(2R,4R)-4-amino-1,2-Piperidinedicarboxylic acid 1-(1,1-dimethylethyl) 2-methyl ester

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 4-isocyanatobenzonitrile (1.17 g, 8.13 mmol) was added to a solution of (2R,4R)-1-tert-butyl 2-methyl 4-aminopiperidine-1,2-dicarboxylate (2.0 g, 7.7 mmol) and NEt3 (1.3 mL, 9.3 mmol) in THF (30 mL), and the resulting solution was stirred at room temperature for 6 hours. 1M ammonia in methanol (5 mL) was then added to the reaction mixture to quench excess isocyanine. Water (100 mL) and ethyl acetate (200 mL) were added to the mixture. The organic layer was separated and dried over MgSO4 and concentrated to give a solid. Purification by Companion (ReadySep, 80 g, silica gel packed) using ethyl acetate/heptane from 40-70% as eluent provided the title compound as a white solid 2.9 g (90%). LC-MS: 403.2, 401.3 (t=2.6 min). to quench excess isocyanine Water (100 mL) and ethyl acetate (200 mL) were added to the mixture The organic layer was separated dried over MgSO4 concentrated to give a solid Purification by Companion (ReadySep, 80 g, silica gel packed)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 4-isocyanatobenzonitrile (1.17 g, 8.13 mmol) was added to a solution of (2R,4R)-1-tert-butyl 2-methyl 4-aminopiperidine-1,2-dicarboxylate (2.0 g, 7.7 mmol) and NEt3 (1.3 mL, 9.3 mmol) in THF (30 mL), and the resulting solution was stirred at room temperature for 6 hours. 1M ammonia in methanol (5 mL) was added to reaction mixture to quench excess isocyanine. Water (100 mL) and ethyl acetate (200 mL) were added to the mixture. The organic layer was separated and dried over MgSO4 and concentrated to give a solid. Purification was done by Companion (ReadySep, 80 g, silica gel packed) with ethyl acetate/heptane from 40-70% to give the urea as a white solid 2.9 g (90%). LC-MS: 403.2, 401.3 (t=2.6 min). to quench excess isocyanine Water (100 mL) and ethyl acetate (200 mL) were added to the mixture The organic layer was separated dried over MgSO4 concentrated to give a solid Purification

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: BOP (6.59 g, 14.9 mmol) was added to a solution of 2,3-dihydrobenzo[b][1,4]dioxine-6-carboxylic acid (2.68 g, 14.9 mmol) and DIEA (5.3 mL, 30 mmol) in DMF (50 mL). Then (2R,4R)-1-tert-butyl 2-methyl 4-aminopiperidine-1,2-dicarboxylate (3.5 g, 13.5 mmol) was added to the mixture and the resulting solution was stirred at room temperature for 18 hours. Water (100 mL) was added to quench the reaction, and extracted with ethyl acetate (2×100 mL), organic layers were dried over MgSO4, and concentrated under reduced pressure. The residue was purified by Companion (ReadySep, 120 g, silica gel packed) with ethyl acetate/heptane from 20-50% to give the amide as off-white solid 5.4 g (95%). LC-MC: 421.2 (t=2.4 min). to quench the reaction extracted with ethyl acetate (2×100 mL), organic layers were dried over MgSO4 concentrated under reduced pressure The residue was purified by Companion (ReadySep, 120 g, silica gel packed) with ethyl acetate/heptane from 20-50%

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: (2R,4R)-1-tert-butyl 2-methyl 4-azidopiperidine-1,2-dicarboxylate (22.5 g, 79 mmol) was dissolved in methanol (400 mL), Pd/C (10%, 6 g) was added, and the apparatus was flushed three times with N2 and H2. The reaction mixture was hydrogenated at a pressure of 50 psi at room temperature for 20 hours, filtered through Celite and rinsed with methanol and then concentrated under reduced pressure to give the amine as a colorless oil 20 g (96%). GC-MS: 258 (t=2.8 min). the apparatus was flushed three times with N2 and H2 filtered through Celite rinsed with methanol concentrated under reduced pressure

