Pyrrolidine → 2'-Methyl-6',7'-dihydro-2'H-spiro[piperidine-4,5'-pyrano[3,2-c]pyrazole]-7'-one

HRID 1880335Notes

Reaction equation

HRID 1880335 reaction equation
N1CCCC1.[OH:6][C:7]1[C:8]([C:13](=[O:15])[CH3:14])=[N:9][N:10]([CH3:12])[CH:11]=1.C([N:23]1[CH2:28][CH2:27][CH2:26][CH2:25][C:24]1=O)(OC(C)(C)C)=O>CO>[CH3:12][N:10]1[CH:11]=[C:7]2[O:6][C:26]3([CH2:27][CH2:28][NH:23][CH2:24][CH2:25]3)[CH2:14][C:13](=[O:15])[C:8]2=[N:9]1

Participants

5

Reactant 3

HCID 31268PyrrolidineHCID 7577838tert-Butyl 2-oxopiperidine-1-carboxylateHCID 1341338895884-20-1

Product 1

HCID 581231212'-Methyl-6',7'-dihydro-2'H-spiro[piperidine-4,5'-pyrano[3,2-c]pyrazole]-7'-one

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

Pyrrolidine (3.0 g, 3.5 mL, 42 mmol) was added to a solution of 1-(4-hydroxy-1-methyl-1H-pyrazol-3-yl)ethanone (5.93 g, 42.3 mmol) in methanol (50 mL). The mixture was stirred at room temperature for 2 hours before addition of N-Boc-piperidone (8.43 g, 42.3 mmol). The mixture was stirred at room temperature overnight before concentration to dryness. The crude material was purified by CombiFlash (120 g column, 30-50% EtOAc/hexanes gradient) to afford desired product containing unreacted starting material. This material was triturated with 30% EtOAc/hexanes, the solids were filtered and air dried to afford tert-butyl 2′-methyl-7′-oxo-6′,7′-dihydro-1H,2′H-spiro[piperidine-4,5′-pyrano[3,2-c]pyrazole]-1-carboxylate (6.8 g, 50%).

Workup

  1. customThe crude material was purified by CombiFlash (120 g column, 30-50% EtOAc/hexanes gradient)

Sources & evidence

ORD record
ord-4f830487872647d2b766416f45b9fcda
Source dataset
uspto-grants-2012_11
Patent number
US08318762B2

Reaction notes

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