Stannous chloride dihydrate → 5-(3,5-dichlorophenylthio)-1H-pyrazolo[4,3-b]pyridin-3-amine

HRID 1048770Notes

Reaction equation

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

Participants

Conditions

Temperature: 2.5 °C

Procedure

A solution of 350 mg of NaNO2 (5.07 mmol) in water (2 ml) is added to a stirring solution of 1.5 g of 3-amino-6-(3,5-dichlorophenylthio)picolinonitrile (5.07 mmol) in 100 ml of 50% sulfuric acid at 0° C. The mixture is stirred for 20 minutes at 0-5° C. A solution of 2.9 g of SnCl2.2H2O (12.7 mmol, 2.5 eq) in hydrochloric acid (12 N solution, 10 ml) is then added and the solution is stirred for 1 hour at room temperature. The solid formed is filtered and then washed twice with 20 ml of water. The solid is suspended in 100 ml and the pH is adjusted to 10 by adding 30% soda solution. The organic phase is separated and then dried on anhydrous sodium sulfate before being concentrated under vacuum. A light yellow solid is obtained after recrystallization in ethyl acetate (470 mg, 34%).

Workup

stirringthe solution is stirred for 1 hour at room temperature
customThe solid formed
filtrationis filtered
washwashed twice with 20 ml of water
additionby adding 30% soda solution
customThe organic phase is separated
dry with materialdried on anhydrous sodium sulfate
concentrationbefore being concentrated under vacuum
customA light yellow solid is obtained
customafter recrystallization in ethyl acetate (470 mg, 34%)

Sources & evidence

ORD record: ord-db9067dedcf54c33801cb3cc1bba52ab
Source dataset: uspto-grants-2016_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09381195B2

Reaction notes

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