Flavonoid derivative compounds and method for preparing same by depolymerization of condensed tannins

Patent metadata

Field	Value
Publication number	US-10030009-B2
Application number	US-201515329991-A
Country	US
Kind code	B2
Filing date	Aug 3, 2015
Priority date	Aug 4, 2014
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

A compound of general formula (I) in which R 1 , R 2 , R 3 and R 5 , identical or different, each represent a hydrogen atom or a hydroxyl group, optionally protected by a protecting group. R 4 represents a hydrogen atom or an —OR 7 group, in which R 7 represents a hydrogen atom, a protecting group or a gallate group. R 6 represents a hydroxyl group, optionally protected by a protecting group. R′ 1 , R′ 2 , R′ 3 and R′ 4 , identical or different, each represent a hydrogen atom or a substituent not comprising a mesomeric electron withdrawing group conjugated with the furan ring. A substituent from R′ 1 , R′ 2 , R′ 3 and R′ 4 representing the covalent bond with the pyran ring or one of the salts of same. A method for obtaining such a compound includes a step of depolymerization of condensed tannins in the presence of an acid by means of a nucleophile derived from furan.

First claim

The invention claimed is:

1. A compound of general formula (I):

or a salt thereof, in which:
R 1 , R 2 , R 3 and R 5 , which may be identical or different, each represent a hydrogen atom or a hydroxyl group, optionally protected by a hydroxyl-function-protecting group,
R 4 represents a hydrogen atom or an —OR 7 group, in which R 7 represents a hydrogen atom, a hydroxyl-function-protecting group, or a group of general formula (II):

in which R″ 1 , R″ 2 and R″ 3 , which may be identical or different, each represent a hydrogen atom or a hydroxyl-function-protecting group,
R 6 represents a hydroxyl group, optionally protected by a hydroxyl-function-protecting group, and
R′ 1 , R′ 2 , R′ 3 and R′ 4 , which may be identical or different, each represent a hydrogen atom or a substituent which does not comprise:
any mesomeric-effect electron-withdrawing group which is conjugated to the furan nucleus,

where one of R′ 1 , R′ 2 , R′ 3 and R′ 4 is a covalent bond with the pyran ring.

2. The compound as claimed in claim 1 , in which R′ 1 , R′ 2 , R′ 3 and R′ 4 , which may be identical or different, each representing, with the exception of said covalent bond with the pyran ring:
a hydrogen atom,
a group comprising an electron-donating radical, said electron-donating radical being bonded directly or by conjugation to the furan ring and being optionally substituted, or
a linear, branched or cyclic carbon-based radical, comprising a single ring or several condensed rings, which is saturated or unsaturated, optionally aromatic, which is optionally substituted, optionally comprising one or more heteroatoms or one or more groups comprising one or more heteroatoms.

3. The compound as claimed in claim 1 , in which at least one substituent among R′ 1 , R′ 2 , R′ 3 and R′ 4 represents a hydrogen atom.

4. The compound as claimed in claim 1 , in which R′ 1 is said covalent bond with the pyran ring.

5. The compound as claimed in claim 1 , in which R′ 3 and R′ 4 each represent a hydrogen atom.

6. The compound as claimed in claim 1 , in which R′ 2 represents a hydrogen atom or a C 1 -C 18 alkyl group.

7. A method for obtaining a compound as claimed in claim 1 , comprising a depolymerization step of depolymerizing condensed tannins in the presence of an acid by means of a nucleophile of general formula (III):

in which R′ 1 , R′ 2 , R′ 3 and R′ 4 , which may be identical or different, each represent a hydrogen atom or a substituent which does not comprise:
any mesomeric-effect electron-withdrawing group which is conjugated to the furan nucleus,

at least one substituent among R′ 1 , R′ 2 , R′ 3 and R′ 4 representing a hydrogen atom.

