FI89913B - Naphthisoxazolcarboxylic acid derivative and method for production thereof - Google Patents

Description

! 89913

Naphthisoxazolecarboxylic acid derivatives and process for their preparation

Divided by application 861508 5

This invention relates to intermediates of formula X.

R1

10 R

'' COOR 3

OR

as further defined below, and a method for their preparation. These compounds can be used as intermediates in the overall synthesis of epipodophyllotoxin and related compounds.

Epipodophyllotoxin (I) is a 4-hydroxy epimer of podophyllotoxin (II), a known lignan-lactone isolated from several Podophyllum species and having potent cytotoxic activity. Numerous other related compounds are known which have a typical aryl-tetralin ring structure, which either occur in nature or are derivatives of some naturally occurring compounds; some of these compounds have antitumor activity, while others are useful for conversion to compounds having such activity. The structural formulas of epipodophyllotoxin (I) and podophyllotoxin (II) are shown below.

2 P9913

OH

5 'ώ' ”ΟΗ, ο'ΊΤ ΧΙΙ3 och3 10 Epipodophyllotoxin (I) oh 15 ^ (f o [* Ίΐ

CH30 OCH-J

OCH

20

Podophyllotoxin (II)

Many of these compounds, including podophyllotoxin, have now been prepared by total synthesis.

In J. Org. Chem. 31, 4004-4008 (1966), 25 W.J. Gensler and C.D. Gatsonis describe the overall synthesis of podophyllotoxin (II), the final step of which is epimerization by treatment of the enolate of the O-tetrahydropyranyl derivative of picropodophylline. However, this epimerization does not proceed to completion, and requires separation of a mixture of about 45:55 podophyllotoxin (II) and picropodophylline (III). The structural formula of picropodophyllin (III), which is the cis-lactone isomer of podophyllotoxin (II), is 3. 5 ·} 9 913

OH

ch3o / n <^^ och3 OCH3 ^ Picropodophyllin (III)

In J. Am. Chem. Soc., 82, 1714-1727 (1960), W.J. Gensler et al. Describe the overall synthesis of picropodophyllin (III) using an elongated method involving 13 steps and with a total yield of al-15. The process using the intermediate compounds of this invention is completely different from that described by Gensler et al. And completely avoids the preparation of picropodophyllin (III).

In J. Org. Chem. 46, 2826-2828 (1981) 20 A.S. Kende et al. Report improved overall podophyllotoxin (II) synthesis in 12 steps with a total yield of 4.5% piperonal. However, the Kende synthesis requires the preparation of picropodophyllin (III) and then subsequent epimerization in the same manner as in the Gensler synthesis mentioned above.

In J. C. S. Perkin I, 271-276 (1982), W.S. Murphy and S. Wattanasin describe an improved synthesis of aryl litetralone (IV) with a structural formula of 30 to 35 Λ

Cli30 and OCH3

Aryltetralone (IV) 4,89913

Aryltetralone (IV) is an intermediate used in the synthesis of picropodophyllin (III) described above in J. Am. Chem. Soc. 82, 1714-1727 (1960). Aryltetralone (IV) is also used as a starting material in the overall synthesis of epipodophyllotoxin in which the compounds of the invention are intermediates.

In J. Am. Chem. Soc. 103, 6208-6209 (1981), D. Rajapaksa and R. Rodrigo, and J. Org. Chem. 45, 4538-4540 (1980), R. Rodrigo, describe a novel synthesis of podophyllotoxin (II) and epipodophyllotoxin (I) which avoids the thermodynamic inconvenience of converting picropodophyllin (III) to podophyllotoxin (II) in a manner previously known. described in the above-mentioned 15 references by Gensler et al. and Kende et al. However, the synthesis of Rodrigo requires the preparation of a two-ring precursor (Compound 9 in the 1980 reference), and a satisfactory yield can only be obtained using circular distillation methods.

The use of the compounds of this invention as intermediates also avoids the formation of the picropodophyllin (III) intermediate and further provides a novel and efficient stereospecific synthesis using inexpensive chemicals so that the novel method described herein is technically feasible.

25 U.S. Patent No. 3,524,844, issued August 18.

1970, in the name of Keller-Juslen et al., describes the preparation of 4'-demethylepipodophyllotoxin-8-D (substituted) Glu cosides of the formula

B

30 R

35 CXXjQ0 ΟΗ, Ο '^ Υ''0 ^

OH

li 5 8991 3 ...... ({5 Λ ch3o ^ y ^ och3

ALRIGHT

4'-dimethylepipodophyllotoxin (V) 10, which in turn is prepared from podophyllotoxin (II). 4'-Dimethylepipodophyllotoxin-8-D- (substituted) glucosides, and in particular etoposide (R1 = methyl) and teniposide (R1 * 2-thienyl), are antitumor agents useful in the treatment of human cancers, especially testicular cancer. .

The compounds of this invention are intermediates in the efficient and stereospecific overall synthesis of epipodophyllotoxin (I) and related compounds, which compounds are readily converted to known antitumor agents. Accordingly, the invention relates to novel intermediates of formula X in the following Scheme 1 and a process for their preparation from compounds of formula (IX).

Scheme 1 25 i- R2 r2> ^^ \ ^> C00R3 O U z s

r 'r: K

* «· Η ·? * Β Ή -'-: <c OR3 OR5 35

VI

VII

6 89913 r: m .., ^ riaa R Ҥ" ^ R2 ^^ AAxAAoOR0 - ^

5 jfil A

R4 AN 'R4 "Av ° R U5

VIII TV

i n T, _ ^ Γ n 1 7 ^ \ / \ / 'tOOR3 ^ R2 ^ A ^ A \ A' '' COOR3 A A A.

0R A

X xi

20 XI

OH

-> r2Xa ^ Q

A ° R4 A ^ R6 OR5

XII

7 89913 wherein R1 and R2 independently of one another are hydrogen or lower alkoxy or together form a methylenedioxy group, R3 is hydrogen or a carboxyl protecting group, R4 and R6 independently of one another are hydrogen or lower alkoxy, R5 is hydrogen or a phenol protecting group and R7 is hydrogen , halogen, lower alkoxycarbonyl, carboxyl, cyano, trimethylsilyl, phenylsulfonyl or phenoxycarbonyl, wherein the phenyl ring in R 7 may be substituted with one or two substituents selected from lower alkyl, halogen, lower alkoxy and trifluoromethyl, or its suole; and R 8 is cyano, aminomethyl, formyl or carbamoyl; or an acid addition salt thereof.

Aryltetraions VI can be prepared from the novel intermediate compounds XIV, which can optionally be isolated and have the formula shown in Scheme 2.

Figure 2 0 o 11 o

. XC'R

20 P-000 * 3-> 'Xn ά, 1 H4 · ^ * 6

25 0RS

- - XIII

A: XIV

:: 30 0 „χΛ.

VI

- 35

0RJ

8 ti 9 91 3 wherein R1, R2, R3, R4, R5 and R6 are as previously defined; and R 9 is phenyl or lower alkyl optionally substituted with one or more halogen atoms selected from fluorine, chlorine and bromine.

The present invention also provides the use of stereoselective methods for the preparation of intermediate compounds in the overall synthesis of epipodophyllotoxin and derivatives close to epipodophyllotoxin. The use of the compounds and methods of this invention avoids the inconveniences that need to be considered in the prior art and provides a technically conceivable synthesis of compounds useful as antitumor agents, such as etoposide and teniposide.

The terms "lower alkyl" and "lower alkoxy" as used herein and in the claims (unless the context otherwise indicates) denote unbranched or side chain alkyl or alkoxy groups having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, isopropyl, isyl, isyl , t-butyl, amyl, hexyl, etc. Preferably, these groups have 1 to 4 carbon atoms, and most preferably have one or two carbon atoms. Unless otherwise indicated in a particular case, the term "halogen", as used herein and in the claims, is intended to include chlorine, fluorine, bromine and iodine. The term "acid addition salt" is intended to include non-toxic carboxylic acid and phenolic acid salts, e.g., non-toxic metal salts such as sodium, potassium, calcium, and magnesium salts, ammonium salt, and salts with non-toxic amines, e.g., trialkylamines, proxane amines. , with dibenzylamine, pyridine, N- *: methylmorpholine, N-methylpiperidine and other amines used to prepare salts of carboxylic acid and phenols.

I, 9 EJ9913

The compounds mentioned in Schemes 1 and 2 may have one or more asymmetric carbon atoms, so that many of the compounds of the general formulas shown in Schemes 1 and 2 may exist in different enantiomeric and dia-5 stereomeric forms. Mixtures of isomers can be separated into the individual isomers according to methods known per se, e.g. by fractional crystallization, adsorption chromatography or using other suitable separation methods. The resulting racemates can be separated into the antipodes in the usual manner after the addition of suitable salt-forming groups, e.g. by forming a mixture of diastereoisomeric salts with optically active salt-forming agents, separating the mixture into diastereoisomeric salts and converting the separated salts into free compounds. Possible enantiomeric forms can also be separated by fractionation through optically active high performance liquid chromatography columns.

If it is desired to prepare the natural (-) isomer of epipodophyllotoxin, the synthetically prepared (±) -20 form can be separated by separation methods well known to those skilled in the art. Alternatively, the separation may be performed at an earlier stage of the synthesis by the same general methods using one of the intermediates described herein that is capable of forming an optically active salt of epipodophyllotoxin to give the desired optically active (+) or (-) isomer. As an example of a separation method for this general class of compounds, W.J. Gensler. . et al., in J. Am. Chem. Soc. 82, 1714-1717 (1969), described the separation of DL-α-apopodophyllinic acid into naturally occurring optically active α-apopodophyllinic acid by forming and isolating the corresponding optically active quinine salt.

Carboxyl protecting groups that can be used in the context of this invention to block or protect the carboxylic acid function are well known to those skilled in the art and include groups such as lower alkyl, phenyl (lower alkyl), ring-substituted phenyl (lower alkyl), methoxymethyl, benzyloxymethyl, allyl, diphenylmethyl and the like. Also, phenol-5 protecting groups that can be used in the present invention to block or protect a phenol function are well known to those skilled in the art and include groups such as lower alkyl, phenyl (lower alkyl), ring-substituted phenyl (lower alkyl), benzyloxy-10 carbonyl, 2 , 2,2-trichloroethoxycarbonyl, methoxymethyl, allyl and the like. Other suitable protecting groups are disclosed in Protective Groups in Organic Synthesis, Theodora W. Greene (John Wiley and Sons, 1981), paragraph 3 for phenol and paragraph 5 for carboxyl-15, which are hereby incorporated by reference.

The starting materials for the process for the preparation of the compounds of the formula X which are the subject of the present invention are the compounds of the formula IX contained in the compounds of the following formula: r2 VIII - trans, and ix - cis 3 '

OR

wherein R 1 and R 2 are each independently hydrogen or lower alkoxy or R 1 and R 2 together represent methylenedioxy; R 3 is hydrogen or a carboxyl protecting group; R 4 and R 6 are each independently hydrogen or lower alkoxy; and R 5 is hydrogen or a phenol protecting group; or their acid addition salts.

Of the compounds of formula VIII, preferred are compounds of formula li 11 3 9 913 <oXJU> COOR3 = wool 5 jf \ CH3Cr ^ / v'OCH3 OR5 wherein R3 is hydrogen or a carboxyl protecting group and R5 is hydrogen or a phenol protecting group and their The acid addition salts.

Of the compounds of formula IX, compounds of formula 15 are preferred

0 TY

3 IXa jOl CH, 0 OCH-

20 0R

wherein R 3 is hydrogen or a carboxyl protecting group, and R 5 is hydrogen or a phenol protecting group; and their acid addition salts.

In the compounds of formulas VIII and IAa, R 3 is preferably hydrogen, lower alkyl, phenyl (lower alkyl), ring-substituted phenyl (lower alkyl) or diphenylmethyl, and most preferably is lower alkyl or diphenylmethyl. R 5 is preferably hydrogen, lower alkyl, phenyl (lower alkyl), ring-substituted phenyl (lower alkyl), benzyloxycarbonyl or 2,2,2-trichloroethoxycarbonyl, and most preferably methyl or benzyl. The phenyl ring of R3 and R5 may have one or two substituents independently selected from the group consisting of lower alkyl, halogen, lower alkoxy and trifluoromethyl.

Compounds of formula VIII can be prepared ... from the corresponding aryl tetralones of formula VI by reduction of the ketone radical in compounds VI or Via and subsequent dehydration of the alcohols VII or Vila 12 '(9913 by methods well known to those skilled in the art, as shown in Scheme 3). .

Scheme 3 5 r1 °

^ 2 COOH

R 1 * = 10 ^ Ti (h R 4 ^ Y ^ R 6 R 4 "^ YR 5 VI OR ** 0R via 15 N / V /

9h OH

"frh, ΛνΛ

20 / ^ YVY'COOR’3, J <v. U.> rcH

£ R * - Y Lvljn 4YY ^ R6 4 VI1 0R iR5 Villa • 25 \ /: l / i 3

: 30 r2 'Y / \ YCOORJ

Ok VIII

35 \ / 1 8 9 91 3 13 R1 ^ Τ ^ ίι ", W'C OOR3

5 R “A

A

r4 ^ .6

OR5 IX

10 wherein R1, R2, R3, R4, R5 and R6 are as previously defined.

The aryltetralone starting material of formula VI wherein R 1 and R 2 together represent methylenedioxy, R 3 is hydrogen, CH 3 or C 2 H 5, R 4 and R 6 are methoxy, and R 5 is methyl can be prepared by the general method described in J. Am. Chem. Soc. 82, 1714-1727 (1960), W.J. Gensler et al. The starting materials of formula VI can also be prepared by the improved method described in J. C. S. Perkin I, 271-276 (1982) W.S. Murphy and S. Wattanasin, wherein R 1 is methoxy and R 2 is hydrogen, or R 1 and R 2 together represent methylenedioxy, R 3 is hydrogen or ethyl, R 4 and R 6 are hydrogen or R 4 and R 6 are methoxy, and R 5 is methyl. Alternatively, the starting materials of general formula VI can be prepared by the new and improved process described in more detail in this specification and examples.

