[19]
`United States Patent
`4,751,235
`[45] Anderson
`Date of Patent:
`Jun. 14, 1988
`
`Patent Number:
`
`[11]
`
`[54] ANTI-ATHEROSCLEROTIC INDOLIZINE
`DERIVATIVES
`
`Attorney, Agent, or Firm—Gerald D. Sharkin; Richard
`E. Vila; Melvyn M. Kassenoff
`
`[75]
`
`Inventor:
`
`Paul L. Anderson, Randolph, NJ.
`
`[57]
`
`ABSTRACT
`
`[73] Assignee:
`
`Sandoz Pharm. Corp., East Hanover,
`NJ.
`
`7-(indolizin-2-y1)hept-6-enoic acids of the formula I:
`
`[21] Appl. N0.: 945,750
`
`[22] Filed:
`
`Dec. 23, 1986
`
`Int. Cl.4 ................... A61K 31/435; CO7D 471/04
`[51]
`[52] us. Cl. ..................................... 514/299; 546/112
`[58] Field of Search ......................... 546/112; 514/299
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`2/1981
`4,248,889
`3/1981
`4,255,444
`3/1983
`4,375,475
`4,474,971 10/1984
`4,520,026
`5/1985
`
`............................ 424/308
`Oka et a1.
`Oka et a1. .................... 424/279
`
`............ 549/292
`Willard et a].
`..
`
`Wareing ..............
`549/214
`Rosseels et a]. ..................... 546/112
`
`FOREIGN PATENT DOCUMENTS
`8402131
`6/1984 PCT Int’l App].
`.
`8402903
`8/1984 PCT Int’l Appl..
`8600307
`1/1986 PCTInt’lAppl..
`8603488
`6/1986 PCT Int’l Appl..
`
`Primary Examiner—Richard A. Schwartz
`Assistant Examiner—Bernard I. Dentz
`
`R2
`
`I
`
`/ / Y—Z
`
`\N
`
`R1
`
`wherein each of R1 and R2 is, independently, H, alkyl,
`cycloalkyl, aralkyl or aryl,
`
`Y is —CH=CH—, or -CH2—CH2—; and
`
`z is ('3H—CH2—(l2H—CH2COOR8
`OH
`OH
`
`in which R8 is H, an ester residue or cation; or the lac-
`tone thereof. The compounds are useful as hypocholes—
`teremic agents.
`
`20 Claims, No Drawings
`
`Mylan Exhibit 1020, Page 1
`
`
`
`Mylan Exhibit 1020, Page 1
`
`

`

`1
`
`ANTI-ATHEROSCLEROTIC INDOLIZINE
`DERIVATIVES
`
`4,751,235
`
`2
`
`'°°““““"d
`
`Designation:
`Z =
`Nature
`R8 = M
`type (a);
`R3 = H,
`type (b)
`
`Compounds 13
`
`Compounds 14
`
`free acid
`
`lactone
`
`A preferred type of Compounds I is designated 1'
`where Y=(a) and one of R1 and R2 is H or alkyl, espe-
`cially methyl or isopropyl, and the other is an aryl
`group i.e. (a), especially p-fluorophenyl, phenyl or 3,5-
`dimethylphenyl, and particularly p-fluorophenyl.
`When R8 is R9, it is preferably ethyl, and when it is M,
`it is preferably sodium, potassium, magnesium or cal-
`cium, especially sodium.
`By the term “physiologically acceptable and hydro-
`lyzable ester group” is meant a group which, together
`with the —C00— radical to which it is attached, forms
`an ester group which is physiologically acceptable and
`hydrolyzable under physiological conditions to yield a
`compound of Formula I wherein R8 is hydrogen and an
`alcohol which itself is physiologically acceptable, i.e.,
`non-toxic at the desired dosage level, and which, prefer-
`ably, is free of centers of asymmetry. Examples of such
`groups are C1.3alkyl, n-butyl, i-butyl, t-butyl and ben-
`zyl, collectively referred to as R9’.
`A particular sublcass of Compounds I is Compounds
`11" in which R8 is R9”, i.e. C1.4 primary alkyl, especially
`ethyl.
`Compounds I may further be viewed as two sub-
`classes depending on the nature of the group Y, i.e. Ia
`where Y=(a) and lb where Y=(b), the former being
`preferred.
`As is well known in the art, ester and salt forms of an
`organic acid are interconvertible. Hence, where an ester
`form (here 11) is prepared, it can then be saponified to
`its corresponding salt (12) which can be neutralized to
`the free acid form (I3), which can be cyclized to the
`corresponding lactone (I4), and the reverse; all by
`adapting conventional processes. Accordingly, prepa-
`ration of an ester I 1 where R8 is R9", i.e. 11”, provides
`a compound of the invention, as well as a source of the
`corresponding other forms of Compounds 1.
