Hydroxylamine → tert-Butyl (4E)-4-(hydroxyimino)-3,4-dihydro-1'H-spiro[1-benzopyran-2,4'-piperidine]-1'-carboxylate

HRID 2204117Notes

Reaction equation

HRID 2204117 reaction equation
O=[C:2]1[C:23]2[C:18](=[CH:19][CH:20]=[CH:21][CH:22]=2)[O:17][C:4]2([CH2:9][CH2:8][N:7]([C:10]([O:12][C:13]([CH3:16])([CH3:15])[CH3:14])=[O:11])[CH2:6][CH2:5]2)[CH2:3]1.[NH2:24][OH:25].O>CO.C(OCC)(=O)C>[OH:25]/[N:24]=[C:2]1\[CH2:3][C:4]2([O:17][C:18]3[C:23]\1=[CH:22][CH:21]=[CH:20][CH:19]=3)[CH2:9][CH2:8][N:7]([C:10]([O:12][C:13]([CH3:16])([CH3:15])[CH3:14])=[O:11])[CH2:6][CH2:5]2

Participants

6

Reactant 3

HCID 787HydroxylamineHCID 962WaterHCID 40427565Tert-butyl 4-oxo-3,4-dihydrospiro[1-benzopyran-2,4'-piperidine]-1'-carboxylate

Product 1

HCID 58551619tert-Butyl (4E)-4-(hydroxyimino)-3,4-dihydro-1'H-spiro[1-benzopyran-2,4'-piperidine]-1'-carboxylateYield 98%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 8857Ethyl AcetateSolvent

Procedure

tert-Butyl 4-oxospiro[chroman-2,4′-piperidine]-1′-carboxylate (450 mg, 1.41 mmol) and hydroxylamine 50 wt % in water (940 μL of 50% w/v, 14 mmol) were combined in methanol (9.0 mL) and heated at reflux. After 24 hours, the reaction mixture was diluted with ethyl acetate and was washed with water. The organics were dried over MgSO4, filtered and evaporated to dryness to yield (E)-tert-butyl 4-(hydroxyimino)spiro[chroman-2,4′-piperidine]-1′-carboxylate (450 mg, 98%). ESI-MS m/z calc. 332.4, found 333.3 (M+1)+; Retention time: 1.68 minutes (3 min run).

Workup

  1. temperatureheated
  2. temperatureat reflux
  3. washwas washed with water
  4. dry with materialThe organics were dried over MgSO4
  5. filtrationfiltered
  6. customevaporated to dryness

Sources & evidence

ORD record
ord-17591adb94214c6eb919b5b644d54445
Source dataset
uspto-grants-2016_06
Patent number
US09365588B2

Reaction notes

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