Nitric Acid → (+/-)-6-fluoro-8-nitro-2,3-dihydrospiro[4H-1-benzopyran-4,5'-thiazolidine]-2',4'-dione
Reaction equation
[N+:1]([O-:4])(O)=[O:2].[F:5][C:6]1[CH:7]=[CH:8][C:9]2[O:21][CH2:20][CH2:19][C:12]3([S:16][C:15](=[O:17])[NH:14][C:13]3=[O:18])[C:10]=2[CH:11]=1>>[F:5][C:6]1[CH:7]=[C:8]([N+:1]([O-:4])=[O:2])[C:9]2[O:21][CH2:20][CH2:19][C:12]3([S:16][C:15](=[O:17])[NH:14][C:13]3=[O:18])[C:10]=2[CH:11]=1Participants
3
Procedure
Into 2.5 ml of fuming nitric acid (96%, d 1.50), which had been cooled to -20° C. while stirring, there was introduced rapidly 500 mg of (±)-6-fluoro-2,3-dihydrospiro[4H-1-benzopyran-4,5'-thiazolidine]-2',4'-dione so that the temperature did not exceed -15° C. After stirring at -20° C. for 3 minutes, there was obtained a clear solution which was then poured immediately on to 15 ml of ice-water. After stirring briefly, the resulting precipitate was filtered, washed with cold water and dried. There was obtained (±)-6-fluoro-8-nitro-2,3-dihydrospiro[4H-1-benzopyran-4,5'-thiazolidine]-2',4'-dione in the form of yellow crystals which melted at 192°-194° C. after recrystallization from ethyl acetate/hexane.
Workup
- customdid not exceed -15° C
- stirringAfter stirring at -20° C. for 3 minutes
- customthere was obtained a clear solution which
- stirringAfter stirring briefly
- filtrationthe resulting precipitate was filtered
- washwashed with cold water
- customdried
Sources & evidence
- ORD record
- ord-037da0c8f9d3486892214be168c08b17
- Source dataset
- uspto-grants-1986_05
- Patent number
- US04587256
Reaction notes
Loading…