`Compounds Ila" (i.e. Compounds I (in which Y=(a),
`Z=(a) and R3=R9"), are obtainable by a multi-step
`procedure which may conveniently be represented by
`Reaction Schemes A and B below, in which R1, R2 and
`R9” are as defined above, R16 and R17, are, indepen-
`dently, alkyl (C1-3) Preferably ethyl, R20 is a primary or
`secondary C2-C4alkyl, eg ethyl; and R21 is allyl or C1-
`C4alkyl, preferably not tertiary, e.g. methyl, X is Cl, Br
`or I, and Q has the structure:
`
`R2
`
`Q
`
`/ / l
`
`\ N
`
`R1
`
`This invention pertains to organic compounds, and 5
`more particularly to 7-(indolizine-Z-yl)—hept-6-enoic
`acid derivatives as well as to the use of such compounds
`and pharmaceutical compositions containing such com-
`pounds, as well as to intermediates and methods of
`preparation.
`The final compounds involved in the invention may
`be conveniently represented by formula I:
`
`10
`
`R2
`
`//1
`
`Y—Z
`
`\ N
`
`R1
`
`wherein each of R‘ and R2 is, independently:
`
`R5
`
`R6
`
`R7
`
`I
`
`15
`
`.
`
`‘20
`
`(3)
`
`25
`
`(b) hydrogen or a primary or secondary C1.6alkyl not 30
`containing an asymmetric carbon atom, (c) C3-5cycloal-
`kyl or (d) phenyl—(CH2)m—,
`wherein R5 is hydrogen, C1-3alkyl, n-butyl, i-butyl, t-
`butyl, C1-3alkoxy, n-butoxy,
`i-butoxy,
`trifluoro-
`methyl, fluoro, chloro, phenoxy or benzyloxy;
`R6 is hydrogen, C1-3alkyl, C1-3alkoxy, fluoro or chloro;
`R7 is hydrogen, C1-2alkyl, C1-2alkoxy, fluoro or chloro;
`m is l, 2 or 3;
`
`35
`
`45
`
`50
`
`H|
`
`Y is (a) —C=tf- or (b) —CH2—CH2—-, and
`H
`
`z is -CH—CH2—$H-CH2—COOR8 (a) or
`|
`on
`
`in which R8 is hydrogen, R9 or M, wherein
`R9 is a physiologically acceptable and hydrolyzable
`ester group, and
`M is a pharmaceutically acceptable cation
`Compounds I may be viewed as consisting of various
`sub-classes depending upon the definition of their vari-
`able portions. Compounds I may be of the following
`subclasses depending on the nature of Z;
`—-———-———_..___________
`65
`Designation:
`Z =
`Nature
`Compounds I 1
`ester
`
`55
`
`60
`
`~ Compounds I2
`
`351%
`type (a);
`
`salt
`
`in which RI and R2 are as defined above.
`
`Mylan Exhibit 1020, Page 2
`
`Mylan Exhibit 1020, Page 2
`
`

`

`REACTION SCHEME A
`
`i‘
`c=o
`
`/ I
`\ N
`
`condensation
`(9mm 3)
`
`E
`(ll)
`Rl-C-CHg—C—OR'6
`
`A
`
`Grignard Reaction
`
`(process b)
`
`/ C\
`I
`\ N
`
`c—COOR16
`(IS—R1
`
`/O
`2
`\J/R ng
`
`4,751,235
`
`4
`-continued
`REACTION SCHEME B
`
`G
`
`i‘
`i‘
`Q—$=C—C=O
`H
`o
`
`10
`
`Addition
`(process h)
`
`ll:
`/ \
`
`CH3
`
`CH2
`
`0
`
`g
`/ \
`
`0R9”
`
`AE
`
`/
`H QWCOOR
`0H
`o
`
`9"
`
`15
`
`308% in THF/RZIOH
`
`.
`
`Reduction
`(process i)
`
`20
`
`NaBH4
`
`CH30H
`
`25
`
`Ila” QM C00R9”
`6H
`6H
`
`30
`
`35
`
`45
`
`50
`
`55
`
`60
`
`65
`
`Individually, each of the above described reactions is
`analogous to reactions, known in the art, except for
`process (i), and may be carried out in the conventional
`manner, unless indicated otherwise.
`The parameters applicable to the processes illustrated
`in the Reaction Schemes, above, are listed in the follow-
`ing tables, in which general parameters are described
`with preferences as examples. In processes in which a
`medium is employed, it is understood that the medium is
`an inert solvent under the reaction conditions and is
`essentially anhydrous, i.e. moisture-free, if dry, i.e. es-
`sentially anhydrous conditions are called for. Where
`anhydrous conditions are called for, it is preferred that
`such reaction be carried out in an inert atmosphere eg
`under dry nitrogen gas.
`In the tables, Q indicates an alkali metal salt usually
`used in situ, and [
`]indicates an adduct or complex
`reaction product which is reacted in a subsequent
`quenching step, usually quenched to hydrolyze or de-
`compose it. Where a quenching step is employed, water
`is used, but often as an aqueous solution, 6. g. saturated
`aqueous NH4C1. LAH=lithium aluminum hydride;
`ether=diethyl ether; RT=20° to 30° C., THF=tet—
`rahydrofuran and PTS=p-toluenesulfonic acid. All
`temperatures are in degrees centigrade; these abbrevia-
`tions etc., also applying to the Examples hereinafter
`presented.
