6-(Trifluoromethoxy)-4-(trimethylsilyl)-2-benzothiazolamine → 6-Trifluoromethoxy-4-nitro-2-benzothiazolamine

HRID 21701

Reaction equation

F[B-](F)(F)F.[O:6]=[N+:7]=[O:8].[NH2:9][C:10]1[S:11][C:12]2[CH:18]=[C:17]([O:19][C:20]([F:23])([F:22])[F:21])[CH:16]=[C:15]([Si](C)(C)C)[C:13]=2[N:14]=1>C(#N)C.O>[NH2:9][C:10]1[S:11][C:12]2[CH:18]=[C:17]([O:19][C:20]([F:23])([F:21])[F:22])[CH:16]=[C:15]([N+:7]([O-:8])=[O:6])[C:13]=2[N:14]=1

Participants

Conditions

Temperature: 0 °C

Procedure

0.68 g of nitronium tetrafluoroborate are added in small portions to a solution of 0.76 g of 2-amino-4-trimethylsilyl-6-trifluoromethoxybenzothiazole in 20 cm3 of acetonitrile cooled to 0° C. Stirring is continued for 12 hours at a temperature close to 20° C. The solution is then diluted with 50 cm3 of water and extracted with 2 times 50 cm3 of ethyl acetate. The organic phases are combined, dried over sodium sulphate and concentrated in vacuum. The residue is purified by flash chromatography on silica gel with a cyclohexane-ethyl acetate mixture (7-3 by volume) as eluent. After recrystallization from a cyclohexane-ethyl acetate mixture (3-2 by volume), 0.3 g of 2-amino-4-nitro-6-trifluoromethoxybenzothiazole melting at 260° C. is obtained.

Workup

customclose to 20° C
extractionextracted with 2 times 50 cm3 of ethyl acetate
dry with materialdried over sodium sulphate
concentrationconcentrated in vacuum
customThe residue is purified by flash chromatography on silica gel with a cyclohexane-ethyl acetate mixture (7-3 by volume) as eluent
customAfter recrystallization from a cyclohexane-ethyl acetate mixture (3-2 by volume)

Sources & evidence

ORD record: ord-3b531de0c67245a583860bb8674cac48
Source dataset: uspto-grants-1995_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05424439

Linked notes

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