N-bromobutanimide → Tert-butyl 6-bromo-2-methyl-spiro[3,4-dihydropyrrolo[1,2-a]pyrazine-1,4'-piperidine]-1'-carboxylate

HRID 1405350Notes

Reaction equation

HRID 1405350 reaction equation
[CH3:1][N:2]1[C:10]2([CH2:15][CH2:14][N:13]([C:16]([O:18][C:19]([CH3:22])([CH3:21])[CH3:20])=[O:17])[CH2:12][CH2:11]2)[C:6]2=[CH:7][CH:8]=[CH:9][N:5]2[CH2:4][CH2:3]1.[Br:23]N1C(=O)CCC1=O>C(Cl)Cl.[O-]S([O-])(=S)=O.[Na+].[Na+]>[Br:23][C:9]1[N:5]2[CH2:4][CH2:3][N:2]([CH3:1])[C:10]3([CH2:11][CH2:12][N:13]([C:16]([O:18][C:19]([CH3:22])([CH3:21])[CH3:20])=[O:17])[CH2:14][CH2:15]3)[C:6]2=[CH:7][CH:8]=1

Participants

5

Reactant 2

HCID 67184N-bromobutanimide2×HCID 68153652tert-Butyl 2'-methyl-3',4'-dihydro-2'H-spiro[piperidine-4,1'-pyrrolo[1,2-a]pyrazine]-1-carboxylate

Product 1

HCID 68153511Tert-butyl 6-bromo-2-methyl-spiro[3,4-dihydropyrrolo[1,2-a]pyrazine-1,4'-piperidine]-1'-carboxylate

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolventHCID 24477Sodium ThiosulfateSolvent

Conditions

Temperature
0 °C

Procedure

To tert-butyl 2-methylspiro[3,4-dihydropyrrolo[1,2-a]pyrazine-1,4′-piperidine]-1′-carboxylate (10 g, 32.74 mmol) in methylene chloride (73.5 mL) at 0° C. was added N-bromosuccinimide (5.53 g, 31.10 mmol) portionwise. The reaction was stirred at 0° C. After 30 minutes, additional N-bromosuccinimide (291.4 mg, 1.64 mmol) was added and the reaction was stirred for 1 hour. The reaction was diluted with 0.5 M Na2S2O3 (135 mL) and the aqueous phase was removed. The organic layer was washed with brine (135 mL). The organic layer was dried over sodium sulfate, filtered and the solvent was evaporated under reduced pressure to yield tert-butyl 6-bromo-2-methyl-spiro[3,4-dihydropyrrolo[1,2-a]pyrazine-1,4′-piperidine]-1′-carboxylate as a red viscous liquid that was used in the next step without further purification. 1H NMR (400 MHz, DMSO) δ 6.09 (d, J=3.7 Hz, 1H), 5.99 (d, J=3.7 Hz, 1H), 3.78-3.65 (m, 4H), 3.27 (t, J=6.0 Hz, 2H), 3.17-2.92 (m, 2H), 2.21 (s, 3H), 2.03-1.93 (m, 2H), 1.65-1.53 (m, 2H), 1.40 (s, 9H). ESI-MS m/z calc. 383.1, found 386.0 (M+1)+; Retention time: 1.13 minutes (3 minute run).

Workup

  1. stirringthe reaction was stirred for 1 hour
  2. customthe aqueous phase was removed
  3. washThe organic layer was washed with brine (135 mL)
  4. dry with materialThe organic layer was dried over sodium sulfate
  5. filtrationfiltered
  6. customthe solvent was evaporated under reduced pressure

Sources & evidence

ORD record
ord-2062b0b1012d42a095eae00c371b6d13
Source dataset
uspto-grants-2014_12
Patent number
US08916565B2

Reaction notes

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