`Process (i) is novel and is not claimed as part of this
`invention. In an alternative method of carrying out
`process (i), in place of a trialkyl borane reagent there
`may be used an equivalent amount of a monoalkoxy
`dialkyl borane of the formula Gk:
`
`RZZO—B—(R20)2
`
`Gk
`
`in which R20 and R21 are defined hereinafter in the
`tables, and R22 is allyl or a lower alkyl having from 1 to
`4 carbon atoms, preferably not tertiary. R20, R21 and
`R22 may be the same, but need not be. Preparation of
`Compounds Gk are described by Koster et al, Ann.,
`I975, 352. R21 and R22 are preferably methyl.
`
`Mylan Exhibit 1020, Page 3
`
`B
`
`cyclization
`(process c)
`
`c
`
`Reduction
`(process d)
`
`D
`Oxidation
`(process e)
`
`R2
`
`5 H
`/ , H\l
`N
`\
`(IS—COOR16
`C—Rl
`
`\
`
`/O
`
`R2
`
`/
`
`l
`\ N /
`R1
`
`COOR16
`
`Q—CHz—OH
`
`Q—‘C=O
`
`REACTION SCHEME B
`
`0R17
`
`Br
`
`H |
`
`Q—c=o
`Li
`
`Addition
`
`\
`
`C=C
`
`(process I)
`
`/
`
`H
`
`/
`
`\
`
`H
`
`/
`
`H
`
`\
`
`H
`
`H H
`
`I lC=C
`
`/
`Q—C
`H\ OH
`
`\
`
`0Rl7
`
`hydrolysis
`(process g)
`
`Mylan Exhibit 1020, Page 3
`
`

`

`5
`
`TABLE A
`Condensation
`Process (a):
`Reactant(s):
`Z-pyridyl-CHO + Z a A
`Medium:
`Neat
`Temperature:
`20° to 80° C., eg RT, then 80° C.
`Conditions:
`Catalytic amount of piperidine; dry.
`Process (b):
`Grignard Reaction
`Reactant(s):
`(1) A + 122ng —. [1;
`(2) quench, eg, aq. NH4C1 —+ B.
`Cyclic ether, eg THF, with Grignard reagent
`Medium:
`in ether.
`‘
`(l) —70 to RT (add Cu(1)l at about 0“).
`Temperature:
`Dry, cat. amt. of Cu(I)I.
`Conditions:
`Cyclization
`Process (0):
`(1) B + Acetic Acid Anhydride; —- [ ];
`Reactant(s):
`(2) quench (water) —» C
`Excess AAA.
`Medium:
`Temperature: Reflux.
`Conditions:
`—
`Process (d):
`Ester Reduction
`Reactant(s):
`(l) C + LAH » [ ];
`(2) Destroy excess LAH with ethyl acetate,
`then quench with ice-water —> D.
`THF
`(1) —5“ C. to 30° C., eg add LAH at 0° C. to raise
`to RT;
`(2) Cold. eg ice-water bath.
`(1) dry; (2) add ethylacetate cautiously.
`Oxidation to aldehyde
`D + MnOz —’ E
`Inert hydrocarbon, eg toluene.
`20 to 140“, eg reflux conditions.
`Dry
`-
`Addition of olefinic unit
`(1) BrCH=CH—0Rl7, eg R” = ethyl, +
`lithium —> Y
`Li$ source, eg t-butyl
`(2) Y + E —> [I
`(3) [ ] + quench, eg ice-water or sat. aq.
`NH4C], —> F
`(1) Cyclic ether, eg THF; (1) = (2).
`(1) —40 to ~-100° C., eg about —70°;
`(1) = (2); (3) 0° c. to RT.
`Essentially anhydrous for (l) + (2).
`Hydrolysis
`F + aq. PTS —’ G
`Cyclic ether, eg THF + water in ratio of
`about 4:1.
`Temperature: RT
`Conditions:
`——
`Process (h):
`Addition via dianion (3 stages)
`Reactant(s):
`(1) AE, eg ethyl acetate, + 2 equivalents of
`alkali cation, eg 2 LDA —> Q.
`(2) Q + G —> I l-
`(3) [ ] + quench, eg ice-water or saturated
`aqueous NH4C1 —> H.
`(1) Cyclic ether, eg THF.
`(1) = (2) = (3)-
`(1) -—60 to +5°, eg 0 to +5°.
`(2) «80° to —2o°, eg —75° to —60°.
`(3) 0° to R.T.
`Dry for (l) + (2).
`Reduction (3 stages)
`(l) H + B(RZO)3 eg R20 = ethyl, in a ratio of
`about 121.02 to 1.3 —> H.
`(2) NaBH4 + [l—’ l 1'-
`(3) []' + H63, eg acetic acid, —> Ila”
`(1)1‘HF/R210H, eg, R21 = methyl; ratio = 3 to
`6:1, eg 3—4zl.
`(1) = (2) = (3).
`(1) R.T.
`(2) -100 to —40“, eg —75°.
`(3) —100 to —40", eg —~75°, then to R.T.
`Dry for (1) + (2).
`Optionally, air may be bubbled through
`
`reaction mixture in (1).
