Sulfuryl chloride → 4-(methoxycarbonyl)-2-methylthiophen-3-aminium chloride
Reaction equation
[NH2:1][C:2]1[CH:6]([CH3:7])[S:5][CH2:4][C:3]=1[C:8]([O:10][CH3:11])=[O:9].S(Cl)([Cl:15])(=O)=O>ClC1C=CC=CC=1>[ClH:15].[NH2:1][C:2]1[C:3]([C:8]([O:10][CH3:11])=[O:9])=[CH:4][S:5][C:6]=1[CH3:7]Participants
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- -10 °C
Procedure
80.7 g of methyl 4-amino-5-methyl-2,5-dihydrothiophene-3-carboxylate (2) (338 mmol, content: 72.6%) were dissolved in 88 ml of chlorobenzene and cooled to −10° C. A solution of 50.2 g of sulfuryl chloride (372 mmol) in 59 ml of chlorobenzene in the temperature range of −10-0° C. was added dropwise to this solution over a period of 1 h. The reaction mixture was subsequently stirred at −10-0° C. for another 1 h and then warmed to room temperature. For workup, the reaction mixture was concentrated under reduced pressure. 95 g of methyl 4-amino-5-methylthiophene-3-carboxylate hydrochloride (5) were obtained (96% of theory, content: 58.7%, determined as the free amine). The product was characterized after release of the amine with NaHCO3 solution (m.p.: 65° C.; 1H NMR (400 MHz, d3-DMSO): 2.62 (s), 4.25 (s), 5.18 (bs), 8.22 (s)).
Workup
- temperaturewarmed to room temperature
- concentrationFor workup, the reaction mixture was concentrated under reduced pressure
Sources & evidence
- ORD record
- ord-c6c18199cb27450f8f620c0e9c1e1de4
- Source dataset
- uspto-grants-2011_04
- Patent number
- US07923571B2
Reaction notes
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