Method for producing rosefuran precursor and intermediates therefor
AssigneeToyotama Perfumery Co., Ltd.
InventorsHidemichi Fukawa, Masamichi Nishitani, Mitsuo Chiba, Ruriko Murakami
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Abstract
Disclosed are 3,7-dimethyl-4-oxo-7-octenoic acid and its alkyl esters which are intermediates for producing a fragrance, rosefuran and which are represented by: ##STR1## where R is H or a lower alkyl. The compounds [1] are obtained by reacting 2-methyl-3-alkoxycarbonylpropionic acid halide and 3-methyl-3-butenylmagnesium halide. The octenoic acid [1] is treated with acetic anhydride under heat in the presence of an acidic catalyst to give 3,7-dimethyl-2,6-octadien-4-olide. The olide is reduced in an ordinary manner to give rosefuran.
Claims6
3,7-Dimethyl-4-oxo-7-octenoic acid and its esters of a formula:
- ##STR6## wherein R represents hydrogen or a lower alkyl group.
A method for producing compounds of a formula:
- ##STR7## wherein R represents hydrogen or a lower alkyl group, comprising reacting 2-methyl-3-alkoxycarbonylpropionic acid halide with 3-methyl-3-butenylmagnesium halide.
A method for producing 3,7-dimethyl-2,6-octadien-4-olide of a formula:
- ##STR8## comprising treating 3,7-dimethyl-4-oxo-7-octenoic acid of a formula:
- ##STR9## wherein R represents hydrogen, with acetic anhydride under heat in the presence of an acid catalyst.
A method for producing 3,7-dimethyl-2,6-octadien-4-olide of a formula:
- ##STR10## comprising obtaining methyl 3,7-dimethyl-4-oxo-7-octenoate of a formula:
- ##STR11## wherein R represents methyl, by coupling reaction of 2-methyl-3-methoxycarbonylpropionic acid chloride with 3-methyl-3-butenylmagnesium chloride (Grignard reagent), then hydrolyzing the resulting keto-ester into 3,7-dimethyl-4-oxo-7-octenoic acid and thereafter subjecting the resulting acid to cyclization and dehydration along with rearrangement of the double bond in the molecule.
Dependencies are inferred from the claim text.