`
`Medium:
`Temperature:
`
`Conditions:
`Process (e):
`Reactant(s):
`Medium:
`Temperature:
`Conditions:
`Process (0:
`Reactant(s):
`
`Medium:
`Temperature:
`
`Conditions:
`Process (g):
`Reactant(s):
`Medium:
`
`Medium:
`
`Temperature:
`
`Conditions:
`Process (i):
`Reactant(s):
`
`Medium:
`
`Temperature:
`
`Conditions:
`
`4,751,235
`
`5
`
`10
`
`15
`
`20
`
`25
`
`3O
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`6
`and then reducing such compound in a manner analo-
`gous to process (i).
`Process (i) may be carried out in the conventional
`manner for hydrogenating an ethylenically unsaturated
`bond, under conditions that do not alter the remainder
`of the compounds; for example at about 20° to 40° C.,
`e.g. R.T. under a pressure of about 40 to 50 p.s.i. of
`hydrogen gas in the presence of a hydrogenation cata-
`lyst e.g., 5% palladium on charcoal or 5% rhodium on
`charcoal, in an inert medium, e.g. a lower alkanol, such
`as ethanol. alternatively a compound Ila” can be re-
`duced by the procedure of process (j) to obtain its cor-
`responding saturated analog (a compound Ilb”). As
`described above, such esters can be converted by
`known means to their corresponding free acid, salt and
`lactone forms.
`
`The products described herein may be recovered and
`refined, where such is desired, by conventional means,
`such as by crystallization, distillation or chromato-
`graphic techniques such as column or thin layer chro-
`matography, (TLC) e.g., silica gel column chromatog-
`raphy. Where appropriate,
`intermediates can be em-
`ployed directly in a subsequent reaction.
`Reagents and starting materials employed in the
`above-described processes, e.g. 2-pyridine carboxalde-
`hyde and Y, Z, AE and B(R2°)3, are either known and
`may be obtained as described in the literature, or where
`not known may be prepared by methods reported in the
`literature for the preparation of known analogues. Some
`are commercially available.
`
`UTILITY STATEMENT
`
`The compounds of Formula I are competitive inhibi-
`tors of 3-hydroxy-3-methylglutaryl
`coenzyme A
`(HMG-CoA) reductase,
`the rate limiting enzyme in
`cholesterol biosynthesis, and, therefore, they are inhibi-
`tors of cholesterol biosynthesis. Consequently, they are
`useful for lowering the blood cholesterol level in ani-
`mals, e.g., mammals, especially larger primates such as
`humans, and,
`therefore, as hypolipoproteinemic and
`anti-atherosclerotic agents. The biological activity of
`the compounds of Formula I may be demonstrated in
`the following two tests:
`Test A. In Vitro Microsomal Assay of HMG—COA
`Reductase Inhibition:
`This test is known and is carried out as described on
`pages 59—60 of application Ser. No. 06/741,903 (filed
`June 6, 1985) and on page 30 of World (PCT) Published
`Patent Application No. 84/02131 both of which are
`hereby incorporated by reference as if set forth herein
`in their entirety. The concentration of the test substance
`(compound of Formula I)
`in the assay system is
`0.0005—2,000 umolar. The obtained IC50 is the concen-
`tration of the test substance in the assay system ob-
`served or calculated to produce a 50% inhibition of
`HMG-CoA reductase activity.
`Test B. In Vivo Cholesterol Biosynthesis Inhibition
`Test:
`This test is also known and is carried out as described
`on pages 60—61 of said application Ser. No. 06/741,903
`and on page 33 of World (PCT) Published Patent Ap-
`plication No. 84/02131, both of which are hereby incor-
`porated by reference as if set forth herein in their en-
`tirety. In this test the rats are orally administered the
`test substance (compound of Formula I) at a dose of
`0.025—200 mg/kg. body weight. The obtained EDso is
`the dose of the test substance observed or calculated to
`
`Mylan Exhibit 1020, Page 4
`
`Analogs of Compounds Ila" in which Y is of type (b)
`i.e. Compounds Ilb” are conveniently obtained by a 65
`two-step procedure, by first saturating the olefinic unit
`of a corresponding compound H (process j) to yield a
`saturated analog of a compound H, i.e. a compound Hb,
`
`Mylan Exhibit 1020, Page 4
`
`

`

`4,751,235
`
`7
`produce a 50% inhibition of 3 B-hydroxysterol synthe-
`51s.
`
`In Test A, tested compounds of Formula I had ICso’s
`of about 0.006 to over 10 umolar whereas that of Com-
`pactin was 1.01 umolar and that of Mevinolin was 0.14
`umolar. The preferred compound of this application,
`that of Example 2, had an IC50 of 0.011 umolar. In Test
`B, the compound of Example 1 had an EDso of 0.05
`mg/kg. whereas that of Compactin was 3.5 mg/kg. and
`that of Mevinolin was 0.41 mg/kg.
`Since they inhibit cholesterol biosynthesis, the com
`pounds of Formula I (including those of each subgroup
`thereof) are useful for lowering the blood cholesterol
`level in animals, eg., mammals, especially larger pri-
`mates, in particular humans, and, therefore, as hypolipo-
`proteinemic and anti-atherosclerotic agents.
