Methods for preparation of bile acids and derivatives thereof

1. A method of preparing a compound of Formula (I):

or a pharmaceutically acceptable salt, solvate, or amino acid conjugate thereof, wherein R 1 is H, α-OH, β-OH, or an oxo group, from compound 2 comprising the steps of:

(1) converting compound 2 to compound 5

(2) converting compound 5 into compound 6:

(3) converting compound 6 into compound 9:

(4) converting compound 9 into compound 10

(5) alkylating compound 10 regioselectively and stereoselectively to yield compound 11

wherein P 1 is a protecting group or H;

(6) regioselectively and stereoselectively reducing compound 11 to yield compound

wherein P 2 is a protecting group; and

(7) selectively reducing compound 13 and deprotecting to yield the compound of Formula (I), wherein R 1 is H; or

(8) oxidizing compound 13 regioselectively to yield compound 15

and

(9) selectively reducing compound 15 and deprotecting to yield the compound of Formula (I), wherein R 1 is α-OH, β-OH, or an oxo group.

2. The method of claim 1 , where in the compound of Formula (I) is a compound of Formula (Ia) or a pharmaceutically acceptable salt, solvate, or amino acid conjugate thereof, further comprising the steps of:

(a) stereoselectively reducing compound 13 to yield compound 14

wherein P 1 is a protecting group or H and P 2 is a protecting group;

(b) selectively deprotecting compound 14 to yield compound 14a

and

(c) hydrolyzing compound 14a to form the compound of Formula (Ia)

3. The method of claim 2 , wherein the deprotecting in step b) and the hydrolyzing in step c) occur in a single step.

4. The method of claim 2 , wherein the stereoselective reduction in step a) comprises hydrogenation.

5. The method of claim 4 , wherein the hydrogenation is conducted with a catalyst and hydrogen gas.

6. The method of claim 1 , wherein the compound of Formula (I) is a compound of Formula (Ib) or a pharmaceutically acceptable salt, solvate, or amino acid conjugate thereof, further comprising the steps of:

(9a) stereoselectively reducing compound 15 to yield compound 16A

and

(10) stereoselectively reducing compound 16A and deprotecting to yield the compound of Formula (Ib), wherein step 10 comprises the steps of

(a) stereoselectively reducing compound 16A to yield compound 17

(b) selectively deprotecting compound 17 to yield compound 17A

and

(c) hydrolyzing compound 17A to yield the compound of Formula (Ib)

7. The method of claim 6 , wherein the deprotecting in step b) and the hydrolyzing in step c) occur in a single step.

8. The method of claim 6 , wherein the stereoselective reduction comprises hydrogenation.

9. The method of claim 8 , wherein the hydrogenation is conducted with a catalyst and hydrogen gas.

10. The method of claim 1 , where in the compound of Formula (I) is a compound of Formula (Ic) or a pharmaceutically acceptable salt, solvate, or amino acid conjugate thereof, further comprising the steps of:

(9b) stereoselectively reducing compound 15 to yield compound 16B

(10) stereoselectively reducing compound 16B and deprotecting to yield the compound of Formula (Ic), wherein step 10 comprises the steps of

(a) stereoselectively reducing compound 16B to yield compound 18

(b) deprotecting compound 18 to yield compound 18A

and

(c) hydrolyzing compound 18A to yield the compound of Formula (Ic)

11. The method of claim 8 , wherein the deprotecting in step b) and the hydrolyzing in step c) occur in a single step.

12. The method of claim 11 , wherein the stereoselective reduction comprises hydrogenation.

13. The method of claim 12 , wherein the hydrogenation is conducted with a catalyst and hydrogen gas.

14. The method of claim 1 further comprising the steps of:

(9c) selectively reducing compound 15 to compound 19

and

(10) deprotecting compound 19 to yield compound of Formula (I), wherein R 1 is oxo, or a pharmaceutically acceptable salt, solvate, or amino acid conjugate thereof.

15. The method of claim 14 , wherein the selective reduction comprises hydrogenation.

16. The method of claim 15 , wherein the hydrogenation is conducted with a catalyst and hydrogen gas.

17. The method of claim 6 , wherein the stereoselective reduction of compound 15 to compound 16A comprises reacting compound 15 with K-Selectride.

18. The method of claim 10 , wherein stereoselective reduction of compound 15 to compound 16B comprises reacting compound 15 with NaBH 4 and CeCl 3 .7H 2 O.

19. The method of claim 1 , wherein alkylating of compound 10 comprises reacting compound 10 with methyl acrylate or methyl propiolate in the presence of EtAlCl 2 or MeAlCl 2 to yield compound 11.

20. The method of claim 1 , wherein one or more steps is conducted under flow chemistry conditions.