AU2004200117B2

AU2004200117B2 - Production of isoflavone derivatives

Info

Publication number: AU2004200117B2
Application number: AU2004200117A
Authority: AU
Inventors: Andrew Heaton; Naresh Kumar
Original assignee: Novogen Research Pty Ltd
Current assignee: Kazia Research Pty Ltd
Priority date: 1999-02-15
Filing date: 2004-01-12
Publication date: 2007-04-26
Anticipated expiration: 2020-02-15
Also published as: AU2004200117A1

Description

Our Ref: 12204781 P/00/011 Regulation 3:2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): Novogen Research Pty Ltd 140 Wicks Road North Ryde New South Wales 2113 Australia Address for Service: Invention Title: DAVIES COLLISON CAVE Patent Trade Mark Attorneys Level 10, 10 Barrack Street Sydney, New South Wales, Australia, 2000 Production ofisoflavone derivatives The following statement is a full description of this invention, including the best method of performing it known to me:- 5951 P:\WPCS\Hjw\Sps\H1rog AU div.doc-121//04 -1- PRODUCTION OF ISOFLAVONE DERIVATIVES Introduction The present invention relates to the hydrogenation ofisoflavones and products thereof. The invention also relates to the synthesis of phytoestrogenic isoflavone metabolites and derivatives from the hydrogenation products of isoflavones.

Background of the Invention Isoflavone metabolites possess a very wide range of important biological properties including oestrogenic effects (WO 98/08503). Isoflavone metabolites can be isolated from the urine of human volunteers subjected to diets rich in plant isoflavanoids such as soya, lentils, peas and beans.

In spite of the recently discovered biological significance of isoflavone metabolites there is not at present a general method suitable for the large scale synthesis of these metabolites.

The few reported syntheses of these metabolites utilise either catalytic hydrogenation or hydrogen transfer reduction of the corresponding isoflavones. These reduction reactions are found to be non-selective, extremely difficult to control and lead to mixtures of different products.

The reduction of 5,7-dihydroxyisoflavylium salts have been reported to give mixtures of isoflav-2-enes, isoflav-3-enes and isoflavans. The individual compounds are difficult to separate and can be obtained only in low yields. Sodium borohydride reductions of isoflavones are known, see Adam Major et al. Liebigs Ann. Chem. (1988) 555-558, however the reactions are low yielding, typically not clean and substituents on the basic isoflavone ring structure require tedious protective groups not affected by metal hydrides.

Chromatography is often required to separate the reaction products and only low yields of isoflavanones, isoflavan-4-ols, isoflavenes and isoflavans are obtained. The chromatography required is tedious and often impracticable for large scale reactions.

Furthermore, attempts to improve the yield and purity of products obtained from P \WPDOCS\Hjw\Spcs\H>yrog AU 2spa pgs doc-2703/2007 -2hydrogenation reactions has been met with limited success as evidenced by published results which are largely contradictory.

Solvents used in hydrogenation reactions of isoflavones reported in the literature include Nmethylpyrrolidinone, see Liepa, Aust. J Chem., 1981, 34, 2647-55. However this solvent is unsuitable for pharmaceutical preparations of isoflavone metabolites and derivatives because N-methylpyrrolidinone is a severe eye irritant and a possible carcinogen.

Furthermore the high boiling point of the solvent makes it extremely difficult to remove after the reduction.

Isoflavan-4-ols are key intermediates in the synthesis of isoflavenes and accordingly there is a need for more efficient and reliable syntheses of isoflavan-4-ols, or at least comparable alternatives, acceptable than those known in the art. There is also a need for synthetic methods for isoflavone hydrogenation which utilise solvents pharmaceutically more acceptable than those previously reported. Therefore it is an object of the present invention to overcome or at least alleviate one or more of the above-mentioned disadvantages of the prior art. It is an other object of the present invention to synthesise novel isoflavone metabolites and derivatives.

Surprisingly hydrogenation conditions have been found by the present inventors which enable the synthesis of isoflavone derivatives in good to excellent yields. In particular the conditions found by the present inventors allow for the hydrogenation of isoflavones to relatively pure tetrahydroisoflavan-4-ol products in excellent yields, and without the need for pharmaceutically unsuitable solvents and extensive chromatography in the hydrogenation reactions.

Summary of the Invention Thus the present invention as claimed provides a method for the large scale preparation of an oxy-substituted isoflavan-4-ol compound of formula II P \WPDCXS\Hj,\Spccs\IIydrog AU 2Sp4 pgb d -27/32007 -3- R7 R1, 0 R8 R4 (II) I R4

R

5 OH R R 2 R- R2

R

3 wherein RI, R 2

R

3 R4, R 5

R

6

R

7 and Rs are independently hydrogen, hydroxy, OR 9 OC(O)Rg,

OS(O)R

9 alkyl, haloalkyl, aryl, arylalkyl, thio, alkylthio, amino, alkylamino, dialkylamino, nitro, or halo,

R

9 is alkyl, haloalkyl, aryl, arylalkyl or alkylaryl, and at least one ofRI, R 2

R

3

R

4

R

5

R

6 and R 7 is an oxy substituent selected from hydroxy, OR 9 and OC(O)R 9 comprising the steps of: protecting the free hydroxy groups of an isoflavone compound of formula I R7 R 1 0O° R 8 IR4 1 R 5 O

R

2 R3 wherein

R

1

R

2

R

3

R

4

R

5

R

6

R

7 and R 8 are as defined above and at least one of R, R 2

R

3 R4,

R

5

R

6 and R 7 is a free hydroxy group, to prepare a protected isoflavone compound, where the at least one free hydroxy group ofRI, R 2

R

3

R

4

R

5

R

6 and R 7 is protected as OR 9 or OC(O)R,; hydrogenating the protected isoflavone compound of step to prepare the oxysubstituted isoflavan-4-ol compound of formula II where the at least one of Ri, R 2

R

3 R4, R 5 R, and R 7 is OR 9 or OC(O)R 9 wherein the hydrogenation step is performed with hydrogen in the presence of a reduction catalyst selected from palladium on activated carbon and a solvent selected from methanol and ethanol; and P \WPDOCS\Hjw Sms\Hyd-g Al; 2 sp pgs doc.27/O3/207 -4- 0 N optionally deprotecting the isoflavan-4-ol compound from part by hydrolysis of C the OC(O)R 9 protecting groups to prepare the isoflavan-4-ol compound of formula II, where Sthe at least one of R, R 2

R

3

R

4

R

5

R

6 and R 7 is a free hydroxy group.

The present invention as claimed also provides a method for the preparation of an oxysubstituted isoflav-3-ene compound of formula III R7 R, 0 R8 RR R2

R

3 wherein

R

1

R

2

R

3

R

4

R

5

R

6

R

7 and R 8 are independently hydrogen, hydroxy, OR 9

OC(O)R

9

OS(O)R

9 alkyl, haloalkyl, aryl, arylalkyl, thio, alkylthio, amino, alkylamino, dialkylamino, nitro, or halo, and

R

9 is alkyl, haloalkyl, aryl, arylalkyl or alkylaryl, and at least one of RI, R 2

R

3

R

4

R

5

R

6 and R 7 is an oxy substituent selected from hydroxy,

OR

9 and OC(O)R,, including the steps of: protecting the free hydroxy groups of an isoflavone compound of formula I R7 R 4 (1)

O

0 R3

R

2 wherein RI, R 2

R

3

R

4

R

5

R

6

R

7 and R 8 are as defined above and at least one of R 1

R

2

R

3

R

4

R

5 R6 and R 7 is a free hydroxy group, to prepare a protected isoflavone compound, where the at least one free hydroxy group of R, R 2

R

3

R

4

R

5 R and R 7 is protected as OR, or OC(O)R 9 hydrogenating the protected isoflavone compound of step to prepare an oxysubstituted isoflavan-4-ol compound of formula II P \WPDOICS\HjuwSpcs\HI1rog AU 2spj pgs do-27/03/2007 R7 R6 R, OH R

R

OH

R3 R2 wherein RI, R 2

R

3

R

4

R

5 Rs, R 7 and Rg are as defined above, and where the at least one of RI, R 2

R

3

R

4 Rs, Ro and R7 is OR 9 or OC(O)R 9 wherein the hydrogenation step is performed with hydrogen in the presence of a reduction catalyst selected from palladium on activated carbon and a solvent selected from methanol and ethanol; dehydrating the compound of formula II to prepare the isoflav-3-ene compound of formula III; and optionally deprotecting the isoflav-3-ene compound from part by hydrolysis of the OC(O)R 9 protecting groups to prepare the isoflav-3-ene compound of formula III, where the at least one of R, R 2

R

3

R

4

R

5 R6 and R 7 is hydroxy.

The present invention also provides a method for the hydrogenation of a compound of formula I to prepare a compound of formula IV R7 R1, 0 R8 R4

(IV)

00I

R

3 wherein Ri, R 2

R

3

R

4

R

5 Re, R 7

R

8 and R 9 are as defined above.

The present invention also provides a method for the hydrogenation of a compound of formula III to prepare a compound of formula V P \W?I OCS\1lj, Sms\Hydrog AU 2 spj pgs dcx-27/O3/2007 5A wherein RI, R 2

R

3 R4, R 5

R

6

R

7

R

8 arnd R 9 are as defined above.

P:\WPDOCS\Hjw\Specs\Hydrog AU div.doc-12//04 -6- The present invention also provides compounds of formulae II, III, IV and V when prepared by a method described above and compositions comprising same.

The present invention also provides novel compounds of the formulae I, II, III, IV and V and compositions comprising same.

These and other aspects and preferred embodiments of the invention are further described in the description, Examples and claims which follow.

Detailed Description of the Invention In the methods of the present invention, the starting isoflavone of formula I, the hydrogenation products isoflavan-4-ol of formula I, isoflavan-4-one of formula IV and isoflavan of formula V, and the dehydration product isoflav-3-ene of formula III preferably have the following substituents wherein

R

1

R

2

R

3

R

4 Rs, R 6

R

7 and Rg are independently hydrogen, hydroxy, OR 9

OC(O)R

9

OS(O)R

9 alkyl, aryl, arylalkyl, thio, alkylthio, bromo, chloro or fluoro, and

R

9 is alkyl, fluoroalkyl or arylalkyl; more preferably they have the following substituents wherein

R

1 is hydroxy, OR 9 or OC(O)R 9

R

2

R

3

R

4

R

5

R

6 and R 7 are independently hydrogen, hydroxy, OR 9

OC(O)R

9 alkyl, aryl or arylalkyl,

R

8 is hydrogen, and

R

9 is methyl, ethyl, propyl, isopropyl or trifluoromethyl; and most preferably they have the following substituents wherein

R

1 is hydroxy, OR 9 or OC(O)R 9

R

2

R

3

R

4

R

5 and R 7 are independently hydrogen, hydroxy, OR 9

OC(O)R

9 alkyl, aryl or arylalkyl,

R

6 and R 8 are hydrogen, and

R

9 is methyl.

P:\WPflOCS\Hjwv\Spocs\Hydrog AU di.doc-12101f04 -7- The particularly preferred compounds of formula I are 4',7-diacetoxyisoflavone (daidzein diacetate) and 7-acetoxy-4'-methoxyisoflavone; the particularly preferred compounds of formula II are 4',7-diacetoxyisoflavan-4-ol (tetrahydrodaidzein diacetate) and 7-acetoxy-4'-methoxyisoflavan-4-ol; the particularly preferred compounds of formula I1H are 4',7-diacetoxyisoflav-3-ene (dehydroequol diacetate), 4',7-dihydroxyisoflav-3-ene (dehydroequol), 7-acetoxy-4'methoxyisoflav-3 -ene and 7-hydroxy-4'-methoxyisoflav-3-ene; the particularly preferred compounds of formula IV are 4',7-diacetoxyisoflavan-4-one (diacetoxydihydrodaidzein) and 4',7-dihydroxyisoflavan-4-one (dihydrodaidzein); and the particularly preferred compounds of formula V are 4',7-diacetoxyisoflavan (equol diacetate) and 4',7-dihydroxyisoflavan (equol).

The novel compounds of the formulae I, 11, 111, IV and V preferably have the following substituents wherein R, is hydroxy, OR 9

OC(O)R

9 thio, alkylthio, or halo,

R

2

R

3

R

4

R

5

R

6 R(7 and R8 are independently hydrogen, hydroxy, OR 9

OC(O)R

9

OS(O)R

9 q, alkyl, aryl, thio, alkylthio or halo, and

R

9 is alkyl, fluoroalkyl or arylalkyl with the proviso that at least one of R 5

R

6 and R 7 is not hydrogen, or when R(5, R 6 and R 7 are all hydrogen, then R 3 is hydroxy, OR 9

OC(O)R

9

OS(O)R

9 alkyl, aryl, thio, alkylthio or halo; and more preferably they have the following substituents wherein R, is hydroxy, OR 9 or OC(O)R 9 R2 and R(3 are independently hydrogen, hydroxy, OR 9 or OC(O)R 9

R

4

R

5 R(6, and R 8 are hydrogen,

R

7 is hydroxy, OR 9

OC(O)R

9 alkyl, aryl or halo, and

R

9 is methyl, ethyl, propyl, isopropyl, trifluoromethyl or benzyl; or wherein R, is hydroxy, OR 9

OC(O)R

9 R(2 and 1(3 are independently hydrogen, hydroxy, OR 9 or OC(O)R 9 P \WPDOCS\Hjw\Sp~s\Hydfrog AU div.doo-12/O1/04 -8-

R

5 is OR 9

OC(O)R

9 alkyl, aryl or halo,

R

4 Rr, R 7 and R 8 are hydrogen, and

R

9 is methyl, ethyl, propyl, isopropyl, trifluoromethyl or benzyl.

