Process for Producing Flavone C Glycoside Derivatives
It is intended to provide a process for efficiently producing a flavone C glycoside derivative represented by the formula (1) which is an antiallergic substance or its salt, or a flavone C glycoside derivative represented by the formula (4) or its salt. According to this process, the flavone C glycoside derivative represented by the formula (1) or its salt and the flavone C glycoside derivative represented by the formula (4) can be easily and efficiently synthesized by using isovitexine and vitexine contained in herbs and so on as the starting materials.
1 . A process of producing a flavone C-glycoside derivative represented by the formula (1):
or a salt thereof comprising the step of reacting isovitexin used as a raw material in an organic solvent in the presence of a compound represented by the formula (2):
wherein R 1 and R 2 each are OR 4 or N(R 4 ) 2 , and R 4 is C 1 to C 4 alkyl or phenyl, and a compound represented by the formula (3):
[Formula 3]
(R 3 ) 3 P (3)
wherein R 3 is C 1 to C 4 alkyl or phenyl.
2 . A process of producing a flavone C-glycoside derivative represented by the formula (4):
or a salt thereof comprising the step of reacting vitexin used as a raw material in an organic solvent in the presence of a compound represented by the formula (2):
wherein R 1 and R 2 each are OR 4 or N(R 4 ) 2 , and R 4 is C 1 to C 4 alkyl or phenyl, and a compound represented by the formula (3):
[Formula 6]
(R 3 ) 3 P (3)
wherein R 3 is C 1 to C 4 alkyl or phenyl.
3 . The production process according to claim 1 or claim 2 , wherein the organic solvent is selected from the group consisting of benzene, toluene, THF, and xylene.
4 . The production process according to claim 3 , wherein the organic solvent is THF.
5 . The production process according to claim 1 or claim 2 , wherein the compound represented by the formula (2) is 1,1′-azobis(N,N′-dimethylformamide).
6 . The production process according to claim 1 or claim 2 , wherein the compound represented by the formula (3) is tri-n-butylphosphine.
7 . The production process according to claim 1 or claim 2 , wherein the compound represented by the formula (2) is 1,1′-azobis(N,N′-dimethylformamide) and the compound represented by the formula (3) is tri-n-butylphosphine.
8 . The production process according to claim 1 , wherein the isovitexin is protected by a protecting group.
9 . The production process according to claim 2 , wherein the vitexin is protected by a protecting group.
10 . The production process according to claim 1 , wherein the yield of the flavone C-glycoside derivative represented by the formula (1) or the salt thereof is 40% or more.
11 . The production process according to claim 2 , wherein the yield of the flavone C-glycoside derivative represented by the formula (4) or the salt thereof is 40% or more.
12 . The production process according to claim 5 , wherein the compound represented by the formula (3) is supported on a styrene resin.
13 . The production process according to claim 1 , wherein unreacted isovitexin is recycled.
14 . The production process according to claim 2 , wherein unreacted vitexin is recycled.