3-Aminopyridine → (RS)-3-(Pyrid-3-ylimino)-9,9a-dihydrothiazolo[3,4-a]indole

HRID 262119Notes

Reaction equation

HRID 262119 reaction equation
[I-].CS[C:4]1[S:5][CH2:6][CH:7]2[CH2:15][C:14]3[CH:13]=[CH:12][CH:11]=[CH:10][C:9]=3[N+:8]=12.[NH2:16][C:17]1[CH:18]=[N:19][CH:20]=[CH:21][CH:22]=1>N1C=CC=CC=1>[N:19]1[CH:20]=[CH:21][CH:22]=[C:17]([N:16]=[C:4]2[N:8]3[C:9]4[CH:10]=[CH:11][CH:12]=[CH:13][C:14]=4[CH2:15][CH:7]3[CH2:6][S:5]2)[CH:18]=1

Participants

4

Reactant 2

HCID 100093-AminopyridineHCID 21320148(RS)-3-Methylthio-9,9a-dihydrothiazolo[3,4-a]indolium iodide

Product 1

HCID 21320150(RS)-3-(Pyrid-3-ylimino)-9,9a-dihydrothiazolo[3,4-a]indoleYield 76.5%

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent

Procedure

(RS)-3-Methylthio-9,9a-dihydrothiazolo[3,4-a]indolium iodide (14.0 g) is added to a solution of 3-aminopyridine (4.5 g) in pyridine (150 cc). The suspension gradually passes into solution. After 24 hours at a temperature of about 20° C., the mixture is concentrated to dryness under reduced pressure (25 mm Hg) at 50° C. The residue is dissolved in a mixture of methylene chloride (500 cc) and 2 N aqueous sodium hydroxide solution (150 cc). The organic phase is decanted, washed with water (200 cc), dried over magnesium sulphate, filtered and then concentrated to dryness under reduced pressure (40 mm Hg) at 40° C. The residue obtained is recrystallised from absolute ethanol (40 cc). (RS)-3-(Pyrid-3-ylimino)-9,9a-dihydrothiazolo[3,4-a]indole (8.2 g), melting at 131° C., is obtained.

Workup

  1. concentrationthe mixture is concentrated to dryness under reduced pressure (25 mm Hg) at 50° C
  2. dissolutionThe residue is dissolved in a mixture of methylene chloride (500 cc) and 2 N aqueous sodium hydroxide solution (150 cc)
  3. customThe organic phase is decanted
  4. washwashed with water (200 cc)
  5. dry with materialdried over magnesium sulphate
  6. filtrationfiltered
  7. concentrationconcentrated to dryness under reduced pressure (40 mm Hg) at 40° C
  8. customThe residue obtained
  9. customis recrystallised from absolute ethanol (40 cc)

Sources & evidence

ORD record
ord-ae68dcc0bca14c06a61108bc3106b710
Source dataset
uspto-grants-1979_05
Patent number
US04153699

Reaction notes

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