Most preferably the novel compounds of formulae 1, 11 and III are: 4',7,8-Triacetoxyisoflavone 7,8-Diacetoxy-4'-methoxyisoflavone 7-Diacetoxy-8-methylisoflavone 7-Diacetoxy-8-methylisoflavone 7-Acetoxy-4'-methoxy-8-methylisoflavone 4',7-Diacetoxy-3 '-methoxy-8-mtyiolvn ,7-Triacetoxyisoflavone 4',7,8-Triacetoxyisoflavan-4-ol 7,8-Diacetoxy-4'-methoxyisoflavan-4-oI 7-Diacetoxy-8-methylisoflavan-4-ol 7-Diacetoxy-8-methylisoflavan-4-ol 7-Acetoxy-4'-methoxy-8-methylisoflavan-4-oI 7-Diacetoxy-3'-methoxy-8-methylisoflavan-4-ol 4',5,7-Tniacetoxyisoflavan-4-ol 4',7,8-Trihydroxyisoflavan-4-ol 7,8-Dihydroxy-4'-methoxyisoflavan-4-oI 4',7-Dihydroxy-8-methylisoflavan-4-oI 3',7-Dihydroxy-8-methylisoflavan-4-ol 7-Hydroxy-4'-methoxy-8-methylisoflavan-4-oI 4',7-Dihydroxy-3 '-methoxy-8-methylisoflavan-4-ol ,7-Trihydroxyisoflavan-4-ol 4',7,8-Triacetoxydehydroequol (4',7,8-Triacetoxyisoflav-3-ene) 7,8-Diacetoxy-4'-methoxydehydroequol (7,8-Diacetoxy-4'-methoxyisoflav-3-ene) 7-Diacetoxy-8-rnethylisoflav-3-ene 7-Diacetoxy-8-methylisoflav-3-ene P:\WPDOCS\Hjw\Spms\Hydrog AU divdo-12OI/O4 -9- 7-Acetoxy-4'-methoxy-8-methylisoflav-3-ene 7-Diacetoxy-3'-methoxy-8-methylisoflav-3-ene ,7-Triacetoxyisoflav-3-ene Isoflav-3-ene-4',7,8-triol 4'-Methoxyisoflav-3-ene-7,8-diol 8-Methylisoflav-3 -ene-4',7-diol 8-Methylisoflav-3 -ene-3 ',7-diol 4'-Methoxy-8-methylisoflav-3 -ene-7-ol 3'-Methoxy-8-methylisoflav-3 -ene-4',7-diol Isoflav-3 -ene-4',5 ,7-triol 4',7-Dihydroxy-8-methylisoflavan-4-ol 7-Hydroxy-4'-methoxy-8-methylisoflavan-4-ol The term "alkyl" is taken to mean both straight chain and branched chain alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secbutyl, tertiary butyl, and the like.

Preferably the alkyl group is a lower alkyl of 1 to 6 carbon atoms. The alkyl group may optionally be substituted by one or more of fluorine, chlorine, bromine, iodine, carboxyl, C I-

C

4 -alkoxycarbonyl, C 1

-C

4 -alkylamnino-carbonyl, di-(CI -C 4 -alkyl)-amino-carbonyl, hydroxyl, CI -C 4 -alkoxy, formyloxy, C 1

-C

4 -alkyl-carbonyloxy, C 1

-C

4 -alkylthio, C 3

-C

6 -cylcoalkyl or phenyl.

The term "aryl" is taken to include phenyl and naphthyl and may be optionally substituted by one or more CI-C 4 -alkyl, hydroxy, CI-C 4 -alkoxy, carbonyl, CI-C 4 -alkoxycarbonyl C 1

C

4 -alkylcarbonyloxy or halo.

The term "halo" is taken to mean one or more halogen radicals selected from fluoro, chloro, bromo, iodo and mixtures thereof; preferably fluoro and chloro, more preferably fluoro.

Reference to for example "haloalkyl" includes monohialogenated, dihialogenated and up to perhalogenated alkyl groups. Preferred perhalogenated groups are trifluoromethyl and pentafluoroethyl.

P:\WPDOCS\HIjw\Spes\Hydrog AU div.doc-12/01/04 The compounds of the invention include all salts, such as acid addition salts, anionic salts and zwitterionic salts, and in particular include pharmaceutically acceptable salts.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The hydrogenation is ideally preformed with hydrogen in the presence of a reduction catalyst and a solvent. The reaction is preferably conducted under hydrogen at a pressure of 1-20 atmospheres, more preferably 1-5 atmospheres. The reaction may be performed from to 60 0 C and is typically carried out at room temperature.

The reaction time may range from 12 hours to 96 hours or more and is typically about hours or more. Generally better yields and cleaner reactions are achieved with longer reaction times. It will be appreciated that reaction conditions may be varied depending on the individual nature of the compounds and the progress of the hydrogenation reaction.

The reduction catalysts may be selected from heterogeneous catalysts (whereby the catalyst is insoluble in the reaction medium) or homogenous catalysts (whereby the catalyst is soluble in the reaction medium). Examples of heterogeneous reduction catalysts include Raney nickel, palladium black, palladium hydroxide on carbon, palladium on activated carbon Pd to 30% Pd), palladium on alumina powder, palladium on various barium salts, sodium borohydride reduced nickel, platinum metal, platinum black, platinum on activated carbon Pt to 10% Pt), platinum oxide, rhodium salts, ruthenium salts and their chiral salts and zinc oxide. Preferably the catalyst is palladium on activated carbon Pd to 10% Pd), more preferably about 5% palladium on carbon. Platinum oxide (Adam's catalyst) is also a very useful hydrogenation catalyst for the methods of the present invention to produce predominantly cis-isomers of isoflavan-4-ols.

Examples of homogeneous reduction catalysts include chlorotris (triphenylphosphine)rhodium, chloro(trisphenylphosphine)hydridoruthenium (II) and pentacyanocobaltate (II).

P:\WPDOCS\Hjw\Specs\Hdrog AU div.doc-12/01/04 11 The solvents suitable for use in the present invention include but are not limited to C 1

-C

8 alcohols and polyols, alkyl acetates, tetrahydrofuran, ethers, dioxane and C 1

-C

3 acids.

Preferably the solvent is a C 1

-C

6 alcohol or C 1

-C

6 alkyl acetate, more preferably methanol, ethanol or ethyl actate, as well as propanol, isopropanol, butanol, isobutanol, secbutanol, tertiary butanol, methyl formate, ethyl formate and methly acetate. Most preferably the solvent is absolute methanol, ethanol or ethyl acetate.

The present inventors have found that with a judicious choice of catalysts, solvents and optionally protecting groups, isoflavones are reduced cleanly and in high yields to corresponding isoflavanols. In particular the use of absolute methanol or ethanol as a solvent provided for very clean catalytic hydrogenation over 5% palladium on charcoal of isoflavones to afford up to quantitative yields of isoflavanols. In methods where, for example, 10% palladium on charcoal is employed, the reaction can proceed more rapidly, at times being complete within 12 hours. The ratio of cis- and trans-isomers of the isoflavan- 4-ol hydrogenation product can vary with the choice of catalysts and the nature of the isoflavone substitute. By varying the methods of the present invention it is possible to influence the isomeric ratio achieved during the reduction process.

Of particular interest are isoflavones with oxygen substitution (or precursors to oxygen substitution) at the and 7-positions as reduction of these compounds leads to the biologically important dehydroequol or precursors thereof. A convenient starting material is daidzein which is readily obtained by established routes.

It will be understood that some moieties on the isoflavone rings may require protection or derivatisation prior to being subjected to hydrogenation. For example it may be desirable to protect free hydroxy moieties with groups such as an acetoxy group to assist in the solubility of the substituted isoflavones and/or their susceptibility to hydrogenation. Protecting groups can be carried out be well established methods known in the art, for example as described in Protective Groups in Organic Synthesis, T. W. Greene.

In particular the present inventors have found it is useful to protect hydroxy groups when present as esters or ethers prior to reduction, with acetoxy or methoxy groups most favoured.

P:\WPDOCS\Hjw\Spcs\Hydrog AU divdoc-12/01/04 -12- Acylation is preferably carried out with the hydroxy compounds in a solvent mixture of a carboxylic acid anhydride and base. Protecting free hydroxy groups prior to hydrogenation increases yields up to and including quantitative yields. The reaction products are generally cleaner and do not require a chromatography step in the purification and isolation of the hydrogenation products.

Thus surprisingly, tetrahydrodaidzein diacetate was obtained in quantitative yield when the catalytic hydrogenation of diacetoxydaidzein in ethanol was continued for 55 h.

Spectroscopic analysis established the product to be a 1:1 mixture of cis- and trans-isomers.

Pleasingly, no further reduction of tetrahydrodaidzein was observed even if the reduction was continued for longer periods of time.

In a similar manner it was also surprisingly found that the protected isoflavone 7-acetoxy-4'methoxydaidzein smoothly and cleanly underwent hydrogenation in ethanol to afford a quantitative yield of a 1:1 mixture of cis- and trans-isomers of 7-acetoxy-4'methoxyisoflavan-4-ol. This reaction appears to be quite general and was repeated on many different substrates in amounts of up to one half gram and more.

In this regard the inventors have found conditions which allow for the large scale generation of clean and near quantitative yields of isoflavan-4-ols compounds by hydrogenation of corresponding isoflavones. In particular, it has been found that kilogram quantities of diacetoxy daidzein undergo smooth and efficient reduction to the isomeric cis- and trans- 4',7-diacetoxyisoflavan-4-ols. The isomeric ratios can be influenced by the percentage of palladium in the catalyst.

The cis-/trans-isomeric mixtures are able to be dehydrated to isoflav-3-enes without the need for separation. However, is desired, the mixtures are able to be separated by a variety of methods as set out below.

The mixture of cis- and trans-tetrahydrodaidzein compounds are able to be separated by preparative HPLC. This mode of separation is quite tedious and limited to small amounts of material. Since reasonable quantities of the diacetoxy isoflavanols were able to be prepared, fractional crystallisation was attempted to separate the cis- and trans-isomers. A single

I

P:\WPDOCS\ljw\Specs\Hydrog AU div.doc-12/01/04 -13recrystallisation of the 1:1 mixture from ethanol gave predominantly transdiacetoxytetrahydrodaidzein (50% yield: 73% purity) (cis-isomer Subsequent recrystallisations from ethanol afforded the pure trans- isomer in 25% overall yield.

Likewise the 7-acetoxy-4'-methoxyisoflavan-4-ol was able to be fractionally recrystallised to give the pure trans-isomer, with the filtrate containing increased proportions of the cisisomer.

Most hydrogenations yielded 1:1 mixtures of cis- and trans-isoflavan-4-ols. However one derivative of note was 7-hydroxy-4'-methoxy-8-methylisoflavone, the hydrogenation of which afforded predominantly the trans- isomer in excellent yield.

Synthesis of tetrahydrodaidzein and related derivatives was achieved by removal of the protecting acetoxy groups under mild conditions, preferably with imidazole in ethanol at reflux. Tetrahydrodaidzein was isolated in 80% yield after crystallisation from aqueous ethanol.

Dehydration of isoflavan-4-ols leads to the unsaturated isoflav-3-enes. Thus reaction of a cis-/trans-mixture of isoflavan-4-ols with benzoyl chloride/dimethylformamide at 100 0 C has been reported in the literature by Liepa to give the desired isoflav-3-ene dehydration product. However this reaction could only be repeated in low yield. Dehydration may also be effected by treatment with acids such as sulfuric acid, hydrochloric acid, polyphosphoric acid, thionyl chloride and the like. Alternative methods of dehydration using ptoluenesulfonic acid or trifluoroacetic acid in refluxing dichloromethane were also investigated, but these methods also afforded the isoflavenes in low yields.

Generally the present inventors found the dehydration reagent of choice to be phosphorus pentoxide in dichloromethane, which can yield isoflavenes in yields of greater than The dehydration reactions can be carried out on the hydrogenation products directly, or deprotected derivatives thereof.

Synthesis of dehydroequol was achieved by removal of the protecting acetoxy groups under mild conditions as described for the synthesis of tetrahydrodaidzein, and dehydroequol was P:\WPDoCS\HjpMs\Hydrog AU div.dc-12/01/04 -14purified by standard crystallisation solvent mixtures such as ethanol/water. Other isoflav-3ene derivatives may be prepared by similar methods.

Hydrogen reduction of 4',7-diacetoxydaidzein with Adam's catalyst (platinum(IV)oxide) in ethyl acetate under an atmosphere of hydrogen afforded 4',7-diacetoxytetrahydrodaidzein.

However unlike the palladium-on-charcoal reduction in ethanol, reductions with Adam's catalyst gave predominantly the cis-isomer of 4',7-diacetoxytetrahydrodaidzein.

In another embodiment of the invention, hydrogenation of 4',7-diacetoxy daidzein with palladium-on-charcoal in ethyl acetate as solvent under an atmosphere of hydrogen gave 4',7-diacetoxydihydrodaidzein in excellent yield These conditions provide access to isoflavan-4-ones from the corresponding isoflavones in good to excellent yields.

Access to isoflavan derivatives such as equol is possible by hydrogenation of isoflav-3-enes with, preferably, palladium-on-charcoal in an alkyl acetate solvent under an atmosphere of hydrogen. Excellent yields of 75% and more of the hydrogenated products are obtainable by these methods. The products are clean and are readily recrystallised.

