CA2064481C - Method of producing .alpha.,.beta.-unsaturated ketolactones - Google Patents
Method of producing .alpha.,.beta.-unsaturated ketolactonesInfo
- Publication number
- CA2064481C CA2064481C CA002064481A CA2064481A CA2064481C CA 2064481 C CA2064481 C CA 2064481C CA 002064481 A CA002064481 A CA 002064481A CA 2064481 A CA2064481 A CA 2064481A CA 2064481 C CA2064481 C CA 2064481C
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- halogen atom
- alkyl group
- aldehyde
- atom
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
- C07D307/77—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom ortho- or peri-condensed with carbocyclic rings or ring systems
- C07D307/93—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom ortho- or peri-condensed with carbocyclic rings or ring systems condensed with a ring other than six-membered
- C07D307/935—Not further condensed cyclopenta [b] furans or hydrogenated cyclopenta [b] furans
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D407/00—Heterocyclic compounds containing two or more hetero rings, at least one ring having oxygen atoms as the only ring hetero atoms, not provided for by group C07D405/00
- C07D407/02—Heterocyclic compounds containing two or more hetero rings, at least one ring having oxygen atoms as the only ring hetero atoms, not provided for by group C07D405/00 containing two hetero rings
- C07D407/12—Heterocyclic compounds containing two or more hetero rings, at least one ring having oxygen atoms as the only ring hetero atoms, not provided for by group C07D405/00 containing two hetero rings linked by a chain containing hetero atoms as chain links
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/55—Design of synthesis routes, e.g. reducing the use of auxiliary or protecting groups
Abstract
The present invention provides a method of preparing .alpha.,.beta.-unsaturated ketolactones which are useful in the production of prostaglandins having one or more halogen substituent(s) at position 16 or 17 in high yield, in which, a dimethyl (2-oxoalkyl) phosphonate having one or more halogen substituents (as a starting material) is reacted with a bicyclolactone aldehyde in the presence of an alkali metal hydride and a zinc compound.
Description
20~4481 Method of Produc; na ~, B-Unsat~r~ted Ketolactones The present invention relates to a method of producing ~, B-unsaturated ketolactones which are useful as synthetic int~ -~;AteS in the preparation of prostaglandins.
When studying various types of prostaglandin derivatives, s it has been found that there eYist many prostagl~n~;n~ having the prostanoic acid skeleton with at least one halogen atom, especially fluorine atom, at position 16 or 17 [16(17)-mono or 16,16 (17,17)-dihalo-prostaglandins]. Such prostaglandins are represented by the following formula:
~_f ~ COOH (o~-chain) ~ 2 0 ( ~-chain ) 10 and eYhibit characteristic rh~ cological activities.
The Corey method has been known for a long time and is still a typical procedure `for synthesis of ~
prostaglandins .
The Corey method includes the step of producing an 15 c~,~-unsaturated ketolactone (III) from a Corey lactone via a Corey aldehyde (II):
~' .
~ - 2 - 2064481 o o ~ CrO3 PY2 > ~
0~ OH ,, CHO
OCAr OCAr O ( I ) (Il) o ' O o ,0~~
(CH30) 2PCH2CCsH
.~aH V~~~CH~
l,2-d~methoxyethane (D.~E) ,' n OC.4 r (111) twherein Ar represents an aromatic group. ]
The Corey lactone (I) is oxidized to a Corey aldehyde (II) using a complex of pyridine and chromium trioxide (so called Collins oxidation), followed by a reaction between this 5 aldehyde and an anion generated by reacting a dimethyl ( 2 -oxoalkyl ) phosphonate with sodium hydride to giYe the ~:,B-unsaturated ketolactone (III).
These reactions were considered simply to be applicable to the synthesis of 16(17)-mono or 16,16(17,17)-dihalo-10 prostaglAnA;nq. However, when dimethyl (2-oxoalkyl) rhns~rhnn;~tes having one or two halogen atoms at the 3-position are used as a replacement for the phosphonate, the yield of the desired c~, J3-unsaturated ketolactone decreases to a level of below 1096.
Many attempts have been made to improve the yield by reactions carried out in the presence of sodium hydride and a copper ul-d or a thallium compound. Use of the copper compound, however, does not result in an adequate improvement - in the yield, while the thallium compound, showing; ~ luv~ ent in the yield to some extent, is toxic and very expensive.
Thus, it is still desirable to further improve the reaction and the results obtained therefrom.