·. According to one reaction route, if it is desired to change the protecting group of the R3 carboxyl, the aryltetralone VI is first hydrolyzed by conventional methods, such as hydrolysis with an acid or base, and preferably by hydrolysis with a base, for example potassium hydroxide. The resulting acid Via is then treated selectively by reduction under conditions such that the ketone radical is obtained to the reduced alcohol Vila. The reduction can be performed by catalytic hydrogenation using hydrogenation catalysts such as palladium, platinum, Raney nickel or ruthenium, optionally supported on a conventional support such as carbon, diatomaceous earth, etc. in non-reducing inert solvents such as water, methanol. -5 in ethyl or ethyl acetate. The hydrogenation is carried out primarily at room temperature and atmospheric pressure or at a slightly higher pressure. More preferably, aryl litetralone Via is reduced in a suitable solvent with a selective reducing agent, e.g., sodium borohydride, sodium cyanoborohydride, zinc borohydride, sulfurized sodium borohydride (NaBH 2 S 3), disodium boride, lithium boride, lithium boride; -butyl borohydride, or other similar reducing agents which do not reduce the carboxylic acid radical. The formed alcohol Vila is then treated under standard dehydration conditions with a small amount of an organic or inorganic acid such as p-toluenesulfonic acid or sulfuric acid to give trans-olefin VIII where R 3 is hydrogen. The reaction is carried out in a suitable inert organic solvent, e.g. toluene, benzene, ether or methylene chloride, in the presence of a drying agent, e.g. Na 2 SO 4, MgSO 4, molecular sieve, etc., or preferably, the water formed is azeotroped with a Dean-Stark trap. using a similar device. The trans-olefin VIII in which R 3 is hydrogen can then be esterified in the usual manner with a suitable carboxyl protecting group and preferably with benzhydryl.

30 Those skilled in the art are aware that the alcohol Vila can form the corresponding lactone XV in the dehydration reaction. The formation of lactone XV depends on the relative stereochemical configuration of the hydroxyl and carboxyl radicals of the alcohol Vila used in the dehydration reaction.

Il 15 89913

O

^ VrV "5 2 ^ R2 Λ ih * <^ vf r6 ^ 'V' * 6

0Rä 0R

10 v /

Villa n.> / ^

VIII

15

Trans-olefin VIII, wherein R 3 is a carboxyl protecting group, can then be prepared directly by adding an alcohol, for example benzhydryl alcohol, to the dehydration reaction using lactone XV.

In a specific example where R1 and R2 together represent methylenedioxy, R4 and R6 are methoxy and R5 is methyl, the alcohol VIIIb was dehydrated and then esterified in the usual manner with benzhydryl alcohol to give the trans-olefin VIIIa.

In another specific example, lactone XVa was isolated from one of the dehydration reactions using the corresponding alcohol VIIIb. Treatment of the resulting lactone XVa with benzhydryl alcohol under standard acidic dehydration conditions afforded the desired trans-olefin VIIIa as described in the art.

- 35 16 3991 3 coiL __ <χ & “5 Λ ch3o ^ <^^ och3 ch, c ^ y ^ och3 och3 och3 10 VIIb>: va 15 <° ΥΎ \ 0 - ^^^^^ SZOOCHPh ^ 20 CH30 '^ Xy ^> V'OCH3 OCH3

Villa

In an alternative reaction pathway, if it is desired to retain the same R3 carboxyl protecting group, the aryltetralone VI

Selective reduction can be accomplished by catalytic hydrogenation using hydrogenation catalysts such as palladium, platinum, Raney nickel, or ruthenium, optionally supported on a common support such as carbon, diatomaceous earth, etc. in non-reducing inert solvents such as methanol, ethanol, or ethanol. The hydrogenation is carried out primarily at room temperature and atmospheric pressure or at a slightly higher pressure. More preferably, the aryltetralone VI is reduced in a suitable solvent with a selective reducing agent, e.g. sodium borohydride, sodium cyanoborohydride I; 17. "3991 3 ia, zinc borohydride, sulfurized sodium borohydride (NaBH 2 S 3), disiamylborane, diborane, ammonium borane, t-butylamineborane, pyridineborane, not the same carboxylic acid, lithium tri-s-butylborohydride, The alcohol VII formed is then treated under standard dehydration conditions with a small amount of an organic or inorganic acid, such as p-toluenesulfonic acid or sulfuric acid, to give trans-olefin VIII, wherein R 3 is a carboxyl protecting group in a suitable organic solvent. , e.g., in toluene, benzene, ether, or methylene chloride, in the presence of a desiccant, e.g., Na 2 SO 4, MgSO 4, molecular sieve, etc., or primarily, the water formed is azeotropically removed using a Dean-Stark trap or the like.

Conversion of trans-olefin VIII to cis-olefin IX can be accomplished by epimerization of the carboxylic ester radical. This epimerization is usually carried out in an inert organic solvent such as THF and at low temperatures, about -78 ° C to + 20 ° C and preferably about -78 ° C using a strong base such as lithium hydride, potassium bis (trimethylsilyl) amide , lithium diisopropylamide or lithium bis (trimethylsilyl) amide. The anion formed is then treated with an acid, e.g. . with inorganic acids such as hydrochloric acid, sulfuric acid or the like to stereoselectively obtain cis-olefin IX.

Compounds of formula IXC may also be prepared from: 30 compounds of formula

k -WS

__ r2 WI

O O: £ ..O- ,.

R i 5

OR

18 S 9133 wherein R1 and R2 are each independently hydrogen or lower alkoxy, or R1 and R2 together represent methylene dioxide; R 3 is hydrogen or a carboxyl protecting group; R 4 and R 6 are each independently hydrogen or lower alkoxy; 5 and R 5 is hydrogen or a phenol protecting group; or their acid addition salts.

Preferred compounds of formula XVI are compounds of formula 10 O COOR3 XVIa 15 CH30 "tV ° CH3

OR

wherein R3 is hydrogen or a carboxyl protecting group, and R5 is hydrogen or a phenol protecting group and acid addition salts thereof.

Most preferred are compounds of formula XVIa wherein R 3 is lower alkyl or diphenylmethyl and R 5 is methyl or benzyl.

The cis-aryltetralone of formula XVI can be prepared by epimerizing the corresponding trans-aryltetralones VI. The compounds of formula XVI are then reduced and dehydrated to give cis-olefins of formula IX according to Reaction Scheme 4.

I;

Scheme 4 is 89913 g R1 7 C00R'3 2 '' 'A ^ A \ ^' / '' COOR3 “Λ ή.

r4 Av * 6 r4

10 OR OR

VI XVI

15 2 J ^ O ^ Cx ^^ COOR3 r2 ^^^ v ^^ COOR3 Λ A-

R4 R R4 ς R

OR5 OR "

20 XVII IX

The aryltetralone VI starting material, with the ester radical in the trans configuration, is epimerized to the cis: ': aryltetralone XVI at low temperatures, at about 25-70 ° C at -20 ° C, and preferably at about -78 ° C, via enol formation using a strong base such as lithium hydride, potassium bis (trimethylsilyl) amide,. . lithium diisopropylamide or lithium bis (trimethylsilyl) amide in an inert organic solvent such as THF and then adding an inorganic acid, for example hydrochloric acid.

The resulting cis-aryltetralone XVI can then be treated under selective reduction conditions to reduce the keto radical to alcohol XVII, wherein R 3 is a 35 carboxyl protecting group. The reduction can be performed by catalytic hydrogenation using hydrogenation catalysts such as palladium, platinum, Raney nickel or ruthenium, optionally supported on a conventional support such as carbon, diatomaceous earth, etc., in non-reducing inert solvents such as water, methanol. in ethanol 5 or ethyl acetate. The hydrogenation is carried out primarily at room temperature and atmospheric pressure or at a slightly higher pressure. More preferably, aryltetralone XVI is reduced in a suitable solvent with a selective reducing agent, e.g. sodium borohydride, sodium 10 cyanoborohydride, zinc borohydride, sulfurized sodium borohydride (NaBH 2 S 3), ammonium-borane-butane, butane, borane, butyl borohydride, or other similar reducing agents that do not reduce, hydrosylate or epimerize the carboxylic ester radical. The alcohol XVII formed can then be treated under standard dehydration conditions with a small amount of an organic or inorganic acid, such as p-toluenesulfonic acid or sulfuric acid, to give cis-olefin IX, wherein R 3 is a carboxyl protecting group. The reaction is carried out in a suitable inert organic solvent, e.g. toluene, benzene, ether or methylene chloride, in the presence of a desiccant, e.g. Na 2 SO 4, MgSO 4, molecular sieve, etc., or the water formed is preferably azeotroped to a Dean-Stark trap. or similar device.

Alternatively, cis-aryltetralone XVI is reduced in a suitable solvent with a selective reducing agent, preferably lithium borohydride, to give the alcohol XIIa and / or the lactone of formula XVIII.

i.

21, 09913: .0 ^ “κ1 - .;" -, Λ ·. / - ° JX>

5 r2 ^> ^ / '"= 00Η S

A · Α

R4 I 5 R 0R

OR

10 Xlla XVIII

Those skilled in the art are aware that alcohol XIIa may form the corresponding lactone XVIII during reduction and further processing. The amount of lactone XVIII isolated from the reaction mixture depends on the relative stereochemical configuration of the hydroxyl and carboxyl radicals of the alcohol Xlla formed in the reduction. In a specific example where R 1 and R 2 together represent methylenedioxy, R 1 and R 6 are methoxy and R 5 is methyl, lactone Tone XVIIIa was the primary product isolated from the reaction mixture.

/ v_ ·: ··: 25 Ξ

Jfil OCH3 30

The resulting lactone XVIIIa can then be treated with an alcohol, and preferably benzhydryl alcohol, under standard acidic dehydration conditions, as described above for lactone XVa, to give the desired cis-olefin IX, wherein R 3 is a carboxyl protecting group.

The present invention relates to compounds of the formula = COOK3 v if11 R4 '^ SX ^ R6 10 OR5 wherein R1 and R2 independently represent hydrogen or lower alkoxy or together form a methylenedioxy group, R3 is hydrogen or a carboxyl protecting group, R * and R 6 independently of one another are hydrogen or lower alkoxy, R 5 is hydrogen or a phenol protecting group and R 7 is hydrogen, halogen, lower alkoxycarbonyl, carboxyl, cyano, trimethylsilyl, phenylsulphonyl or phenoxycarbonyl, in which the phenyl ring in R 7 may be substituted With one or two substituents selected from the group consisting of lower alkyl, halogen, lower alkoxy and trifluoromethyl, or salts thereof.

Preferred compounds of formula X are compounds of formula

25 O-N

(XXX '

C00RJ

Wherein R3 is hydrogen or a carboxyl protecting group, R5 is hydrogen. 35 or a phenol protecting group; and R 7 is hydrogen, halogen, lower alkoxycarbonyl, carboxyl, cyano, trimethylsilyl, phenylsulfonyl or phenoxycarbonyl, wherein the phenyl ring of R 7 may have one or two substituents independently selected from lower alkyl, halo, lower; and trifluoromethyl.

Most preferred are compounds of formula Xa wherein R 3 is hydrogen, lower alkyl or diphenylmethyl; R 5 is methyl or benzyl; and R7 is bromine or chlorine.

The present invention also relates to a process for the preparation of compounds of formula X 10 from the corresponding cis-olefins of formula IX using the [3 + 2] cyclo addition reaction as shown in Scheme 5.

Figure 5

15 -N

7 © Θ / ^ ~ r7

Jj N | R -C = N-0 R

3 XX Jv 7 R C00RJ -> "COOR3 20 r ^ Yi k * 1 6 L h R I 5 R I r Rb OR OR5 ϊ .: ix x 25

Cis-olefin IX is reacted with at least one. . with an equivalent of substituted nitrile oxide of formula XX at temperatures between about -20 ° C and boiling point in an inert solvent (water or organic solvent, or a mixture of water and organic solvent) such as water, C 1 -C 6 alcohols, ethyl acetate, dioxane, tetrahydrofuran , in acetone, nitromethane, methylene chloride or chloroform-35 to give the isoxazole adduct X. Although 24 9 91 3 is not critical to the solvent and the reaction temperature, it is recommended that when R 7 is halogen, the reaction be carried out near a solvent such as acetone or the boiling point of ethyl acetate.

It is preferable to use an excess of nitrile oxide XX in the above-mentioned 1,3-dipolar cycloaddition reaction, and more preferably it is used in an excess of 3 equivalents. It is also preferred to generate nitrile oxide XX in situ from the corresponding formaldoxime XIX in the presence of an inorganic base such as KHCO 3 or Na 2 CO 3 or a tri-substituted amine such as triethylamine or pyridine as shown below: © e 15 C = N-OH-R 7 -C ~ N— 0 /

br

XIX XX

To prepare compound XXa wherein R7 is bromine, bromonitrile is generated from dibromoformaldoxime XIX wherein R7 is bromine as described in Tetrahedron Letters 21, 229-230 (1980), or more preferably by the modified method described in Example 25 20, in step A. Other nitrile oxides of formula XX, wherein R 7 is hydrogen; ethoxycarbonyl, carboxyl and cyano, trimethylsilyl; and phenylsulfonyl, can be prepared by standard methods described, respectively, in Tetrahedron Letters, 24, 1815-1816 (1983); J. Org. Chem. 48, 366-372 (1983); Synthesis, 719 (1982); and J. Org. Chem. 48, 1196-1800 (1983), and references therein.

In a specific example in connection with compound X, wherein R 1 and R 2 together represent methylenedioxy; R4 and R6 are methoxy; R5 is methyl; R7 is bromine; and R3 is diphenyl.

25.8991 3 Limethyl, cleavage of the carboxyl protecting group with dry HCl in an inert organic solvent such as nitromethane gave crystalline isoxazolic acid Xc where R3 is hydrogen and R7 is chlorine. The cleavage procedure of this particular compound of formula X5 resulted in the replacement of halogen, whereby the bromine radical of R7 in the isoxazole ring was replaced by chlorine. If it is desired to preserve the bromine radical of R7, then the cleavage procedure is performed primarily with trifluoroacetic acid as described herein for the preparation of isoxazolic acid Xd.

The stereospecific construction of the isoxazole ring of Compound X formed by the diastereoselective attachment of substituted nitrile oxide XX to the β-side of cis-olefin IX is readily determined by 1 H NMR spectroscopy. However, in order to further demonstrate the region-specific and stereospecific nature of this invention, the [3 + 2] cycloaddition reaction was repeated with trans-olefin VIIIb as shown below.

20 0 — n

; \\ _ BI

<^ '' '0CXoOC H Br- = JL? {f. OOC2H5 rC- „O ^ '' ^ 'V ^ COOC2H5: jJL Jx CH3cr ^ Y ^ OCH3 CH3 OCH3 OCHCH0CH3

: 30 VIIIb XXI

Isolation of Compound XXI in which the isoxazole ring is attached in a stereochemically opposite position confirms that the process of the present invention for the preparation of Compound X is a highly stereoselective process for achieving the desired region specificity necessary for epipodophyllotoxin and epipodocylotoxin. efficient synthesis of existing derivatives.

