Spiro(1-benzopyran-2,4'-piperidin)-4(3H)-one--hydrogen chloride (1/1) → Spiro[chroman-2,4'-piperidine]

HRID 266895Notes

Reaction equation

HRID 266895 reaction equation
Cl.[NH:2]1[CH2:7][CH2:6][C:5]2([CH2:12][C:11](=O)[C:10]3[CH:14]=[CH:15][CH:16]=[CH:17][C:9]=3[O:8]2)[CH2:4][CH2:3]1.[BH4-].[Na+]>CO.[Pd].C(O)C>[NH:2]1[CH2:7][CH2:6][C:5]2([CH2:12][CH2:11][C:10]3[CH:14]=[CH:15][CH:16]=[CH:17][C:9]=3[O:8]2)[CH2:4][CH2:3]1

Participants

6

Reactant 2

HCID 2771097Spiro(1-benzopyran-2,4'-piperidin)-4(3H)-one--hydrogen chloride (1/1)HCID 4311764Sodium borohydride

Product 1

HCID 15187049Spiro[chroman-2,4'-piperidine]Yield 208.5%

Reagents, catalysts & solvents 3

HCID 23938PalladiumCatalystHCID 702EthanolSolventHCID 887MethanolSolvent

Procedure

To a stirred solution of the spiro[2H-1-benzopyran-2,4'-piperidin]-4(3H)-one, hydrochloride (53 mg, 0.21 mmol) in methanol (5 mL) at 0° C., was added sodium borohydride (38 mg, 1 mmol) in several portions. After 30 minutes the mixture was evaporated and then treated with concentrated hydrochloric acid (2 mL) for 30 min. Evaporation gave a residue which was hydrogenated with palladium on carbon (10%, 10 mg), H2 (1 atm) in ethanol for two hours. Filtration to remove the catalyst gave the crude intermediate (89 mg) which was used without further purification.

Workup

  1. customAfter 30 minutes the mixture was evaporated
  2. additiontreated with concentrated hydrochloric acid (2 mL) for 30 min
  3. customEvaporation
  4. customgave a residue which
  5. filtrationFiltration
  6. customto remove the catalyst

Sources & evidence

ORD record
ord-9a73530504a5413ab212661e9806b65b
Source dataset
uspto-grants-1997_07
Patent number
US05652235

Reaction notes

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