The object o~ the present invention is to provide a method of producing an l~ ,B-unsaturated ketolactone (III) substituted with one or two halogen atoms at a position which corresponds to position 16 or 17 of the prostaglandin skeleton when they are derived from the ~,B-unsaturated ketolactones.
As mentioned above the yield of the ~,B-unsaturated ketolactone is low, when it is produced by the reaction of a Corey aldehyde with a dimethyl (2-oxoalkyl) phosphonate substituted with one or two halogen atoms at the 3-position using sodium hydride and a copper ~ nfl.
According to the present invention the yield of the ~,B-unsaturated ketolactones is improved using a zinc compound instead of a copper _ ~ uulld.
When studying various types of prostaglandin derivatives, s it has been found that there eYist many prostagl~n~;n~ having the prostanoic acid skeleton with at least one halogen atom, especially fluorine atom, at position 16 or 17 [16(17)-mono or 16,16 (17,17)-dihalo-prostaglandins]. Such prostaglandins are represented by the following formula:
~_f ~ COOH (o~-chain) ~ 2 0 ( ~-chain ) 10 and eYhibit characteristic rh~ cological activities.
The Corey method has been known for a long time and is still a typical procedure `for synthesis of ~
prostaglandins .
The Corey method includes the step of producing an 15 c~,~-unsaturated ketolactone (III) from a Corey lactone via a Corey aldehyde (II):
~' .
~ - 2 - 2064481 o o ~ CrO3 PY2 > ~
0~ OH ,, CHO
OCAr OCAr O ( I ) (Il) o ' O o ,0~~
(CH30) 2PCH2CCsH
.~aH V~~~CH~
l,2-d~methoxyethane (D.~E) ,' n OC.4 r (111) twherein Ar represents an aromatic group. ]
The Corey lactone (I) is oxidized to a Corey aldehyde (II) using a complex of pyridine and chromium trioxide (so called Collins oxidation), followed by a reaction between this 5 aldehyde and an anion generated by reacting a dimethyl ( 2 -oxoalkyl ) phosphonate with sodium hydride to giYe the ~:,B-unsaturated ketolactone (III).
These reactions were considered simply to be applicable to the synthesis of 16(17)-mono or 16,16(17,17)-dihalo-10 prostaglAnA;nq. However, when dimethyl (2-oxoalkyl) rhns~rhnn;~tes having one or two halogen atoms at the 3-position are used as a replacement for the phosphonate, the yield of the desired c~, J3-unsaturated ketolactone decreases to a level of below 1096.
Many attempts have been made to improve the yield by reactions carried out in the presence of sodium hydride and a copper ul-d or a thallium compound. Use of the copper compound, however, does not result in an adequate improvement - in the yield, while the thallium compound, showing; ~ luv~ ent in the yield to some extent, is toxic and very expensive.
Thus, it is still desirable to further improve the reaction and the results obtained therefrom.
The object o~ the present invention is to provide a method of producing an l~ ,B-unsaturated ketolactone (III) substituted with one or two halogen atoms at a position which corresponds to position 16 or 17 of the prostaglandin skeleton when they are derived from the ~,B-unsaturated ketolactones.
As mentioned above the yield of the ~,B-unsaturated ketolactone is low, when it is produced by the reaction of a Corey aldehyde with a dimethyl (2-oxoalkyl) phosphonate substituted with one or two halogen atoms at the 3-position using sodium hydride and a copper ~ nfl.
According to the present invention the yield of the ~,B-unsaturated ketolactones is improved using a zinc compound instead of a copper _ ~ uulld.
2 0 The present invention relates to a method of producing ~,B-unsaturated ketolactones, which comprises reacting a bicyclolactone aldehyde with a dimethyl (2-oxoalkyl) phosphonate which is substituted by at least one halogen atom at the 3-position of said alkyl group, in the presence of an alkali metal hydride and a zinc compound.