The surprising results obtained by the present inventors are in sharp contrast to those reported in the literature for other attempted hydrogenations of isoflavones. One such marked advantage is the use of alkyl acetates or alcohol solvents such as absolute methanol or ethanol in the hydrogenation reactions. The isoflavanols prepared by the methods of the present invention are typically very crystalline and can be isolated in good purity, and without the need for chromatography. The isoflavanols can be converted to isoflav-3-enes by dehydration. Further deprotection or derivatisation steps can be employed by those skilled in the art to obtain natural isoflavan-4-ones, isoflavans, isoflavenes, metabolites and novel derivatives thereof as required.

The invention is further described in and illustrated by the following Examples. The Examples are not to be construed as limiting the invention in any way.

P:\WPDOCS\Hjw\Specs\Hydrg AU div.doc-12/01/04

EXAMPLES

Acetylation Reactions Example 1 4',7 Diacetoxydaidzein Method A A mixture of daidzein (1.0g, 3.9 mmol), acetic anhydride (5 ml) and pyridine (5 ml) was left in the dark at room temperature for 24 h. The reaction mixture was poured into water (100 ml), stirred for 2h and then extracted with dichloromethane (3 x 50 ml). The dichloromethane layer was washed with water, dried over anhydrous sodium sulfate and evaporated. The white residue was crystallised from methanol to yield daidzein diacetate as white prisms (1.1 g, 'H NMR (CDCl 3 6 2.32 3H, OCOCH 3 2.36 3H,

OCOCH

3 7.18 2H, J 9.2 Hz, ArH), 7.19 1H, J 9.0 Hz, H6), 7.31 1H, J 2.0 Hz H8), 7.59 2H, J 9.2 Hz, ArH), 8.00 1H, H2), 8.33 2H, J 8.2 Hz, ArH).

Method B A mixture of daidzein (2.0 g, 7.9 mmol), acetic anhydride (10 ml) and pyridine (2 ml) was heated on an oil bath at 105-110 C for lh. After cooling the mixture to room temperature, it was stirred for a further 30 min during which time the diacetate crystallised from the solution. The product was filtered, washed thoroughly with water and recrystallised from methanol to yield daidzein diacetate as colourless prisms (2.4 g, Example 2 7-acetoxy-4'-methoxyisoflavone A mixture of 7-hydroxy-4'-methoxyisoflavanone (2.0g, 7.5 mmol), acetic anhydride (10 ml) and pyridine (2 ml) was heated on an oil bath at 105-110 C for 1 hour. After cooling the mixture to room temperature, it was poured into water (100 ml), stirred for 2 hours and then extracted with dichloromethane (3 x 50 ml). The dichloromethane layer was washed with water, dried over anhydrous sodium sulfate and evaporated. The white residue was crystallised from methanol to yield 7-acetoxy-4'-methoxyisoflavone as colourless prisms (2.1g, 'H NMR (CDC1 3 5 2.36 3H, OCOCH 3 3.84 3H, OCH 3 6.98 2H, P:\WPDOCS\Hjwv\Specs\Hydrog AU divdo-12I01/04 16 J 8.7 Hz, ArH), 7.16 (dd, I1H, J 1. 9 Hz 8.6 Hz, H6), 7.3 0 I1H, J 1. 9 Hz H8), 7.5 0 2H, J 8.7 Hz, ArH), 8.00 1H, H2), 8.32 1H, J 8.6 Hz, Example 3 3 ',7-Diacetoxyisoflavone 3',7-Diacetoxydaidzein was prepared from 3',7-dihydroxyisoflavone (0.98g, 3.9 mmol), acetic anhydride (6 ml) and pyridine (1.1 ml) as described for 4',7-diacetoxydaidzein. Yield: 77%) m.p. 152'C. 1 H NMR (CDC1 3 8 2.31 and 2.36 (each s, 3H, OCOCHA) 7.14 (in, 1H, ArH), 7.18 (dd, 1H, J 2.0 Hz 8.6 Hz, H6), 7.31 1H, J 2.0 Hz H8), 7.37-7.45 (in, 3H, ArH), 8.03 1H, H2), 8.32 1H, J 8.6 Hz, H5). Mass spectrum: mlz 338 296 254 (100); 253 Example 4 7-Acetoxy-3 -methoxyisoflavone 7-Acetoxy-3 '-methoxyisoflavone was prepared from 7-hydroxy-3'-inethoxyisoflavone (1 .7g, 6.3 mmol), acetic anhydride (6 ml) and pyridine (1.0 ml) as described for 4',7diacetoxydaidzein. Yield: (1.6g, 81%) m.p. 118'C. 1 H NMR (CDCl 3 8 2.36 3H, OCOCHA) 3.85 3H, OMe), 6.95 (dd, 1 H, J 2.0 Hz 8.3 Hz, H6), 6.70-7.40 (in, 5H, ArH), 8. 01 I1H, H2), 8.3 2 I1H, J 8.7 Hz, Example 4',7-Diacetoxy-3 '-methoxyisoflavone 4',7-Diacetoxy-3 '-methoxyisoflavone was prepared from 4',7-dihydroxy-3inethoxyisoflavone (0.37g, 1.3 inmol), acetic anhydride (2.5 ml) and pyridine (0.4 ml) as described for 4',7-diacetoxydaidzein. Yield: (0.36g, 75%) m.p. 197TC. IH NMR (CDCl 3 2.33, 2.36 (each s, 3H, OCOCHA) 3.88 3H, OMe), 7.06-7.17 (in, 2H, ArH), 7.19 (dd, 1H, J 2.3 Hz 9.0 Hz, ArH), 7.32 (dd, 2H, J 2.3 Hz 7.6 Hz, ArH), 8.03 1H, H2), 8.32 (d, I1H, J 8.6 Hz, P:\WPDOCS\Hjw\SpsHydfrog AU div.doo-12/OI/04 17 Example 6 7-Acetoxyisoflavone 7-Acetoxyisoflavone was prepared from 7-hydroxyisoflavone (2.6g, 10.9 mmol), acetic anhydride (16 ml) and pyridine (3.0 ml) as described for 4',7-diacetoxydaidzein. Yield: (2.5g, 82%) m.p. 133'C. IH NMR (CDCl 3 8 2.36 3H, OCOCHA) 7.18 (dd, 1H, J 2.2 Hz 8.6 Hz, H6), 7.31 1H, J 2.2 Hz H8), 7.39-7.57 (in, 5H, ArH), 8.00 III, H2), 8.33 1H, J 8.6 Hz, H5). Mass spectrum: m/z 280 237 238 (57).

Example 7 4',7,8-Triacetoxyisoflavone A mixture of 4',7,8-trihydroxyisoflavone (1 .4g, 5.2 mmol), acetic anhydride (8.4 ml) and pyridine (2 ml) was heated on an oil bath at 105-1 10'C for lh. After cooling the mixture to room temperature, it was stirred for a further 30 min during which time the diacetate crystallised from the solution. The product was filtered, washed thoroughly with water and recrystallised from ethyl acetate to yield 4',7,8-triacetoxyisoflavone as colourless prisms (1.49g, 73%) m.p. 190-192 0 C. 1 H NMR (CDCL 3 8 2.32, 2.36, 2.42 (each s, 3H1, OCOCHA) 7.18 2H, J 8.6 Hz, ArH), 7.28 1H, J 8.9 Hz, H6), 7.56 2H, J 8.6 Hz H8), 7.98 I1H, ArH), 8.18 I1H, J 8.9 Hz, Example 8 7,8-Diacetoxy-4'-metboxyisoflavone 7,8-Diacetoxy-4'-methoxyisoflavone was prepared from 7,8-dihydroxy-4'methoxyisoflavone (0.82g, 2.9 inmol), acetic anhydride (4.9 ml) and pyridine (0.9 ml) as described for 4',7,8-triacetoxyisoflavone. Yield: (0.9g, 85%) m.p. 165'C. 1 H NMR (CDCl 3 8 2.36, 2.42 (each s, 3H, OCOCHA) 3.84 3H1, OCHA) 6.98 2H, J 9.0 Hz, ArH), 7.25 1H, J 8.7 Hz, H6), 7.48 2H, J 9.0 Hz H8), 7.95 1H, H2), 8.20 1H, J 9.1 Hz, H5). Mass spectrum: m/z 368 326 312 284 Example 9 4',7-Diacetoxy-8-methylisoflavone A mixture of 4',7-dihydroxy-8-methylisoflavone (2.9g, 10. 8 mmol), acetic anhydride (18 ml) and pyridine (3 ml) was heated on an oil bath at 105-1 10'C for lh. After cooling the P:\WPDOCS\Hjw\Spm\Hiydrog AU div.doc-12101/04 18mixture to room temperature, it was stirred for a further 30 min during which time the diacetate crystallised from the solution. The product was filtered, washed thoroughly with water and recrystallised from ethyl acetate to yield 4',7-diacetoxy-8-methylisoflavone as colourless prisms (3.2g, IH NMR (CDCl 3 8 2.31 3H, CHA) 2.32, 2.39 (each s, 3H1, OCOCHA) 7.13 1H, J 9.0 Hz, H6), 7.17 2H4, J 8.7 Hz, ArH), 7.59 2H, J 8.7 Hz, ArH), 8.07 IlH, H2), 8.19 1H, J 8.7 Hz, Example 3 ',7-Diacetoxy-8-methylisoflavone 3 ',7-Diacetoxy-8-methylisoflavone was prepared from 3 ',7-dihydroxy-8-methylisoflavone (1.3g, 4.8 mmol), acetic anhydride (8 ml) and pyridine (1.5 ml) as described for 4',7diacetoxy-8-methylisoflavone. Yield: (1.2g, 70%) m.p. 112 0 C. 1 H NMR (CDC1 3 8 2.31 3H, CHA) 2.32, 2.39 (each s, 3H, OCOCHA) 7.13 (in, 2H, ArH), 7.37-7.45 (in, 3H, ArH), 8.1 1H, H2), 8.18 1H, J 8.7 Hz, H5). Mass spectrum: m/z 352 310 268 (100); 267 Example 11 7-Acetoxy-4 '-methoxy-8-methylisoflavone 7-Acetoxy-4'-methoxy-8-methylisoflavone was prepared from 7-hydroxy-4'-methoxy-8methylisoflavanone (3.0g, 10.6 mmol), acetic anhydride (10 ml) and pyridine (2.0 ml) as described for 4',7-diacetoxy-8-methylisoflavone. Yield: (2.0g, 58%) m.p. 190-1 92 0 C. IH NMR (CDCl 3 6 2.31 3H, CHA) 2.3 8 3H, OCOCHA) 3.84 3H, OMe), 6.98 2H, J 8.7 Hz, ArH), 7.12 1H, J 8.6 Hz, H6), 7.52 2H, J 8.7 Hz, ArH), 8.03 111, H2), 8.18 1H, J 8.6 Hz, H5). Mass spectrum: 325 (M 1, 324 282 (100); 281 (42).

Example 12 4',7-Diacetoxy-3 '-methoxy-8-methylisoflavone 4',7-Diacetoxy-3 '-methoxy-8-methylisoflavone was prepared from 4',7-dihydroxy-3methoxy-8-methylisoflavone (0.42g, 1.4 mamol), acetic anhydride (2.6 ml) and pyridine ml) as described for 4',7-diacetoxy-8-methylisoflavone. Yield: (0.4g, 74%) m.p. 209'C. 1

H

NN4R (CDC1 3 6 2.22 3H, CHA) 2.32, 2.39 (each s, 3H, OCOCHA) 3.89 3H, OMe), P:\WPDOCS\Hjw\Spacs\Hydrog AU div.doc120104 -19- 7.07-7.11 2H, ArH), 7.13 1H, J 8.6 Hz, H6), 7.32 1H, J 1.5 Hz, ArH), 8.09 1H, H2), 8.18 1H, J 8.7 Hz, Hydrogenation Reactions:- Isoflavone Isoflavan-4-ol Example 13 4',7-diacetoxytetrahydrodaidzein (4',7-Diacetoxyisoflavan-4-ol) Method A Palladium-on-charcoal 0.08 g) was added to a suspension of 4',7-diacetoxydaidzein g, 1.5 mmol) in absolute ethanol (400 ml) and the mixture was stirred at room temperature under a hydrogen atmosphere for 55 hours. The catalyst was removed by filtration through Celite and the filtrate was evaporated in vacuo to yield 4',7diacetoxytetrahydrodaidzein (0.51 g, 100%) in quantitative yield. A nuclear magnetic resonance spectrum revealed the product to be a clean 1:1 mixture of cis- and trans-4',7diacetoxytetrahydrodaidzein.

The cis- and trans-isomers were able to be separated by fractional recrystallisation. A 1:1 mixture of cis- and trans-4',7-diacetoxytetrahydrodaidzein (0.17 prepared as above, was dissolved in excess absolute ethanol and concentrated on a rotary evaporator. At the first sign of crystallisation, further concentration of ethanol was stopped and the flask was cooled in an ice-bath. The resulting crystals were filtered and washed with a small amount of cold absolute ethanol. A nuclear magnetic resonance spectrum of the product (0.08 g) revealed it to be a mixture trans-4',7-diacetoxytetrahydrodaidzein and cis-4',7diacetoxytetrahydrodaidzein Further recrystallisations of the mixture from ethanol yielded the pure trans-4',7-diacetoxytetrahydrodaidzein (0.04 g, 24%).

