1-Piperazinecarboxylic acid, ethyl ester → Ethyl 4-(1,2-benzisothiazol-3-yl)-1-piperazinecarboxylate
Reaction equation
[N:1]1([C:7]([O:9][CH2:10][CH3:11])=[O:8])[CH2:6][CH2:5][NH:4][CH2:3][CH2:2]1.Cl[C:13]1[C:17]2[CH:18]=[CH:19][CH:20]=[CH:21][C:16]=2[S:15][N:14]=1>CN(C)C(=O)C>[S:15]1[C:16]2[CH:21]=[CH:20][CH:19]=[CH:18][C:17]=2[C:13]([N:4]2[CH2:5][CH2:6][N:1]([C:7]([O:9][CH2:10][CH3:11])=[O:8])[CH2:2][CH2:3]2)=[N:14]1Participants
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 150 °C
Procedure
A mixture of 32 parts of ethyl 1-piperazinecarboxylate, 17 parts of 3-chloro-1,2-benzisothiazole and 45 parts of N,N-dimethylacetamide was stirred for 0.5 hours at 150° C. After cooling to 50° C., the reaction mixture was poured into ice water. The aqueous layer was decanted and the oily layer was stirred in water. The product from the oil layer was extracted with trichloromethane. The extract was dried, filtered and evaporated. The residue was purified by column chromatography over silica gel using a mixture of trichloromethane and methanol (95:5 by volume) as eluent. The pure fractions were collected and the eluent was evaporated, yielding 13 parts (44%) of ethyl 4-(1,2-benzisothiazol-3-yl)-1-piperazinecarboxylate as a residue (int. 3).
Workup
- temperatureAfter cooling to 50° C.
- customThe aqueous layer was decanted
- stirringthe oily layer was stirred in water
- extractionThe product from the oil layer was extracted with trichloromethane
- customThe extract was dried
- filtrationfiltered
- customevaporated
- customThe residue was purified by column chromatography over silica gel using
- additiona mixture of trichloromethane and methanol (95:5 by volume) as eluent
- customThe pure fractions were collected
- customthe eluent was evaporated
Sources & evidence
- ORD record
- ord-cb935a4db7904f58acc323bdb36b6c10
- Source dataset
- uspto-grants-1991_05
- Patent number
- US05015740
Reaction notes
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