The bicyclolactone aldehyde ( 1) which is a starting material of the present invention is represented by the ~A~
following formula (l):
o ,0 '~
~X B--CHO ( l) AO
[wherein A represents a hydroxyl protection group for hydroxyl groups, for instance:
0,~
~X~
R
--Si--Rs >< \R7 --C--R
R~ R 11 R6 ~ O
5 (wherein X3 is a hydrogen or halogen atom, R4, Rs and R6 each represent an alkyl group having C1 ~ C4 carbon atoms or a phenyl group, R7 is an alkyl group with C1 ~ C4 carbon atoms, which may have an alkoxy or a silyl group, and R10 is an alkyl group with C1 ~ C4 carbon atoms) and wherein B represents a 10 simple bond or a methylene group, -C~z-]. This bicyclolactone aldehyde (l) can be obtained from a Corey lactone (I) through an oxidation reaction using dimethylsul:Eoxide (hereinafter simply referred to as DMSO oxidation). Examples of this DMSO
oxidation include a so-called Pfilzner-Moffatt oxidation in ~A
5 20~4481 which DMS0, dicyclohexylcarbodiimide, trifluoroacetic acid and pyridine are used, a so-called Swern oxidation in which DMS0, oxarylchloride and triethylamine are used and a so-called Parikh-Doering oxidation in which DMS0, a complex of sulfur 5 trioxide and triethylamine are used. DMS0 oxidation allows the reaction to be easily controlled and allows the alcohols to be oxidized to the corresponding aldehydes in high yields since the aldehydes produced are prevented from further oxidation to the corresponding carboxylic acid.
lo This bicyclolactone aldehyde (l) can also be prepared by the oxidation, a similar reaction as described above, of a bicyclolactone carrying an alkyl r_ j rlr~rh:- i n elongated by one in the number of carbon atoms by subjecting the Corey lactone (I~
to the reactions as shown below.
For the carbon-number increasing reaction, a leaving group (tosyl group, for example) is first introduced into the Corey lactone t I ) having an appropriate protection group (4-phenylbenzoyl group, for example) for the 7-hydroxylgroup followed by reacting a cyanide generating compound to yield a 20 nitrile ~ ~ '. The hydroxyl protection group is eliminated from this nitrile compound and the cyano group is then hydrolysed to the carboxyl group. Then, after introducing another protection group (acetyl group, for example) for the 7-hydroxyl group, the carboxyl group is reduced to yield the 25 bicyclolactone carrying an alkyl sidechain elongated by one in the number of carbon atoms.
A feature of the present invention exists in that the condensation reaction between the bicyclolactone aldehyde ( 1) ~A
1'~ 6 2064481 and a dimethyl (2-oxoalkyl) phosphonate to yield an cY,i~-unsaturated ketolactone of the formula (3) represented by the f ormul a:
o (3) ~ \~R2 [wherein A represents a hydroxyl protection group; X1 and X2 represent a hydrogen atom or a halogen atom respectively, provided that at least one of X1 and X2 is a halogen atom; and R2 represents an alkyl group having 1 to 10 carbon atoms which may have a branch or a double bond and which may be substituted by a C1 6 alkoxy group, a phenyl group or a phenoxy group or -Y--~(wherein Y represents a single bond or an oxygen atom; and R3 represents a hydrogen or halogen atom, or a Cl 4 alkyl or a halogenated C1 4 alkyl group) and ~ represents =CH- or -CE=CH-] is carried out in the presence of an alkali metal hydride and a zinc compound.
With regard to the alkali metal hydrides, hydrides of alkali metals or alkali earth metals can be used, and examples include sodium hydride, potassium hydride or calcium hydride Sodium hydride is particularly preferred Zinc halides, e.g. zinc chloride, zinc bromide, or zinc salts of organic acids, e.g. zinc acetate may be used for the zinc compounds. ~inc halides are particularly preferred.
~ -.
_ ~ ~ r , ~-. . . .. . , .. , . . , ~
~`; ~ 6a 2064481 The amount of the alkali metal hydride to be used is preferably about 1 molar equivalent relative to the amount of a dimethyl (2-oxoalkyl) phosphonate ~2) and the amount of the zinc compound is preferably from 0 . 5 to 1 molar equivalent 5 relative to the amount of the dimethyl (2-oxoalkyl) phosphonate ( 2 ) .
Reaction solvents are not particularly specified, but eolvents such as tetrahydrofuran, dimethoxyethane, dichloromethane, ethylether, 1,4- dioxane, benzene and toluene 10 are preferred.
The amount of the reaction solvent is preferably in the range of 5 to 30 ml relative to 1 g of the Corey aldehyde (1).
A range of 10 to 20 ml is particularly preferred.
The reaction temperature range may be from 0 to 50C and 15 a range of 10 to 50C is particularly preferred.
The reaction time may be in the range o 4 to 72 hour~
preierably in the range of 24 to 50 hours.
The present invention is illustrated by the following ~ J , ,~
7 2~64481 examples but it should not be construed to be limited to these examples .