5 In the overall synthesis of epipodophyllotoxin and related compounds, compounds of formula X are prepared from compounds of formula

OH

10 R

L il R2 0 OR 3 ·

XI

4 6 15 R T 5 10 OR ”1 wherein R 1 and R 2 are each independently hydrogen or lower alkoxy, or R 1 and R 2 together represent methylene diox; R 3 is hydrogen or a carboxyl protecting group; R 4 and R 6 are each independently hydrogen or lower alkoxy; R 5 is hydrogen or a phenol protecting group; and R 8 is cyano, aminomethyl, formyl or carbamoyl; or an addition salt thereof.

Preferred compounds of formula XI are compounds of formula

OH

30 1 / Coor3 XIa

5 J

R 35 is wherein R 3 is hydrogen or a carboxyl protecting group; and R 5 is hydrogen or a phenol protecting group; or an acid addition salt thereof.

27 * J 9 91 3

Highly preferred are compounds of formula X1a wherein R 3 is hydrogen, lower alkyl or diphenylmethyl and R 5 is methyl or benzyl; or an acid addition salt thereof.

Also preferred are compounds of formula XI of formula

OH

10 C X iT T

^^^^ '"' COOR3 xib

Jfjl CH30 Vri'CH: wherein R3 is hydrogen or a carboxyl protecting group; and R 5 is hydrogen or a phenol protecting group; or an addition salt thereof.

Particularly preferred are compounds of formula Xib wherein R 3 is hydrogen, lower alkyl or diphenylmethyl and R 5 is methyl or benzyl; or their addition salts.

Epipodophyllotoxin of formula XII and derivatives close to epipodophyllotoxin can be prepared from the corresponding isoxazole compounds of formula X by the reaction sequence shown in Scheme 6.

28> S 9 913

Figure 6

OH

s i X> -a7 R R2 '^> ^^' "'COOR3 _.

r = r i f ^ Yl

10 4J ^> 6 R T .- R

R R6 ord OR5

X

15

OH 9H

I il J, aJ-LJ / 20 r2 - ^> y ^ "" C00r3 _ ^ R2 ^^ Y li „> 4a - · αα

OR ^ CR

25

Xld XI1

Compounds of formula X are treated under reaction conditions to heterolyze the N-O bond. The cleavage conditions of the isoxazo-30 ring usually vary depending on the R7 substituent and whether R3 is hydrogen or a carboxyl protecting group. For example, when R 7 is trimethylsilyl, thermal rearrangement and subsequent hydrolysis according to the general methods described in Heterocycles, 20, 511-518 (1983), form compounds of formula XIc. When R 7 is alkoxycarbonyl, phenylcarbonyl or cyano, as a result of hydrolysis to compound X wherein R 7 is carboxyl, followed by decarboxylation according to the general methods described in J. Org. Chem. 48, 366-372 (1983) also provide compounds of formula XIc. In the case where R7 is phenylsulfonyl and R3 is hydrogen or a carboxyl protecting group, by selective reduction, for example with sodium borohydride or 2% sodium amalgam according to the general methods described in J. Org. Chem. 49, 123-115 (1984) and J. Am. Chem. Soc. 101, 1319 (1979), compounds of formula XIc are formed. In addition, if a stronger reducing agent such as lithium aluminum-15 minium hydride is used in conjunction with a compound of formula X wherein R 3 is hydrogen, the cyano compound of formula XIc formed may be further reduced without isolation to give the aminomethyl compound of formula Xld. It has further been found that an isoxazole of formula X, if R 7 is bromine, can be reduced to compound XIc with tributyltin hydride in the presence of a free radical initiator such as 2,2'-azobisisobutyronitrile. Preferably, the reduction of compounds wherein R 7 is chlorine or bromine is accomplished by catalytic hydrogenation. The reduction 25 is preferably performed at initial hydrogen pressures of about 40 to 50 psi in the presence of a catalyst such as Raney nickel, platinum oxide, palladium / carbon or nickel boride in a non-reducing solvent, e.g., alcohols, ethyl acetate, water and the like. When the reduction is performed in formula X ... When R 3 is other than hydrogen, the pH of the solution may be adjusted to prevent possible epimerization of the carboxyl group by the addition of a suitable buffering agent such as boric acid or other mild buffering acid. If a compound X in which R3 is hydrogen is used, then the reduction is less sensitive to the reaction conditions and the buffering agent can be omitted.

Compounds of formula XIc wherein R 3 is hydrogen or a carboxyl protecting group are then selectively reduced, to reduce the cyano radical, to aminomethyl compounds of formula Xld. When R 3 is a carboxyl protecting group, the reduction can be performed by catalytic hydrogenation using hydrogenation catalysts such as platinum oxide or Raney nickel in non-reducing inert solvents such as water, methanol, ethanol or ethyl acetate, or mixtures thereof. The hydrogenation is carried out primarily at room temperature and atmospheric pressure or at a slightly higher pressure. Alternatively, the reduction may be performed with selective reducing agents such as diborane in tetrahydrofuran or other similar reducing agents that do not reduce or epimerize the carboxylic ester radical. The resulting compounds of formula Xld, wherein R 3 is a carboxyl protecting group, can then be liberated under non-epimeric conditions, for example by hydrogenolysis or hydrolysis using an acid.

More preferably, the cyano radical reduction of compounds XIc where R 3 is hydrogen is accomplished by catalytic hydrogenation using hydrogenation catalysts such as platinum oxide or Raney nickel in non-reducing inert solvents such as methanol, ethanol, ethyl acetate, methylene, or methylene. The hydrogenation is carried out primarily at room temperature and atmospheric pressure, or at a slightly higher pressure. Most preferably, the reduction is performed with lithium aluminum hydride in a suitable solvent such as tetrahydrofuran. The resulting product of formula Xld, wherein R 3 is hydrogen, can be isolated, if desired, in the form of an addition salt such as, for example, an acetic acid salt.

Q 9 1 5 31 '' '10

The aminomethyl compounds of formula Xld wherein R 3 is hydrogen are then cyclized by diazotization of the primary amine, and preferably with sodium nitrile or i-amyl nitrite in an aqueous acidic medium such as aqueous acetic acid or aqueous trifluoroacetic acid. Cyclization proceeds directly to the desired lactones of formula XII in which the relative stereochemical structure of epipodophyllotoxin and podophyllotoxin is correct.

If desired, compounds of formula XIc may be selectively converted to compounds of formula XI wherein R 8 is formyl by methods well known to those skilled in the art, such as by catalytic hydrogenation with Raney-Nikke in the presence of sodium hypophosphite in aqueous acetic acid or zinc in acetic acid. Compounds of formula XI wherein R 8 is formyl and R 3 is hydrogen may then be selectively reduced to the alcohol epipodophyllic acid, which may be converted to epipodophyllotoxin and related compounds by the methods described in J. Am. Chem. Soc. 103, 6208-6209 (1981).

If desired, compounds of formula XIc may be selectively converted to compounds of formula XI wherein R 8 is carbamoyl, e.g. with hydrogen peroxide. Compounds of formula XI wherein R 8 is carbamoyl and R 3 is hydrogen may then be selectively reduced, e.g. with lithium aluminum minide hydride, to give compounds of formula Xld wherein R 3 is hydrogen which are converted to epipodophyllotoxin and adjacent compounds. compounds by the methods described herein.

... When using the more preferred reaction route, the formula

The compounds of Xlb do not need to be isolated and can be further reacted to give the desired epipodophyllotoxin (I) and related compounds. Thus, for example, a compound of formula X1a wherein R 5 is 32,399 3 methyl and R 3 is hydrogen is first treated with a reducing agent such as lithium aluminum hydride to reduce the cyano radical. The crude product of formula Xlb obtained after evaporation of the solvent is then treated with sodium nitrite solution to diazotize the product and then lactonize to give the desired epi-podophyllotoxin (I) as shown below:

OH OH

^ OOH3 _ '' COOR3 _ ^ j Ä Oi 15 CHjO ^ Y ^ OCHj CH.O ^^ CX ^ OR5 OR5

Using the increasingly preferred route of reaction, the compounds of formulas Xla and Xlb do not need to be isolated and can be further processed to the desired epipodophyllotoxin (I). Thus, for example, a compound of formula Xa wherein R 5 is methyl, R 3 is hydrogen and R 7 is chlorine is treated sequentially with nickel boride and then platinum oxide at room temperature with an initial hydrogen pressure of about 40 to 50 psi. The crude product of formula Xlb obtained, without isolation and further purification, is treated with a diazotizing agent and preferably with sodium nitrite in an acidic medium such as aqueous acetic acid to give the desired epipodophyllotoxin (I).

The aforementioned compounds of formula VI may be prepared from compounds of formula 1; 33 3- ^ 13 o 11 o. O-C-R 'R N ^ Ty <v 5,' \ jl i

^^^^ COCR3 XIV

Xil.

10 OR5

Scheme 7 15 ° 1 0 R2XX 2 ^ X t> C00 * 3 20 ^ VoR5 '(]} OR3

XXII

-: - XIII

25 H q

O-C-R

: .. 'r2 ^^^ \ ^ / ^ coor3 r2 ::. “Ä, *.

R i 5 R I

OR3 OR5

XIV VI

: ... ‘35 1 3 9 91 3 34

The starting materials of formula XXII are readily prepared from known ketones and aryl aldehydes by the general methods described by S. Wattanas and W.S. Murphy in Synthesis, 647-650 (1980).

Cyclopropanation of chalcone compounds of formula XXII to give cyclopropyl ketones XIII can be preferably performed with well known cyclopropanating agents, e.g. ethoxycarbonyldimethylsulfonium methyl, by the general methods described in W.S. 10 Murphy and S. Wattanas, J. C. S. Perkin I, 271-276 (1982). However, the method of Murphy and Wattanasin causes the formation of a mixture of α-COOR3 and p-COOR3 epimers of the compounds of formula XIII in a ratio of about 1: 1. Murphy et al. Have also suggested that the α-15 isomer is the more significant isomer for the subsequent cyclization reaction because the α-isomer epimerizes to the β-isomer under Lewis acid conditions in 10 minutes.

We have now found that the α-C 20 R 3 isomer of cyclopropyl ketone X alone is formed in 96% yield when the cyclopropanation reaction is carried out in dimethyl sulfoxide with the corresponding chalcone compound xxila, wherein R 1 and R 2 together represent methylenedioxy; R4 and R6 are methoxy; R5 is methyl and R3 is ethyl.

Direct conversion of some cyclopropyl ketones of formula XIII to trans-aryl tetralones of formula VI by a Lewis acid catalyzed reaction W.S. Murphy and S. Wattanas have well documented in J.C.S. Perkin I, 271-276 (1982) and references therein. Murphy et al. Describe the successful ring-30 ringing of compound xiila, wherein R1 and R2 together represent methylenedioxy; R 4 and R 6 are each methoxy; R5 is methyl and R3 is ethyl, to the corresponding important Gensler ketone VIb. Cyclization is characterized by a substantial effect resulting from the use of nitromethane as a solvent, and failed attempts to cause this rearrangement; 35 ί; 9913 sex in benzene and methylene chloride under different conditions [W.S. Murphy and S. Wattanasin, J.C.S. Chem.

Comm., 262-263 (1980)]. However, the conversion of compound IIIa to the aryltetralone of formula VIb by the method of Murp-5 hy'n et al. Continued rather slowly and gave a mixture of products. By the best method, using a mixture of BF33.Et2O in nitromethane for 15 days, a mixture of products was obtained and at best 57% was obtained in VIb after preparative oxochromatography as described in Scheme 8.

Scheme 8 0 o 15 p ^ cooc ^ 5 <0 ^ Χ ~ Ί jOl * 0 AεοοεΛ CH3O ^ V ^> CH3 k 1

OCK, CH.O OCIU

20 J J I j zu och3

Xllla VIb

Aryltetralones VI can be advantageously prepared via the novel enol compounds XIV.

A compound of formula XIII is treated at about room temperature with about 0.5 equivalent of a Lewis acid, for example SnS1 *, BF3, Et2O, ZnCl2 or the like, and at least one equivalent of anhydride, for example acetic anhydride or trifluoroacetic anhydride, in an inert organic solvent such as nitromethane, methylene chloride, benzene, tetrahydrofuran, ethyl acetate, toluene, chloroform, dioxane, etc. to give a compound of formula XIV. The solvent used in this embodiment 36 '; 9913 is not critical. It is preferred to use one equivalent of Lewis acid and one or more equivalents, more preferably two equivalents of an acid anhydride of formula 0 9 "(RyC-) 2 O 10 wherein R 9 is as defined above. When using Lewis acid BF 3 .Et 2 O, it is preferred to carry out the reaction and further work-up in about five minutes However, if a weaker Lewis acid such as ZnCl 2 is used in the reaction, the reaction is preferably continued for 24 hours before isolating the corresponding enol compound XIV.

If it is desired to prepare aryl tetralones VI, the cyclization of the corresponding cyclopropyl ketones XIII is carried out under the same conditions as described above for the preparation of enol compounds XIV, except that the reaction is allowed to proceed until the conversion to aryl tetralones is complete. In addition, it has been found that the cyclization reaction can be carried out using catalytic amounts, about 0.1 equivalent of acid anhydride. It is preferred that the cyclization be performed using one equivalent of acid polyanhydride, and most preferably about two equivalents, to complete the reaction in about 1-2 hours and to obtain a purer product. In a process using a weak Lewis acid such as ZnCl 2 and 2 equivalent acid anhydride, it is recommended that the reaction be allowed to proceed for more than 24 hours. It will be appreciated that if less than about 1-2 equivalents of acid anhydride are used in the cyclization reaction, then longer reaction times may be necessary to complete the reaction.

In one of the specific examples illustrated in Scheme 9, I: 37 '39913

Diagram 9 ° °

(] XCOOC2H5 (H

CH70 '^ V ^ ÖCH3 J ^ TlL

OCH CH3O ^ V ^ OCH3 ± U OCH3

Xllla \ -7i VIb 0 /

15 II

O-C-CH

Compound XIIIa of OCH 3 XIVb was treated with one equivalent of 25 BF 3 .Et 2 O and 2 equivalents of acetic anhydride to give the enol intermediate XIVV in about 1 hour in 96% yield of the aryl tetral. In another example, compound XIII was treated with one equivalent of ZnCl 2 and two equivalents of acetic anhydride to give the enol compound XIVb in greater than 90% yield in about 24 hours. The above examples as well as other examples in which anhydride has been used clearly and generally illustrate the general applicability and advantages of said method.