`The precise dosage of the compound of Formula I to
`be employed for inhibitng cholesterol biosynthesis de-
`pends upon several factors including the host, the na-
`ture and the severity of the condition being treated, and
`the mode of administration and the particular active
`substance (compound of Formula I) employed. How-
`ever, in general, suitable oral daily dosages of the com-
`pounds of Formula I for the satisfactory inhibition or
`reduction of cholesterol biosynthesis (i.e., the satisfac-
`tory reduction of blood cholesterol level and satisfac-
`tory treatment of hyperlipoproteinemia and athero-
`sclerosis) are indicated by the test data to be 0.025—100
`mg/kg. body weight, e.g., 0.025—5 mg/kg. body weight
`for the more active compounds. For most larger pri-
`mates such as humans, a suitable oral daily dosage is
`indicated to be 0.1—2,000 mg., e.g., 2—140 mg. for the
`more active compounds. The daily dosage of the com-
`pound of Example 2, is indicated to be from about 2 to
`140 mg., preferably from about 2 to 20 mg., for most
`larger primates such as humans. For administration by
`injection, a dosage somewhat lower than would be used
`for oral administration of the same active substance to
`the same host having the same condition is usually em-
`ployed. However, the above dosages are also typically
`used for IV. administration.
`The daily dosage may be administered in a single dose
`but more typically is administered in two to four equal
`portions, typical doses being 0.5 to 1000 mg. Often, a
`small dosage is administered initially, and the dosage is
`gradually increased until the optimal dosage for the host
`under treatment is determined.
`A typical dosage unit for oral administration may
`contain 0.5 to 500 e.g. 0.5 to 10 mg of a compound of
`Formula I.
`
`The compounds of Formula I may be formulated into
`conventional pharmaceutical compositions and admin—
`istered by any conventional mode of administration, in
`particular enterally, e.g.,
`in the form of capsules or
`tablets, or parenterally, e.g., in the form of sterile injec-
`table solutions or suspensions. The pharmaceutical
`compositions comprise a compound of Formula I and at
`least one pharmaceutically acceptable solid or liquid
`carrier (or diluent). They may be formulated in conven-
`tional manner. The compounds of each subgroup
`thereof may likewise be formulated into such pharma-
`ceutical compositions and administered by such routes.
`The compounds of Formula I (including those of
`each subgroup thereof) may be formulated into such
`pharmaceutical compositions containing an amount of
`the active substance that is effective for inhibiting cho-
`lesterol biosynthesis in unit dosage form and such com-
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`60
`
`65
`
`8
`positions comprising at least one solid pharmaceutically
`acceptable carrier.
`A representative formulation suitable for encapsula-
`tion in a hard gelatin capsule by conventional
`tech-
`niques is:
`Compound of Formula I, e.g., the compound of
`
`Compound of Formula I, e.g., the compound of
`Example 2
`1 mg.
`Corn starch
`248 mg.
`Magnesium stearate
`1 mg.
`
`As is self-evident to those in the art, each compound
`of formula I (and every sub-scope and species thereof)
`has at least two centers of asymmetry (e.g.
`the two
`carbon atoms bearing the hydroxy groups in the struc-
`ture when Z=a) and the carbon atom bearing the hy-
`droxy group and the carbon atom having the free va-
`lence in the structure when Z=b), and these lead (e. g.
`with two centers) to four stereoisomeric forms (enantio-
`mers) of each compound (two racemates or pairs of
`diastereoisomers). The preferred compounds have only
`two such centers of asymmetry and these four stereoiso-
`mers may be designated as the R,R; R,S; S,R; and 5,8
`enantiomers, all four stereoisomers being within the
`scope of this invention.
`The preferred stereoisomers of the compounds of
`formula I having only two centers of asymmetry
`wherein Y is a) and Z is a) are the 3R,SS and 3R,5R
`isomers and the racemate of which each is a constituent,
`i.e., the 3R,5S-3S,5R (erythro) and 3R,5R-38,SS (threo)
`racemates, with the 3R,SS isomer and the racemate of
`which it is a constituent being more preferred and the
`3R,SS isomer being most preferred.
`The preferred stereoisomers of the compounds of
`formula I having only two centers of asymmetry
`wherein Y is (b) and Z is (a) are the 3R,5R and 3R,SS
`isomers and the racemate of which each is a constituent,
`i.e., the 3R,5R-BS,SS (erythro) and 3R,SS-3S,5R (threo)
`racemates, with the 3R,5R isomer and the racemate of
`which it is a constituent being more preferred and the
`3R,5R isomer being most preferred.
`The preferred stereoisomers of the compounds of
`formula I having only two centers of asymmetry
`wherein Y is (a) and Z is (b) are the 4R,6S and 4R,6R
`isomers and the racemate of which each is a constituent,
`i.e., the 4R,6S-4S,6R (trans lactone) and 4R,6R-45,68
`(cis lactone) racemates, with the 4R,6S isomer and the
`racemate of which it is a constituent being more pre-
`ferred and the 4R,6S isomer being most preferred.
`The preferred stereoisomers of the compounds of
`formula I having only two centers of asymmetry
`wherein Y is (b) and Z is (b) are the 4R,6R and 4R,6S
`isomers and the racemate of which each is a constituent,
`i.e., the 4R,6R-48,68 (trans lactone) and 4R,6S-4S,6R
`(cis lactone) racemates, with the 4R,6R isomer and the
`racemate of which it is a constituent being more pre-
`ferred and the 4R,6R isomer being most preferred.