Example 1 Oxalyl chloride (2 M in CH2Cl2 176.7 ml) was added to 5 dichluL ?th~n~ (530 ml) and, after cooling to -78-C, a solution of dimethylsulfoxide (50.7 ml; hereinafter, referred to as DMSO) in dichloromethane (50.7 ml) was added dropwise over a period of 20 minutes with stirring at -78-C. Into the above obtained solution was added dropwise a solution of Corey 10 lactone (A) (45 . 3g) o ~I~ (A
~OH
~0 in dichloromethane (200 ml), and after stirring at -50-C for 1 hour, triethylamine (101.3 ml) was added dropwise, ~ollowed by stirring for 1 hour at a temperature increased to -2 0 C . This 15 solution was poured into a saturated aqueous solution of ammonium chloride. After the usual work-up, the aldehyde (B) rQ~
8 20~g481 CH0 (B) ~0 was obtained.
Sodium hydride (60%, 8.48 g~ was suspended in THF
5 (300 ml) at O C, into which a solution of dimethyl (3,3-difluoro-2-oxoheptyl)phosphonate (54.8 g) in THF (loO ml) was added. The mixture was stirred for 20 minutes. To the resultant mixture zinc chloride (14 . 5 g) was added with stirring for 2 hours at room temperature. The mixture was 10 cooled to 0C, followed by the addition of a solution of the above-described aldehyde in THF (200 ml), and by stirring for 18 hours at room temperature. The additional anion prepared from dimethyl (3, 3-difluoro-2-oxoheptyl) phosphonate (22 . 8 g), sodium hydride (60%, 3.5 g) and zinc chloride (6.0 g) was 15 added, and the mixture was stirred for 6 hours at room temperature, followed by the addition of acetic acid (12.1 ml) at O-C. The crude product obtained after the usual work-up was purified on a silica gel column and (lS, 5R, 6R, 7R)-6-[ (E) -4,4-difluoro-3-oxo-1-octenyl]-7-tetrahydro-20 pyranyloxy-2-oxabicyclo[3. 3. O]octan-3-one (referred to as ,B-unsaturated ketolactone (C) hereinafter) was obtained.
9 20~4481 o;~
(C) o ~o Yield: 52 . 8 g (77%) C- mn;~ratiYe ~ m}~le 1 An aldehyde (B) was obtained by subjecting a Corey 5 lactone (A) (2 . 37 g) to Swern oxidation using oxalyl chloride (1.8 ml), DMS0 (2.9 ml) and triethylamine (12.5 ml) in dichlu~ h~n~.
Dimethyl (3l3-difluoro-2-oxoheptyl)rhnsrh~n~te was added dropwise to a solution of thallium ethoxide (0. 06 ml) in 10 methylene chloride (60 ml), and the solution was stirred for 3 0 minutes . The reaction temperature was adj usted to 0 C and a solution of the aldehyde (B) in dichloromethane (30 ml) was added dropwise, followed by stirring for 5 hours at room temperature. The crude product obtained after the usual 15 work-up was chromatographed on a column of silica gel to yield the a,B-unsaturated ketolactone (C).
Yield: 2.35 g (66%) Com~aratiVç Examl~le 2 Aldehyde (B) was obtained by subj ecting a Corey lactone 20 (A) (1. 25 g) to Swern oxidation using oxalyl chloride (0.88 ml), DMS0 (1.42 ml) and triethylamine (6.1 ml) in dichloromethane .
A
lO 206~81 Sodium hydride (60%, 0.195 g) was suspended in 30 ml o~
THF, and a solution of dimethyl (3,3-difluoro-2-oxoheptyl)rh~srhf~n~te (1.27 g) in THF (5 ml) was added dropwise to the suspension, followed by stirring for 1 hour.
5 Copper iodide (0.929 g) was added to the solution and the mixture was stirred for 1 hour at room temperature. After adjusting the reaction temperature to 0C, an aldehyde (B) solution in THF (10 ml) was added dropwise, followed by stirring overnight at room temperature. The crude product 10 obtained after the usual work-up was chromatographed on a column o~ silica gel, thereby obtaining the ~,B-unsaturated ketolactone (C).
Yield: 0.431 g (23%) ComParatiVe E~mnle 3 Aldehyde (B) was obtained by subjecting a Corey lactone (A) (0.523 g) to Swern oxidation by the same method as described in Comparative Example 2.
