Phenanthridine → Phenanthridinesulfonic acid
Reaction equation
[CH:1]1[C:14]2[C:5](=[N:6][CH:7]=[C:8]3[C:13]=2[CH:12]=[CH:11][CH:10]=[CH:9]3)[CH:4]=[CH:3][CH:2]=1.Cl[S:16]([OH:19])(=[O:18])=[O:17]>>[C:1]1([S:16]([OH:19])(=[O:18])=[O:17])[C:14]2[C:5](=[N:6][CH:7]=[C:8]3[C:13]=2[CH:12]=[CH:11][CH:10]=[CH:9]3)[CH:4]=[CH:3][CH:2]=1Participants
3
Conditions
- Temperature
- 10 °C
Procedure
Add phenanthridine (5 g, 28 mmol) in portions to chlorosulfonic acid (5.6 mL, 84 mmol) cooled to 10° C. over 20 minutes Heat the reaction mixture to reflux for 20 hours. Cool the now black reaction mixture to 0° C. and add cautiously to crushed ice (500 mL). Filter the solid and dry in vacuo to give the sulfonic acid (3.61 g) as an ivory colored solid consisting of a partially resolved 7:3 mixture of regioisomers. Rf=0.35 (major), 0.19 (minor (15:85 methanol:methylene chloride, 0.2% acetic acid buffer).