`The preferences set forth in the preceding four para-
`graphs also apply to the compounds of formula I having
`more than two centers of asymmetry and represent the
`preferred configurations of the indicated positions.
`Compounds I having one or more of the following
`characteristics are preferred:
`(a) Y=(a);
`(b) Z=(a) ;
`(c) when Z=a, R8=M, especially sodium;
`
`Mylan Exhibit 1020, Page 5
`
`Mylan Exhibit 1020, Page 5
`
`

`

`4,751,235
`
`10
`
`HC(CH3)2
`
`/ l CH—CH-COOCH;
`N
`
`\
`
`o=c
`
`F
`
`1.89 ml of 2 M (0.0035 M) isopropyl magnesium chlo~
`ride (in diethyl ether) is added to 25 ml dry THF. At 0°,
`40 mg of cuprous iodide (Cu(1)I) 0.17 mM is added and
`the mixture cooled to —70°. One gram of the 2-
`propenoic acid ester of Step 1 in 8 ml of dry THF is
`added rapidly. The temperature of the mixture is raised
`to —50°, and maintained and then maintained for one-
`half hour at ——50° to —70°. There is then added 40 mg
`of cuprous iodide and the mixture is allowed to slowly
`warm to R.T. and stirred for about 16 hours.
`Saturated aqueous ammonium chloride is then added
`to the mixture, and crude product of this step extracted
`by ethyl acetate. The extracts are combined and evapo-
`rated to obtain crude product which is used as such in
`the next step (step 3).
`Step
`3,
`3-(4-fluorophenyl)-l-(l-methylethyl)-2-
`indolizinecarboxylic acid, methyl ester (a Compound
`C).
`
`HC(CH3)2
`0
`t_
`
`/
`\ N /
`
`3
`
`23 g of the crude 2-pyridinepropanoic acid ester
`product of Step 2, above, is added to 300 m1 of acetic
`acid anhydride. The mixture is slowly heated to reflux
`and gently refluxed for 3.5 hours. The mixture is then
`added to ice-water and 0.5 liter of 2N NaOH and ex-
`tracted with ethyl acetate. The organic phase is dried
`and evaporated to obtain crude title product of this step.
`The product is refined by chromatographing through
`silica gel (eluting with ethyl acetate/hexane (20:80).
`The fractions are combined and product recovered by
`crystallizing (mp 139°—l42°).
`Step
`4,
`3-(4-fluoropheny1)-1-(l-methylethyl)-2-
`indolizinemethanol
`(may also be called 3-(4-fluoro~
`phenyl)-l-isopropyl-2-hydroxymethylindolizine)
`(a
`Compound D).
`
`HC(CH3)2
`
`N / CHz—OH
`
`F
`
`/ \
`
`5.1g (0.016 M) of the indolizine product of Step 3,
`above, in 300 m1 of dry THF is cooled to 0°. 1.8 g of
`LAH is slowly added over a 1 hour period. With stir-
`ring, the temperature of the mixture is to rise to room
`temperature. The mixture is then cooled (in a ice-water
`
`Mylan Exhibit 1020, Page 6
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`4O
`
`45
`
`50
`
`55
`
`60
`
`65
`
`9
`(d) and when Y=(a) and Z=(a) the optically active
`isomer of the 3R,SS form.
`Reagents and reaction products which are mixtures
`of stereoisomers (cis, trans and optical) can be separated
`by conventional means at whatever stage of synthesis is
`appropriate. Such methods include re-crystallization,
`chromatography, e.g. HPLC, formation of esters with
`optically pure acids and alcohols or of amides and salts
`with subsequent reconversion with retention of optical
`purity. For example diastereoisomeric (—)-a-naphthyl-
`phenylmethylsilyl derivatives of a lactone type end
`product of formula I may be separated by conventional
`means, e.g. as disclosed in US. Pat. No. 4,613,610.
`The following examples are illustrative of the inven-
`tion. All temperatures are centigrade and room temper-
`ature (R.T.) is 20° to 30° C., unless indicated otherwise.
`Unless indicated otherwise, evaporations are done
`under reduced pressure, drying of extracts is done over
`anhydrous sodium sulfate, all ratios of liquid mixtures
`are volume to volume, and moisture-free solvents and
`dry nitrogen atmosphere are employed for all reactions
`which are indicated to be carried out under essentially
`anhydrous conditions.
`
`EXAMPLE 1
`
`7-[3-(4—fluorophenyl}1-(1-methy1ethyl)-2-indolizinyl]-
`3,5,-dihydroxy-6‘heptenoic acid, ethyl ester (trans) (a
`Compound 11)
`
`HC“ CH
`(
`
`OH
`OH
`'
`3)2 H v
`C=C—CH—CH_5-CH
`\
`
`CH2 COOCzi-Is
`
`Step I, 2-(4'-fluorobenzoyl)3-(2-pyridinyl)propenoic
`acid, methyl ester (a Compound A).