35 38 9 913 The compounds of formula X of this invention are intermediates in the preparation of a compound of formula 1 ^ i {i ..... ° r2 ^ - 'Mr "ii>: I1 o

Ml 10 „4 R 1 5

OR

wherein R 1 and R 2 are each independently hydrogen or lower alkoxy, or R 1 and R 2 together represent methylene-dioxy; R 4 and R 6 are each independently hydrogen or lower alkoxy; and R 5 is hydrogen or a phenol protecting group, or a pharmaceutically acceptable addition salt thereof, by a method comprising the following steps; (a) a cis-olefin having the formula 20 00R 3

R = IX

i ", -Φ * OR5 wherein R3 is hydrogen or a carboxyl protecting group; and R 1, R 2, R 4, R 5 and R 6 are as defined above, are reacted with nitrile oxide of formula Θ Θ

r7-c = n — 0 XX

I; 35 oo '3 9 9 1 3 39 wherein R7 is hydrogen, halogen, lower alkoxycarbonyl, carboxyl, cyano, trimethylsilyl, phenylsulfonyl or phenoxycarbonyl, wherein the phenyl ring of R7 may have one or two substituents which independently of one another are lower alkyl. , halogen, lower alkoxy and trifluoromethyl members, in an inert solvent to give isoxazole of the formula 10 VyY "7 JY3 x

r2 Y COOR

15 R <ΫΥ

OR

wherein R 1, R 2, R 3, R 4, R 5, R 6 and R 7 are as defined above; (b) cleaving the isoxazole ring of a compound of formula X to give a compound of formula

OH

; : 25 i2 YY'-cooi3 Xlc

jfjL

OR5 wherein R1, R2, R3, R4, R5 and R6 are as defined above; (c) selectively reducing the nitrile of formula Xlc to give a compound of formula 40 S 9 91 3

OH

R 1 s s "" i -j 5 R CCOR 3 XId OR ° 10 wherein R 1, R 2, R 3, R 4, R 5 and R 6 are as defined above, or a salt thereof; and if R 3 is a carboxyl protecting group, said carboxyl protecting group is removed, whereby obtaining a compound of formula XId wherein R 3 is hydrogen, and (d) cyclizing the compound of formula XId by diazotizing the amino radical and then lactonating to give a compound of formula

20 rI

r2 XU

J. o ::, 4 • 25 * 5

. . OR

wherein R 1, R 2, R 4, R 5 and R 6 are as defined above.

A preferred embodiment of this method is a method of preparing epipodophyllotoxin compounds of the formula

OH

0 kjl CH.O - ^^ OCH.

3 T 5 o OR

> · J 9 Q1 3 41 is * ιο wherein R5 is hydrogen or a phenol protecting group, the process comprising the steps of: (a) a cis-olefin having the formula ego.

'COOR3 01 10 CH3o / NTV OCH3 ord j wherein R3 is hydrogen or a carboxyl protecting group and R5 is hydrogen or a phenol protecting group, is reacted with nitrile oxide 15 having the formula © Θ

r7-c = n — 0 XX

Wherein R 7 is hydrogen, halogen, (lower) alkoxycarbonyl, carboxyl, cyano, trimethylsilyl, phenylsulfonyl or phenoxycarbonyl, wherein the phenyl ring of R 7 may have one or two substituents independently selected from lower alkyl, halogen, lower alkoxy and trifluoroalkoxy. in an inert solvent to give: isoxazole of formula

n- N

: 30: v ^ - ^^ v ^ '' '' coor3 Za Λ

OR

· '35 0 913

42 · "7 1 J

wherein R3, R5 and R7 are as defined above; (b) cleaving the isoxazole ring of a compound of formula Xa to give a compound of formula 5 R 3 1 5 -5 OR "5 wherein R 3 and R 5 are as defined above; (c) selectively reducing the nitrile of formula Xla to give a compound of formula

OH

20 3 o "CCOR3 VT.

r Xl D

ifil 25 »T e 3

OR

wherein R3 and R5 are as defined above, or a salt thereof; and, if R 3 is a carboxyl protecting group, removing said carboxyl protecting group to give a compound of formula Xlb wherein R 3 is hydrogen; and (d) cyclizing the compound of formula Xlb by diazotizing the amino radical and then lactonating to give an epipodophyllotoxin compound of the formula: li 8 9 91 3 43

OH

la CH Äl 3, 5 0CH3

OR

wherein R5 is as defined above.

10 A cis-olefin of the formula I ^ '1 J. "5"' COOK "τχ 1ζ R sf} k ^ Vk6 OR5 20 wherein R1 and R2 are each independently hydrogen or lower alkoxy, or R1 and R2 together denote methylene- R3 is hydrogen or a carboxyl protecting group, R4 and R6 are each independently hydrogen or lower alkoxy, and R5 is hydrogen or a phenol protecting group, may be prepared by a process comprising the steps of: (a) dehydrating an alcohol of formula

OH

'' OÖ. .

: -: r2 VII

.

r4 • 35 0R ° 0 9 913 44 wherein R3 is a carboxyl protecting group; R4 is a phenol protecting group; and R 1, R 2, R 4 and R 5 are as defined above, in the presence of an acid to give a trans-olefin of formula 5 2 COOR 3

R ^ VIII

· Λ1-

OR

wherein R 1, R 2, R 3, R 4, R 5 and R 6 are as defined above; and (b) epimerizing the trans-olefin of formula

According to Vili, by treatment with a strong base at low temperatures in an inert organic solvent, followed by treatment with an acid to give a cis-olefin of formula

R2r \ ^ Y "'COOR3 IX

: 25 jDl r4 -? OR5 wherein R1, R2, R3, R4, R5 and R6 are as defined above, and optionally and selectively cleavage to give a compound of formula IX wherein R3 is hydrogen and R5 is a phenol protecting group or R5 is hydrogen and R3 is a carboxyl protecting group .

: 35 li 45 39913

A preferred embodiment of the process of this invention is a stereospecific process for the preparation of an isoxazole compound of the formula ζΊ ^ Τί j xa ^ .....-> - · -> · 'CCOR3 "Λ

OR

Wherein R3 is hydrogen or a carboxyl protecting group; R 5 is hydrogen or a phenol protecting group and R 7 is hydrogen, halogen, lower alkoxycarbonyl, carboxyl, cyano, trimethylsilyl, phenylsulfonyl or phenoxycarbonyl, wherein the phenyl ring of R 7 may have one or two substituents independently of one another formed by lower alkyl. -li, halogen, lower alkoxy and trifluoromethyl, the process comprising the step of reacting a cis-olefin of formula I orN • COOR3 IXa

jfäL

::: 30 CH3 ° ^ TVocH, OR33 wherein R3 and R5 are as defined above are reacted with nitrile oxide of formula 35 46; ^ 91 3 ® Θ

R7-C = N - 0 XX

wherein R 7 is as defined above, in an inert solvent which is water or an organic solvent, or in a mixture of water and an organic solvent at about -20 ° C - at the boiling point of the solvent to stereoselectively obtain said isoxazole compound of formula Xa, and optionally and selectively cleaving said compound of formula Xa wherein R 3 is a carboxyl protecting group to give a compound of formula

0'N

15 '.......

o '"COOH xb Λ -5 le ->

20 OR

wherein R5 and R7 are as defined above.

A preferred process for using the compounds of this invention as intermediates is also a process for preparing an epipodophyllotoxin compound of the formula

ALRIGHT

iV

- I 5 -3

• 35 0R

47 ο 9 51 3 wherein R 5 is hydrogen or a phenol protecting group, the process comprising the steps of: (a) cleaving the isoxazole ring in a compound of formula 5 f> -r 7

o OOH

10 OCH3 OR1 wherein R5 is hydrogen or a phenol protecting group and R7 is chlorine or bromine to give a nitrile of formula

OH

T ON

20 0 C00H Xie CH, 0 ^ s / oCH,

·: ·: 25 3 1 5 J

OR1 · "" wherein R5 is hydrogen or a phenol protecting group; (b) selectively reducing the nitrile of formula Xie to give a compound of formula 30

OH

o N ^ VIVCH2NH2 0 ^^ Y '' '' coOH XIf:: 35

I 5 J OR

48: 9913 wherein R5 is hydrogen or a phenol protecting group; and (c) cyclizing the compound of formula XIf by diazotizing the amino radical and then lactonating to give the epipodophyllotoxin compound of formula 5.

OH

10

O

C, 3 ° ^ V ^ OCH 3

0R

Wherein R5 is hydrogen or a phenol protecting group.

A variation of the above process for the preparation of compounds of formula XII involves the selective reduction of a trans-aryltetralone of formula VI under hydrolysis conditions or the hydrolysis of a carboxylic acid ester of a trans-aryltetralone of formula VI followed by selective reduction of the resulting acid Va to give compound. Compound VIIa is then treated under dehydration conditions in the presence of an acid to give a trans-lactone of formula 25:

f.2 Y- V

30

Re OR "5 l ·; 35 49:.) 9 91 3 wherein R 1, R 2, R 4, R 5 and R 6 are as defined above. Compound XV is dehydrated in the presence of an acid and an alcohol R 3 OH to give a trans-olefin of formula VII wherein R 3 The trans-olefin VIII epi-5 is then polymerized via enolate formation to give a cis-olefin of formula IX. Compound IX is then reacted with a nitrile oxide of formula XX and the isoxazole of formula X, which is then sequentially formed, is cleaved by formula Xla. and reduced to the amine of formula Xlb, and then diazotized according to the method described above to give the desired compound of formula XII.

Further, variant 15 of the process described above for preparing compounds of formula XII close to epipodophyllotoxin and epipodophyllotoxin involves epimerization of a trans-aryltetralone of formula VI via enolate formation to give a cis-aryltetralone of formula 20.

r2 ^^^ C ^^ coor3 XVI

;: 25 O

0RS

::: 30 wherein R1, R2, R3, R4, R5 and R6 are as defined above.

Compound XVI is then selectively reduced to give a compound of formula 50,913

l? H

r2 3 6 4 6 R3 νΓ ^ 5 OR3 10 wherein R1, R2, R3, R4, R5 and R6 are as defined above. Compound XVII is then dehydrated in the presence of an acid by removing the water formed to give a cis-olefin of the formula 15 ° C2 - "A''n ^ Asv ^ /, / C00R3

IX

20 6 a4 X'6

OR

wherein R 1, R 2, R 3, R 4, R 5 and R 6 are as defined above.

The cis-olefin of formula IX is then reacted with a nitrile oxide of formula XX, and the resulting isoxazole of formula X is sequentially cleaved to the nitrile of formula Xla and reduced to the amine of formula Xlb, and then diazotized according to the procedure described above to give X compound. Still further, a variation of the process described above for the preparation of compounds of formula XII involves the epimerization of a transaryl tetralone of formula VI via enolate formation to give a cis-aryl tetralone of formula I 51 '9 91 3 *

R X Jl Λ 3 COORJ

-X ·

OR

wherein R 1, R 2, R 3, r 4, r 5 and R 6 are as defined above.

Compound XVI is then selectively reduced under hydrolysis conditions or hydrolyzed and then selectively reduced to give a compound of formula

20 R’VX

OR5 wherein R1, R2, R4, R5 and R6 are as defined above. Compound XVIII is dehydrated in the presence of an acid and an alcohol R 3 OH to give a cis-olefin of the formula BrXX 2 O 3, OR 5:35 52 ^ 915 wherein R 1, R 2, R 3, R 4, R 5 and R6 are as defined above.

The cis-olefin of formula IX is then reacted with a nitrile oxide of formula XX, and the resulting isoxazole of formula X is sequentially cleaved to the nitrile of formula Xla and reduced to the amine of formula Xlb, and then diazotized according to the procedure described above to give the desired Compound according to XII.

A compound of formula 10

O

" Joy

o-c- and DTl 15 R2 X - '"^ SV ^ * C00R3 A.

K4 OR "5 wherein R1 and R2 are each independently hydrogen or lower alkoxy, or R1 and R2 together represent methylenedioxy; R3 is hydrogen or a carboxyl protecting group; R4 and R6 are each independently hydrogen or lower alkoxy; and R5 is hydrogen or phenol protecting group, can be prepared by a process comprising the step of cyclizing a cyclopropyl compound of the formula

I j J> - COORJ

: X XIII

jfjL

'Ύ *' I: 53 53913 wherein R 1, R 2, R 3, R 4, R 5 and R 6 are as defined above, by treatment with at least 0.5 equivalents of Lewis acid and at least one equivalent with an acid anhydride of formula 5

O

9 "(R * C-) 2 O wherein R 9 is phenyl or lower alkyl optionally substituted with one or more halogen atoms from fluorine, chlorine and bromine in an inert solvent until a compound of formula of formula

O

15 II g

0-C-R

h xiv 20 f '' 1.'V »OR5 wherein R1, R2, R3, R4, R5, R6 and RY9 are as defined above. 25 A compound of the formula 30 L 1 _,

:; : 2 '^ vwx', '\ x ^ CCCR-S

R 'Ξ VI

R 0 R 35 35 54 3 R 9 wherein R 1 and R 2 are each independently hydrogen or lower alkoxy, or R 1 and R 2 together represent methylenedioxy; R 3 is hydrogen or a carboxyl protecting group; R 4 and R 6 are each independently hydrogen or lower alkoxy; 5 and R 5 is hydrogen or a phenol protecting group, can be prepared by a process comprising the step of cyclizing a cyclopropyl compound of formula 0 R 3

| COOR

A XI11 -V "Is 4

R T 5 R

15 0R

wherein R 1, R 2, R 3, R 4, R 5 and R 6 are as defined above, by treatment with at least 0.5 equivalents of Lewis acid and at least with a catalytic amount of an acid anhydride of formula

O

9 "(R * C-) 20 wherein R9 is phenyl or lower alkyl optionally substituted with one or more halogen atoms of fluorine, chlorine and bromine in an inert organic solvent until a trans-aryltetralone of formula: : 30 vi 35 ·. AA »6 r k5 55 '19913 wherein R1, R2, R3, R4, R5 and R6 are as defined above.

A preferred embodiment of this process is a process for preparing a trans-aryltetralone of the formula 5 wherein R 1 is hydrogen or a carboxyl protecting group and R 5 is hydrogen or a phenol protecting group, the process comprising the step of cyclizing a compound of formula

O

5 · Zlllb

XX

OCH,

J 1 5 J

Wherein R3 is a carboxyl protecting group and R5 is a phenol protecting group, by treatment with about one equivalent of Le-wis acid and about one to two equivalents of an acid polyanhydride of formula

O

g «(R c -) 20 35 wherein R 9 is lower alkyl optionally substituted with one or more halogen atoms of fluorine, chlorine and bromine in an inert organic solvent until a predominantly transaryltetralone of formula 5 0 VIc

A

J T 5 J OR

Wherein R 3 and R 5 are as defined above, and optionally and selectively cleavage to give a compound of formula VIc wherein R 3 is hydrogen and R 5 is a phenol protecting group or R 5 is hydrogen and R 3 is a carboxyl protecting group.

