dienone Musk Odorants
Author(s) -
Geyer Marcel,
Bauer Jennifer,
Burschka Christian,
Kraft Philip,
Tacke Reinhold
Publication year - 2011
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201100161
Subject(s) - chemistry , odor , trimethylsilyl , steric effects , substituent , carbon atom , stereochemistry , carbon fibers , quaternary carbon , atom (system on chip) , medicinal chemistry , organic chemistry , ring (chemistry) , catalysis , materials science , composite number , computer science , composite material , embedded system , enantioselective synthesis
With an odor threshold value of 0.54 ng L –1 air, (3 E ,5 E )‐7,7‐dimethyl‐5‐ tert ‐butylocta‐3,5‐dien‐2‐one ( 1a ) constitutes the most potent member of a new family of acyclic musk odorants with ionone aspects. Replacement of the quaternary carbon atoms of 1a with silicon atoms leads to the (di)sila analogues 1b (replacement of the carbon atom C‐7), 1c (replacement of the quaternary carbon atom of the 5‐ tert ‐butyl group), and 1d (replacement of both quaternary carbon atoms). Compounds 1b – 1d were prepared in multistep syntheses, and their olfactory properties were characterized. The disila analogue 1d turned out to be the weakest compound of the series (197 ng L –1 air), with only very faint musky aspects. The 7‐sila analogue 1b was very floral, of iononeand rose character, and also had a distinct musky note (1.63 ng L –1 air). The 5‐trimethylsilyl analogue 1c was the most musky sila odorant of the series (10.6 ng L –1 air), with rosy but not ionone‐like facets. Thus, exchange of one or both tert ‐butyl groups of 1a for a trimethylsilyl substituent had quite dramatic effects on the odor, and steric bulk at the carbon atom C‐5 seems to be important for creating a musk odor impression.