Synthesis of carminic acid and principal intermediates
AssigneeEuropean Colour PLC
InventorsJohn H. P. Tyman, Alberto Fiecchi, deceased
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Abstract
The invention relates to the synthesis of 6-deoxykermesates, 6-deoxykermesic acid, and carminic acid, based on a reaction of a 2-halogenonapthazarin with a bis-trimethylsilyl-diene.
Claims28
A method of synthesis of R' 6-deoxykermesates comprising reacting a 2-halogeno-5,8-dihydroxy-1,4-naphthoquinone with a R' 1-methyl-1,3-bis-(trimethylsilyl)-1,3-butadiene-2-carboxylate, wherein R' is one of an alkyl and benzyl.
A method of synthesis of 5-methoxy cochinellic anhydride, comprising the steps of first reacting a R' 1-methyl-1,3-bis(trimethylsilyl)-1,3-butadiene-2-carboxylate by Diels-Alder addition with either chloromaleic anhydride or bromomaleic anhydride followed by methylation of the 5-hydroxyl group, wherein R' is one of an alkyl and a benzyl.
A method of producing a C-glucosylated compound, comprising the step of C-glucosylation of a R' 3,5,8,9,10-pentamethoxy-1-methylanthracen-2-carboxylate with a 1-trifluoroacetate glucose derivative to give the 7-glucosyl derivative of a R' 3,5,8,9,10-pentamethoxy-1-methylanthracen-2-carboxylate, wherein said glucose derivative is first converted to the 1-trifluoroacetate in situ and C-glucolysation is carried out using the boron trifluoride etherate as a catalyst.
A method 26, wherein the Friedel-Crafts reaction is catalyzed by boron trifluoride etherate.
Dependencies are inferred from the claim text.