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 4-isocyanatobenzonitrile (1.17 g, 8.13 mmol) was added to a solution of (2R,4R)-1-tert-butyl 2-methyl 4-aminopiperidine-1,2-dicarboxylate (2.0 g, 7.7 mmol) and NEt3 (1.3 mL, 9.3 mmol) in THF (30 mL), and the resulting solution was stirred at room temperature for 6 hours. 1M ammonia in methanol (5 mL) was then added to the reaction mixture to quench excess isocyanine. Water (100 mL) and ethyl acetate (200 mL) were added to the mixture. The organic layer was separated and dried over MgSO4 and concentrated to give a solid. Purification by Companion (ReadySep, 80 g, silica gel packed) using ethyl acetate/heptane from 40-70% as eluent provided the title compound as a white solid 2.9 g (90%). LC-MS: 403.2, 401.3 (t=2.6 min). to quench excess isocyanine Water (100 mL) and ethyl acetate (200 mL) were added to the mixture The organic layer was separated dried over MgSO4 concentrated to give a solid Purification by Companion (ReadySep, 80 g, silica gel packed)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 4-isocyanatobenzonitrile (1.17 g, 8.13 mmol) was added to a solution of (2R,4R)-1-tert-butyl 2-methyl 4-aminopiperidine-1,2-dicarboxylate (2.0 g, 7.7 mmol) and NEt3 (1.3 mL, 9.3 mmol) in THF (30 mL), and the resulting solution was stirred at room temperature for 6 hours. 1M ammonia in methanol (5 mL) was added to reaction mixture to quench excess isocyanine. Water (100 mL) and ethyl acetate (200 mL) were added to the mixture. The organic layer was separated and dried over MgSO4 and concentrated to give a solid. Purification was done by Companion (ReadySep, 80 g, silica gel packed) with ethyl acetate/heptane from 40-70% to give the urea as a white solid 2.9 g (90%). LC-MS: 403.2, 401.3 (t=2.6 min). to quench excess isocyanine Water (100 mL) and ethyl acetate (200 mL) were added to the mixture The organic layer was separated dried over MgSO4 concentrated to give a solid Purification

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: BOP (6.59 g, 14.9 mmol) was added to a solution of 2,3-dihydrobenzo[b][1,4]dioxine-6-carboxylic acid (2.68 g, 14.9 mmol) and DIEA (5.3 mL, 30 mmol) in DMF (50 mL). Then (2R,4R)-1-tert-butyl 2-methyl 4-aminopiperidine-1,2-dicarboxylate (3.5 g, 13.5 mmol) was added to the mixture and the resulting solution was stirred at room temperature for 18 hours. Water (100 mL) was added to quench the reaction, and extracted with ethyl acetate (2×100 mL), organic layers were dried over MgSO4, and concentrated under reduced pressure. The residue was purified by Companion (ReadySep, 120 g, silica gel packed) with ethyl acetate/heptane from 20-50% to give the amide as off-white solid 5.4 g (95%). LC-MC: 421.2 (t=2.4 min). to quench the reaction extracted with ethyl acetate (2×100 mL), organic layers were dried over MgSO4 concentrated under reduced pressure The residue was purified by Companion (ReadySep, 120 g, silica gel packed) with ethyl acetate/heptane from 20-50%

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: (2R,4R)-1-tert-butyl 2-methyl 4-azidopiperidine-1,2-dicarboxylate (22.5 g, 79 mmol) was dissolved in methanol (400 mL), Pd/C (10%, 6 g) was added, and the apparatus was flushed three times with N2 and H2. The reaction mixture was hydrogenated at a pressure of 50 psi at room temperature for 20 hours, filtered through Celite and rinsed with methanol and then concentrated under reduced pressure to give the amine as a colorless oil 20 g (96%). GC-MS: 258 (t=2.8 min). the apparatus was flushed three times with N2 and H2 filtered through Celite rinsed with methanol concentrated under reduced pressure

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The title compound was prepared from 4-benzo[b]thiophen-2-yl-2-chloro-pyrimidine and (2R,4R)-4-amino-piperidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester according to Step C of Method A. Yield 45 mg (45%).