Sacubitril intermediate and preparation method thereof

1. A method of preparing sacubitril,

comprising the following steps:

a) preparing a compound of Formula (VI) by an enzymic catalytic reaction of a compound of Formula (V) in the presence of ω-transaminase and phosphopyridoxal,

b) optionally, preparing a compound of Formula (VII) from the compound of Formula (VI):

c) preparing sacubitril from the compound of Formula (VII),

wherein:

R 1 is phenyl, methoxy, hydroxy, chloro, bromo, iodo, mesylate, triflate or 4-methylbenzenesulfonate;

R 2 is

R 3 is H, —(C 1 -C 4 )alkyl or —(C 1 -C 4 )alkyl-aryl; and

R 4 is H, —(C 1 -C 4 )alkyl, —(C 3 -C 6 )heterocyclyl, —(C 1 -C 4 )alkyl-aryl, trimethylsilyl, triethylsilyl or t-butyldimethylsilyl.

2. The method of claim 1 ,

wherein the compound of Formula (V) is prepared by a deprotection reaction of a compound of Formula (IV):

in the presence of a base or an acid, wherein:

R 1 is phenyl, methoxy, hydroxy, chloro, bromo, iodo, mesylate, triflate or 4-methylbenzenesulfonate;

R 2 is

 and when R 1 is phenyl, R 2 is not

R 3 is H, —(C 1 -C 4 )alkyl or —(C 1 -C 4 )alkyl-aryl;

R 4 is H, —(C 1 -C 4 )alkyl, —(C 3 -C 6 )heterocyclyl, —(C 1 -C 4 )alkyl-aryl, trimethylsilyl, triethylsilyl or t-butyldimethylsilyl; and

R 5 is H, —(C 1 -C 4 )alkyl or —(C 1 -C 4 )alkyl-aryl.

3. The method of claim 2 , compound of Formula (IV) is prepared by a substitution reaction of a compound of Formula (II) with a compound of Formula (III) in the presence of a base;

4. The method of claim 3 , compound of Formula (II) is prepared by a condensation reaction of a compound of Formula (I);

wherein R 1 is as defined above; and

R 5 is H, —(C 1 -C 4 )alkyl or —(C 1 -C 4 )alkyl-aryl.

5. The method according to claim 2 , wherein the compound of the Formula (IV) is prepared by a process comprising the following steps:

a) preparing a compound of Formula (II) by a condensation reaction of a compound of Formula (I) in the presence of a base,

b) preparing a compound of Formula (IV) by a substitution reaction of the compound of Formula (II) with a compound of Formula (III) in the presence of a strong base;

wherein R 1 is phenyl;

R 2 is

R 3 is H, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl or benzyl;

R 4 is H, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, benzyl, trimethylsilyl, triethylsilyl, t-butyldimethylsilyl, triphenylmethyl, tetrahydrofuryl;

R 5 is H, methyl, ethyl, n-propyl, i-propyl, n-butyl or benzyl; and

R 6 is triflate, mesylate or 4-methylbenzenesulfonate.

6. The method of claim 5 wherein the compound of Formula (II) is prepared by a condensation reaction of the compound of Formula (I) with N,N′-carbonyldiimidazole and a compound of Formula (VIII):

in the presence of magnesium chloride and triethylamine, wherein R 5 is H, —(C 1 -C 4 )alkyl or —(C 1 -C 4 )alkyl-aryl.

7. The method of claim 5 , wherein the compound of Formula (II) is prepared by a condensation reaction of the compound of Formula (I) with Meldrum's acid, 4-dimethylaminopyridine, R 5 OH and pivaloyl chloride in the presence of N,N-diisopropylethylamine, R 5 is H, —(C 1 -C 4 )alkyl or —(C 1 -C 4 )alkyl-aryl.

8. The method of claim 1 , wherein R 1 is phenyl; R 2 is

and R 3 is methyl, ethyl, propyl, i-propyl, n-butyl, t-butyl, benzyl or optionally substituted benzyl.

9. The method of claim 1 , comprising the following steps:

a) preparing a compound of Formula (VII) by an enzymic catalytic reaction of a compound of Formula (V):

in the presence of ω-transaminase and phosphopyridoxal; and

b) preparing sacubitril by an amide condensation reaction of the compound of Formula (VII) with succinic anhydride,

wherein R 1 is phenyl, and R 2 is

and R 3 is ethyl.

10. The method of preparing sacubitril of claim 1 , wherein the compound of Formula (VII) is prepared by a hydrolysis reaction of the compound of Formula (VI) and then an esterification reaction of the hydrolysis product with ethanol.

11. The method of claim 1 , wherein the compound of the Formula (VII) is prepared by a process comprising the following steps:

a) preparing a compound of Formula (X) by a reaction of a compound of Formula (V) with a compound of Formula (IX),

b) preparing a compound of Formula (XI) from the compound of Formula (X),

c) preparing a compound of Formula (XII) from the compound of Formula (XI),

d) preparing a compound of Formula (VII) from the compound of Formula (XII),

wherein:

R 1 is phenyl, methoxy, hydroxy, chloro, bromo, iodo, mesylate, triflate or 4-methylbenzenesulfonate;

R 2 is

R 3 is H, —(C 1 -C 4 )alkyl or —(C 1 -C 4 )alkyl-aryl; and

R 7 is phenyl, —(C 1 -C 4 )alkyl or —(C 1 -C 4 )alkyl-aryl.

12. The method of claim 11 , wherein the compound of Formula (IX) in step a) is D-phenylglycinol.

13. The method of claim 11 , wherein the compound of Formula (XI) is prepared from the compound of Formula (X) in the presence of titanium tetrachloride and triethyl silicane in step b).

14. The method of claim 11 , wherein the compound of Formula (XII) is prepared from the compound of Formula (XI) in the presence of palladium-carbon in step c).

15. The method of claim 11 , wherein the compound of Formula (VII) is prepared from the compound of Formula (XII) in ethanol in the presence of an acid in step d).

16. The method of claim 11 , wherein the compound of the Formula (VII) is prepared by a process comprising the following steps:

a) preparing a compound of Formula (XIII) by a reaction of (R)-5-([1,1′-biphenyl]-4-yl)-2-methyl-4-oxopentanoic acid with D-phenylglycinol,

b) preparing a compound of Formula (XIV) from the compound of Formula (XIII) in the presence of titanium tetrachloride and triethyl silicane,

c) preparing a compound of Formula (XII) from the compound of Formula (XIV) in the presence of palladium-carbon,

d) preparing a compound of Formula (VII) by a ring opening reaction of the compound of Formula (XII):