The filtrate yielded predominantly cis-isomer. Nuclear magnetic resonance spectroscopic analysis revealed the substance to be a mixture of cis-4',7-diacetoxytetrahydrodaidzein and trans-4',7-diacetoxytetrahydrodaidzein For trans-4',7-Diacetoxyisoflavan-4-ol; 'H NMR (CDC13): 6 2.28 3H, OCOCH 3 2.29 (s, 3H OCOCH 3 3.14 (ddd, 1H, J 3.7 Hz, 7.9 Hz, 9.1 Hz, H3), 4.24 (dd, 1H, J 9.1 Hz, 11.3 Hz,

I

P:\WPDOCS\Hjw\Spcs\Hydrog AU div.doc-12/01/04 H2); 4.35 (dd, 1H, J 3.7 Hz, 11.3 Hz, H2), 4.87 1H, J 7.9 Hz, H4), 6.61 1H, J 2.3 Hz, H8), 6.70 (dd, 1H, J 2.3 Hz, 8.4 Hz, H6), 7.06 2H, J 8.6 Hz, ArH), 7.23 2H, J 8.4 Hz, ArH), 7.44 (dd, 1H, J 0.8 Hz, 8.4 Hz, H5). 13 C NMR (CDC1 3 20.98 (OCOCH 3 46.18 68.04 69.01 109.67 114.26 121.96, 128.96 (ArCH), 129.40 For cis-4',7-Diacetoxyisoflavan-4-ol: 'H NMR (CDC13): 6 2.28 3H, OCOCH 3 2.29 (s, 3H, OCOCH 3 3.30 (dt, 1H, J 3.4 Hz, J 11.8 Hz, H3), 4.31 (ddd, 1H, J 1.4 Hz, 3.6 Hz, 10.5 Hz, H2); 4.56 (dd, 1H, J 10.5 Hz, 11.8 Hz, H2), 4.75 (dd, 1H, J 1.3 Hz, 3.2 Hz, H4), 6.66 (dd, 1H, J 2.3 Hz, 8.7 Hz, H6), 6.69 1H, J 2.3 Hz, H8), 7.08 2H, J 8.6 Hz, ArH), 7.26 1H, 8.4 Hz, H5), 7.29 2H, J 8.6 Hz ArH). 1 3 C NMR (CDC1 3 20.98 (OCOCH 3 43.52 64.10 66.46 110.08 114.09 121.82, 129.40 (ArCH), 131.10 Method B Palladium-on-charcoal 3.1 g) was added to a suspension of 4',7-diacetoxydaidzein (30.0 g) in absolute methanol (3600 ml) and the mixture was stirred at room temperature under a hydrogen atmosphere for 55 hours. The catalyst was removed by filtration through Celite and the filtrate was evaporated in vacuo to yield 4',7-diacetoxytetrahydrodaidzein (29.5g, A nuclear magnetic resonance spectrum revealed the product to be a clean 2:1 mixture of cis- and trans-4',7-diacetoxytetrahydrodaidzein.

Method C Palladium-on-charcoal 3.0 g) was added to a suspension of 4',7-diacetoxydaidzein (30.1g) in absolute methanol (3600 ml) and the mixture was stirred at room temperature under a hydrogen atmosphere for 15 hours. The catalyst was removed by filtration through Celite and the filtrate was evaporated in vacuo to yield 4',7-diacetoxytetrahydrodaidzein (28.5g, A nuclear magnetic resonance spectrum revealed the product to be a clean 1:1 mixture of cis- and trans-4',7-diacetoxytetrahydrodaidzein.

Method D Palladium-on-charcoal 100g) was added to a suspension of 4',7-diacetoxydaidzein (980g) in absolute methanol (100L) and the mixture was stirred at room temperature under a P:\WPDOCS\Hj0Spes\Hydrog AU divdoc12101/04 -21hydrogen atmosphere for 78 hours. The catalyst was removed by filtration through a ceramic candle filtratation apparatus and the filtrate was evaporated in vacuo to yield 4',7diacetoxytetrahydrodaidzein (820g, A nuclear magnetic resonance spectrum revealed the product to be a clean 2:1 mixture of cis- and trans-4',7-diacetoxytetrahydrodaidzein.

Example 14 Synthesis of 7-Acetoxy-4'-methoxyisoflavan-4-ol Palladium-on-charcoal 0.08g) was added to a suspension of 7-acetoxy-4'methoxyisoflavone (0.5g, 1.6 mmol) in absolute ethanol (400 ml) and the mixture was stirred at room temperature under a hydrogen atmosphere for 55 hours. The catalyst was removed by filtration through Celite and the filtrate was evaporated in vacuo to yield 7acetoxy-4'-methoxyisoflavan-4-ol (0.51g, 100%) in quantitative yield. A nuclear magnetic resonance spectrum revealed the product to be a clean 1:1 mixture of cis- and trans-7acetoxy-4'-methoxyisoflavan-4-ol.

The cis- and trans-isomers were able to be separated by fractional recrystallisation. A 1:1 mixture of cis- and trans-4',7-diacetoxytetrahydrodaidzein, prepared as above, was recrystallised three times from ethanol to yield pure trans-7-acetoxy-4'-methoxyisoflavan-4ol. The filtrate yielded predominantly cis-isomer.

For trans-7-Acetoxy-4'-methoxyisoflavan-4-ol; 1H NMR (CDC1 3 8 2.31 3H,

OCOCH

3 3.14 (dt, 1H, J 3.8 Hz, 8.6 Hz, H3), 3.82 3H, OCH 3 4.25 (dd, 1H, J 9.4 Hz, 11.3 Hz, H2); 4.37 (dd, 1H, J 4.1 Hz, 11.3 Hz, H2), 4.93 1H, J 7.8 Hz, H4), 6.63 1H, J 2.3 Hz, H8), 6.73 (dd, 1H, J 2.3 Hz, 8.3 Hz, H6), 6.93 2H, J 8.7 Hz, ArH), 7.19 2H, J 8.7 Hz, ArH), 7.51 1H, J 7.9 Hz, For cis-7-Acetoxy-4'-methoxyisoflavan-4-ol; 1H NMR (CDC1 3 5 2.30 3H, OCOCH 3 3.28 (dt, 1H, J 3.4 Hz, J 12.1 Hz, H3), 3.84 3H, OCH3), 4.36 (ddd, 1H, J 1.4 Hz, 3.8 Hz, 10.1 Hz, H2); 4.57 (dd, 1H, J 10.1 Hz, 11.3 Hz, H2), 4.75 (bs, 1H, H4), 6.58 1H, J 2.3 Hz, H8), 6.75 (dd, 1H, J 2.3 Hz, 8.3 Hz, H6), 6.96 2H, J 8.6 Hz, ArH), 7.25 2H, 8.6 Hz, ArH), 7.34 1H, J 8.3 Hz, P:%WPDOCS\Hj.Sp-s\Iy&.g AU div~do-I2/OI/04 22 Example 3 '-7-Diacetoxyisoflavan-4-ol Palladium-on-charcoal 0.03g) was added to a suspension of 3',7-diacetoxyisoflavanone (0.2g, 0.6 mmol) in methanol (50 ml) and the mixture was stirred at room temperature under a hydrogen atmosphere for 55h. The catalyst was removed by filtration through Celite and the filtrate was evaporated in vacuo to yield 3'-7-cliacetoxyisoflavan-4-ol in quantitative yield. A nuclear magnetic resonance spectrum revealed the product to be a clean 1 1 mixture of cis- and trans-3'-7-diacetoxyisoflavan-4-ol.

For trans-3'-7-diacetoxyisoflavan-4-ol; 1 H NMR (CDCl 3 6 2.31 and 2.32 (each s, 3H, OCOCHA) 3.17 (ddd, 1H, J 3.6 Hz, 8.6 Hz, 11.2 Hz, H13), 4.26 (dd, 1H, J 9.2 Hz, 11.6 Hz, 4.3 3 (in, I1H, 4.91 I1H, J 7.9 Hz, H14), 6.60-6.73 (in, ArH), 6.97-7.16 (in, ArH), 7.25-7.48 (in, ArH).

For cis-3'-7-diacetoxyisoflavan-4-ol; 1 H NMR (CDCl 3 8 2.30 and 2.31 (each s, 311, OCOCHA) 3.31 (dt, 1H, J 3.3 Hz, J 11.6 Hz, 4.31 (in, 111, 4.57 (dd, 1H, J 10.6 Hz, 11.9 Hz, 4.79 (bs, 1H, 6.60-6.73 (in, ArH), 6.97-7.16 (in, ArH), 7.25-7.48 (in, ArH).

Example 16 7-Acetoxy-3 '-methoxyisoflavan-4-ol Cis- and trans-7-acetoxy-3 '-methoxyisoflavan-4-ol was prepared from 7-acetoxy-3methoxyisoflavone (0.5g, 1.6 mmol) and palladium-on-charcoal 0.12g) in methanol (100 ml) by the method described above.

For trans-7-acetoxy-3'-methoxyisoflavan-4-ol; 1 H NMR (CDCl 3 8 2.28 3H, OCOCH- 3 3.15 (ddd, 1H, J 3.8 Hz, 8.3 Hz, 12.0 Hz, H3), 3.80 3H, OMe), 4.26 (dd, 1H, J 9.4 Hz, 11.3 Hz, 112); 4.32 (in, 1H, H2), 4.95 1H, J 7.9 Hz, 6.60-6.93 (in, ArH), 7.23-7.33 (in, AMH), 7.49 J 8.7 Hz, ArH).

P:\WPDOCS\Uiw\Specs\Hydrog AU div.doc-12101/04 23 For cis-7-acetoxy-3'-methoxyisoflavan-4-ol; 1 H NMR (CDC1 3 8 2.28 3H, OCOCHA) 3.30 (dt, 1H, J 3.3 Hz, J 11.7 Hz, H3), 4.31 (in, 1H, H2); 4.58 (dd, III, J 10.5 Hz, 11.7 Hz, H2), 4.81 (bs, 1H, H4), 6.60-6.93 (in, ArH), 7.23-7.33 (in, ArHl), 7.49 J 8.7 Hz, ArH).

Example 17 4',7-Diacetoxy-3 '-methoxyisoflavan-4-ol Cis- and trans-4'-7-diacetoxy-3'-methoxyisoflavan-4-ol was prepared from 4'-7-diacetoxy- 3'-methoxyisoflavone (0.25g, 0.7 mmol) and palladium-on-charcoal 0.06g) in methanol ml) by the method described above.

For trans-4'-7-diacetoxy-3'-methoxyisoflavan-4-ol; 1 H NMR (CDCl 3 6 2.29, 2.31 (each s, 3H, OCOCHA) 3.17 (ddd, 1 H, J 3.8 Hz, 8.7 Hz, 12.5 Hz, H3), 3.79 3H, OMe), 4.26 (dd, 1H, J 9.4 Hz, 11.3 Hz, H2); 4.32 (in, 1H, H2), 4.93 1H, J 7.9 Hz, H4), 6.62-6.73 (in, ArHl), 6.8 1-6.91 (in, ArH), 6.99-7.05 (in, ArH), 7.30 J 8.3 Hz, ArH), 7.48 J 9.0 Hz, ArH).

For cis-7-acetoxy-3'-inethoxyisoflavan-4-ol; IH NMR (CDC1 3 6 2.31,2.32 (each s, 3H, OCOCHA) 3.33 (dt, 1H, J 3.3 Hz, J 11.3 Hz, H3), 3.83 3H, OMe), 4.31 (in, 1H, H2); 4.58 1H, J 10.5 Hz, H2), 4.82 (bs, 1H, H4), 6.62-6.73 (in, ArH), 6.81-6.91 (in, ArH), 6.99-7.05 (in, ArH), 7.30 J 8.3 Hz, ArH), 7.48 J 9.0 Hz, ArH).

Example 18 7-Acetoxyisoflavan-4-ol Cis- and trans-7-acetoxyisoflavan-4-ol was prepared from 7-acetoxyisoflavone (0.4g, 1.4 nimol) and palladium-on-charcoal 0.09g) in absolute methanol (60 ml). in.p. Mass spectrum: ma/z 284 226 138 (100); 137 (58).

For trans-7-acetoxyisoflavan-4-ol; IH NMR (CDCl 3 6 2.29 3H, OCOCHA) 3.17 (in, I1H, H3), 4.27 1 H, J 10. 6 Hz, H2); 4.3 0 (mn, I1H, H2), 4.97 I1H, J 8.3 Hz, H4), 6.60-6.73 (in, ArH), 7.08 J 8.7 Hz, ArH), 7.23-7.37 (in, ArH), 7.49 J 8.7 Hz, ArH).

PAPDOCS\iwSp=c\Hyrog AU div.doc-12101/04 24 For cis-7-acetoxyisoflavan-4-ol; 1 H NMR (CDCl 3 5 2.30 3H, OCOCHA) 3.33 (dt, 1H, J 3.4 Hz, J 11.7 Hz, H3), 4.36 (in, 1H, H2); 4.62 1H, J 10.5 Hz, H2), 4.80 (bs, LH, H4), 6.60-6.73 (in, ArH), 7.08 J 8.7 Hz, ArH), 7.23-7.37 (in, ArH), 7.49 J 8.7 Hz, ArH).

