Acetic Acid → 8-Amino-2-benzylthio[1,2,4]triazolo[1,5-a]pyridine

HRID 1940899Notes

Reaction equation

HRID 1940899 reaction equation
[CH2:1]([S:8][C:9]1[N:20]=[C:12]2[C:13]([N+:17]([O-])=O)=[CH:14][CH:15]=[CH:16][N:11]2[N:10]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C(O)(=O)C.CCOCC>O.ClCCl.[Fe]>[NH2:17][C:13]1[C:12]2[N:11]([N:10]=[C:9]([S:8][CH2:1][C:2]3[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=3)[N:20]=2)[CH:16]=[CH:15][CH:14]=1

Participants

7

Reactant 3

HCID 176Acetic AcidHCID 3283Diethyl EtherHCID 190807302-Benzylthio-8-nitro[1,2,4]triazolo[1,5-a]pyridine

Product 1

HCID 190807538-Amino-2-benzylthio[1,2,4]triazolo[1,5-a]pyridineYield 68%

Reagents, catalysts & solvents 3

HCID 23925IronCatalystHCID 962WaterSolventHCID 6344DichloromethaneSolvent

Procedure

2-Benzylthio-8-nitro[1,2,4]triazolo[1,5-a]pyridine (174.0 g, 0.61 mol), iron filings (204.2 g., 3.65 mol) and acetic acid (2 L) were combined and heated with stirring at 70°-80° C. for 6 hours. The reaction mixture was cooled and diluted with water and dichloromethane. The resulting mixture was filtered through Celite®, the liquid phases in the filtrate were separated, and the aqueous layer was extracted with a little more dichloromethane. The organic phase and extract were combined and washed several times with water and then with dilute aqueous sodium hydroxide. The resulting organic solution was concentrated by evaporation under reduced pressure and the residue obtained was mixed with ether. The insoluble solids were collected by filtration and dried to obtain 106.3 g of the title compound as a brown powder melting at 116°-117° C. An additional 14.2 g of lower purity product was isolated from the ether filtrate (77 percent of theory total yield). This reduction was also carried out with iron powder and calcium chloride in aqueous ethanol and with stannous chloride in hydrochloric acid.

Workup

  1. temperatureheated
  2. temperatureThe reaction mixture was cooled
  3. filtrationThe resulting mixture was filtered through Celite®
  4. customthe liquid phases in the filtrate were separated
  5. extractionthe aqueous layer was extracted with a little more dichloromethane
  6. extractionThe organic phase and extract
  7. washwashed several times with water
  8. concentrationThe resulting organic solution was concentrated by evaporation under reduced pressure
  9. customthe residue obtained
  10. filtrationThe insoluble solids were collected by filtration
  11. customdried

Sources & evidence

ORD record
ord-1024d420196f45d0a5ec17d5fb5aecc1
Source dataset
uspto-grants-1997_12
Patent number
US05700940

Reaction notes

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