Реакция #1091

Уравнение реакции

methanol

2-carboxy-5-nitrobenzenesulfonic acid

thionyl chloride

→

2-methoxycarbonyl-5-nitrobenzenesulfonic acid

Растворители

DMF

Условия реакции

Обработка

1. 1
   Температураis heated
2. 2
   ДругоеAfter separating off the insoluble constituents
3. 3
   Фильтрацияby filtration
4. 4
   Концентрированиеthe filtrate is concentrated
5. 5
   Другоеresults
6. 6
   workup.ADDITIONWhen addition
7. 7
   ДругоеThe solid which precipitates
8. 8
   Фильтрацияis filtered off
9. 9
   Другоеdried

Методика

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.

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