Sodium hydride (60%, 0.082 g) was suspended in THF and a THF solution of dimethyl (3,3-difluoro-2-oxoheptyl) 20 phosphonate (0.464 g) was added to the suspension, and the mixture was stirred for 30 minutes. The reaction temperature was adjusted to 0C and the THF solution of aldehyde (B) obtained as described above was added and the mixture was stirred overnight. The residue obtained after the usual 25 work-up was chromatographed on a column of silica gel, but no ~,B-unsaturated ketolactone (C) was obtained.
ll 2064481 ~xam~le 2 Dimethyl (3,3-difluoro-2-oxononyl)phosphonate (3.918 g) and sodium hydride (60%, 0.547 g) was stirred in THF (30 ml) for 15 minutes at room temperature. Zinc chloride (0.933 g) 5 was added, and the solution was stirred for 2 hours. To the solution was added a Corey aldehyde (1. 69 g) in TEiF (20 ml), which was prepared from a Corey lactone according to the same method as described in Example 1, and the solution was stirred for 50 hours at room temperature. The crude product obtained 10 by the usual work-up was chromatographed to give (lS, 5R, 6R, 7R) - 6- [ (E ) 4, 4 -di f luoro-3 -oxo-1-decenyl ] -7 -tetrahydropyranyl oxy- 2 - oxab icycl o [ 3 . 3 . o ] octan- 3 -one .
Ylol~: 1.789 ~ (65~), P~
The bicyclolactone aldehyde ( 1) which is a starting material of the present invention is represented by the ~A~
following formula (l):
o ,0 '~
~X B--CHO ( l) AO
[wherein A represents a hydroxyl protection group for hydroxyl groups, for instance:
0,~
~X~
R
--Si--Rs >< \R7 --C--R
R~ R 11 R6 ~ O
5 (wherein X3 is a hydrogen or halogen atom, R4, Rs and R6 each represent an alkyl group having C1 ~ C4 carbon atoms or a phenyl group, R7 is an alkyl group with C1 ~ C4 carbon atoms, which may have an alkoxy or a silyl group, and R10 is an alkyl group with C1 ~ C4 carbon atoms) and wherein B represents a 10 simple bond or a methylene group, -C~z-]. This bicyclolactone aldehyde (l) can be obtained from a Corey lactone (I) through an oxidation reaction using dimethylsul:Eoxide (hereinafter simply referred to as DMSO oxidation). Examples of this DMSO
oxidation include a so-called Pfilzner-Moffatt oxidation in ~A
5 20~4481 which DMS0, dicyclohexylcarbodiimide, trifluoroacetic acid and pyridine are used, a so-called Swern oxidation in which DMS0, oxarylchloride and triethylamine are used and a so-called Parikh-Doering oxidation in which DMS0, a complex of sulfur 5 trioxide and triethylamine are used. DMS0 oxidation allows the reaction to be easily controlled and allows the alcohols to be oxidized to the corresponding aldehydes in high yields since the aldehydes produced are prevented from further oxidation to the corresponding carboxylic acid.
lo This bicyclolactone aldehyde (l) can also be prepared by the oxidation, a similar reaction as described above, of a bicyclolactone carrying an alkyl r_ j rlr~rh:- i n elongated by one in the number of carbon atoms by subjecting the Corey lactone (I~
to the reactions as shown below.
For the carbon-number increasing reaction, a leaving group (tosyl group, for example) is first introduced into the Corey lactone t I ) having an appropriate protection group (4-phenylbenzoyl group, for example) for the 7-hydroxylgroup followed by reacting a cyanide generating compound to yield a 20 nitrile ~ ~ '. The hydroxyl protection group is eliminated from this nitrile compound and the cyano group is then hydrolysed to the carboxyl group. Then, after introducing another protection group (acetyl group, for example) for the 7-hydroxyl group, the carboxyl group is reduced to yield the 25 bicyclolactone carrying an alkyl sidechain elongated by one in the number of carbon atoms.