Example 19 4',7,8-Triacetoxyisoflavan-4-oI Palladium-on-charcoal 0.07g) was added to a suspension of 4',7,8-triacetoxyisoflavone 1.3 mmol) in methanol (100 ml) and the mixture was stirred at room temperature under a hydrogen atmosphere for 55h. The catalyst was removed by filtration through Celite and the filtrate was evaporated in vacuo to yield 4',7,8-triacetoxyisoflavan-4-ol in quantitative yield. A nuclear magnetic resonance spectrum revealed the product to be a clean 1: 1 mixture of cis- and trans-4',7,8-triacetoxyisoflavan-4-ol. Mass spectrum: m/z 400 358 298 256 196 162 154 (100); 120 For trans-4',7,8-triacetoxyisoflavan-4-ol; 1 H NMR (CDCl 3 8 2.28, 2.29. 2.31 (each s, 3H, OCOCHA) 3.20 (in, 1 H, H3), 4.27 (dd, I1H, H2); 4.3 7 (in, I1H, H2), 4.93 I1H, J 7.9 Hz, H4), 6.78 1H, J 8.3 Hz, H8), 7.09 (in, ArH), 7.11-7.31 (in, ArH), 7.39 1H, J 8.7 Hz, ArH).

For cis-4',7,8-triacetoxyisoflavan-4-ol; IH NMR (CDCl 3 8 2.30, 2.31, 2.32 (each s, 3H, OCOCHA) 3.35 (in, lH, H3), 4.38 (in, lH, H2); 4.57 1H, J 10.6 Hz, H2), 4.75 (bs, 1H, H4), 6.78 1H, J 8.3 Hz, 7.09 (in, ArH), 7.11-7.3 1 (in, ArH), 7.39 1H, J 8.7 Hz, ArH).

Example 7,8-Diacetoxy-4'-methoxyisoflavan-4-ol 7,8-Diacetoxy-4'-methoxyisoflavan-4-ol was prepared from 7,8-dihydroxy-4'inethoxyisoflavone (0.4g, 1.1 iniol) in methanol (120 ml) using palladium-on-charcoal 0.08g) by the method described above.

For trans-7,8-diacetoxy-4-inethoxyisoflavan-4-ol; 1 H NMR (CDCl 3 8 2.29, 2.30 (each s, 3H, OCOCH 3 3.14 (ddd, I1H, J 3.9 Hz, 9.2H1z, 12.5 Hz, H3), 3.79 3H, OCHA) 4.24 (dd, P:\WPDOCS\1jwSpmc\Hydrog AU div.doc.12/01/04 1H, J 9.6 Hz, 11.2 Hz, 4.35 (in, 1H, 4.92 1H, J 7.8 Hz, H4), 6.78 1H, J 8.6 Hz, H6), 6.90 (in, ArH), 7.13 -7.22 (mn, ArH), 7.3 8 J 8.6 Hz, ArH).

For cis-7,8-diacetoxy-4'-methoxyisoflavan-4-ol; IH NMR (CDCl 3 6 2.30, 2.31 (each s, 3H, OCOCHA) 3.29 (dt, 114, J 3.0 Hz, J 12.0 Hz, H3), 3.80 3H, OCHA) 4.36 (in, III, H2); 4.57 1H, J 10.6 Hz, H2), 4.75 (bs, 1H, H4), 6.77 1H, J 8.6 Hz, H6), 6.90 (in, ArH), 7.13-7.22 (in, ArH), 7.38 J 8.6 Hz, ArH).

Example 21 4',7-Diacetoxy-8-methylisoflavan-4-ol Palladium-on-charcoal 0.12g) was added to a suspension of 4',7-diacetoxy-8methylisoflavone (1 .0g, 2.8 mmol) in methanol (200 ml) and the mixture was stirred at room temperature under a hydrogen atmosphere for 5 5h. The catalyst was removed by filtration through Celite and, the filtrate was evaporated in vacuo to yield 4',7-diacetoxy-8methylisoflavan-4-ol in quantitative yield, m.p. 135-37C. A nuclear magnetic resonance spectrum revealed the product to be a clean 1:1 mixture of cis- and trans-4',7-diacetoxy-8methylisoflavan-4-ol. Mass spectrum: 356 254 253 (100); 240 196 (37).

For trans-4',7-diacetoxy-8-methylisoflavan-4-ol; IH NMR (CDC1 3 8 2.02 3H, CHA) 2.30, 2.31 (each s, 3H, OCOCHA) 3.15 (ddd, III, J 3.8 Hz, 8.6 Hz, 11.7, H3), 4.27 (dd, 1H, J 9.4 Hz, 11. 3 Hz, H2); 4.3 9 (in, I1H, H2), 4.92 1 H, J 7.5 Hz, H4), 6.64 I1H, J 8. 0 Hz, H6), 7.06-7.32 (in, ArH).

For cis-4',7-diacetoxy-8-inethylisoflavan-4-ol; III NMR (CDCl 3 6 2.02 3H, CHA) 2.31, 2.32 (each s, 3H, OCOCHA) 3.28 (dt, 1H, J 3.4 Hz, J 11.7 Hz, H3), 4.40 (in, 1H, H2); 4.58 (dd, 1H, J 10. 1 Hz, 11.7 Hz, H2), 4.78 (bs, 1H, H14), 6.67 1H, J 8.0 Hz, 146), 7.06-7.32 (in, ArH).

P:\WPDOCS\Hjwv\Spems\Hydrog AU divdoc12/Ol/04 26 Example 22 3 ',7-Diacetoxy-8-methylisoflavan-4-ol 3',7-Diacetoxy-8-methylisoflavan-4-ol was prepared from 3 ',7-diacetoxy-8-methylisoflavone (0.25g, 0.7 mmol) in methanol (50 ml) using palladium-on-charcoal 0.06g) by the method described above.

For trans-3',7-diacetoxy-8-methylisoflavan-4-ol; 1 H NMR (CDCl 3 8 2.03 3H, CHA) 2.30, 2.32 (each s, 3H, OCOCHA) 3.18 (ddd, 1H, J 3.8 Hz, 8.3 Hz, 12.1 Hz, H3), 4.28 (dd, 1H, J 9.0 Hz, 10.9 Hz, H2); 4.39 (in, 1H, H12), 4.94 1H, J 8.7 Hz, H4), 6.65 lH, J 7.9 Hz, H6), 6.98-7.39 (in, ArH).

For cis-3',7-diacetoxy-8-methylisoflavan-4-ol; 1 H NMR (CDCl 3 5 2.05 3H, CHA) 2.30, 2.32 (each s, 3H, OCOCHA) 3.32 (dt, 1H, J 3.4 Hz, J 12.0 Hz, H3), 4.39 (in, 1H, H12); 4.59 (dd, III, J 10.5 Hz, 11.7 Hz, H2), 4.80 (bs, 111, H14), 6.68 1H, J 8.3 Hz, H16), 6.98-7.39 (in, ArH).

Example 23 7-Acetoxy-4'-methoxy-8-methylisoflavan-4-oI 7-Acetoxy-4'-methoxy-8-methylisoflavan-4-ol was prepared from 7-hydroxy-4'-methoxy-8methylisoflavone (0.25g, 0.8 mmol) in methanol (50 ml) using palladium-on-charcoal 0.08g) by the method described above. This hydrogenation reaction predominantly yielded the trans-isomer.

For trans-7-Acetoxy-4'-methoxy-8-methylisoflavan-4-ol; 1 H NMR (CDC1 3 8 2.02 3H, CHA) 2.32 3H, OCOCH 3 3.11 (ddd, III, J 3.8 Hz, 9.4 Hz, 12.1 Hz, H3), 3.80 3H, OMe), 4.25 (dd, 1H, J 9.4 Hz, 11.3 Hz, H2); 4.40 (dd, 1H, J 3.8 Hz, 12.6 Hz, H2), 4.92 (bd, 1H, H4), 6.67 1H, J 8.3 Hz, H6), 6.89 2H, J 8.7 Hz, ArH), 7.16 2H, J 8.7 Hz, ArH), 7.34 1H, J 8.3 Hz, PAWPDOCS\4- \Sp=c\Hydrog AU div.do-l12/01/f4 27 Example 24 4',7-Diacetoxy-3 '-methoxy-8-methylisoflavan-4-ol 4',7-Diacetoxy-3 t -methoxy-8-methylisoflavan-4-ol was prepared from 4',7-diacetoxy-3'methoxy-8-methylisoflavone (0.25g, 0.7 mmol) in methanol (50 ml) using palladium-oncharcoal 0.07g) by the method described above.

For trans-4',7-diacetoxy-3'-methoxy-8-methylisoflavan-4-ol; 1 H NMR (CDCl 3 8 2.05 (s, 3H, CHA) 2.30, 2.32 (each s, 3H, OCOCHA) 3.18 (ddd, 1H, J 3.8 Hz, 8.3 Hz, 11.4 Hz, H3), 3.79 3H, OMe), 4.28 (dd, 1H, J 9.0 Hz, 11.3 Hz, H2); 4.41 (in, 1H, H2), 4.93 1H, J 7.9 Hz, H4), 6.64 1H, J 7.9 Hz, H6), 6.75-6.92 (in, ArH), 7.00 1H, J 7.9 Hz, ArH), 7.16 114, J 8.3 Hz, ArH).

For cis-3',7-diacetoxy-8-methylisoflavan-4-ol; IH NMR (CDCl 3 8 2.05 3H, CHA) 2.30, 2.32 (each s, 3H, OCOCHA) 3.29 (dt, 1H, J 3.4 Hz, J 11.7 Hz, H3), 4.40 (in, 1H, H2); 4.59 1H, J 10.5 Hz, H2), 4.81 (bs, 1H, H4), 6.67 1H, J 7.9 Hz, H6), 6.75-6.92 (in, ArH), 7.03 1H, J 8.3 Hz, ArH), 7.33 1H, J 8.3 Hz, ArH).

Dehydration Reactions Example 4',7-Diacetoxydehydroequol (4',7-Diacetoxyisoflav-3-ene) Method A Distilled trifluoroacetic acid (0.1 ml) was added to a solution of cis- and trans-4',7diacetoxytetrahydrodaidzein 1 g) in dry distilled dichloromethane (15 ml) and the mixture was refluxed under argon. Progress of the reaction was monitored by thin layer chromatography and further 0.1 ml portions of trifluoroacetic acid were added. After refluxing for 4 hours, the reaction mixture was cooled and washed successively with saturated sodium bicarbonate solution, water and brine. The resulting organic phase was dried, concentrated, chromatographed and crystallised to yield 4',7-diacetoxydehydroequol as colourless prisms (0.034g, 1 H NMR (CDC1 3 d 6 -DMSO): 8 2.29 3H, OCOCHA) 2.31 3H, OCOCHA) 5.15 2H, H2), 6.62 (bs, IlH, H4), 6.65 (dd, I1H, J 2.1 PAWPDOCS\Hjw\Spes\Hydrog AU div.dc-12/01/04 -28- Hz 8.2 Hz, H6), 6.75 (bs, 1H, H8), 7.06 1H, J 8.2 Hz H5), 7.12 2H, J 8.2 Hz, ArH), 7.43 2H, J 8.2 Hz, ArH).

Method B p-Toluenesulfonic acid (0.02 g) was added to a solution of cis- and trans-4'7diacetoxytetrahydrodaidzein (0.1 g) in dry distilled dichloromethane (15 ml) and the mixture was refluxed under argon. Progress of the reaction was monitored by thin layer chromatography and after 4h at reflux, the reaction mixture was passed through a short column of silica gel and the eluant recrystallised from ethanol to yield 4',7diacetoxydehydroequol as colourless prisms (0.025 g, 26%).

Method C Phosphorous pentoxide (5g) was added with stirring to a solution of cis- and trans-4',7diacetoxytetrahydrodaidzein (1.0g) in dry dichoromethane (80 ml). The mixture was stirred at room temperature for 2 hours and filtered through a pad of Celite. The dichoromethane solution was concentrated and chromatographed on silica gel to yield 4',7diacetoxydehydroequol as colourless prisms (0.64g, 67%).

Example 26 7-Acetoxy-4'-methoxyisoflav-3-ene Phosphorus pentoxide (1.0g) was added with stirring to a solution of cis- and trans-7acetoxy-4'-methoxyisoflavan-4-ol (0.1g, 0.3 mmol) in dry dichloromethane (20 ml). The mixture was stirred at room temperature for 2 hours and filtered through a pad of Celite.

The organic phase was concentrated and chromatographed on silica gel to yield 7-acetoxy- 4'-methoxyisoflav-3-ene (0.04g, 1H NMR (CDC1 3 6 2.28 3H, OCOCH3), 3.83 3H, OCH3), 5.14 2H, H2), 6.61 (dd, 1H, J 2.3 Hz 6.4 Hz, H6), 6.65 1H, J 2.3 Hz, H8), 6.69 (bs, 1H, H4), 6.92 2H, J 9.0 Hz ArH), 7.04 1H, J 7.9 Hz, H5), 7.37 2H, J Hz, ArH).

Example 27 3',7-Diacetoxydehydroequol (3',7-Diacetoxyisoflav-3-ene) 3',7-Diacetoxyisoflav-3-ene was prepared from cis- and trans-3',7-diacetoxyisoflavan-4-ol (0.2g, 0.6 mmol) in dry dichloromethane (50 ml) using phosphorus pentoxide Yield: PAWPDOCS\Spms\Hytrog AU divdoc1201/04 29 (0.09g, 1 H NMR (CDCI 3 8 2.29 and 2.32 (each s, 3H, OCOCHA) 5.14 2H, H2), 6.61 I1H, J 2.3 Hz, H8), 6.66 (dd, I H, J 2.3 Hz 7.9 Hz, H6), 6.79 (bs, I1H, H4), 7.02-7.15 (in, 3H, ArH), 7.25-7.44 (in, 2H, ArH).