20 Description of Specific Embodiments

The following examples further illustrate the invention as well as the preparation of the starting materials of the process of the invention and the overall synthesis of epipodophyllotoxin in which the compounds of the invention are intermediates.

25 In the following examples, all temperatures are il

reprimanded in degrees Celsius. Melting points were recorded on a Thomas-Hoover capillary melting point apparatus and are uncorrected. * 1 H NMR spectra were recorded on a Bruker WM

360 spectrometer in CHCl 3. Chemical shifts are reported in 6 units and coupling constants in Hertz. The pilk accumulation patterns are labeled as follows: s, singlet; d, doublets; t, triplets; g, quartet; m, multiplet; bp, wide peak; and dd, doublet doublet. Infrared spectra were determined on a Beckman Model 4240 spectrophotometer and are reported in inverted centimeters. Thin layer chromatography! 57 3 9 91 3 set (TLC) assays were performed on precoated silica gel plates (60F-254) using UV light and / or ion vapors to visualize the substances. Flash chromatography was performed on Woelm silica gel (32-63 μm) and 5 in said solvents. All solvent evaporations were performed in vacuo. As used herein, the term Skellysol-ve B is a petroleum solvent fraction having a bp range of 60 to 68 ° C, containing predominantly n-hexane, and the term "ether" means diethyl ether, unless otherwise indicated.

53 .3991 3

Example 1

Ethyl 2- (3,4-methylenedioxybenzoyl) -3- (3,4,5-trimethoxyphenyl) cyclopropanecarboxylate (XHIa) - 5

I 11 WaH

10 T ^ 0ch3 © ^ 'UJ ^ oc · - · OCH3 (CHO-SCH CO-CH, Cn30 T “3 3 Ji Δ L · Z, D npy ^ C) 3 XXI Ia ar ~ ^ XHIa 15 In a three-necked liter round-bottomed flask Equipped with a magnetic stirrer, a dropping funnel, a nitrogen inlet tube and a septum, sodium hydride (8.2 g, 0.17 mol, 50% dispersion) was applied. The dispersion was washed with petroleum ether (2 x 100 mL) and dried under nitrogen. Trimethylsulfoxonium iodide (37.7 g, 0.17 mol) was added, followed by dropwise addition of dry dimethyl sulfoxide (45 mL) via syringe over 30 minutes. The suspension was stirred at room temperature for 1.5 hours and then a solution of carbethoxymethyl * dimethylsulfonium bromide (41.1 g, 0.18 mol) in dimethyl sulfoxide (60 ml) was added over 10 minutes with constant stirring. The milky white suspension was further stirred at room temperature for 1.5 hours. added; a suspension of 3,4,5-trimethoxy-3 ', 4'-methylenedioxychalcone XXIIa (55.9 g, 0.16 mol) / prepared by S. Wattanasin and WS According to the procedure described by Murphy, Synthesis, 647 (1980) in dimethyl sulfoxide (185 mL), and then the reaction mixture was stirred at room temperature for 17 hours. The reaction mixture was poured into cold 0.1 N HCl (700 mL). ml), and the resulting gummy substance was separated from the aqueous solution.

59 S9913 was extracted with ether (2 x 500 mL). The combined extract together with the added amount of ether (500 ml) was used to dissolve the gummy precipitate. The ether solution was washed successively with aqueous NaHCO 3 (500 mL, 5%) and water, dried (Na 2 SO 4 and MgSO 4) and evaporated to dryness to give the α-isomer of the title compound (68.0 g) as a pale yellow glass. The NMR spectral values of this material were identical to W.S. With the α-isomer values reported by Murphy and S. Wattanasin, J.C.S. Perkin I, 271 10 (1982). In the second experiment, the trimethylsulfoxonium iodide used in the above process was omitted from the reaction mixture to give, in high yields, the α-isomer of the title compound. Thus, to a solution of sodium hydride (0.67 g, 1.4 mmol, 50% dispersion) in 10 mL of dry dimethyl sulfoxide was added carbethoxymethyl dimethylsulfonium bromide (2.98 g, 1.2 mmol). and then another 19 ml of dimethyl sulfoxide. After about 75 minutes, a solution of chalcone XXIIa (3.42 g, 1.0 mmol) in 21 mL of 20 tetrahydrofuran and 4 mL of dimethyl sulfoxide was added slowly over 35 minutes. The reaction mixture was worked up as in the above procedure to give the α-isomer of the title compound in 96% yield.

Example 2

Trans-ethyl 1,2,3,4-tetrahydro-6,7-methylenedioxy-4-oxo-1-25 (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylate (VIb) _

·: ··: O O

3 ° c h

· "'· \ L M ° 2C2n5 -x L 1 I

-. · ^ Ό ^ SnL ^ xvvXs * COOC2K5 CC H,: ^ OCH, J CP., O "'y OCH, 35 J 3 och3 3 X111 a VIb 60 -59913

To a solution of cyclopropyl ketone XHI (0.8 g, 1.8 mmol) in methylene chloride (40 mL) was added BF 3. Et 2 O (0.24 mL, 19 mmol) followed by acetic anhydride (0.36 mL, 3.8 mmol). The solution was stirred at room temperature for 2.5 hours and then diluted to 0.2 norm. sodium hydroxide solution (50 ml) and methylene chloride (50 ml). The organic layer was separated, washed (H 2 O)> dried (MgSO 4) and concentrated to an oily solid (0.72 g). Recrystallization from absolute ethanol, treatment with charcoal gave the title compound as a white crystalline solid (0.46 g); mp. 157-159 ° C. The NMR spectral values were consistent with the values reported by W.S. Murphy and S. Wattanasin had reported, J.C.S. Perkin I, 271 (1982).

1 5 Example 3

Trans-ethyl 1,2,3,4-tetrahydro-6,7-dimethylenedioxy-4-oxo-1- (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylate (VIb)

The procedure of Example 2 was repeated with 50 mg (0.12 mmol) of cyclopropyl ketone XHI, except that

the methylene chloride used as this was replaced with nitromethane to give 45 mg of the title compound; TLC

/ silica gel / ether: Skellysolve B (3: 2) gave an Rf of 1 r 0.26. The 1 H NMR spectral values were identical to those of the product prepared in Example 2.

Example 4

Trans-ethyl 1,2,3,4-tetrahydro-6,7-methylenedioxy-4-oxo-1- (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylate (VIb): (a) The procedure of Example 2 was repeated. procedure in methylene chloride with 50 mg (0.12 mmol) of a cyclopropyl ketone of formula XHIa, except that BF-j used therein. Et 2 O was replaced with SnCl 2 to give the title compound in about 90% yield.

(b) The above procedure (a) was repeated except that the methylene chloride used therein was replaced with nitromethane to give the title compound in about 90% yield.

li 61, .8991 3 (c) The above procedure (a) was repeated again, except that the methylene chloride used therein was replaced with benzene to give the title compound.

In the TLC analysis of each of the above three products / silica / ether: Skellysolve B (3: 2] -7Rf was 1 L 0.26, and the 1 H NMR spectral values were identical to those of the product prepared in Example 2.

Example 5

Trans-ethyl 1,2,3,4-tetrahydro-6,7-methylenedioxy-4-oxo-10- (3,4,5-triroethoxyphenyl) naphthalene-2-carboxylate (VIb

The procedure of Example 3 was repeated using 428 mg (1.0 mmol) of cyclopropyl ketone XHI and 204 mg (2.0 mmol) of acetic anhydride in 5 mL of nitromethane, except that 1 equivalent of BF 2 was used. Et 2 O was replaced with 0.5 equivalents of BF 3. Et-0 (71 mg, 0.5 mmol) to give the title compound. The 1 H NMR spectral values were identical to those of the product prepared in Example 3.

Example 6 Trans-ethyl 1,2,3,4-tetrahydro-6,7-methylenedioxy-4-oxo-1- (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylate_ (VIb)

To a solution of cyclopropyl ketone XHI (428 mg, 1.0 mmol) in 5 mL of nitromethane was added a catalytic amount of acetic anhydride (10.2 mg 0.1 mmol-25) followed by BF 3. Et 2 O (142 mg, 1.0 mmol). The reaction mixture was stirred at room temperature and then subjected to high pressure liquid chromatography. After about 100 hours, the reaction mixture was treated with 10 mL of 0.2-norm. NaOH and diluted with 5 mL of methylene chloride. The organic phase was separated, dried and evaporated to dryness in vacuo to give the title compound. The 1 H NMR spectrum was otherwise identical to that of the product prepared in Example 2, except that some impurities were present.

Example 7

Trans-ethyl 1,2-dihydro-6,7-methylenedioxy-4-acetoxy-1- (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylate (XIVb) 62,39913

O

5 0 ϋ \ o-cch3 / 0 / ° - {| J O-CO 2 C 2 H 5 (k'1 'A -r >> ^ \ ^ y ^ cc 2c

10 KH3 Jkj_ OCH ^ CH.O OCH.

3 J OOH, J

To a solution of cyclopropyl ketone XHIa (1.40 g, 3.24 mmol) in methylene chloride (50 mL) was added acetic anhydride (0.61 mL, 6.47 mmol) followed by BF 3. Et 2 O (0.40 mL, 3.25 mmol). The solution was stirred for 5 minutes and then treated with 0.5 norm.

With 20 sodium hydroxide solution (35 ml). The organic layer was separated, washed (H 2 O), dried (MgSO 4) and concentrated to a syrup (1.53 g). TLC (ethyl acetate: methylene chloride (5:95)) gave two main spots at Rf = 0.47 and Rf = 0.27 (starting material Rf = 0.36). Chromatography on a silica gel column using 3 as eluent % ethyl acetate in methylene chloride, the two compounds were obtained analytically pure.

The faster component (0.52 g, Rf = 0.47) was characterized as the title compound, m.p. 1 24-129 ° C.

Analysis calculated for C 25 H 26 O 9: C ^ 3> 82; H 5> 57 found: C 63.52; H, 5.74.

1 H NMR (CDCl 3, δ); 1.18, (t, 3H, 7.2 Hz), 2.31 (s, 3H), 3.62 (t, 1H, 5.5 Hz), 3.81 (s, 9H), 4.10 (q 2H), 4.49 (d, 1H, 5.5 Hz), 5.55 (d, 1H, 5.7 Hz), 5.92 (s, 2H =, 6.52 (s, 3H ), 6.68 (s, 1H).

63 3991 3

The slower component (0.40 g, = 0.27) was identified as tetralone VIb, which was identical to the compound obtained in Example 2.

Example 8 Trans-ethyl 1,2-dihydro-6,7-methylenedioxy-4-acetoxy-1- (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylate (XIVV

The procedure of Example 7 was repeated, it was decided that the BF 3 -Et 2 O used therein was replaced with ZnCl 2 and after 24 hours at room temperature, the reaction gave the title compound in> 90% yield; TLC / silica gel / ethyl acetate: methylene chloride (5.95) gave an Rf of 0.47. The 1 H NMR spectral values were identical to those of the product obtained in Example 7.

Example 9

Cis-ethyl-1,2,3,4-tetrahydro-6,7-methylenedioxy-4-oxo-1-5 (3,4,5-trimethoxyphenyl) -naphthalene-2-carboxylate (XVIb)

O O

(. 7 i Γ ^ ΐί ^ Ί> 0 OOC2H5 -—> 0 20 ^ = A 5 jf \ f \ -> T J 3 i 3 0CH3 OCH, 2 5 VIb XVIb

To a solution of 1.7 mol. n-Butyllithium in hexane (10.6 mL, 18.0 mmol), tetrahydrofuran (10 mL) at -78 ° C, and under nitrogen protection, diisopropylamine (2.52 mL, 18.0 mmol) was added slowly. After stirring for 20 minutes, the solution was added dropwise. a solution of trans-tetralone VIb (1.93 g, 4.51 mmol) in tetrahydrofuran (40 mL) over 30 minutes at -78 ° C. After the addition was complete, the orange mixture was slowly warmed to -40 ° C over 1 hour and stirred for an additional 30 minutes. A concentrated solution of 64,8991 3 HCl (3.5 mL) in tetrahydrofuran (3.5 mL) was then added in one portion to give a pale yellow solution. After warming to room temperature, the mixture was diluted with 50 ml of water and extracted with ethyl acetate. The combined organic extract was dried (MgSO 4) and evaporated to dryness to give 2.1 g of product which was crystallized from 95% ethanol. Recrystallization from absolute ethanol, cooling slowly to room temperature, gave the title compound as a crystalline solid, m.p. 1 36.5 - 137.5 ° C.

1 H NMR (CDCl 3, f); 1.24 (t, 3H, 8 Hz), 2.88 (m, 2H), 3.52 (m, 1H), 3.76 (s, 6H), 3.84 (s, 3H), 4 , 16 (q 2H, 8 Hz), 4.72 (d, 1H, 6 Hz), 6.10 (s, 2H), 6.24 (s, 2H), 6.68 (s, 1H), 7 .64 (s, 1H).

Example 10 Ethyl 1,2,3,4-tetrahydro-6,7-methylenedioxy-4-hydroxy-1- (3,4,5-trimethoxyphenyl) naphthalene, 2-carboxylate (VI Id)

0 OH

20 <(T, .Λ (i ^ i i I

fX "^ rX

IX I H

0CH3 0CH3 GCH7 .25 3

Vlb Vlld

To a solution of tetralone VIb (6.25 g, 14.6 mmol) in 95% ethanol (100 mL) and methylene chloride 30 (50 mL) was added a cold solution of sodium borohydride (0.42 mmol). g, 11.1 mmol) in water (5 mL). The solution was stirred at room temperature for 3 hours and at 40 ° C for 30 minutes. The solution was diluted with water (50 ml) and evaporated to a solid residue at 35 ° C. The residue was partitioned between methylene chloride (100 ml) and water (100 ml). The aqueous layer was further extracted with methylene chloride (65 ml) and the combined organic extract was dried (MgSO 4) and evaporated to a solid residue (5.95 g). .

Recrystallization from 95% ethanol gave the title compound as a crystalline solid; 5 sp. 151-152 ° C.

Analysis calculated for C 23 H 26 O 8: C, 64.18; H, 6.09 Found: C, 64.03; J, 6.02.

1 H NMR (CDCl 3, δ): 1.15 (t, 3H, 7.2 Hz), 2.06 (m, 1H), 2.35 (m, 1H), 2.46 (d, 1H, δ) , 6 Hz), 2.95 (m, 1H), 3.78 (s, 6H), 3.82 (s, 3H), 4.06 (q, 2H, 7.2 Hz), 4.31 (d, 1H, 7.7 Hz), 4.83 (m, 1H), 5.91 (2H), 6.24 (s, 2H), 7.07 (s, 1H).

