Odorous compounds and method of preparation thereof

A compound of formula (I):

• wherein A represents —CH2OH or —CHO, —CH2OAc and is selected from the following compounds:
• 1) 3-methyl-5-methyleneheptan-1-ol;
• 2) 3,5-dimethylhept-4-en-1-ol;
• 3) 3,5-dimethylhept-5-en-1-ol;
• 4) 3-methyl-5-methylideneheptanal;
• 5) 3,5-dimethylhept-4-enal;
• 6) 3,5-dimethylhept-5-enal;
• 7) 3-methyl-5-methyleneoctan-1-ol;
• 8) 3,5-dimethyloct-4-en-1-ol;
• 9) 3,5-dimethyloct-5-en-1-ol;
• 10) 3-methyl-5-methylideneoctanal;
• 11) 3,5-dimethyloct-4-enal;
• 12) 3,5-dimethyloct-5-enal;
• 13) 5-ethyl-3-methylhept-4-en-1-ol;
• 14) 5-ethyl-3-methylhept-5-en-1-ol;
• 15) 5-ethyl-3-methylheptan-1-ol;
• 16) 5-ethyl-3-methylhept-5-enal;
• 17) 5-ethyl-3-methylhept-4-enal;
• 18) 5-ethyl-3-methylheptanal;
• 19) 3-methyl-5-methylenenonan-1-ol;
• 20) 3,5-dimethylnon-5-en-1-ol;
• 21) 3,7-dimethyl-5-methyleneoctan-1-ol;
• 22) 3,5,7-trimethyloct-4-en-1-ol;
• 23) 3,5,7-trimethyloct-5-en-1-ol;
• 24) 3,5,7-trimethyloctan-1-ol;
• 25) 3,7-dimethyl-5-methylideneoctanal;
• 26) 3,5,7-trimethyloct-4-enal;
• 27) 3,5,7-trimethyloct-5-enal;
• 28) 3,5,7-trimethyloctanal;
• 29) 3-methyl-5-methylidenedecan-1-ol;
• 30) 3,5-dimethyldecan-1-ol;
• 31) 3-methyl-5-methylidenedecanal;
• 32) 3,5-dimethyldec-4-enal;
• 33) 3,5-dimethyldecanal;
• 34) 3-methyl-5-methylideneundecan-1-ol;
• 35) 3,5-dimethylundec-4-en-1-ol;
• 36) 3,5-dimethyldec-4-en-1-ol;
• 37) 3,5-dimethylundecanal;
• 38) 5-isobutyl-3,7-dimethyloct-4-en-1-ol;
• 39) 5-isobutyl-3,7-dimethyloct-5-en-1-ol;
• 40) 5-isobutyl-3,7-dimethyloctan-1-ol;
• 41) 3,7-dimethyl-5-(2-methylpropyl)oct-5-enal;
• 42) 3,7-dimethyl-5-(2-methylpropyl)oct-4-enal;
• 43) 3,7-dimethyl-5-(2-methylpropyl)octanal;
• and
• 44) the compound of formula (I) wherein R1 is methyl and R2 is tertiary-butyl.

A process for preparation of a compound of formula (I),

• wherein:
• A represents —CH2OH or —CHO, —CH2OAc;
• dotted line represents double bond or single bond;
• and
• R1 is an alkyl or alkylidene group, R2 is an alkyl or alkylidene group,
• the process comprising the steps of:
• a. Reacting a compound of formula (II)
• with alcohol of formula
• to get a compound of formula (III)
• wherein R1 is an alkyl or alkylidene group,
• R2 is an alkyl or alkylidene group,
• dotted line represents double bond or single bond;
• b. Reacting the compound of formula (III) with Ra-Ni and hydrogen to get a compound of formula (IV)
• and
• c. Reacting the compound of formula (IV) with acetic anhydride to get a compound of formula (V), which is the compound of formula (I) wherein A represents —CH2OAc,
• and optionally:
• d. Reacting the compound of formula (V) with sodium hydroxide in water to get a compound of formula (VI) which is the compound of formula (I) wherein A represents —CH2OH,
• and optionally
• e. oxidation of compound of formula (VI) employing (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO) or 4-hydroxy-TEMPO (4-Hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) along with N-chlorosuccinimide and a phase transfer catalyst to obtain a compound of formula (VII) which is the compound of formula (I) wherein A represents —CHO,
• or optionally the compound of formula (VI) is hydrogenated using Ra-Ni catalyst at elevated temperature to get a compound of formula (VIII) which is the saturated compound of formula (I) wherein A represents —CH2OH,
• and optionally TEMPO-mediated oxidation of compounds of formula (VIII) to afford a compound of formula (IX) which is the saturated compound of formula (I) wherein A represents —CHO,