Example 28 7-Acetoxy-3'-methoxydehydroequol (7-Acetoxy-3'-methoxyisoflav-3-ene) 7-Acetoxy-3 '-methoxyisoflav-3 -ene was prepared from cis- and trans-7-acetoxy-3'methoxyisoflavan-4-ol (0.25g, 0.8 minol) in dry dichioromethane (20 ml) using phosphorus pentoxide Yield: (0.15g, 1 H NMR (CDC1 3 6 2.28 3H, OCOCHA) 3.85 311, OMe), 5.15 2H, H2), 6.60-6.67 (in, 2H, ArH), 6.78 (bs, 1H, H4), 6.84-7.06 (in, 4H, ArH), 7.3 5 I1H, J 8.6 Hz, ArH).

Example 29 4',7-Diacetoxy-3 '-methoxyisoflav-3-ene 4',7-Diacetoxy-3'-methoxyisoflav-3-ene was prepared from cis- and trans-4',7-diacetoxy-3methoxyisoflavan-4-ol (0.20g, 0.5 inmol) in dry dichioromethane (20 ml) using phosphorus pentoxide Yield: (0.llg, 58%).

Example 7-Acetoxyisoflav-3-ene 7-acetoxyisoflav-3-ene was prepared from cis- and trans-7-acetoxyisoflavan-4-ol (0.4g, 1.4 mmol) in dry dichioromethane (60 ml) using phosphorus pentoxide Yield: (0.2g, IH NMR (CDC1 3 6 2.29 3H, OCOCHA) 5.18 2H, H2), 6.61-6.67 (in, 2H, ArH), 6.79 (bs, I1H, H4), 7.07 I1H, J 7.9 Hz, H5), 7.23-7.45 (in, 5H, ArH).

Example 31 4',7,8-Triacetoxydehydroequol (4',7,8-Triacetoxyisoflav-3-ene) Phosphorus pentoxide (5.0g) was added with stirring to a solution of cis- and trans-4',7,8triacetoxyisoflavan-4-ol (0.5g, 1.3 inmol) in dry dichioromethane (50 ml). The mixture was stirred at room temperature for 2h and filtered through a pad of Celite. The resulting solution was concentrated and chromatographed on silica gel to yield 7,8triacetoxyisoflav-3-ene (0.3g, 1 H NMR (CDCl 3 8 2.29, 2.31, 2.32, (each s, 3H, PAWPDOCS\Spccs\Hydrog AU div.doc-12/01104 OCOCHA) 5.15 2H, H2), 6.72 1 H, J 8.3 Hz, H6), 6.75 (bs, I1H, H4), 6.97 1 H, J 7.9 Hz, H5), 7.12 2H, J 8.7 Hz ArH), 7.41 2H, J 8.7 Hz, ArH).

Example 32 7,8-Diacetoxy-4'-methoxydehydroequol (7,8-Diacetoxy-4-methoxyisoflav-3-ene) 7,8-Diacetoxy-4'-methoxyisoflav-3-ene was prepared from cis- and trans-7,8-diacetoxy-4'methoxyisoflavan-4-ol (0.4g, 1.1 mmol) in dry dichtoromethane (60 ml) using phosphorus pentoxide Yield: (0.18g, 1 H NMR (CDCI 3 8 2.29, 2.32 (each s, 3H, OCOCHA) 3.83 3H, OCHA) 5.14 2H, H2), 6.69 (bs, 1H, H4), 6.71 1H, J 8.3 Hz, H6), 6.90 2H, J 8.6 Hz ArH), 6.95 I1H, J 7.9 Hz, H5), 7.3 6 2H, J 8.6 Hz, ArH).

Example 33 4?,7..Diacetoxy..8-.methylisoflav.3-.ene Phosphorus pentoxide (3.0g) was added with stirring to a solution of cis- and trans-4',7diacetoxy-8-methylisoflavan-4-ol (0.55g, 1.5 mmol) in dry dichioromethane. (25 ml). The mixture was stirred at room temperature for 2h and filtered through a pad of Celite. The resulting solution was concentrated and chromatographed on silica gel to yield 4',7diacetoxy-8-methylisoflav-3-ene (0.25g, m.p. 140 0 C. 1 H NMR (CDC1 3 8 2.04 (s, 3H, CHA) 2.31, 2.32 (each s, 3H, OCOCHA) 5.16 2H, H2), 6.61 1H, J 8.3 Hz, H6), 6.75 (bs, I1H, H4), 6.94 I1H, J 8.3 Hz, H5), 7.13 2H, J 8.7 Hz, ArH), 7.45 2H, J 8.7 Hz, ArH). Mass spectrum: mlz 339 338 26); 296 254 253 (100).

Example 34 3 ',7-Diacetoxy-8-methylisoflav-3-ene 3',7-Diacetoxy-8-methylisoflav-3-ene was prepared from cis- and trans-3',7-diacetoxy-8methylisoflavan-4-ol (0.25g, 0.7 mmol) in dry dichioromethane (20 ml) using phosphorus pentoxide Yield: (0.13g, 54%) m.p. 116'C. 1 H NMR (CDC1 3 8 2.04 3H, CHA) 2.31, 2.32 (each s, 3H, OCOCHA) 5.16 2H, H2), 6.61 1H, J 8.3 Hz, H6), 6.79 (bs, lH, H4), 6.92 lH, J 8.3 Hz, ArH), 7.05 (dd, lH, J 2.0 Hz, 8.0 Hz, ArH), 7.15 1H, ArH), 7.26 lH, J 8.0 Hz, ArH), 7.37 1H, J 8.0 Hz, ArH). Mass spectrum: m/z 339 (M±1, 338 22); 296 254 P:\WPDOCS\ijw Sp=s\Hidrog AU div.dc- 12101/04 -31 Example 7-Acetoxy-4'-methoxy-8-methylisoflav-3-ene 7-Acetoxy-4'-methoxy-8-methylisoflav-3 -ene was prepared from cis- and trans-7-acetoxy- 4'-methoxy-8-methylisoflavan-4-ol (0.25g, 0.7 mmol) in dry dichioromethane (20 ml) using phosphorus pentoxide Yield: (0.11g, 46%) m.p. 107 0 C. 1 H NMR (CDCl 3 62.04 (s, 3H, CHA) 2.31 3H, OCOCHA) 3.83 3H, OMe), 5.16 2H, H2), 6.59 1H, J 8.3 Hz, H6), 6.68 (bs, 1H, 6.90 1H, J 8.3 Hz, H15), 6.93 2H, J 9.0 Hz, ArH), 7.37 (d, 2H, J 9.0 Hz, ArH). Mass spectrum: m/z 311 (M-I1, 310 68); 267 (100); 152 135 Example 36 4',7-Diacetoxy-3 '-methoxy-8-methylisoflav-3-ene 4',7-Diacetoxy-3 '-methoxy-8-methylisoflav-3-ene was prepared from cis- and trans-4'. 7diacetoxy-3'-methoxy-8-methylisoflavan-4-ol (0.25g, 0.6 mmol) in dry dichioromethane ml) using phosphorus pentoxide Yield: (0.14g, 58%) m.p. 123'C. IH NMR (CDCl 3 6 2.05 3H, CHA) 2.31. 2.32 (each s, 3H, OCOCHA) 3.88 3H, OMe), 5.16 (s, 2H1, H2), 6.61 I1H, J 8.3 Hz, H6), 6.73 (bs, IlH, H4), 6.94 I1H, J 8.3 Hz, H5), 6.97 (dd, 1H, J 1.9 Hz, 8.3 Hz, ArH), 7.03 1H, J 1.9 Hz, ArH), 7.05 1H, J 7.9 Hz, ArH).

Deprotection Reactions Example 37 Dehydroequol (Isoflav-3-ene-4',7-diol) Imidazole (0.09 g) was added to a suspension of 4',7-diacetoxydehydroequol (0.03 g, 0.09 mmol) in absolute ethanol (2.0 ml) and the mixture was refluxed for 45 min under argon.

The solution was concentrated under reduced pressure and the product was precipitated by addition of distilled water (10 ml). The mixture was left overnight in the fidge and filtered to yield dehydroequol. The crude product was reprecipitated from methanol by addition of benzene to yield dehydroequol as fluffy white solid (0.012 g, 'H NMR (CDC1 3 d 6 DMSO): 8 4.93 2H, H2), 6.26 (bs, 1 H, H4), 6.29 (dd, 1H, J 2.0 Hz, 8.2 Hz, H6), 6.50 (bs, 1H, H8), 6.73 2H, J 8.2 Hz, ArH), 6.76 2H, J 8.2 Hz, H5), 7.13 2H, J 8.2 Hz, ArH).

PA\WPDOCS\F~jw\Spe-\Hyiog AU div~do-12101/04 32 Example 38 7-Hydroxy-4'-methoxyisoflav-3-ene Imidazole (0.1 8g) was added to a suspension of 7-acetoxy-4'-methoxyisoflav-3-ene (0.06g, 0.02 mmol) in absolute ethanol (5.0 ml) and the mixture was refluxed for 45 minutes under argon. The solution was concentrated under reduced pressure and the product was precipitated by addition of distilled water (10 ml). The mixture was left overnight in the fridge and filtered to yield isoflav-3-ene. The crude product was recrystallised from methanol/benzene to yield 7-hydroxy-4'-methoxyisoflav-3-ene (0.034g, 'H NMR (CDC1 3 d 6 -DMSO): 8 3.74 3H, OCHA) 4.99 2H, 112), 6.21 1H, J 2.3 Hz, H18), 6.29 (dd, 1H1, J 2.3 Hz, 8.3 Hz, H6), 6.67 (bs, 111, H4), 6.85 111, J 8.3 Hz, H5), 6.86 (d, 2H, J 8.7 Hz, ArH), 7.33 2H, J 8.7 Hz, ArH).

Example 39 Isoflav-3-ene-3',7-diol Isoflav-3-ene-3',7-diol was prepared from 3',7-diacetoxyisoflav-3-ene (0.09g, 0.3 mmol) and imidazole (0.3g) in ethanol (2.0 ml) as described for isoflav-3-ene-4',7-diol. Yield: (0.04g, 111 NMIR (CDCl 3 d 6 -DMSO): 6 4.94 211, H2), 6.21 1H, J 2.0 Hz, H8), 6.29 (dd, 1H, J 2.3 Hz, 8.3 Hz, 116), 6.62 (in, 111, ArH), 6.64 (bs, 111, 114), 6.75-6.82 (in, 3H, ArH), 7.07 111, J 7.9 Hz, AMH), 8.99-9.17 (bs, 211, OH).

Example 3 '-Methoxylsoflav-3-ene-7-ol 3'-Methoxylsoflav-3 -ene-7-ol was prepared from 7-acetoxy-3 '-methoxyisoflav-3 -ene (0.1 g, 0.3 mmol) and imidazole (0.15g) in ethanol (2.0 ml) as described for isoflav-3-ene-4',7-diol.

Yield: (0.06g, 70%) m.p. 75'C. 111 NMR (CDC1 3 8 3.84 3H, OMe), 5.12 2H, H2), 6.38 111, J 2.0 Hz, 118), 6.40 (dd, 111, J 2.0 Hz, 8.3 Hz, 116), 6.76 (bs, 111, 114), 6.84 (dd, 111, J 1.9 Hz, 8.3 Hz, ArH), 6.95 (in, 311, ArH), 7.29 1H1, J 8.3 Hz, ArH).

P:\WPDOCS\Hjw\Specs\Hydrog AU divdoc-2/I/D4 33 Example 41 3 '-Methoxylsoflav-3-ene-4',7-diol 3 '-Methoxylsoflav-3 -ene-4',7-diol was prepared from 4',7-diacetoxy-3-methoxyisoflav-3-ene (0.11 ig, 0.3 mmol) and imidazole (0.3g) in ethanol (2.0 ml) as described for isoflav-3-ene- 4',7-diol. Yield: (0.06g, IH NMR (d6-acetone): 5 3.90 3H1, OMe), 5.07 2H, H2), 6.31 1H, J 2.3 Hz, H8), 6.40 (dd, 1H, J 2.3 Hz, 8.3 Hz, 6.78 (bs, 1H, 6.83 1H, J 8.3 Hz, ArH), 6.92 (dd, 2H, J 1.9 Hz, 8.3 Hz, ArH), 7.14 IIH, J 1.9 Hz, ArH), 7.04,7.63 (each s, 1H, OH).

Example 42 Isoflav-3-ene-7-ol Isoflav-3-ene-7-ol was prepared from 7-acetoxyisoflav-3-ene (0.2g, 0.75 mmol) and imidazole (0.24g) in ethanol (3.5 ml) as described for isoflav-3-ene-4',7-diol. Yield: 1 1g, 66%) m.p. 120'C. 1 H NMR (d 6 -DMSO): 8 5.07 2H, H2), 6.24 1H, J 2.2 Hz, H18), 6.33 (dd, 1H, J 1.9 Hz, 7.9 Hz, H6), 6.96 1H, J 7.9 Hz, H5), 7.00 IIH, H4), 7.26-7.47 (in, 5H, ArH), 9.65 (bs, 1H, OH). Mass spectrum: m/z 224 (in, 223 (100), 175 (28); 165 147 (41).

Example 43 Isoflav-3-ene-4',7,8-triol Imidazole (0.6g) was added to a suspension of 7,8-triacetoxyisoflav-3-ene (0.1 6g, 0.4 mmol) in absolute ethanol (5.0 ml) and the mixture was refluxed for 45 min under argon.

