Process for preparing tetracyclic heterocycle compounds
View Patent ↗The present invention is directed to a process for preparing Tetracyclic Heterocycle Compounds of formula (I): which are useful as HCV NS5A inhibitors. The present invention is also directed to compounds that are useful as synthetic intermediates for making the compounds of formula (I).
1. A process for preparing a compound of Formula I:
and pharmaceutically acceptable salts thereof,
wherein said process comprises:
(A) (i) contacting the compound of Formula VI with bis(pinacoloato)diboron in the presence of an acetate or pivalate base, a transition metal catalyst, and optionally in the presence of a phosphorus ligand source, in a mixture of water and an organic solvent E, to provide an intermediate compound of Formula VII:
then (ii) contacting the intermediate compound of formula VII with a compound of formula VIIb
in the presence of a carbonate, acetate or pivalate base and a transition metal catalyst, and optionally in the presence of a phosphorus ligand source, in said mixture of water and organic solvent E, to provide a compound of formula VIII:
wherein organic solvent E is selected from dimethylacetamide, toluene, acetonitrile, N,N-dimethylformamide, tetrahydrofuran, 2-methyl tetrahydrofuran, cyclopentyl methyl ether, isopropanol, ethanol, ethyl acetate, isopropyl acetate and dimethoxyethane; and
(B) (i) contacting the di-p-nitrobenzoate salt of the compound of Formula VIII with an inorganic base, in an organic solvent F, for a time sufficient to remove the Boc protecting groups from the compound of Formula VIII, then (ii) contacting the deprotected compound in situ with HCl to provide a compound of Formula IX:
wherein organic solvent F is selected from methanol, acetonitrile, tetrahydrofuran, 2-methyl tetrahydrofuran, ethanol, isopropanol and toluene; and
(C) contacting the compound of Formula IX with: (i) an additive selected from 2-hydroxypyridine-N-oxide, N-hydroxysuccinimide, HOBt and pyridine, and (ii) a non-nucleophilic base) in the presence of (i) a compound of formula Xa:
and (ii) an amide coupling reagent in an organic solvent G to provide a compound of Formula I:
wherein organic solvent G is selected from tetrahydrofuran, N,N-dimethylformamide, dimethylacetamide, N-methylpyrrolidinone and dimethylsulfoxide; and
wherein
each occurrence of R 1 is independently C 1 -C 6 alkyl, C 3 -C 7 cycloalkyl or C 6 -C 10 aryl;
each occurrence of R 2 is independently C 1 -C 6 alkyl, C 3 -C 7 cycloalkyl, 3 to 7-membered monocyclic heterocycloalkyl or C 6 -C 10 aryl;
R 3 is C 1 -C 6 alkyl, C 3 -C 7 cycloalkyl, C 6 -C 10 aryl, 5 or 6-membered monocyclic heteroaryl or 9 or 10-membered bicyclic heteroaryl, wherein said C 3 -C 7 cycloalkyl group, said C 6 -C 10 aryl group, said 5 or 6-membered monocyclic heteroaryl group or said 9 or 10-membered bicyclic heteroaryl group can be optionally substituted with up to three groups, each independently selected from C 1 -C 6 alkyl and C 3 -C 7 cycloalkyl; and
R a is Br, Cl or I.
2. The process according to claim 1 , wherein:
Step A, part (i) is conducted at a temperature in a range of from about 40° C. to about 110° C.;
the organic solvent employed in step A, part (i) is N,N-dimethylformamide;
the acetate or pivalate base employed in Step A, part (i) is selected from NaOAc, CsOAc, KOPiv, NaOPiv and potassium acetate;
the transition metal catalyst employed in Step A, part (i) is selected from Pd 2 dba 3 , Pd(OAc) 2 and PdCl 2 ;
the optional phosphine ligand employed in Step A, part (i) is selected from N-Bu(Ad) 2 P, Am-phos, n-BuP(t-Bu) 2 -HBF 4 , XPhos, SPhos, BrettPhos, DTBPF, PCy 3 and P(t-Bu) 3 ;
Step A, part (ii) is conducted at a temperature in a range of from about 40° C. to about 110° C.;
the organic solvent employed in step A, part (ii) is N,N-dimethylformamide;
the carbonate, acetate or pivalate base employed in Step A, part (ii) is selected from K 2 CO 3 , NaOAc, CsOAc, KOPiv, NaOPiv and potassium acetate;
the transition metal catalyst employed in Step A part (ii) is selected from Pd 2 dba 3 , Pd(OAc) 2 and PdCl 2 ;
the optional phosphine ligand employed in Step A, part (ii) is selected from N-Bu(Ad) 2 P, Am-phos, n-BuP(t-Bu) 2 -HBF 4 , XPhos, SPhos, BrettPhos, DTBPF, PCy 3 and P(t-Bu) 3 ;
Step B, part (i) is conducted at a temperature in a range of from about 0° C. to about 60° C.;
the organic solvent employed in step B is N,N-dimethylformamide;
the inorganic base employed in step B is selected from a carbonate base, a phosponate base or an alkali metal hydroxide base;
Step B, part (ii) is conducted at a temperature in a range of from about 20° C. to about 60° C.;
Step C is conducted at a temperature in a range of from about −10° C. to about 60° C.;
the organic solvent employed in step C is N,N-dimethylformamide;
the non-nucleophilic base employed in step C is selected from (N-methylmorpholine, triethylamine, diisopropylethylamine and pyridine;
the amide coupling reagent employed in step C is selected from DCC, HATU, T3P and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride.
