Hydrochloric Acid → HCID 11845250, compound

HRID 1158891Notes

Reaction equation

[Li+].[BH4-].[N+:3]([C:6]1[CH:29]=[CH:28][C:9]([CH2:10][O:11][C:12]([N:14]2[CH2:19][CH2:18][N:17]3[N:20]=[C:21]([C:23](OCC)=[O:24])[CH:22]=[C:16]3[CH2:15]2)=[O:13])=[CH:8][CH:7]=1)([O-:5])=[O:4].Cl.C([O-])([O-])=O.[K+].[K+]>CO.C1COCC1>[N+:3]([C:6]1[CH:29]=[CH:28][C:9]([CH2:10][O:11][C:12]([N:14]2[CH2:19][CH2:18][N:17]3[N:20]=[C:21]([CH2:23][OH:24])[CH:22]=[C:16]3[CH2:15]2)=[O:13])=[CH:8][CH:7]=1)([O-:5])=[O:4]

Participants

Conditions

Temperature: 40 °C

Procedure

LiBH4 (640 mg) and MeOH (1.2 mL) was added to the THF (267 mL) solution of 6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-2,5-dicarboxylic acid 2-ethyl ester 5-(4-nitrobenzyl) ester (10 g) under a nitrogen atmosphere at room temperature and stirred for 3 h at 40° C. Additional LiBH4 (523 mg) and MeOH (1.0 mL) was added to the solution and stirred for 1 h at 40° C. and 1 h at 50° C. The mixture was acidified with 3 mol/L HCl to pH 2 and stirred for 1 h at room temperature, then solid K2CO3 was added to the solution to adjust pH to 8. The insoluble material was filtered off and the filtrate was extracted with AcOEt. The organic layer was dried (K2CO3), and concentrated under reduced pressure. The residue was purified with silica gel column chromatography (CHCl3/MeOH=49/1-19/1) to afford titled compound as pale yellow crystals (8.44 g, 95%).

Workup

stirringstirred for 1 h at 40° C. and 1 h at 50° C
stirringstirred for 1 h at room temperature
filtrationThe insoluble material was filtered off
extractionthe filtrate was extracted with AcOEt
dry with materialThe organic layer was dried (K2CO3)
concentrationconcentrated under reduced pressure
customThe residue was purified with silica gel column chromatography (CHCl3/MeOH=49/1-19/1)

Sources & evidence

ORD record: ord-5a1b18978862410db8d9a2a5ff0ff547
Source dataset: uspto-grants-2010_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07812014B2

Reaction notes

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