The solution was concentrated under reduced pressure and the product was precipitated by addition of distilled water (10 ml). The mixture was left overnight in the fridge and filtered to yield isoflav-3-ene. The crude product was recrystallised from methanol/benzene to yield Jsoflav-3-ene-4', 7-8-triol (0.08g, 1 H NMR (CDCl 3 d 6 -DMSO): 6 4.97 2H, H12), 6.30 1H, J 8.2 Hz, 6.36 1H, J 8.3 Hz, H15), 6.55 (bs, 1H, 6.72 1H, J 8.7 Hz, ArH), 7.17 2H, J 8.7 Hz, ArH).

P:\WPDOCS\Hjw\Specs\HydrOg AU di~doc-12101/04 -34- Example 44 4'-Methoxyisoflav-3-ene-7,8-diol 4'-Methoxyisoflav-3 -ene-7,8-diol was prepared from 7,8-diacetoxy-4-methoxyisoflav-3-ene (0.1 5g, 0.4 mmol) and imidazole (0.4g) in ethanol (1.6 mil) as described for isoflav-3-ene- 4',7-8-triol. Yield: (0.73g, 1 11 NMR (CDCl 3 d 6 -DMSO): 8 3.83 3H, OCHA) 5.15 2H, H12), 6.51 1 H, J 8.3 Hz, H6), 6.58 1H, J 8.3 Hz, H5), 6.68 (bs, lH, H4), 6.92 1H, J 8.7 Hz, ArH), 7.35 2H, J 8.7 Hz, ArHl). Mass spectrum: m/z 270 256 (100); 255 239 181 Example 8-Methylisoflav-3-ene-4',7-diol Imidazole (0.6g) was added to a suspension of 4',7-diacetoxy-8-methylisoflav-3-ene (0.25g, 0.7 mmol) in absolute ethanol (5.0 ml) and the mixture was refluxed for 45 min under argon.

The solution was concentrated under reduced pressure and the product was precipitated by addition of distilled water (10 ml). The mixture was left overnight in the fridge and filtered to yield isoflav-3-ene. The crude product was recrystallised from methanol/benzene to yield 8-methylisoflav-3-ene-4',7-diol (0.13g, m.p. 190-93 0 C IH NMR (CDC1 3 d 6 DMSO): 8 1.94 3H, CH 3 4.98 2H, H2), 6.32 1H, J 7.9 Hz, H6), 6.58 (bs, 1H, H4), 6.67 (bd, 1H, H5), 6.72 2H, J 8.7 Hz, ArH), 7.21 (bd, 2H, ArH). Mass spectrum: m/z 255 254 79); 253 (100); 161 (32).

Example 46 8-Methylisoflav-3-ene-3 ',7-diol 8-Methylisoflav-3-ene-3 ',7-diol was prepared from 3 ',7-diacetoxy-8-methylisoflav-3-ene (0.12g, 0.4 mmol) and imidazole (0.3g) in ethanol (2.5 ml) as described for 8-methylisoflav- 3-ene-4r,7-dio1. Yield: (0.07g, 77%) m.p. 130'C. 1 H NMR (CDCl 3 d 6 -DMSO): 6 1.95 (s, 3H, CHA) 4.98 2H, H2), 6.34 1H, J 8.0 Hz, H6), 6.61-6.94 (in, 5H, ArH), 7.08 (bt, 1H, ArH). Mass spectrum: ml/z 254 100%); 253 161 P:\WPDOCS\Hjw\ASpems\Hydfrog AU div.doc-12101,04 Example 47 4'-Methoxy-8-methylisoflav-3-ene-7-ol 4'-Methoxy-8-methylisoflav-3 -ene-7-ol was prepared from 7-acetoxy-4'-methoxy-8methylisoflav-3-ene (0.11ig, 0.3 mmol) and imidazole (0.14g) in ethanol (1.5 ml) as described for 8-methylisoflav-3-ene-4',7-diol. Yield: (0.05g, 53%) m.p. 103 0 C. IH NMR (d 6 -acetone): 6 1.99 3H1, CHA) 3.81 3H, OMe), 5.11 2H, H2), 6.43 1H, J 8.3 Hz, H16), 6.77 (bs, 11H, H14), 6.80 1H, J 8.3 Hz, H5), 6.95 2H, J 9.0 Hz, ArH), 7.44 (d, 2H1, J 9.0 Hz, ArH). Mass spectrum: 282 267 (100); 268 134 (52).

Example 48 3 '-Methoxy-8-methylisoflav-3-ene-4 ',7-diol 3'-Methoxy-8-methylisoflav-3 -ene-4',7-diol was prepared from 4',7-diacetoxy-3 '-methoxy-8methylisoflav-3-ene (0.21ig, 0.6 mmol) and imidazole (0.52g) in ethanol (4 ml) as described for 8-methylisoflav-3-ene-4',7-diol. Yield: (0.1g, IH NMR (CDCl 3 8 2.14 3H1, CHA) 3.94 3H, OMe), 5.11 2H, H2), 6.42 1H, J 8.3 Hz, H6), 6.64 (bs, 1H, ArH), 6.80 I1H, J 7.9 Hz, ArH), 6.94 (in, 2H, ArH), 7.12 (in, I1H, ArH), 7.26, 7.70 (each bs, I1H,

OH).

Deprotection Reactions Example 49 cis- and trans-Tetrahydrodaidzein Imidazole (0.2 g) was added to a suspension of 4',7-diacetoxytetrahyrodaidzein (0.10 g, 0.3 mmol) in absolute ethanol (4.0 ml) and the mixture refluxed for 45 min under argon. The solution was concentrated under reduced pressure and distilled water (10 ml) was added.

The mixture was left overnight in the fidge and the crystalline product was filtered to yield cis- and trans-tetrahydrodaidzein (0.06 g, Example trans-Tetrahydrodaidzein (trans-4',7-Dihydroxyisoflavan-4-ol) Trans-4',7-dihydroxyisoflavan-4-ol was prepared from trans-4',7-dihydroxyisoflavan-4-ol and imidazole in ethanol as described for cis- and trans-tetrahydrodaidzein. 1 H NMR (d 6 P:\WPDOCS\Hjw\Spems\Hydrog AU div.doc-12101104 36 acetone): 8 2.99 (ddd, 1H, J 3.4 Hz, 6.8 Hz, 10.6 Hz, H3), 4.13 (dd, 1H, J 7.0 Hz, 10.9 Hz, H2); 4.24 (dd, 1H, J 3.8 Hz, 11.3 Hz, H12), 4.70 1H, J 6.4 Hz, H4), 6.20 1H, J 2.6 Hz, H8), 6.3 8 (dd, I1H, J 2.3 Hz, 8.3 Hz, H6), 6.71 2H, J 8.7 Hz, ArH), 7.04 2H, J 8.7 Hz, ArH), 7.18 I1H, J 8.3 Hz, Example 51 cis- and trans-7-Hydroxy-4 '-methoxyisoflavan-4-ol Imidazole (0.4 g) was added to a suspension of 7-acetoxy-4'-methoxyisoflavan-4-ol (0.20 g, 0.6 mmol) in absolute ethanol (8.0 ml) and the mixture refluxed for 45 minutes under argon.

The solution was concentrated under reduced pressure and distilled water (10 ml) was added. The mixture was left overnight in the fridge and the crystalline product was filtered to yield cis- and trans-7-hydroxy-4'-methoxyisoflavan-4-ol 16g, 79%).

Example 52 cis- and trans-7-Hydroxyisoflavan-4-ol 7-hydroxyisoflavan-4-ol was prepared from 7-acetoxyisoflavan-4-ol (0.14g, 0.5 mmol) and Imidazole 17g) in ethanol (3.0 ml) as described for cis- and trans-tetrahydrodaidzein.

For trans-7-hydroxyisoflavan-4-ol; IH NMR (d6-acetone): 8 3.08 (in, 1H, H3), 4.00 1H, J 10.2 Hz, H2); 4.30 (in, 1H, 112), 4.81 1H, J 7.2 Hz, H4), 6.25-6.43 (mn, ArH), 6.89 J 8.3 Hz, ArH), 7.07 J 8.3 Hz, ArH), 7.22-7.64 (in, ArH).

For cis-7-acetoxyisoflavan-4-ol; IH NMR (d6-acetone): 8 3.20 (in, 1H, H3), 4.36 (in, 1H, 112); 4.57 (dd, III, J 10.2 Hz, 12.0 Hz, H12), 4.68 (bs, 1H, H4), 6.25-6.43 (in, ArH), 6.89 J 8.3 Hz, ArH), 7.07 J 8.3 Hz, ArH), 7.22-7.64 (in, ArH).

Example 53 cis- and trans-4',7-Dihydroxy-8-methylisoflavan-4-ol 4',7-Dihydroxy-8-inethylisoflavan-4-ol was prepared from 4',7-diacetoxy-8inethylisoflavan-4-ol (0.4g, 1. 1 inol) and imidazole Og) in ethanol 0 ml) as described for cis- and trans-tetrahydrodaidzein.

P:\WPDOCS\Hj \ASpccs\Hi*og AU div~dc- 12/01/04 -37- For trans-4',7-dihydroxy-8-methylisoflavan-4-ol; III NMR (d6-acetone): 8 1.98 3H1, CHA) 2.98 (ddd, 1H, J 3.8 Hz, 10.9 Hz, 12.0 Hz, H3), 4.18 (in, 1H, H2); 4.27 (in, 1H, H2), 4.75 1H, J 6.4 Hz, H4), 6.42 (in, ArH), 6.75 (in, ArH), 7.05-7.19 (in, ArH), 7.66 (bs,

OH).

For cis-4',7-dihydroxy-8-methylisoflavan-4-ol; IH NMR (d6-acetone): 8 1.99 3H1, CHA) 3.01 (dt, 1H, J 3.4 Hz, 12.0 Hz, H3), 4.31 (in, 1H, H2); 4.52 (dd, 1H, J 10.2 Hz, 12.0 Hz, H12), 4.60 (bs, I1H, H4), 6.42 (in, ArH), 6.75 (in, ArH), 7.05-7.19 (in, ArH), 7.66 (bs, OH).

Example 54 trans-7-Hydroxy-4'-methoxy-8-methylisoflavan-4-oI trans-7-Hydroxy-4'-methoxy-8-methylisoflavan-4-ol was prepared from trans-7-acetoxy-4'methoxy-8-methylisoflavan-4-ol (0.23g, 0.7 mmol) and imidazole (0.28g) in ethanol (2.1 ml) as described for cis- and trans-tetrahydrodaidzein. m.p. 162'C. Mass spectrum: 285 M, 268 151 135 134 (100); 119 1 H NMR (d6-acetone): 8 1.97 (s, 3H, CHA) 3.00 (ddd, LH, J 3.4 Hz, 7.2 Hz, 10.2 Hz, H13), 3.72 3H, OMe), 4.20 (dd, 1H, J Hz, 10.9 Hz, H2); 4.27 (in, 1H, H2), 4.73 1H, J 6.8 Hz, H4), 6.45 111, J 8.3 Hz, 116), 6.8 5 2H, J 8.6 Hz, ArH), 7. 10 I1H, J 8.7 Hz, H5), 7.18 2H, J 8.6 Hz, ArH).

Hydrojeenation Reactions:- Iso flavone cis-Isoflavan-4-ol Example cis-4',7-Diacetoxyisoflavan-4-ol Platinuin(IV)oxide (Adam's catalyst) (0.05g) was added to a solution of of 4',7diacetoxyisoflavanone (0.25g, 0.7 inmol) in ethyl acetate (40 ml) and the mixture was stirred at room temperature under a hydrogen atmosphere for 55h. The catalyst was removed by filtration through Celite and the filtrate was evaporated in vacuc to yield predominantly the cis-4',7-diacetoxyisoflavan-4-ol.

For cis-4',7-diacetoxyisoflavan-4-ol; IH NMR (CDCl 3 6 2.28 3H, OCOCH 3 2.29 (s, 3H1, OCOCHA) 3.30 (dt, 1H, J 3.4 Hz, J 11.8 Hz, H3), 4.31 (ddd, IIH, J 1.4 Hz, 3.6 Hz, 10.5 Hz, H2); 4.56 (dd, 1H, J 10.5 Hz, 11.8 Hz, H2), 4.75 (dd, 1H, J 1.3 Hz, 3.2 Hz, H4), 6.66 P:\WPDOCS\Hjw\pmHiydrog AU div.dc-12/01/04 -38- (dd, 1H, J 2.3 Hz, 8.7 Hz, H6),6.69 1H, J 2.3 Hz, H8), 7.08 2H, J 8.6 Hz, ArH), 7.26 1H, 8.4 Hz, H5), 7.29 2H, J 8.6 Hz, ArH). 13 C NMR (CDC13): 5 20.98 (OCOCH 3 43.52 64.10 66.46 110.08 114.09 121.82, 129.40 (ArCH), 131.10 Hvdrogenation Reactions:- Isoflavone Isoflavan-4-one Example 56 4',7-Diacetoxydihydrodaidzein (4',7-Diacetoxyisoflavan-4-one) Palladium-on-charcoal 0.02g) was added to a solution of 4',7-diacetoxydaidzein (0.50g, mmol) in ethyl acetate (80 ml) and the mixture was stirred at room temperature under a hydrogen atmosphere for 72h. The catalyst was removed by filtration through Celite and the resulting filtrate was evaporated in vacuo. The residue was recrystallised from ethanol to yield 4',7-diacetoxydihydrodaidzein (0.40g, 80%) as colourless plates. 'H NMR (CDCl 3 8 2.29 3H, OCOCH 3 2.23 3H, OCOCH 3 3.98 (dd, 1H, J 6.2 Hz, 8.2 Hz, H3), 4.69 2H, H2), 6.78-6.82 2H, ArH), 7.08 2H, J 9.2 Hz, ArH), 7.30 2H, J 8.2 Hz, ArH), 7.98 1H, J 9.2 Hz Hydrogenation Reactions:- Isoflavan-3-ene Isoflavan Example 57 O,O-Diacetylequol Palladium-on-charcoal 0.02g) was added to a solution of 4',7-diacetoxyisoflav-3-ene (0.20g, 0.06 ml) in ethyl acetate (60 ml) and the mixture was stirred at room temperature under a hydrogen atmosphere for 24h. The catalyst was removed by filtration through Celite and the resulting filtrate was evaporated in vacuo. The residue was recrystallised from dichloromethane/light petroleum to yield O,0-diacetylequol (0.15g, 'H NMR (CDC1 3 6 2.29 3H, OCOCH 3 2.31 3H, OCOCH 3 3.00 2H, J 8.3 Hz, H4), 3.25 1H, H3), 4.00 1H, H2), 4.34 (dd, 1H, J 3.4 Hz, 10.9 Hz, H2), 6.61 J 7.5 Hz, 1H, ArH), 6.60 1H, ArH), 7.06 (bd, 3H, J 8.3 Hz, ArH), 7.24 3H, J 8.3 Hz, ArH).