IR (KBr), νmax, cm -1: 3290, 1730, 1725, 1590, 1235, 1122. Example 11

Trans-ethyl 1,2-dihydro-6,7-methylenedioxy-1- (3,4,5-15 trimethoxyphenyl) naphthalene-2-carboxylate (VIIIb)

OH

e.

C H-, OCH, ΟΗ, Ο ^ ν ^ OCH- J och3 3 3 0CH3 3 25 vild VIIIb

A suspension of alcohol Vild (0.43 g, 1.0 mmol) in toluene (15 mL) with p-toluenesulfonic acid monohydrate (4 mg) was heated to reflux. f for 30 n using a Dean-Stark trap. TLC / ethyl acetate: Skellysolve B (1: 1/7 revealed that all starting material (Rf = 0.40) had been converted to the new ... compound (Rf = 0.69). The liquid was cooled, washed with 5% aqueous sodium hydrogen carbonate and water, then concentrated in vacuo to an oily residue to give a residue which was purified by column chromatography on silica gel (20 g) using methylene chloride and 3% ethyl acetate in methylene chloride as eluent to give R ) as a white amorphous solid, mp 129.5-130.5 ° C.

Analysis calculated for C 23 H 24 O 7: C, 66.98; H, 5.87 Found: C, 66.83; H, 5.87.

1 H NMR (CDCl 3, δ): 1.14 (t, 3H, 7.3 Hz), 3.58 (m, 2H), 3.80 (s, 6H), 3.83 (s, 3H), δ .07 (q, 2H, 7.3 Hz), 4.40 (d, 1H, 9.4 Hz), 5.82 (dd, 1H, 3.9 Hz, 9.6 Hz), 5.89 (t, 2H), 6.39 (s, 1H), 6.42 (s, 2H), 6.49 (dd. 1H, 2.0 Hz, 9.6 Hz), 6.63 (s, 1H).

IR (KBr), νmax, cm -1: 1726, 1580, 1240, 1125,

Example 12 1,2,3,4-Tetrahydro-6,7-methylenedioxy-4-hydroxy-1- (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylic acid (VIIb) -

O

Il CH

20 NaBH, ^ Ä '^ ήι "CH, 0. OCH., .A.

J OCH- 3 C "3 ° ^ XT ^ CCH2 3 CC H, 25 ->: VI = VIII

The tetralone VIb prepared in Example 2 was hydrolyzed according to the method described by W.S. Murphy 30 3a S. Wattanasin, J.C.S. Perkin I, 271 (1982), and formed 1,2,3,4-tetrahydro-6,7-methylenedioxy-4-oxo-1- (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylic acid (VId) was treated with sodium borohydride according to the general method described by WJ Gensler vm.

35 J. Am. Chem. Soc., 82, 1714 (1960) to give the title compound as a crystalline solid; mp. 191.5-193 ° C (reported mp 181.4-182 ° C.

Il 61 '3991 3

Example 13

Trans-1,2-dihydro-6,7-methylenedioxy-1- (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylic acid (ynic) ___

5 OH

<n> 1 1 (! I I

= «____ ^ - 2 f ^ l '^ 10 Jo Us CH, 0 || OCH, CH., 0 OCK, och3 j ÖCH3 3

Vllb ville

A suspension of alcohol VIIIb (400 mg, 0.99 mmol) in toluene (20 mL) with p-toluenesulfonic acid monohydrate (10 mg) was boiled for 2 hours using a Dean-Stark trap. The reaction solution was cooled, washed with water (15 ml), dried (MgSO 4) and evaporated to dryness to a white solid (364 mg).

Recrystallization of the solid by treatment with charcoal gave the title compound as a crystalline solid from methanol; mp. 177-180 ° C.

Analysis calculated for C 21 H 20 O 7: C, 65.62; H, 5.24 Found: C, 65.61, H, 5.26.

1 H NMR (CDCl 3, δ): 3.60 (m, 1H), 3.78 (s, 6H), 3.82 (s, 3H), 4.40 (d, 1H, 7, 8 Hz), 5.83 (dd, 1H, 4.6 Hz, 9.6 Hz),: 1.91 (d, 2H), 6.39 (s, 2H), 6.41 (s, 1H), 6.53 (dd, 1H, 1.8 Hz, 9.7 Hz), 6.64 (s, 1H).

1H (KBr), vmax, cm-1: 1745, 1710, 1590, 151 0, 1485, 1250, 30 1 1 30.

Example 14

Trans-benzhydryl-1,2-dihydro-6,7-methylenedioxy-1- (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylate (VIIIa) ___ 68 5 9 913 5 / ° "7 ^

/] il C: I | I

^ - ^, ^ v ^ CO2CHPh2; fii * "0 10 C '" 3 ° ^ H3OC ·' "3

A solution of the acid Ville (1.63 g, 4.24 mmol), benzhydryl alcohol (0.79 g, 4.29 mmol), p-toluenesulfonic acid monohydrate (37 mg) in toluene ( 100 ml), boiled for 2 hours using a Dean-Stark trap. The progress of the reaction was monitored by flash chromatography (2% ethyl acetate in methylene chloride). The solution was cooled to room temperature and washed with 5% aqueous sodium hydrogen carbonate solution (90 ml), water (50 ml), dried (MgSO 4) and concentrated to a brown oil (2.43 g) which was further purified by column chromatography (silica gel). to give the title compound as an amorphous solid; mp. 149-156 ° C.

Analysis calculated for C 1-10 H 2 O 2: C, 74.17; H, 5.49 J J / C, 74.13; H, 5.62.

1 H NMR (CDCl 3, δ): 3.72 (s, 6H), 3.73 (m, 1H), 3.83 (s, 3H), δ 4.41 (d, 1H, 9.6 Hz), 5.84 (dd, 1H, 4.2 Hz, 9.6 Hz), 5.89 (t, 2H), 6.35 (s, 1H), 6.38 (s, 2H) , 6.52 (dd 1H, 2.0 Hz, 9.6 Hz), 6.65 (s, 1H), 6.77 (s, 1H), 7.37-7.07 (m, 10H).

li

Example 15 dl-8,9-Dihydro-9- (3,4,5-trimethoxyphenyl) -5,8-methano-1,3-dioxolo (4,5-h) (2) benzoxepin-7 (5H) -one (5β, 8β, 9α) (XVa) _ 69 0 9 913 OK n 5 n 7 ΎιΓί 1/1 ° CH.O ^ Y ^ OcH3 CH3o'iV ^ OCH3 OCK3 0CH3 leads xvz

A suspension of alcohol VIIIb (42.9 g, 0.107 mol) per liter of toluene with p-toluenesulfonic acid monohydrate (500 mg) was heated at reflux for about 2.5 hours using a Dean-Stark trap. The mixture was then treated with 19.6 grams (0.107 moles) of benzhydryl alcohol in 100 mL of toluene and boiled for an additional 3 hours. The reaction mixture was washed with 5% aqueous Na 2 CO 3 and saturated NaCl solution, dried (MgSO 4) and concentrated to 49.0 g.

The residue was purified by column chromatography on silica gel (350 g) using cetene methylene chloride -5% ethyl acetate in methylene chloride as the eluent to give the title compound. The sample was recrystallized from 95% ethanol by treatment with charcoal to give the title compound as a crystalline: solid; mp. 191.5 - 193 ° C.

. ·: ·. Analysis calculated for C 21 H 20 O 7: C, 65.79; H, 5.26 Found: C, 65.32; H 5.30.

1 H N MR (CDCl 3, δ) s 2.43, (m, 2H), 2.98 (d, 1H, 5.0 Hz), 3.73 (s, 6H), 3.84 (s, 3H) , 4.40 (bs, 1H), 5.25 (d, 1H, 4.8 Hz), 5.97 (m, 2H), 6.29 (s, 2H), 6.49 (s, 1H) , 6.75 (s, 1H).

70 39 91 3

In the second experiment, the above procedure was repeated, except that the benzhydryl alcohol used therein was omitted from the reaction mixture, and the desired lactone XVa was obtained.

5 Example 16

Trans-benzhydryl-1,2-dihydro-6,7-methylenedioxy-1- (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylate (Villa) o.

10 o r ° o <n> <i 1

15 CH, 0 ^ V ^ 0 = H3 CH

3 OCH, o :: ": 3 XVa Villa

A mixture of lactone XVa (3.9 g, 10.2 mmol) and benzhydryl alcohol (1.87 g, 10.2 mmol) in 100 mL of toluene with p-toluenesulfonic acid monohydrate (200 mg) was heated at reflux for about 2.5 hours using a Dean-Stark trap. After collecting a toeretic amount of water (0.2 mL), the reaction mixture was washed with saturated NaHCO 3 solution and saturated NaCl solution, dried (MgSO 4) and concentrated to an oil which was: further purified by eluting the methylene chloride solution of the oil on a silica gel pad. (15 g) with added methylene chloride: di (75 mL). The filtrate was evaporated to dryness in vacuo to give 4.06 g of product as an oil. A sample of this was further purified by column chromatography (Alumina) using mixtures of methylene chloride - 2% ethyl acetate in methylene chloride as eluent to give the title compound as an amorphous solid which was identical to the product prepared in Example 14; mp. 149-156 ° C.

I!

Example 17

Cis-ethyl 1,2-dihydro-6,7-methylenedioxy-1- (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylate (IXb) _ 71 3 9 91 3 u 2 2 5 O 'CC ^ C-, H_

Jk L j ^,! To a solution of a 1.7 M solution of n-butyllithium in hexane (7.3 mL, 12.4 mmol) in tetrahydrofuran (20 mL) - 10 CH O OCH CH 2 O 2 V 2 OCH, OCH 3 OCK 2 VHIb TXb 15 At 78 ° C under nitrogen, diisopropylamine (1.75 mL, 12.5 mmol) was added dropwise. After stirring for 5 minutes, a solution of trans-olefin VHIb (2.06 g, 5.0 mmol) in tetrahydrofuran (10 mL) was added dropwise via syringe over 20 minutes. After the addition was complete, the reaction mixture was warmed to -40 ° C over 30 minutes and stirred at this temperature for 30 minutes. To this stirred solution was added concentrated HCl (2.2 mL) in cold tetrahydrofuran (2.5 mL). The dry ice-acetone bath was removed and the reaction mixture was warmed to room temperature. The tetrahydrofuran was removed in vacuo and the resulting residue was partitioned between water (100 ml) and methylene chloride (100 ml).

The aqueous layer was further extracted with methylene chloride (50 mL), and the combined organic extract was washed with water (100 mL), dried (MgSO 4) and concentrated to an oil (2.1 g). This oil was further purified by column chromatography on silica gel using 5% ethyl acetate in methylene chloride as eluent to give the title compound as an amorphous solid 72,8991 3 (1.74 g). Recrystallization from ethanol gave an analytical sample; mp. 112-113 ° C.

Analysis calculated for C23H24O7: C, 6.98; H '5'87 Found: C, 66.87; H, 5.82.

1 H NMR (CDCl 3, δ): 1.12 (t, 3H, 7.2 Hz), 3.75 (s, 6H), 3.76 (s, 3H), 4.07-3.95 (m , 3H), 4.30 (d, 1H, 7.7 Hz), 6.11 (m, 2H), 6.45 (s, 2H), 6.50 (dd, 1H, 3.0 Hz, 9 .7 Hz), 6.61 (s, 1H), 6.65 (s, 1H).

IR (KBr), vmax. cm -1: 1730, 1592, 1508, 1490, 1250, 1130.

10 Example 18

Cis-benzhydryl-1,2-dihydro-6,7-methylenedioxy-1- (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylate (IXc) _ 15 r ^ 1 ____ ^ CCUCHPh-, ffjL j ^ Ti 20 CE3 ° ΧΓαΗ3 CK3 ° 'T ^ °° H3 0CH3 OCH, iXc

Villa

The procedure of Example 17 was repeated except that the trans-olefin VHIb used as sii-25 was replaced with the trans-olefin VIIIa to give the title compound as a waxy solid.

Analysis calculated for c34H3qO7: C, 74.17; H, 5.49: Found: C, 74.17; H, 5.76.

1 H NMR (CDCl 3, δ): 3.51 (s, 6H), 3.73 (s, 3H), 4.38 (dt, 1H, 7.4 Hz, 2.9 Hz), 4.38 ( d, 1H, 7.5 Hz), 5.91 (2H), 6.19 (dd, 1H, 2.7 Hz, 9.7 Hz), 6.40 (s, 2H), 6.51 (dd , 1H, 2.9 Hz), 6.65 (s, 2H), 6.75 (s, 1H), 7.11-7.37 (m, 10H).

| j 73 8991 3

Example 19 dl-8,9-Dihydro-9- (3,4,5-trimethoxyphenyl) -5,8-methano-1,3-dioxolo (4,5-h) (2) benzoxepin-7 (5H) - oni (5a, 8a, 9a) (XVIIIa) 5 1, - ° \ __

<° JTO

To a solution of cis-aryltetralone XVIb (124 mg, 0.29 nunol) in 10 mL of dry tetrahydrofuran was added 0 ° C (CH 3 C) V OCH, CK, CT 2 CCH., Och 3 and 3 och 3 29 ml 2.0-mol. LiBH 4 in tetrahydrofuran (0.58 mmol). After stirring for 17 hours at room temperature, the reaction mixture was treated with 7 ml of saturated NH 4 Cl solution and the solvent layers were separated. The aqueous layer was further extracted with ether (3 x 5 mL), and the combined organic extract was dried (MgSO 4) and concentrated to a pale yellow oil. This oil was further purified using preparative thin layer chromatography using 5% methanol in methylene chloride as eluent. The appropriate fraction with Rf = 0.53 was collected, filtered and concentrated to give the title compound. as oil; TLC / silica / methanol; methylene chloride (5:95) gave an Rf value = 0.53.

; 1 H NMR (CDCl 3, δ): 2.33 (d, 1H, 11.5 Hz), 2.82 (m, 1H), 3.03 (t, 1H, 4.9 Hz), 3.79 ( s, 6H), 3.85 (s, 3H), 4.36 (d, 1H, 4.5 Hz), 5.24 (d, 1H, 5.2 Hz), 5.94 (bd, 2H) , 6.30 (s, 2H), 6.48 (s, 1H), 6.75 (s, 1H).

74 8991 3

Example 20 dl- (3a8,4α, 5α, 10b6) -ethyl-3a, 4,5,10b-tetrahydro-3-bromo-5- (3,4,5-trimethoxyphenyl) -1,3-dioxolo (6, 7) naphth (2,1-d) -isoxazole-4-carboxylate (Xa) - 5 .mu.l CH10 OCH-CK-O-OCH.

