Réaction #1091

Équation de réaction

methanol

2-carboxy-5-nitrobenzenesulfonic acid

thionyl chloride

→

2-methoxycarbonyl-5-nitrobenzenesulfonic acid

Solvants

DMF

Conditions de réaction

Traitement

1. 1
   Températureis heated
2. 2
   AutreAfter separating off the insoluble constituents
3. 3
   Filtrationby filtration
4. 4
   Concentrationthe filtrate is concentrated
5. 5
   Autreresults
6. 6
   workup.ADDITIONWhen addition
7. 7
   AutreThe solid which precipitates
8. 8
   Filtrationis filtered off
9. 9
   Autredried

Mode opératoire

A suspension of 190.0 g (0.77 mol) of 2-carboxy-5-nitrobenzenesulfonic acid, 10 ml of DMF and 250 ml (3.43 mol) of thionyl chloride is heated at boiling for 3 h. After separating off the insoluble constituents by filtration, the filtrate is concentrated. 200 ml (4.94 mol) of methanol are added to the residue which results. When addition is complete the reaction mixture is cooled to 0° C. The solid which precipitates is filtered off and dried. 70.9 g (35.3% of theory) of colorless, crystalline 2-methoxycarbonyl-5-nitrobenzenesulfonic acid (m.p.: 92°-94° C.) are thus obtained. By distilling off the volatile components from the mother liquor, a second fraction (62.5 g, 31.1% of theory) is obtained.

Source