8. The method as claimed in claim 7 , wherein, for the depolymerization step, the molar ratio of said “nucleophile of general formula (III): depolymerizable condensed tannins” is greater than or equal to the molar ratio of said “nucleophile of general formula (III): 2R,2′R,3R,3′R,4R)-2,2′-Bis(3,4-dihydroxyphenyl)-3,3′,4,4′-tetrahydro-2H,2′H-4, 8′-bichromene-3,3′,5,5′,7,7′-hexol” required to obtain at least a 2.5% yield of compounds of general formula (I), relative to a total of depolymerized compounds formed during a reaction of depolymerization of (2R,2′R,3R,3′R,4R)-2,2′-Bis(3,4-dihydroxyphenyl) -3,3′,4,4′-tetrahydro-2H,2′H-4, 8′-bichromene-3,3′,5,5′,7,7′-hexol by said nucleophile of general formula (III) in a presence of hydrochloric acid at 0.1 N in methanol, at 30° C. and in a reaction time of 10 minutes.

9. The method as claimed in claim 7 , wherein R′ 1 , R′ 2 , R′ 3 and R′ 4 , which may be identical or different, each represent:
a hydrogen atom,
a group comprising an electron-donating radical, said electron-donating radical being bonded directly or by conjugation to the furan ring and being optionally substituted, or
a linear, branched or cyclic carbon-based radical, comprising a single ring or several condensed rings, which is saturated or unsaturated, optionally aromatic, which is optionally substituted, optionally comprising one or more heteroatoms or one or more groups comprising one or more heteroatoms.

10. The method as claimed in claim 7 , wherein, in general formula (III), at least R′ 1 represents a hydrogen atom.

11. The method as claimed in claim 7 , wherein, in general formula (III), at least R′ 3 and R′ 4 each represent a hydrogen atom.

12. The method as claimed in claim 7 , in which R′ 2 represents a hydrogen atom or a C 1 -C 18 alkyl group.

13. The method as claimed in claim 7 , wherein for the depolymerization step, the acid is used in a concentration which is equivalent to the concentration of said acid that is required to confer a pH of between −1 and 3.5 on an aqueous solution.

14. The method as claimed in claim 7 , wherein the depolymerization step is carried out in a polar solvent or in a mixture of solvents containing at least one polar solvent.

15. The method as claimed in claim 7 , wherein the depolymerization step is carried out at a temperature below or equal to a boiling point of the nucleophile of general formula (III) at an applied pressure, and at less than or equal to a boiling point of the solvent at said applied pressure.

16. The method as claimed in claim 7 , comprising a prior step of extracting the condensed tannins from biomass.

17. The method as claimed in claim 7 , wherein the depolymerization step is carried out directly from biomass.

18. A method for depolymerizing condensed tannins, comprising a step of using a compound of general formula (III) to depolymerize the condensed tannins:

wherein R′ 1 , R′ 2 , R′ 3 and R′ 4 , which may be identical or different, each represent a hydrogen atom or a substituent which does not comprise any mesomeric-effect electron-withdrawing group which is conjugated to the furan nucleus,
and wherein at least one of R′ 1 , R′ 2 , R′ 3 and R′ 4 represents a hydrogen atom.

19. The method of claim 18 , wherein R′ 1 represents a hydrogen atom.

20. The method of claim 18 , wherein R′ 3 and R′ 4 each represent a hydrogen atom.

21. The method of claim 18 , wherein R′ 2 represents a hydrogen atom or a C 1 -C 18 alkyl group.

Assignees

• Agronomique Inst Nat Rech
• Centre Int Detudes Superieures En Sciences Agronomiques
• Univ De Montpellier 1

Inventors

• Roumeas Laurent
• Fulcrand Hélène
• Aouf Chahinez
• Dubreucq Eric

Classifications

• C07D307/34

  having two or three double bonds between ring members or between ring members and non-ring members · CPC title

• C07D407/04 Primary

  directly linked by a ring-member-to-ring-member bond · CPC title

• Y02P20/55

  Design of synthesis routes, e.g. reducing the use of auxiliary or protecting groups · CPC title