A feature of the present invention exists in that the condensation reaction between the bicyclolactone aldehyde ( 1) ~A
1'~ 6 2064481 and a dimethyl (2-oxoalkyl) phosphonate to yield an cY,i~-unsaturated ketolactone of the formula (3) represented by the f ormul a:
o (3) ~ \~R2 [wherein A represents a hydroxyl protection group; X1 and X2 represent a hydrogen atom or a halogen atom respectively, provided that at least one of X1 and X2 is a halogen atom; and R2 represents an alkyl group having 1 to 10 carbon atoms which may have a branch or a double bond and which may be substituted by a C1 6 alkoxy group, a phenyl group or a phenoxy group or -Y--~(wherein Y represents a single bond or an oxygen atom; and R3 represents a hydrogen or halogen atom, or a Cl 4 alkyl or a halogenated C1 4 alkyl group) and ~ represents =CH- or -CE=CH-] is carried out in the presence of an alkali metal hydride and a zinc compound.
With regard to the alkali metal hydrides, hydrides of alkali metals or alkali earth metals can be used, and examples include sodium hydride, potassium hydride or calcium hydride Sodium hydride is particularly preferred Zinc halides, e.g. zinc chloride, zinc bromide, or zinc salts of organic acids, e.g. zinc acetate may be used for the zinc compounds. ~inc halides are particularly preferred.
~ -.
_ ~ ~ r , ~-. . . .. . , .. , . . , ~
~`; ~ 6a 2064481 The amount of the alkali metal hydride to be used is preferably about 1 molar equivalent relative to the amount of a dimethyl (2-oxoalkyl) phosphonate ~2) and the amount of the zinc compound is preferably from 0 . 5 to 1 molar equivalent 5 relative to the amount of the dimethyl (2-oxoalkyl) phosphonate ( 2 ) .
Reaction solvents are not particularly specified, but eolvents such as tetrahydrofuran, dimethoxyethane, dichloromethane, ethylether, 1,4- dioxane, benzene and toluene 10 are preferred.
The amount of the reaction solvent is preferably in the range of 5 to 30 ml relative to 1 g of the Corey aldehyde (1).
A range of 10 to 20 ml is particularly preferred.
The reaction temperature range may be from 0 to 50C and 15 a range of 10 to 50C is particularly preferred.
The reaction time may be in the range o 4 to 72 hour~
preierably in the range of 24 to 50 hours.
The present invention is illustrated by the following ~ J , ,~
7 2~64481 examples but it should not be construed to be limited to these examples .
Example 1 Oxalyl chloride (2 M in CH2Cl2 176.7 ml) was added to 5 dichluL ?th~n~ (530 ml) and, after cooling to -78-C, a solution of dimethylsulfoxide (50.7 ml; hereinafter, referred to as DMSO) in dichloromethane (50.7 ml) was added dropwise over a period of 20 minutes with stirring at -78-C. Into the above obtained solution was added dropwise a solution of Corey 10 lactone (A) (45 . 3g) o ~I~ (A
~OH
~0 in dichloromethane (200 ml), and after stirring at -50-C for 1 hour, triethylamine (101.3 ml) was added dropwise, ~ollowed by stirring for 1 hour at a temperature increased to -2 0 C . This 15 solution was poured into a saturated aqueous solution of ammonium chloride. After the usual work-up, the aldehyde (B) rQ~
8 20~g481 CH0 (B) ~0 was obtained.
Sodium hydride (60%, 8.48 g~ was suspended in THF
5 (300 ml) at O C, into which a solution of dimethyl (3,3-difluoro-2-oxoheptyl)phosphonate (54.8 g) in THF (loO ml) was added. The mixture was stirred for 20 minutes. To the resultant mixture zinc chloride (14 . 5 g) was added with stirring for 2 hours at room temperature. The mixture was 10 cooled to 0C, followed by the addition of a solution of the above-described aldehyde in THF (200 ml), and by stirring for 18 hours at room temperature. The additional anion prepared from dimethyl (3, 3-difluoro-2-oxoheptyl) phosphonate (22 . 8 g), sodium hydride (60%, 3.5 g) and zinc chloride (6.0 g) was 15 added, and the mixture was stirred for 6 hours at room temperature, followed by the addition of acetic acid (12.1 ml) at O-C. The crude product obtained after the usual work-up was purified on a silica gel column and (lS, 5R, 6R, 7R)-6-[ (E) -4,4-difluoro-3-oxo-1-octenyl]-7-tetrahydro-20 pyranyloxy-2-oxabicyclo[3. 3. O]octan-3-one (referred to as ,B-unsaturated ketolactone (C) hereinafter) was obtained.
9 20~4481 o;~
(C) o ~o Yield: 52 . 8 g (77%) C- mn;~ratiYe ~ m}~le 1 An aldehyde (B) was obtained by subjecting a Corey 5 lactone (A) (2 . 37 g) to Swern oxidation using oxalyl chloride (1.8 ml), DMS0 (2.9 ml) and triethylamine (12.5 ml) in dichlu~ h~n~.