`
`30 g (0.15 M) of methyl 4—fluorobenzoyl acetate are
`added to 16.05 g (0.15 M) of 2-pyridine carboxaldehyde.
`4 drops of piperidine are then added, and the mixture
`stirred at R.T. for about 16 hours. The mixture is then
`heated at about 80" for about 5 hours during which the
`mixture thickens markedly, yielding crude title product
`of this step. The mixture is then cooled and solidifies on
`standing. The solids are broken up, washed with metha-
`nol, then triurated with hot methanol and the solution
`evaporated to dryness, then crystallized from petroleum
`ether-methanol (50:50), yielding the refined title prod-
`uct of this step for use in Step 2, below.
`Step 2, 2-(4‘fluorobenzoyl)-3-(1—methylethyl)-3-(2-
`pyridinyl)propanoic acid, methyl ester (a Compound
`B).
`
`Mylan Exhibit 1020, Page 6
`
`

`

`4,751,235
`
`11
`bath) and ethyl acetate added dropwise to decompose
`unreacted LAH. Ice-water is then slowly added, and
`the product extracted with ethyl acetate. The extracts
`are combined, dried and evaporated to dryness to ob-
`tain the title product of this step (as a semi-solid).
`Step
`5,
`3-(4-fluorophenyl)-1-(l-methylethyl)—2-
`indolizinecarboxaldehyde (a compound E).
`
`HC(CH3)2
`
`
`
`4.7g (0.17 M) of the alcohol product of Step 4, above,
`is added to 250 ml of toluene. 20g of manganese dioxide
`are then added, and the mixture is heated slowly to
`reflux. When TLC indicates that no starting material
`remain (about 1 hour), the mixture is filtered through
`celite, washing with toluene then methylene chloride.
`The filtrate (organic phase containing the product) is
`evaporated to dryness to recover the title aldehyde
`product of this step.
`Step 6, 1-(2-ethoxyethenyl)-[3-(4—fluorophenyl)-1-(1-
`methylethyl)-2-indolizine]methanol (a Compound F).
`
`HC(CH3)2
`
`
`
`First, a reagent (Y) is prepared by adding 0.815 g (5.4
`mM) of cis-l-bromo-Z—ethoxyethylene to 51 ml of dry
`THF; the mixture cooled to —70°, and 6.47 ml of 1.7 M
`t.-butyl lithium (0.011 M) added dropwise. The result-
`ing mixture is stirred for 1 hour at —70°.
`To the above-described reagent solution is added 1.4
`g (4.9 mM) of the aldehyde product of Step 5, above, in
`a minimum volume of dry THF. The resulting mixture
`is stirred, at —70°, for 2 hours (until none or merely a
`trace of, starting material remains).
`The mixture is added to ice—water, and extracted with
`ethyl acetate, the extracts combined, dried and evapo-
`rated to obtain as a residue crude title olefinic product
`of this step; which is used directly in Step 7, below.
`Step
`7,
`3-[3-(4-fluorophenyl)-1-(1-methylethyl)-2-
`indolizinyl]-2-propenal (trans; a Compound G).
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`12
`The olefinic crude product of Step 6, above, is added
`to a mixture of 160 ml of THF +40 ml water and one
`gram of p-toluene sulfonic acid added. The resultant
`mixture is stirred for about 16 hours at RT. The mixture
`
`is added to water and extracted with ethyl acetate. The
`combined extracts are dried, then evaporated to dryness
`then held for 2 hours under high vacuum. The product
`is then flash chromatographed.
`Step
`8,
`7-[3-(4-fluorophenyl)-1-(l-methylethyl)-2-
`indolizinyl]-5-hydroxy—3-oxo-6-heptenoic
`acid,
`ethyl
`ester (trans).
`
`oH
`
`(IJH
`H—C-(CH3)2 r11
`
`(|3=C—CH—CH2—C—CH-_s-COOC3H5
`
`
`
`Reagent (Q) is first prepared by adding under a dry
`nitrogen atmosphere 1.13g (11.2 mM) of diisopropyl-
`amine to 50 ml of dry THF; the mixture cooled to 0" to
`5° , and 7.22 (11.2 mM) ml of 1.55 M n-butyl lithium (in
`hexane) is added dropwise thereto. The mixture is main-
`tained at 0° to 5° for 15 minutes, then 0.728 g (5.6 mM)
`of ethyl acetoacetate (distilled) is added dropwise, and
`the mixture stirred at 0° to 5° for 1 hour.
`
`The thus-prepared reagent ( ) mixture is then cooled
`to —60° and 0.8721 g (2.8 mM) of the olefinic aldehyde
`product of Step 7, above, in a minimum volume of dry
`THF is added thereto and the mixture stirred at about
`~60“ to ~75° for 1 hour.
`The reaction mixture is allowed to warm, ice-water
`added, and the mixture extracted with ethyl acetate.
`The combined extracts are dried,
`then evaporated to
`dryness to yield the crude title product of this step. This
`product is then flash distilled using ethyl acetate-methy-
`lene chloride (5:95 v/v) to obtain refined product (as a
`thick dark oil) for use in Step 9, below.
`Step
`9,
`7-[3-(4-fluorophenyl)-1-(1-methylethyl)-2-
`indolizinyl]-3,5,-dihydroxy-6-heptenoic acid, ethyl ester
`(trans).
