Hydrochloric Acid → (R)-[1-(2-hydroxy-ethyl)-4,5,6,7-tetrahydro-1H-indazol-4-yl]-carbamic acid benzyl ester

HRID 2387529Notes

Reaction equation

C([O:3][C:4](=O)[CH2:5][N:6]1[C:14]2[CH2:13][CH2:12][CH2:11][C@@H:10]([NH:15][C:16]([O:18][CH2:19][C:20]3[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=3)=[O:17])[C:9]=2[CH:8]=[N:7]1)C.[BH4-].[Na+].Cl>CO>[CH2:19]([O:18][C:16](=[O:17])[NH:15][C@@H:10]1[CH2:11][CH2:12][CH2:13][C:14]2[N:6]([CH2:5][CH2:4][OH:3])[N:7]=[CH:8][C:9]1=2)[C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=1

Participants

Conditions

Temperature: 70 °C

Procedure

To a solution of ((R)-4-benzyloxycarbonylamino-4,5,6,7-tetrahydro-indazol-1-yl)-acetic acid ethyl ester (2.00 g, 5.60 mmol) in methanol (150 mL) was added sodium borohydride (1.61 g, 39.5 mmol). The mixture was stirred at 70° C. for 2 hours. After being cooled to room temperature, the reaction mixture was acidified to pH 7 with 5N hydrochloric acid, and then concentrated to remove methanol. The resulting mixture was extracted with dichloromethane (20 mL). After filtering out any insoluble materials from the organic layer, the filtrate was concentrated in vacuo to give (R)-[1-(2-hydroxy-ethyl)-4,5,6,7-tetrahydro-1H-indazol-4-yl]-carbamic acid benzyl ester (1.68 g, 95%) as a white solid. MS calcd. for C17H21N3O3 315, obsd. (ESI+) [(M+H)+] 316.

Workup

temperatureAfter being cooled to room temperature
concentrationconcentrated
customto remove methanol
extractionThe resulting mixture was extracted with dichloromethane (20 mL)
filtrationAfter filtering out any insoluble materials from the organic layer
concentrationthe filtrate was concentrated in vacuo

Sources & evidence

ORD record: ord-6b933b4625f14f81b91cc6dbd9e8eae1
Source dataset: uspto-grants-2012_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08268870B2

Reaction notes

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