Ammonium Chloride → 3-(7-Pyridin-4-yl-pyrazolo[5,1-b]thiazol-6-yl)-phenylamine

HRID 38093Notes

Reaction equation

[N+:1]([C:4]1[CH:5]=[C:6]([C:10]2[C:17]([C:18]3[CH:23]=[CH:22][N:21]=[CH:20][CH:19]=3)=[C:13]3[S:14][CH:15]=[CH:16][N:12]3[N:11]=2)[CH:7]=[CH:8][CH:9]=1)([O-])=O.[Cl-].[NH4+].C([O-])(O)=O.[Na+]>O1CCOCC1.O.O.[Zn]>[N:21]1[CH:20]=[CH:19][C:18]([C:17]2[C:10]([C:6]3[CH:5]=[C:4]([NH2:1])[CH:9]=[CH:8][CH:7]=3)=[N:11][N:12]3[CH:16]=[CH:15][S:14][C:13]=23)=[CH:23][CH:22]=1

Participants

Conditions

Temperature: 100 °C

Procedure

6-(3-Nitrophenyl)-7-pyridin-4-yl-pyrazolo[5,1-b]thiazole (410 mg, 1.272 mmol) was dissolved in a 3:1 dioxane/water mixture (8 mL). Zinc powder (333 mg, 5.094 mmol, 4 eq) and ammonium chloride (680 mg, 12.72 mmol, 10 eq) were added and the mixture was stirred at 100° C. for 2 hours. It was then diluted with water, made basic by addition of saturated aqueous NaHCO3 and extracted with ethyl acetate (3×20 mL). Combined organic layers were washed with sat. aq. NaHCO3 and brine, dried over Na2SO4 and concentrated under reduced pressure. The crude product was purified by chromatography on silica gel (DCM/MeOH 97:3) to give 255 mg (68%) of 3-(7-pyridin-4-yl-pyrazolo[5,1-b]thiazol-6-yl)-phenylamine as white solid.

Workup

extractionextracted with ethyl acetate (3×20 mL)
washCombined organic layers were washed with sat. aq. NaHCO3 and brine
dry with materialdried over Na2SO4
concentrationconcentrated under reduced pressure
customThe crude product was purified by chromatography on silica gel (DCM/MeOH 97:3)

Sources & evidence

ORD record: ord-d67425bcdd5e47818c01ea2b655a50cc
Source dataset: uspto-grants-2013_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08524707B2

Reaction notes

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