3. The process according to claim 1 , wherein each occurrence of R 1 and R 2 is independently C 1 -C 6 alkyl and R 3 is 5 or 6-membered heteroaryl or C 6 -C 10 aryl, wherein R 3 can be optionally substituted with a group selected from C 1 -C 6 alkyl and C 3 -C 7 cycloalkyl.
4. The process according to claim 1 , wherein:
Step A, part (i) is conducted at a temperature in a range of from about 70° C. to about 90° C.;
the organic solvent employed in step A, part (i) is a mixture of DME and water;
the acetate or pivalate base employed in Step A, part (i) is selected from NaOAc, CsOAc and potassium acetate;
the transition metal catalyst employed in Step A part (i) is Pd 2 dba 3 ;
the optional phosphine ligand employed in Step A, part (i) is N-Bu(Ad) 2 P;
Step A, part (ii) is conducted at a temperature in a range of from about 70° C. to about 90° C.;
the organic solvent employed in step A, part (ii) is a mixture of DME and water;
the carbonate, acetate or pivalate base employed in Step A, part (ii) is Na 2 CO 3 or K 2 CO 3 ;
the transition metal catalyst employed in Step A, part (ii) is Pd 2 dba 3 ;
the optional phosphine ligand employed in Step A, part (ii) is Am-phos;
Step B, part (i) is conducted at a temperature in a range of from about 15° C. to about 30° C.;
the organic solvent employed in step B is an organic alcohol;
the inorganic base employed in step B is an alkali metal carbonate base;
Step D, part (ii) is conducted at a temperature in a range of from about 35° C. to about 50° C.;
Step C is conducted at a temperature in a range of from about 15° C. to about 35° C.;
the organic solvent employed in step C is acetonitrile;
the additive employed in step C is HOBt;
the non-nucleophilic base employed in step C is N-methylmorpholine;
the amide coupling reagent employed in step C is N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride.
5. The process according to claim 4 , wherein:
Step A, part (i) is conducted at a temperature in a range of from about 70° C. to about 90° C.;
the organic solvent employed in step A, part (i) is a mixture of DME and water;
the acetate or pivalate base employed in Step A, part (i) is selected from NaOAc, CsOAc and potassium acetate;
the transition metal catalyst employed in Step A, part (i) is Pd 2 dba 3 ;
the optional phosphine ligand employed in Step A, part (i) is N-Bu(Ad) 2 P;
Step A, part (ii) is conducted at a temperature in a range of from about 70° C. to about 90° C.;
the organic solvent employed in step A, part (ii) is a mixture of DME and water;
the carbonate, acetate or pivalate base employed in Step A, part (ii) is Na 2 CO 3 or K 2 CO 3 ;
the transition metal catalyst employed in Step A, part (ii) is Pd 2 dba 3 ;
the optional phosphine ligand employed in Step A, part (ii) is Am-phos;
Step B, part (i) is conducted at a temperature in a range of from about 15° C. to about 30° C.;
the organic solvent employed in step B is an organic alcohol;
the inorganic base employed in step B is an alkali metal carbonate base;
Step B, part (ii) is conducted at a temperature in a range of from about 35° C. to about 50° C.;
Step C is conducted at a temperature in a range of from about 15° C. to about 35° C.;
the organic solvent employed in step C is acetonitrile;
the additive employed in step C is HOBt;
the non-nucleophilic base employed in step C is N-methylmorpholine;
the amide coupling reagent employed in step C is N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride.
6. A process for preparing Compound A:
wherein said process comprises the steps:
(A) contacting an intermediate compound of formula VII:
with a compound of formula VIIb
wherein R a is Br, Cl or I,
in the presence of a carbonate, acetate or pivalate base and a transition metal catalyst, and optionally in the presence of a phosphorus ligand source, in said mixture of water and organic solvent E, to provide a compound of formula VIII:
wherein organic solvent E is selected from dimethylacetamide, toluene, acetonitrile, N,N-dimethylformamide, tetrahydrofuran, 2-methyl tetrahydrofuran, cyclopentyl methyl ether, isopropanol, ethanol, ethyl acetate, isopropyl acetate and dimethoxyethane; and
(D) (i) contacting the di-p-nitrobenzoate salt of the compound of Formula VIII with an inorganic base, in an organic solvent F, for a time sufficient to remove the Boc protecting groups from the compound of Formula VIII, then (ii) contacting the deprotected compound in situ with HCl to provide a compound of Formula IX:
wherein organic solvent F is selected from methanol, acetonitrile, tetrahydrofuran, 2-methyl tetrahydrofuran, ethanol, isopropanol and toluene; and
(E) contacting the compound of Formula IX with: (i) an additive selected from 2-hydroxypyridine-N-oxide, N-hydroxysuccinimide, HOBt and pyridine, and (ii) a non-nucleophilic base) in the presence of (i) a compound of formula Xa:
and (ii) an amide coupling reagent in an organic solvent G to provide Compound A, wherein organic solvent G is selected from tetrahydrofuran, N,N-dimethylformamide, dimethylacetamide, N-methylpyrrolidinone and dimethylsulfoxide.
7. The process of claim 1 , wherein each occurrence of R 1 is methyl and each occurrence of R 2 is isopropyl.
8. The process of claim 1 , wherein for compound (VIIb), R a is Br.
9. The process of claim 1 , wherein for compound (VIIb), R a is Cl.
10. The process of claim 1 , wherein for compound (VIIb), R a is I.