3 nrw 3 3 I 3 0CH3 OCH., J j IXb Ma 15 A. Dibromoformaldoxime

To glyoxylic acid oxime hydrate (12 g, 112 mmol) in olive water (60 mL) was added methylene chloride (130 mL) and sodium bicarbonate (18.83 g, 224 mmol) with stirring at ice bath temperature (0-4 ° C). . To this biphasic mixture was added bromine (35.84 g, 488 mmol) in methylene chloride (50 mL), and stirring was continued for 7 hours (at 0 ° C), followed by stirring for an additional 13 hours at room temperature. Excess bromine was removed by careful addition of solid sodium thiosulfate.

The organic layer was separated and the aqueous layer was further extracted with methylene chloride (2 x 100 mL). The combined organic extract was dried (Na 2 SO 4) and evaporated to dryness to give the title product as a white solid (11.4 g, 50.13% yield). A portion of this material was recrystallized from Skellysolve B to give an analytical sample; mp. 65-68 ° C.

IR (KBr): 3000-3600, 1580 and 980 cm-1.

Analysis calculated for CHNOB 2: C, 5.91; H, 0.49; N, 6.90 Found: C, 5.40, H, 0.20; N, 6.95.

i, 75 89913 T3. dl- / 3a8,4α, 5α, 10b-7-ethyl-3a, 4,5,10b-tetrahydro-3-bromo-5- (3,4,5-trimethoxyphenyl) -1,3-dioxolo (6,7-r .af t (2,1-d) -isoxazole-4-carboxylate (Xa) __

To a solution of cis-olefin IXb (0.10 g, 0.24 mmol) in acetone was added dibromoformaldoxime (146 mg, 0.72 mmol) / prepared in step a7, followed by KHCO 3 (145 mg , 1.45 mmol). The solution was boiled at 56 ° C for 3 hours. TLC analysis (ether: Skellysolve B (1: 1/7) indicated that almost all of the starting material 10 (Rf = 0.30) was consumed and a product spot Rf = 0.19 had appeared. The solution was cooled, the solids were filtered off and washed. The filtrate was evaporated to dryness to a yellow solid, the pure product (72 mg) was obtained by chromatography on a silica gel column using 4% ethyl acetate in methylene chloride as eluent. Recrystallization from ethanol gave the title compound as a crystalline solid. ).

Analysis calculated for C 24 H 24 NO 8 Br: C, 53.95; H, 4.53; N, 2.62 Found: C, 53.64, H, 4.52; N, 2.91 1H N MR (CDCl 3, 6); 1.19 (t, 3H, 7.2 Hz), 3.14 (dd, 1H, 4.9 Hz, 10.7 Hz), 3.76 (s, 6H), 3.81 (s, 3H) , 3.93 (t, 1H, 10.3 Hz), 4.10 (q, 2H), 4.37 (d, 1H, 4.9 Hz), 5.71 (d, 1H, 9.7 Hz) ), 5.98 (s, 2H), 6.08 (s, 2H), 6.57 (s, 1H), 7.02 (s, 1H).

IR (KBr), wreck. cm -1: 1732, 1 590, 1 495, 1 482, 1235, 1 1 20.

76 8 9 9 1 3

Example 21 dl-? 3a, 4,5,10b-7-Benzhydryl-3a, 4,5,10b-tetrahydro-3-bromo-5- (3,4,5-trimethoxyphenyl) -1,3-dioxolo (6,7 ) naphth (2,1-d) -isoxazole-4-carboxylate (Xb) _

5 Q - N

O / "-" n Br ^ O ^ 0 ^^ 3 ^ .CO2CHPh2 X0 10 ^ ch3o-Xn; ^ y / och3 OCH »OCH„ IXc Xb To a solution of cis-olefin IXc (0.85 g, 1 , 54 mmol) in ethyl acetate (40 mL), dibromo-formaldoxime (0.94 g, 4.63 mmol) was added, followed by KHCO 3 (0.47 g, 4.69 mmol). The suspension was boiled for 3 hours. Thin chromatographic analysis / ether: Skellysolve 20 B (1: 1) revealed that the reaction was about 60% complete. Therefore, more dibromoformaldoxime (0.47 g) and KHCO 3 (0.24 g) were added to the reaction mixture, and the solution was further boiled for 2.5 hours. The solution was cooled and concentrated to an oil which was partitioned between methylene chloride and water. The aqueous layer was further extracted with methylene chloride and the combined organic: extract was dried (MgSO 4) and concentrated to an oil. The title compound (0.61 g, Rf = 0.25) was obtained as a solid by chromatography of the above oil on a silica gel column using 1-3% ethyl acetate in methylene chloride as an eluting solvent. An analytical sample was obtained by tri-trituration with ethanol, m.p. 164-168 ° C.

Analysis calculated for C 18 H 18 NO 3 Br: C, 62.50; H, 4.50; N, 2.06; Br, 11.88 Found: C, 62.12; H, 4.45; N, 2.08; Br, 10.75.

1 H 8 8 1 H NMR (CDCl 3, δ): 3.30 (dd, 1H, 4.7 Hz, 9.4 Hz), 3.44 (s, 6H) / 3.76 (s, 3H), 3.96 (t, 1H, 9.7 Hz), 4.34 (d, 1H, 4.7 Hz), 5.69 (d, 1H, 10.1 Hz), 5.95 (s, 2H) , 5.98 (d, 2H), 6.57 (s, 1H), 6.93 (s, 1H), 7.01 (s, 1H), 7.39-7.12 (m, 10H).

5 IR (KBr), vmax. cm-1: 1750, 1590, 1502, 1483, 1240, 1130. Example 22 dl- / 3a a, 4 g, 5 a, 10ba7-ethyl-3,4,5-10b-tetrahydro-3-bromo-5- (3,4,5-Trimethoxyphenyl) -1,3-dioxolo (6,7-naphth (2,1-d) -isoxazole-4-carboxylate (XXI) __ 10 0 —N / —Er COCW ,, (ajCC ,,, if i ”'- ° Λ CK3 ° T" ^ och3 ch, o- ^ V ^ och, 0CH3 ~ CCK "

VUIb XXI

20

To a solution of trans-olefin VUIb (100 mg, 0.24 mmol) in ethyl acetate (5 mL) was added dibromoformaldoxime (148 mg, 0.73 mmol) followed by KHCO 3 (145 mg, 1, 45 mmol) and water (2 drops). The reaction mixture was stirred at room temperature for 18 hours. Oxo-chromatographic analysis (5% ethyl acetate in methylene chloride) revealed that all of the starting material (Rf = 0.71) was worn and two new spots appeared: at Rf = 0.57 and Rf = 0, 90. The reaction mixture was filtered, and the solid precipitates were washed with ethyl acetate, the filtrate was dried (MgSO 4) and evaporated to a solid residue.

The desired product (Rf = 0.57) was obtained by chromatography on a silica gel column using methylene chloride and methylene chloride containing 10% ethyl acetate as eluting solvents as an amorphous solid (80 mg); ™ 89913 sp. 208-209 ° C (dec.). An analytical sample of the title compound is obtained by recrystallization from 95% ethanol, m.p. 212-214 ° C (dec.).

Analysis calculated for C 24 H 24 NO 8 Br: δ C, 53.95; H, 4.53; N, 2.62 Found: C, 53.95; H, 4.48; N, 2.58.

1 H NMR (CDCl 3, δ): 1.04, (t, 3H, 7.2 Hz), 3.12 (t, 1H, 8.1 Hz), 3.80, (s, 6H), 3.84 (s, 3H), 4.08-3.92 (m, 3H), 4.17 (d, 1H, 8.1 Hz), 5.62 (d, 1H, 10.1 Hz), 5.97 (s, 2H), 6.31 (s, 2H), 6.37 (s, 1H), 6.95 (s, 1H).

IR (KBr), vmax. cm -1: 1735, 1585, 1498, 1480, 1245, 1120. Example 23 dl- / 3a8,4a, 5a, 10b§7-3a, 4,5,10b-tetrahydro-3-chloro-5- (3, 4,5-Trimethoxyphenyl) -1,3-dioxolo (6,7-naphth (2,1-d)) isoxazole-15 4-carboxylic acid (Xc)

0 N

br

20, CHPh2 H

n - * λ: CH ^ CT <:: ^ / ^ OCHt L · '.

J l 3 CH, 0 OCH-.

OCH., -> l 3 J och3 25 xb xc

To a solution of ester Xb (0.41 g, 0.61 mmol) in nitromethane (12 mL) was added 1N HCl (3.5 mL in bitromethane) at room temperature. The solution was stirred: at room temperature for 3 hours and at an ice bath temperature for 30 minutes. The cold solution was filtered to collect the title compound as a white crystalline solid (175 mg); mp. 238.5 ° C.

Analysis calculated for C 22 H 20 NO 4 Cl: 35 C, 57.21; H, 4.36; N, 3.03 Found: C, 57.13; H, 4.39; N, 3.18.

79 3991 3 1H N MR (C DC 1 3, 6); 3.24 (dd, 1H, 4.9 Hz, 11, D Hz), 3.74 (s, 6H), 3.5 SO (s, 3 H), 3.86 (t, 111, 10.7 Hz) ), 4.42 (d, 1H, 4.7 Hz), 5.76 (d, 1H, 9.8 Hz), 5.98 (s, 2H), 6.12 (s, 2H), 6, 58 (s, 1 H), 7.02 (s, 1 H).

5 IR (KBr), make. cn "1; 2800-3100, 1715, 1520, 1 485, 1 250, 11 25.

Example 24 dl- / 3a 3, 4 c <, 5a, 10b37 ~ 3a, 4,5,10b-Tetrahydro-3-bromo-5- (3,4,5-trimethoxyphenyl) -1,3- dioxolo (6,7) naphth (2,1-d) isoxazole-10 4-carboxylic acid (Xd) __

0 N \ 0 — N

„Γ- '~': ..-, '-5-. J J '1 .. * Ä Λ' CH, 0 OCH3 OCH3 cck3 och3 o Q Xb Xd

A cold solution (0 ° C) of ester Xb (134 m, c, 0.2 mmol) in 1.3 Nl of trifluoroacetic acid was allowed to warm to room temperature. After stirring for 2 hours, the trifluoroacetic acid was removed in vacuo at about 35 ° C.

- The residue was treated with water and filtered to give the islands of the title compound. A portion of the solid was purified by chromatography on silica gel using. . 10 S methanol-containing methylene chloride as the eluent solvent to give the title compound (42 mg) as a crystalline solid; mp. 225-229 ° C.

80 8991 3

Example 25 dl- / Ta, 2a, 33,467 ~ 1 / 2,3,4-tetrahydro-3-cyano-4-hydroxy-1- (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylic acid (XIg)

IS

5 ['' Cl ° H

(li I / r'li 'i, // ^ NSSs'j

10 ix IL .M

CH 3 O, CH 2 O 2 CH 3 OCH 3 OCH 3

Xc Xlg

To a suspension of chloroisoxazolinic acid 15 Xc (2.00 g, 0.43 mmol) in methanol (100 mL) was added Raney nickel (about 0.5 cmL) and the suspension was shaken on a Parr apparatus under 42 psi hydrogen pressure. Platinum oxide (50 mg) was added to the solution and shaking was continued in a hydrogenator for a further 2.5 hours The catalysts were filtered off through a pad of diatomaceous earth and the filtrate was evaporated to dryness as a solid residue (2 g). revealed that in addition to the starting material (Rf = 0.53), two other components were present at Rf = 0.30 (higher amount) and Rf = 0.09 (lower amount) The larger component, Rf = 0.30, was isolated as a white solid. as a substance (0.9 g) by chromatography on a silica gel column using a methanol-methylene chloride mixture (1: 5) as the eluent solvent, and recrystallization from methanol gave an analytical sample of 30 of the title compound, m.p. 5-246.5 ° (dec.).

Analysis calculated for C 22 H 21 NO 8: C, 61.82; H, 4.95; N, 3.28 Found: C, 61.67; H, 4.94; N, 3.27.

1 H NMR (CDCl 3, δ); 3.35 (dd, 1H, 3.4 Hz, 12.4 Hz), 3.71 35 (dd, 1H, 12.5 Hz, 5.8 Hz), 3.74 (s, 6H, 3.78) (s, 3H), 4.55 (d, 1H, 5.7 Hz), 4.98 (d, 1H, 3.2 Hz), 5.94 (m, 2H), 6.11 (s, 2H) ), 6.41 (s, 1H), 6.86 (s, 1H).

"1 81 8991 3 IR (KBr), vmax cm; 3490, 2920, 2240, 1750, 1190, 1500, 1485, 1140, 1130, 1035.

Example 26 ά1- [1α, 2α, 3β, 4β7_1,2,3,4-Tetrahydro-3-cyano-4-hydroxy-1- (3,4,5-trimethoxyphenyl)] phthalene-2-carboxylic acid ) o- ^ W "C1, 0 Vo-UJ \ ^ '" - co2h -> \ ^ W ^ A: o2h jfjL jTn CH ^ d' ^ 'r ^ OCH, CK.O' ^ V ^ OCH, J OCH .3 J OCH-

15 XC W

Raney nickel (about 1.0 cm 3) was added to a suspension of chloroisoxazolinic acid Xc (1.40 g, 3.23 mmol) in methanol (200 mL) and the suspension was hydrogenated on a Parr 2Q apparatus with an initial hydrogen pressure of 50 psi, 2 hours.

The catalyst was filtered off through a pad of diatomaceous earth and the solvent was evaporated off in vacuo. The aqueous solution was acidified to 6-norm. HCl and extracted with 10% methanol in methylene chloride. The combined organic extract was dried (MgSO 4) and evaporated to dryness to give the title compound as an amorphous solid (0.8 g, 60%), which had an H NMR spectrum identical to that of the product prepared in Example 25.

82 3991 3

Example 27 ά1- / ϊα, 2α, 3β, 4β7-Ethyl-1,2,3,4-tetrahydro-3-cyano-4-hydroxy-1- (3,4,5-trimethoxyphenyl) naphthalene 2-carboxylate (Xlh) ____ 5

n — N OH

r '\ f f jr- Br. cn nr tr i, X0 ^ 5 ^^^ '"CC2C2H. 0 10 ό 7 / fi OCh ^ -j

Xa XIh 15

To a suspension of ester Xa (0.106 g, 0.2 mmol) in ethyl acetate saturated with water (20 mL) and methanol (5 mL) was added boric acid (36 mg, 0.6 mmol) followed by Raney nickel (about 0.1 cm). The suspension was hydrogenated in a Parr apparatus under 40 psi of hydrogen for 6 hours. Thin chromatographic analysis (5% ethyl acetate in methylene chloride) revealed that in addition to the starting ester Xa (Rf = 0.61) a new component was present, Rf = 0.15. The catalyst was filtered off and the filtrate was evaporated to a solid residue. Chromatography of this residue on a silica gel column using 5% and 10% ethyl acetate in methylene chloride as eluents gave the title compound; compound (Rf = 0.15) as an amorphous solid (54 mg). Recrystallization from 95% ethanol gave the title compound: m.p. 215-216 ° C.

