Betahistine → 6-Methoxy-N-methyl-N-[2-(2-pyridyl)ethyl]-1,2-benzisoxazol-3-amine hydrochloride hemihydrate

HRID 582879Notes

Reaction equation

HRID 582879 reaction equation
[Cl:1][C:2]1[C:6]2[CH:7]=[CH:8][C:9]([O:11][CH3:12])=[CH:10][C:5]=2[O:4][N:3]=1.[CH3:13][NH:14][CH2:15][CH2:16][C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][N:18]=1>>[OH2:4].[ClH:1].[CH3:12][O:11][C:9]1[CH:8]=[CH:7][C:6]2[C:2]([N:14]([CH3:13])[CH2:15][CH2:16][C:17]3[CH:22]=[CH:21][CH:20]=[CH:19][N:18]=3)=[N:3][O:4][C:5]=2[CH:10]=1.[CH3:12][O:11][C:9]1[CH:8]=[CH:7][C:6]2[C:2]([N:14]([CH2:15][CH2:16][C:17]3[CH:22]=[CH:21][CH:20]=[CH:19][N:18]=3)[CH3:13])=[N:3][O:4][C:5]=2[CH:10]=1.[ClH:1]

Participants

3

Reactant 2

HCID 2366BetahistineHCID 158169243-Chloro-6-methoxy-1,2-benzoxazole

Product 1

HCID 699461696-Methoxy-N-methyl-N-[2-(2-pyridyl)ethyl]-1,2-benzisoxazol-3-amine hydrochloride hemihydrate

Conditions

Temperature
140 °C

Procedure

To a sealed tube was added 3-chloro-6-methoxy-1,2-benzisoxazole (2.5 g) and 2-(2-methylaminoethyl)pyridine (11.0 g). The reaction was heated to 140° C. over 72 hours and then cooled to room temperature. The residue was partitioned between EtOAc and brine, washed with brine (4×), and the organic phase was dried over MgSO4 and concentrated in vacuo. Preparative liquid chromatography (silica gel) eluting with 5% acetone/CH2Cl2 provided a residue upon evaporation (1.5 g) which was dissolved in ether and made acidic with ethereal hydrochloric acid. The precipitate was dried in vacuo and recrystallized from ethanol to yield 0.9 g, m.p. 152-153° C.

Workup

  1. temperaturecooled to room temperature
  2. customThe residue was partitioned between EtOAc and brine
  3. washwashed with brine (4×)
  4. dry with materialthe organic phase was dried over MgSO4
  5. concentrationconcentrated in vacuo
  6. washPreparative liquid chromatography (silica gel) eluting with 5% acetone/CH2Cl2
  7. customprovided a residue
  8. customupon evaporation (1.5 g) which
  9. dissolutionwas dissolved in ether
  10. customThe precipitate was dried in vacuo
  11. customrecrystallized from ethanol
  12. customto yield 0.9 g, m.p. 152-153° C.

Sources & evidence

ORD record
ord-147181a74a354901b712daf1ffa93967
Source dataset
uspto-grants-1999_07
Patent number
US05925766

Reaction notes

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