Dimethyl (3l3-difluoro-2-oxoheptyl)rhnsrh~n~te was added dropwise to a solution of thallium ethoxide (0. 06 ml) in 10 methylene chloride (60 ml), and the solution was stirred for 3 0 minutes . The reaction temperature was adj usted to 0 C and a solution of the aldehyde (B) in dichloromethane (30 ml) was added dropwise, followed by stirring for 5 hours at room temperature. The crude product obtained after the usual 15 work-up was chromatographed on a column of silica gel to yield the a,B-unsaturated ketolactone (C).
Yield: 2.35 g (66%) Com~aratiVç Examl~le 2 Aldehyde (B) was obtained by subj ecting a Corey lactone 20 (A) (1. 25 g) to Swern oxidation using oxalyl chloride (0.88 ml), DMS0 (1.42 ml) and triethylamine (6.1 ml) in dichloromethane .
A
lO 206~81 Sodium hydride (60%, 0.195 g) was suspended in 30 ml o~
THF, and a solution of dimethyl (3,3-difluoro-2-oxoheptyl)rh~srhf~n~te (1.27 g) in THF (5 ml) was added dropwise to the suspension, followed by stirring for 1 hour.
5 Copper iodide (0.929 g) was added to the solution and the mixture was stirred for 1 hour at room temperature. After adjusting the reaction temperature to 0C, an aldehyde (B) solution in THF (10 ml) was added dropwise, followed by stirring overnight at room temperature. The crude product 10 obtained after the usual work-up was chromatographed on a column o~ silica gel, thereby obtaining the ~,B-unsaturated ketolactone (C).
Yield: 0.431 g (23%) ComParatiVe E~mnle 3 Aldehyde (B) was obtained by subjecting a Corey lactone (A) (0.523 g) to Swern oxidation by the same method as described in Comparative Example 2.
Sodium hydride (60%, 0.082 g) was suspended in THF and a THF solution of dimethyl (3,3-difluoro-2-oxoheptyl) 20 phosphonate (0.464 g) was added to the suspension, and the mixture was stirred for 30 minutes. The reaction temperature was adjusted to 0C and the THF solution of aldehyde (B) obtained as described above was added and the mixture was stirred overnight. The residue obtained after the usual 25 work-up was chromatographed on a column of silica gel, but no ~,B-unsaturated ketolactone (C) was obtained.
ll 2064481 ~xam~le 2 Dimethyl (3,3-difluoro-2-oxononyl)phosphonate (3.918 g) and sodium hydride (60%, 0.547 g) was stirred in THF (30 ml) for 15 minutes at room temperature. Zinc chloride (0.933 g) 5 was added, and the solution was stirred for 2 hours. To the solution was added a Corey aldehyde (1. 69 g) in TEiF (20 ml), which was prepared from a Corey lactone according to the same method as described in Example 1, and the solution was stirred for 50 hours at room temperature. The crude product obtained 10 by the usual work-up was chromatographed to give (lS, 5R, 6R, 7R) - 6- [ (E ) 4, 4 -di f luoro-3 -oxo-1-decenyl ] -7 -tetrahydropyranyl oxy- 2 - oxab icycl o [ 3 . 3 . o ] octan- 3 -one .
Ylol~: 1.789 ~ (65~), P~
Claims (2)
1. A method of producing .alpha.,.beta.-unsaturated ketolactone represented by the formula:
(3) [wherein A represents a hydroxyl protection group; X1 and X2 represent a hydrogen atom or a halogen atom respectively, provided that at least one of X1 and X2 is a halogen atom; and R2 represents an alkyl group having 1 to 10 carbon atoms which may have a branch or a double bond and which may be substituted by a C1-6 alkoxy group, a phenyl group or a phenoxy group or (wherein Y represents a single bond or an oxygen atom; and R3 represents a hydrogen or halogen atom, or a C1-4 alkyl or a halogenated C1-4 alkyl group) and Z represents =CH- or -CH=CH-], which comprises reacting a bicyclolactone aldehyde of the formula:
(1) [wherein A represents a hydroxyl protection group and B
represents a single bond or -CH2-] with a dimethyl (2-oxoalkyl) phosphonate of the formula:
(2) [wherein X1 and X2 represent a hydrogen atom or a halogen atom respectively, provided that at least one of X1 and X2 is a halogen atom; R1 represents an alkyl group having 1 to 4 carbon atoms; R2 represents an alkyl group having 1 to 10 carbon atoms which may have a branch or a double bond and which may be substituted by a C1-6 alkoxy group, a phenyl group or a phenoxy group or (wherein Y represents a single bond or an oxygen atom; and R3 represents a hydrogen or halogen atom, or a C1-4 alkyl or a halogenated C1-4 alkyl group)] which is substituted by at least one halogen atom at the 3-position of said alkyl group, in the presence of an alkali metal hydride and a zinc compound.