`437 mg (1 mM) of the keto-ester product of Step 8,
`above, is mixed with 60 ml dry THF and then 15 ml of
`dry methanol. At R.T., 1.3 ml of 1 M triethylborane in
`THF are added. Then is added 8 ml of air. The mixture
`is stirred (at R.T.) for 2 hours.
`The mixture is then cooled to ——72°, 56 mg of sodium
`borohydride added and the mixture stirred for 3 hours
`at —72°. 30 mg additional sodium borohydride is added
`and the mixture stirred for 1 more hour at —72°. One ml
`
`of acetic acid is then added dropwise. The temperature
`of the mixture is allowed to rise to RT. The mixture is
`
`
`
`60
`
`then held at RT. for 16 hours. 20 m1 of 10% aqueous
`sodium bicarbonate solution is then added. Additional
`
`65
`
`water is added and the product of this example is ex-
`tracted with ethyl acetate. The combined extracts are
`dried and then evaporated to yield crude title product
`of this example. The product may be refined by
`chromatographing on prep. plates, eluting with me-
`thanol/methylene chloride (5:95), as an oil; the erythro
`isomer predominating about 95:5.
`
`Mylan Exhibit 1020, Page 7
`
`Mylan Exhibit 1020, Page 7
`
`

`

`7-[3-(4-fluorophenyl)-l-(1-methylethyl)—2-indolizinyl]-
`3,5,-dihydroxy-6-heptenoic acid, sodium salt (trans)
`To 14 ml of absolute ethanol is added 147.9 mg of 5
`7-[3-(4—fluorophenyl)-1-(1-methylethyl)-2-indolizinyl]-
`3,5,-dihydroxy-6-heptenoic acid, ethyl ester (Example
`1, above), and the solution cooled to +5“. There is then
`added thereto, dropwise 0.34 ml of 1 N aq. sodium
`hydroxide (0.34 mM). The mixture is stirred for 2 hours
`while the temperature is allowed to rise. The mixture is
`evaporated to dryness, to obtain a residue, which is then
`held under high vacuum for 2 hours at 40". Methylene
`chloride is added, the mixture warmed, filtered, cold
`ether is added dropwise, causing solids to precipitate.
`The solids are collected on by filtration, washed with
`ether, then dried at 40° under high vacuum to yield the
`title product, which decomposes at above 230°,
`the
`erythro isomer predominating about 9:1.
`Adapting the procedure of Examples 1 and 2, the
`following compounds 11 and I2 are obtained in which
`Y: a) and Z: a), (the erythro isomer predominating
`about 9:1); (in the table Et= ethyl, ip=isopropyl, i..e
`1,-methylethyl and ph=phenyl.
`
`Example
`
`
`
`
`
` No. R1 R2 R8 Form
`3
`4-F-ph
`H
`Et
`Oil
`>200“ c.
`solid
`decomp.
`Na
`H
`4-F-ph
`4
`oil
`Et
`4-F-ph
`ip
`5
`6
`ip
`4-F-ph
`Na
`Solid
`>220“ c.
`
`decomp.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`What is claimed is:
`1. A compound of formula I:
`
`R2
`
`/ / Y—Z
`
`\ N
`
`R1
`
`wherein each of RI and R2 is, independently:
`
`I
`
`45
`
`(a)
`
`50
`
`(b) hydrogen, or a primary or secondary C1.5alkyl not
`containing an asymmetric carbon atom, (c) C3.6cyc10al-
`kyl or (d) phenyl-(CH2)m-,
`wherein
`
`'
`
`R5 is hydrogen, C1-3alky1, n-butyl, i-butyl,
`trifluoro-
`t-butyl, C1-3alkoxy, n-butoxy,
`i-butoxy,
`methyl, fluoro, chloro, phenoxy or benzyloxy;
`R6 is hydrogen, C1-3alkyl, C1-3alkoxy,
`fluoro or
`chloro;
`R7 is hydrogen, C1-2alkyl, C1.2alkoxy,
`chloro;
`
`fluoro or
`
`55
`
`60
`
`65
`
`13
`
`EXAMPLE 2
`
`4,751,235
`
`14
`
`Vmisl,20r3;
`
`H
`
`Y is (a) -C=(|:— or (b) -CH2—CH2—, and
`H
`
`z is —(l2H-CH2-(IJH-—CH2—COOR3 (a) or
`on
`OH
`
`CH2
`
`/OH
`\CII—H (b);
`—c1i1’
`CH2
`0
`\ C /
`II
`
`in which R8 is hydrogen, R9 or M,
`wherein
`
`R9 is a physiologically acceptable and hydrolyzable
`ester group, and
`M is a pharmaceutically acceptable cation.
`2. A compound of claim 1 in which Y is of type (a).
`3. A compound of claim 2 in which R1 is of type (a).
`4. A compound of claim 3 in which R2 is a primary
`alkyl.
`5. A compound of claim 2 in which R2 is isopropyl.
`6. A compound of claim 1 in which R3 is hydrogen.
`7. A compound of claim 1 in which R8 is a physiologi-
`cally acceptable and hydrolyzable ester group.
`