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2.
Magn Reson Chem ; 43(1): 27-30, 2005 Jan.
Article in English | MEDLINE | ID: mdl-15390022

ABSTRACT

The 15N NMR spectra of three N-alkyl-delta-carbomethoxyvalerothiohydroxamic acids (2) and six synthesized N-isopropylbenzothiohydroxamic acids (3) were measured and compared with appropriate spectra of structurally similar hydroxylamines (1), benzohydroxamic acids (4), benzamides (5) and thiobenzamides (6). The analysis of the chemical shifts of the thiohydroxamic acids under investigation indicates that the inductive effect of the hydroxyl group rather than steric hindrance is responsible for non-additivity of the effect of substituents. Additionally, N-hydroxyl diminishes the effect of aromatic ring substituents on the 15N chemical shifts in the thiohydroxamic acids 3 which is approximately half that in the respective thiobenzamides 6. The chemical shift values correlate best with Brown's sigma+ parameter.


Subject(s)
Hydroxamic Acids/chemistry , Hydroxylamines/chemistry , Magnetic Resonance Spectroscopy/methods , Alkylation , Molecular Conformation , Nitrogen Isotopes , Sulfhydryl Compounds/chemistry
3.
Chem Biodivers ; 1(12): 1921-35, 2004 Dec.
Article in English | MEDLINE | ID: mdl-17191829

ABSTRACT

We have discovered that alpha-[dimethyl(thexyl)silyl]acetaldehyde (= [dimethyl(1,1,2-trimethylpropyl)silyl]acetaldehyde; 31) has a strong, woody odor. Structural analysis has shown resemblance to known odorants with similar organoleptic properties. On the basis of structure-odor relationships, new and more-powerful woody and ambery sila odorants were prepared. Further derivatization led to a set of compounds with very interesting organoleptic properties. Selected chiral compounds were also prepared stereoselectively. The influence of the absolute configuration on the olfactory properties was in agreement with theoretical assumptions. We also designed other groups of organosilicon odorants. The compounds discovered can be obtained in a few simple steps from commercially available reagents, and may find application in the fragrance and flavor industry. Their structures provide interesting data for further research on structure-odor relationships.


Subject(s)
Odorants , Silicones/chemistry , Silicones/isolation & purification , Stereoisomerism
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