(3) [wherein A represents a hydroxyl protection group; X1 and X2 represent a hydrogen atom or a halogen atom respectively, provided that at least one of X1 and X2 is a halogen atom; and R2 represents an alkyl group having 1 to 10 carbon atoms which may have a branch or a double bond and which may be substituted by a C1-6 alkoxy group, a phenyl group or a phenoxy group or (wherein Y represents a single bond or an oxygen atom; and R3 represents a hydrogen or halogen atom, or a C1-4 alkyl or a halogenated C1-4 alkyl group) and Z represents =CH- or -CH=CH-], which comprises reacting a bicyclolactone aldehyde of the formula:
(1) [wherein A represents a hydroxyl protection group and B
represents a single bond or -CH2-] with a dimethyl (2-oxoalkyl) phosphonate of the formula:
(2) [wherein X1 and X2 represent a hydrogen atom or a halogen atom respectively, provided that at least one of X1 and X2 is a halogen atom; R1 represents an alkyl group having 1 to 4 carbon atoms; R2 represents an alkyl group having 1 to 10 carbon atoms which may have a branch or a double bond and which may be substituted by a C1-6 alkoxy group, a phenyl group or a phenoxy group or (wherein Y represents a single bond or an oxygen atom; and R3 represents a hydrogen or halogen atom, or a C1-4 alkyl or a halogenated C1-4 alkyl group)] which is substituted by at least one halogen atom at the 3-position of said alkyl group, in the presence of an alkali metal hydride and a zinc compound.
2. A method according to claim 1, wherein at least one of X1 and X2 is a fluorine atom.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP7148391 | 1991-04-04 | ||
JP71483/1991 | 1991-04-04 |
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CA2064481A1 CA2064481A1 (en) | 1992-10-05 |
CA2064481C true CA2064481C (en) | 1996-12-24 |
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CA002064481A Expired - Fee Related CA2064481C (en) | 1991-04-04 | 1992-03-31 | Method of producing .alpha.,.beta.-unsaturated ketolactones |
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US (1) | US5229529A (en) |
EP (1) | EP0507625B1 (en) |
JP (1) | JPH089608B2 (en) |
KR (1) | KR970003125B1 (en) |
AT (1) | ATE141921T1 (en) |
CA (1) | CA2064481C (en) |
DE (1) | DE69213067T2 (en) |
DK (1) | DK0507625T3 (en) |
ES (1) | ES2093776T3 (en) |
GR (1) | GR3020903T3 (en) |
TW (1) | TW197439B (en) |
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1992
- 1992-03-28 TW TW081102387A patent/TW197439B/zh active
- 1992-03-30 JP JP4073782A patent/JPH089608B2/en not_active Expired - Lifetime
- 1992-03-31 CA CA002064481A patent/CA2064481C/en not_active Expired - Fee Related
- 1992-04-01 US US07/861,518 patent/US5229529A/en not_active Expired - Lifetime
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- 1992-04-04 KR KR1019920005662A patent/KR970003125B1/en not_active IP Right Cessation
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Also Published As
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JPH089608B2 (en) | 1996-01-31 |
GR3020903T3 (en) | 1996-11-30 |
ES2093776T3 (en) | 1997-01-01 |
EP0507625A1 (en) | 1992-10-07 |
KR920019771A (en) | 1992-11-20 |
ATE141921T1 (en) | 1996-09-15 |
DE69213067D1 (en) | 1996-10-02 |
TW197439B (en) | 1993-01-01 |
DE69213067T2 (en) | 1997-01-16 |
DK0507625T3 (en) | 1996-09-16 |
KR970003125B1 (en) | 1997-03-14 |
EP0507625B1 (en) | 1996-08-28 |
JPH0592965A (en) | 1993-04-16 |
CA2064481A1 (en) | 1992-10-05 |
US5229529A (en) | 1993-07-20 |
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