I

P:\WPDOCS\Hjw\Specs\Hydrog AU div.doc-12/01/04 -39- Deprotection Reactions Example 58 Dihydrodaidzein (4',7-Dihydroxyisoflavan-4-one) Imidazole (0.63g) was added to a suspension of 4',7-diacetoxydihydrodaidzein (0.26g, 0.08 mmol) in absolute ethanol (5.0 ml) and the mixture was refluxed for 45 min under argon.

The solution was concentrated under reduced pressure and distilled water (10 ml) was added to the residue. The mixture was left overnight in the fridge and the resulting precipitate was filtered. The crude product was recrystallised from ethyl aceate/dichloromethane to yield 4',7-diacetoxydihydrodaidzein (0.14g, 71%) as a white powder. 'H NMR (d 6 -acetone): 6 3.83 1H, J 7.2 Hz, H3), 4.60 2H, J 6.2 Hz, H2), 6.39 1H, J 2.0 Hz, H8), 6.55 (dd, 1H, J 8.2, J 2.0 Hz, ArH), 6.80 2H, J 8.2 Hz, ArH), 7.10 1H, J 8.2 Hz, ArH), 7.74 (d, 1H, J 8.2 Hz, Example 59 Equol (4',7-Dihydroxyisoflavan) Imidazole 0.5g) was added to a suspension of O,0-diacetylequol (0.15g, 0.08 mmol) in absolute ethanol (5.0 ml) and the mixture was refluxed for 45 min under argon. The solution was concentrated under reduced pressure and distilled water (10 ml) was added to the residue. The mixture was left overnight in the fridge and the resulting product was filtered to yield equol (0.09g, 80%) as a white powder. 'H NMR (d 6 -DMSO): 8 2.70 2H, J 9.2 Hz, H4), 2.92 1H, H3), 3.73 1H, J 10.3 Hz, H2), 4.06 (dd, 1H, J 3.0 Hz, 11.2 Hz, H2), 6.16 (bs, 1H, ArH), 6.21 (bd, J 8.2 Hz, 1H, ArH), 6.63 2H, J 8.2 Hz, ArH), 6.69 1H, J 8.2 Hz, ArH), 6.87 2H, J 8.2 Hz, ArH) Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the invention includes all such variations and modifications. The inventions also includes all of the steps, features, compositions and compounds referred to or indicated in the specification, individually or collectively, and any and all combinations of any two or more of said steps or features.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

Claims

2. A method of claim 1, wherein kilogram quantities of the compound of formula II are prepared.
3. A method of claim 1 or claim 2, wherein the reduction catalyst is 5% or 10% palladium on activated carbon.
4. A method of any one of claims 1 to 3, wherein the solvent is absolute methanol or absolute ethanol. A method of any one of claims 1 to 4, wherein the compounds of formula II have the following substituents R, is hydroxy, OR 9 or OC(O)R 9 R 2 R 3 R4, R 5 R 6 and R 7 are independently hydrogen, hydroxy, OR), OC(O)R 9 alkyl, aryl or arylalkyl, R 8 is hydrogen, and R 9 is methyl, ethyl, propyl, isopropyl or trifluoromethyl.
6. A method of any one of claims 1 to 5, wherein the compound of formula II is 4',7- diacetoxyisoflavan-4-ol, 7-acetoxy-4'-methoxyisoflavan-4-ol, 3',7-diacetoxyisoflavan-4-ol or 7-acetoxy-3'-methoxyisoflavan-4-ol. P XWkPDOCS\Hj Apcps\Hydrog AU 2spad d.26/03/2007 -42-
7. A method for the preparation of an oxy-substituted isoflav-3-ene compound of formula III R7 R 1, O R 81 I R6 R/ R 2 R3 wherein RI, R 2 R 3 R 4 R 5 R6, R 7 and Rs are independently hydrogen, hydroxy, OR 9 OC(O)R 9 OS(O)R 9 alkyl, haloalkyl, aryl, arylalkyl, thio, alkylthio, amino, alkylamino, dialkylamino, nitro, or halo, and R 9 is alkyl, haloalkyl, aryl, arylalkyl or alkylaryl, and at least one of R 1 R 2 R 3 R 4 R 5 R6 and R7 is an oxy substituent selected from hydroxy, OR 9 and OC(O)R,, including the steps of: protecting the free hydroxy groups of an isoflavone compound of formula I R7 R1 Oy R8 RR4 (1) 0 R2 R OR2 R 3 wherein RI, R2, R3, R4,5, R, R7 and R 8 are as defined above and at least one of RI, R 2 R3, R 4 R R6 and R 7 is a free hydroxy group, to prepare a protected isoflavone compound, where the at least one free hydroxy group of RI, R 2 R 3 R4, R 5 R and R 7 is protected as OR 9 or OC(O)Rg; hydrogenating the protected isoflavone compound of step to prepare an oxy- substituted isoflavan-4-ol compound of formula II P \WPIXOCS\IljwSpccs\Hydrog AU 2spj doc26/03/2007 -43 R 7 R1, R8 q J4(II) R 5 OH R 3 R2 wherein RI, R 2 R 3 R 4 R 5 R6, R 7 and R 8 are as defined above, and where the at least one of RI, R 2 R 3 R 4 R 5 R 6 and R 7 is OR 9 or OC(O)R, wherein the hydrogenation step is performed with hydrogen in the presence of a reduction catalyst selected from palladium on activated carbon and a solvent selected from methanol and ethanol; dehydrating the compound of formula II to prepare the isoflav-3-ene compound of formula III; and optionally deprotecting the isoflav-3-ene compound from part by hydrolysis of the OC(O)R 9 protecting groups to prepare the isoflav-3-ene compound of formula III, where the at least one of R 1 R 2 R 3 R 4 R 5 R 6 and R 7 is hydroxy.
8. A method of claim 7, wherein the dehydration step is effected with trifluoroacetic acid, p-toluenesulphonic acid or phosphorus pentoxide.
9. A method of claim 7 or claim 8, wherein the reduction catalyst is 5% or 10% palladium on activated carbon. A method of any one of claims 7 to 9, wherein the solvent is absolute methanol or absolute ethanol.
11. A method of any one of claims 7 to 10, wherein the compounds of formula Ill have the following substituents RI is hydroxy, OR 9 or OC(O)R 9 R 2 R 3 R 4 R 5 R 6 and R 7 are independently hydrogen, hydroxy, ORg, OC(O)R 9 alkyl, aryl or arylalkyl, Rg is hydrogen, and P \WPDOCS\IHjwSpcsH~qfrog AU 2spA do.2610.JZOO7 44 R 9 is methyl, ethyl, propyl, isopropyl or trifluoromethyl.
12. A method of claim 11, wherein and the compound of formula III is 4',7- diacetoxyisoflav-3-ene, 4',7-dihydroxyisoflav-3-ene, 7-acetoxy-4'-methoxyi soflav-3-ene, 7- hydroxy-4'-methoxyisoflav-3-ene, 3',7-diacetoxyisoflavan-4-ol, 3',7-dihydroxyisoflav-3-ene, 7-acetoxy-3'-methoxyisoflavan-4-ol or 7-hydroxy-3'-methoxyi soflav-3-ene.
13. An isoflavan-4-ol compound of formnula 11 prepared by a method of any one of claims I to 6.
14. An isoflav-3-ene compound of formula III prepared by a method of any one of claims 7 to 12. A compound of formulae II or 111, wherein R, is hydroxy, OR 9 OC(O)R 9 thio, alkylthio, or halo, R 2 R 3 R 4 R 5 R 6 R 7 and R 8 are independently hydrogen, hydroxy, OR 9 OC(O)R 9 OS(O)R 9 alkyl, aryl, thio, alkylthio or halo, and R 9 is alkyl, fluoroalkyl or arylalkyl with the proviso that at least one of R 5 R 6 and R 7 is not hydrogen, or when R 5 R 6 and R 7 are all hydrogen, then R 3 is hydroxy, OR 9 OC(O)R 9 OS(O)R 9 alkyl, aryl, thio, alkylthio or halo, and provided that the compound 2',7-Dihydroxy-4',8-dimethoxyisoflavan-3-ene is specifically excluded.
16. A compound of claim wherein R 1 is hydroxy, OR 9 or OC(O)R 9 R 2 and R 3 are independently hydrogen, hydroxy, OR 9 or OC(O)R 9 7- P \WPDO(CS\Hj, Swsc\)pda AU 2spi dm-26103/2007 R(4, R 5 R 6 and R 8 are hydrogen, R 7 is hydroxy, OR 9 OC(O)R 9 alkyl, aryl or halo, and is methyl, ethyl, propyl, isopropyl, trifluoromethyl or benzyl.
17. A compound ofelaim 16, wherein R 1 is hydroxy, OR 9 or OC(O)R 9 R 2 and R 3 are independently hydrogen, hydroxy, ORO or OC(O)R 9 R 5 is OR 9 OC(O)R 9 alkyl, aryl or halo, R 4 R 6 R7,, and R8 are hydrogen, and R 9 is methyl, ethyl, propyl, isopropyl, trifluoromethyl or benzyl.
18. A compound of formula I selected from the group consisting of: 4',7,8-Triacetoxyisoflavone 7,8-Diacetoxy-4'-methoxyisoflavone 4',7-Diacetoxy-8-methylisoflavone 3',7-Diacetoxy-8-methylisoflavone 7-Acetoxy-4'-methoxy-8-methylisoflavone 4',7-Diacetoxy-3 '-methoxy-8-methylisoflavone 3',7-Diacetoxyisoflavone 7-Acetoxy-3'-methoxyisoflavone
19. A compound of formula 11 selected from the group consisting of: 4',7,8-Triacetoxyisoflavan-4-ol 7,8-Diacetoxy-4'-methoxyisoflavan-4-oI 4',7-Diacetoxy-8-methylisoflavan-4-oI 3',7-Diacetoxy-8-methylisoflavan-4-oI 7-Acetoxy-4'-methoxy-8-methylisoflavan-4-oI 4',7-Diacetoxy-3'-methoxy-8-methylisoflavan-4-oI ,7-Tri acetoxyisoflavan-4-ol 3',7-Diacetoxyisoflavan-4-ol 7-Acetoxy-3'-methoxyisoflavan-4-oI PAWPDOCSNHjiASpc-\Hyfrg AU 2s;. 260312007 46 4',7,8-Trihydroxyisoflavan-4-ol 7,8-Dihydrox y-4'-methoxyiso flavan-4-ol 4',7-Dihydroxy-8-methylisoflavan-4-ol 3',7-Dihydroxy-8-methylisoflavan-4-ol 7-Hydroxy-4'-methoxy-8-methylisoflavan-4-oI 4',7-Dihydroxy-3'-methoxy-8-methylisoflavan-4-ol 4',5,7-Trihydroxyisoflavan-4-ol 3',7-Dihydroxyisoflavan-4-ol 7-Hydroxy-3 '-methoxyisoflavan-4-ol A compound of formula III selected from the group consisting of: 4',7,8-Triacetoxyisoflav-3-ene 7,8-Diacetoxy-4'-methoxyisofiav-3-ene 4',7-Diacetoxy-8-methylisoflav-3-ene 3',7-Diacetoxy-8-methylisoflav-3-ene 7-Acetoxy-4'-methoxy-8-methylisoflav-3-ene 4',7-Diacetoxy-3'-methoxy-8-methylisoflav-3-ene 4',5,7-Triacetoxyisoflav-3-ene 3',7-Diacetoxyisoflav-3-ene 7-Acetoxy-3'-methoxyisoflav-3-ene Iso fl av-3 -ene-4', 7,8 -trio I 4'-Methoxyisoflav-3-ene-7,8-diol 8-Methylisoflav-3-ene-4',7-diol 8-Methylisoflav-3-ene-3',7-diol 4'-Methoxy-8-methylisoflav-3-ene-7-ol 3'-Methoxy-8-methylisoflav-3-ene-4',7-dioI Isoflav-3-ene-4',5,7-triol Iso flav-3 -ene-3 ',7-dio I 3 t -Methoxyisoflav-3-ene-7-ol
21. Methods for the preparation of a compound of formulae 11 or 111, compounds obtainable by said methods and/or compositions containing same substantially as herein described with reference to the Examples.