Nitrite → 4,5,6,7-Tetrahydrobenzo[d]thiazol-6-amine

HRID 1942381Notes

Reaction equation

Br.Br.[S:3]1[C:7]2[CH2:8][CH:9]([NH2:12])[CH2:10][CH2:11][C:6]=2[N:5]=[C:4]1N.N([O-])=O.P(P(O)(O)=O)(O)(O)=O.[OH-].[Na+]>Cl>[S:3]1[C:7]2[CH2:8][CH:9]([NH2:12])[CH2:10][CH2:11][C:6]=2[N:5]=[CH:4]1

Participants

Conditions

Temperature: -30 °C

Procedure

To a solution of 12.8 g (38.9 mmol) 4,5,6,7-tetrahydro-benzothiazole-2,6-diamine dihydrobromide in 220 mL concentrated aqueous hydrochloric acid at −30° C. is drop wise added 66.3 mL of an aqueous 1N solution nitrite over the course of 30 minutes. After further stirring for 1 hour at the same temperature 5.44 ml (52.5 mmol) of a 50% aqueous solution hypophosphoric acid is added. The reaction mixture is stored at 4° C. overnight. After having cooled down the solution again to −30° C. the mixture is slowly basified with 40% aqueous sodium hydroxide solution while temperature is kept at −30° C. The resulting mixture is warmed up to room temperature and extracted with Chloroform/Ethanol 5:1 (3×250 mL). The solution is dried over anhydrous sodium sulfate and concentrated in vacuum. The product obtained is chromatographically purified over silica gel, eluting with dichloromethane/methanol

Workup

customat −30° C.
customover the course of 30 minutes
additionis added
customis kept at −30° C
temperatureThe resulting mixture is warmed up to room temperature
extractionextracted with Chloroform/Ethanol 5:1 (3×250 mL)
dry with materialThe solution is dried over anhydrous sodium sulfate
concentrationconcentrated in vacuum
customThe product obtained
customis chromatographically purified over silica gel
washeluting with dichloromethane/methanol

Sources & evidence

ORD record: ord-439e4e9ca51b47fd978bce77d16953ce
Source dataset: uspto-grants-2013_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08389555B2

Reaction notes

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