Analysis calculated for C 24 H 25 NO 8: C, 63.29; H, 5.53; N, 3.08 Found: C, 63.16; H, 5.59; N, 3.02.

1 H NMR (CDCl 3, δ); 1.17 (t, 3H, 7.3 Hz), 2.62 (d, 1H, 4.4 Hz), 35 3.44 (dd, 1H, 3.3 Hz, 12.4 Hz), 3, 74 (m, 1H), 3.74 (s, 6H), 3.80 (s, 3H), 4.06, (q, 2H, 7.1 Hz), 4.53 (d, 2H, 5, 9 Hz), li 83 3 991 3 5.07 (t, 1H, 3.8 Hz), 5.97 (dd, 2H), 6.03 (s, 2H), 6.42 (s, 1H), 6.85 (s, 1H).

IR (KBr), vmax. cm: 3560, 2245, 1725, 1590, 1235, 1128. Example 28 5 dl- [1a, 2a, 38,467-ethyl-1,2,3,4-tetrahydro-3-cyano-4-hydroxy-1 - (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylate (Xlh) __________ ON ψ ^ / 'CO2C2H5

A - ”A

.! c.o-V1 ":“ Ά1 OCä3 3

Xa XIh

A solution of ester Xa (64 mg, 0.12 mmol) in 5 mL of dry benzene under nitrogen was treated with tributyltin hydride (0.12 mL, 0.45 mmol) and 2,2'-azobisisobutyronitrile (2 mg ). The mixture was heated at reflux for 6 hours and then stirred at room temperature overnight. The reaction mixture was evaporated to dryness in vacuo and the residue was purified by column chromatography on silica gel using 5% and 15% ethyl acetate in methylene chloride as eluent. . The appropriate fractions were combined and evaporated to dryness. . in vacuo to give the title compound having an NMR spectrum identical to that of the product obtained in Example 27.

84 8991 3

Example 29 dl- βα, 2α, 3β, 4β, 7-ethyl-1,2,3,4-tetrahydro-3-cyano-4-hydroxy-1- (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylic acid tile (Xlh) _

5 o-N

^ OH

0 ^ Vv ^^ NV ^ / ^: o2c2H5 h.

-> kk 3 10 I I ^ Π CH3o ^ r ^ h3 ch3o ^> Sx: h3 OCH3 OCH3

Xa Xlh 15

From a suspension of ester Xa (106 mg, 0.2 mmol) in 10 mL of 90% aqueous methanol with 0.08 mL of concentrated HCl and 10 mg of 10% Pd / C ( 55% by weight in water), hydrogenated under 1 atmosphere of hydrogen for 24 hours and then allowed to stand for 5 days. The catalyst was filtered off through diatomaceous earth and the solution was neutralized to about pH 7 with saturated NaHCO 3 solution before the solvent was evaporated off in vacuo. The residue was purified by silica gel column chromatography using methylene chloride containing 20% ethyl acetate as an eluent to give 40 mg of the title compound, which was identical to the product obtained in Example 27.

I: 85 8 991 3

Example 30 dl- / Ta, 2α, 3β, 4§7-1,2,3,4-Tetrahydro-3-cyano-4-hydroxy-1- (3,4,5-trimethoxyphenyl) naphthalene-2-caroxylic acid ( XL®)

5 O— OH

= 2 r 10 ch.o- ^ V ^ och3 J OCH3 ° = h3

Xc XI9 ^ - To a solution of chloroisoxazolinic acid

Xc (92 mg, 0.2 mmol) in 50 mL of solvent (containing 36 mL of methanol, 10 mL of methylene chloride, and 4 mL of water) was added 30 mg of nickel boride, and the mixture was hydrogenated on a Parr apparatus with an initial hydrogen pressure of 40 psi, 16 hours.

The catalyst was filtered off through diatomaceous earth and the solvent was evaporated in vacuo to give 90 mg of the title compound, which was identical to the product prepared in Example 25.

Example 31 dl- [1a, 2α, 36,4β-1,2,3,4-tetrahydro-3-aminomethyl-4-hydroxy-1- (3,4,5-trimethoxyphenyl) naphthalene-2 -Carboxylic acid (Xli) _

0H OH

': JL> CN n XZH-NH- · 30} <fifi ξ --- f 2 S · Λ Χϊι CH30' ^ y / OCH3 CH3 ° i ^ och3: '* · 35 OCH3 OCH3

Xlg Xl1 86 3991 3

A solution of hydroxynitrile Xgg (0.50 g, 1.2 mmol) in dry tetrahydrofuran (15 mL) was added to a stirred suspension of lithium aluminum hydride (0.16 g, 4.2 mmol) at 0 ° C under nitrogen. in tetrahydrofuran (20 ml). After 16 hours at room temperature, the excess lithium aluminum hydride was decomposed by sequential addition of water (0.16 mL), 15% sodium hydroxide solution (0.16 mL) and water (0.48 mL). The precipitate was filtered off and the tetrahydrofuran was removed in vacuo. The aqueous solution was acidified to pH 6 0.1-norm.

HCl and extracted with methylene chloride. The combined extract was dried (MgSO 4) and evaporated to dryness to give the title compound (0.12 g, 24%). A portion of this batch was dissolved in methanol-methylene chloride (1: 4) and placed in a solid phase silica extract. The column was washed with methanol (4 mL) and the amino acid was eluted with 10% acetic acid in methanol (2 mL). The solvent was evaporated and the resulting solid was dried under high vacuum at 78 ° C to give the title compound as the acetic acid-20 salt.

Analysis calculated for C 22 H 25 NOO.CH 2 COOH.H 2 O: C, 56.57; H, 6.13; N, 275 Found: C, 56.85; H, 6.28; N, 2.68.

1 H NMR (CDCl 3, δ): 6.84, (s, 1H), 6.32 (s, 1H), 6.05 (s, 2H),. 5.88 (d, 2H), 4.86 (bp, 1H), 4.10 (bp, 1H), 3.79 (s, 3H), 3.73 (s, 6H), 3.26 (pb, 2H), 3.13 (m, 1H), 2.60 (m, 1H), 2.30 (m, 1H).

tl 8991 3 87

Example 32 dl-epipodophyllotoxin (I)

is

= 2 --- rv. ? I! X r il in CH 0 OCH- CH30'x ^ y ^ ÖCH, och3 ock3

XC I

To a solution of chloroisoxazolinic acid Xc (200 mg, 0.43 mmol) in 100 mL of CH 2 OH / 1 O 2 / CH 2 Cl 2 (7: 1: 3) was added nickel boride (60 mg, 0 , 86 mmol), and the suspension was hydrogenated on a Parr hydrogenator under 40 psi of hydrogen for 18 hours. Platinum oxide (200 mg, 0.88 mmol) was added to the solution and the suspension was further hydrogenated at 40 psi for 2 hours. Thin chromatographic analysis (5% MeOH Cl 2 Cl 2) showed the disappearance of the starting acid (Rf = 0.48) and the appearance of a highly polar component (Rf = 0.07). The catalysts were filtered off using a silica pad, and the filtrate was concentrated to a syrup. The syrup was dissolved in 50% acetic acid (7 mL), and to the resulting solution was added sodium nitrite (200 mg, 2.9 mmol) as a solution in water (8 mL). After the solution was stirred at room temperature for 4 hours, saturated aqueous sodium hydrogencarbonate solution (20 ml) was carefully added, and the reaction solution was extracted with methylene chloride (5 x 30 ml). The combined organic extract was dried (Ν3250 ^), filtered and evaporated to dryness to give the title compound as a pale yellow solid. as a substance (84 mg) which was homogeneous by thin layer chromatography.

88 39913 1 H NMR (CDCl 3, δ): 2.86 (m, 1H), 3.29 (dd, 1H, 5.1 Hz, 14.1 Hz), 3.75 (s, 6H), 4.38 (m, 2H), 4.63 (d, 1H, 5.1 Hz), 4.88 (t, 1H, 3.4 Hz), 6.00 (d, 2H), 6.29 (s, 2H) ), 6.56 (s, 1H), 6.89 (s, 1H).

5 The above spectral values are consistent with those reported for epipodophyllotoxin in J. Med. Chem. 22, 215 (1979).

Example 33 dl-epipodophyllotoxin (I) 10? ·· 15 A rr, 3 1 3 C. ~ :, O Y OCH., 0CH3 OCH3 -

Xlg I

A solution of hydroxynitrile Xlg (0.25 g, 0.59 mmol) in dry tetrahydrifyran (7 mL) was added under nitrogen protection to a cooled solution of lithium aluminum hydride (0.08 g, 2 mmol) in tetrahydrofuran (20 mL). The reaction mixture was stirred at room temperature for 16 hours. : 25 temperature. The reaction was quenched by the addition of acetic acid: water 1: 1 (v / v) (10 mL) and the tetrahydrofuran was removed in vacuo. A solution of sodium nitrite (200 mg, 2.9 mmol) in water (1 mL) was added to the residue and stirred for 1 hour at room temperature. To neutralize the acidic solution, saturated aqueous NaHCO 3 was added, and then the mixture was extracted with methylene chloride. The combined organic extract was needed (MgSO 4) and evaporated to dryness to give epipodophyllotoxin (I) (0.21 g, "87%) as a light brown foam; the 35 N NMR spectrum was identical to that of Example 32.

ti 89. 8991 3

Example 34

When the general procedures of Examples 1, 2, 10, 11, 17, 20, 23 and 32 are repeated sequentially, except that the starting material 3,4,5-trimethoxy-3 ', 4'-methylenedioxy-5 chlcone XXIIa used in Example 1 is replaced by an equimolar amount of compound of the formula 0 r1 10 I li | n6 U. 'J XXIIb-XXHg R 1 ^ 5 15

where .. R1 R ^ _ «1 j? L

in compound 1αΐϊ5- k ock3 h ch3

20 XXIIC k och3 och3 ch3 K

XXIId och3 och3 h ch3 K

XXIIe OCK3 OCH3 0CH3 CH3 H

XXIIf -0CH 2 O-CH 3 Cn 3 H a XXIIg OCH 3 HH CH 3 K, respectively: 25 · / prepared by the general methods described in ____: Synthesis, 647-650 (1980/7, thus preparing - a compound with the formula 90 8 9 9 1 3

OH

"JfiV '" R2' g X11b-XIIg R4 ^ Y ^ R6 OR5 in which compound R1 r2 r4 r5 r6

XHb H OCH, H CH, H

j j

XI-C H OCH, OCH-CH, H

J 3 3

XHd OCH, OCH, H CH, H

J 3 j

XI Ie OCH, OCH3 OCH3 CH3 H

XI If -OCH 2 O- OCH CH, H and XHg OCH 3 H H CH, H, respectively I;

Example 35 dl- (ia, 2α, 3β, 40) -1,2,3,4-Tetrahydro-3-cyano-4-hydroxy-1- (3,4,5-trimethoxyphenyl) naphthalene-2-carboxylic acid 9i 8 9 91 3 (Xlq) _

5 0 — N

3. f \\ OH

<° ^ Ti rCH

, ο Λ. r8i CH3Cr ^ V ^ '° CH3 ΟΗ, Ο ^ ν ^ 11! OCH. -3 3 OCH3

Xd Xlg

A mixture of solid bromoisoxazolinic acid Xd (160 mg, 0.316 mmol) and dry sodium hydride (39.2 mg, 1.22 mmol) under nitrogen was treated with dry tetrahydrofuran (8 mL). The resulting suspension was stirred at room temperature for 10 minutes, at 60 ° C for 2 minutes and cooled to -78 ° C. Then, n-butyl-20 lithium (1.6 in hexane = 0.22 mL = 0.35 mmol) was slowly added from the burette over one minute to give an initial red solution that turned yellow when the entire addition was complete. The mixture was stirred at -78 ° C for 5 minutes. The cooling bath was removed and the mixture was allowed to warm to 0 ° C over 3-5 minutes and then stirred at 0 ° C for 3 minutes. The mixture was re-cooled to -78 ° C and poured into a mixture of 6-S aqueous ammonium chloride (50 mL), 5% hydrochloric acid (20 mL) and ethyl acetate (40 mL). The organic phase was washed with water (30 mL) and brine (30 mL) and dried (MgSO 4). Evaporated on a rotary evaporator and flash chromatographed on silica gel (5-15% CII3OH in ethyl acetate) to give the title • J. 1 compound (124 mg) having 1 H-NMR spectral values as in Example 25.

Claims (9)

A compound of formula (X) wherein R 2 and a COOR OR wherein R 1 and R 2 independently represent hydrogen or lower alkoxyl or silica form a methylenedioxy group, R 3 is hydrogen or a protecting group for carboxyl, R 4 and R 6 independently of one another represents hydrogen or lower alkoxy, R 5 is hydrogen or a protecting group for phenol and R 7 is hydrogen, halogen, lower alkoxycarbonyl, carboxyl, cyano, trimethylsilyl, phenylsulfonyl or phenoxycarbonyl, in which a phenyl ring 1 R 7 may be substituted by a or two substituents from the lower alkyl group, halogen, lower alkoxy and trifluoromethyl, or a salt thereof. ____ 2. A process for preparing a compound with -; The formula (X). : -Γ: 30 | T J | I: V R2 ^: Τ: X 1 OR5 8991 wherein R1 and R2 independently represent hydrogen or lower alkoxy or together form a methylenedioxy group, R3 is hydrogen or a carboxyl protecting group, R4 and R6 independently represent hydrogen or lower alkoxy, R5 is hydrogen or a phenol and R7 protecting group is hydrogen, halogen, lower alkoxycarbonyl, carboxyl, cyano, trimethylsilyl, phenylsulfonyl or phenoxycarbonyl, in which a phenyl ring in R7 may be substituted by one or two substituents of the lower alkyl group, halogen , lower alkoxy and trifluoromethyl, characterized in that a cis-olefin of formula (IX) R 15, R 2, XOR 5 wherein R 1, R 2, R 3, R 4, R 5 and R 6 are as defined above, is reacted with a nitrile oxide of formula (XX) Θ Θ R7-C = N-O XX where R7 is defined above, in an inert aqueous or organic solvent or in a mixture of water and an organic solvent at a temperature between about 30-20 ° C and the boiling temperature of the solvent to produce a compound of formula X stereoselectively, and optionally selectively removing the protecting group from a compound of formula X, wherein R 3 is a protecting group for carboxyl, to obtain a compound of formula 35 n-99 R COOH, 4, 10R, where R1, R2, R4, R5, R6 and R7 are defined above.