反应详情

To a mixture of potassium thiocyanate (42 g), copper thiocyanate (4s g) and water (400 ml), 2-benzoyl-5-carboxy3-nitrobenzenediazonium tetrafluoroborate (prepared as described in Example 17, step A; 28 g) is added in portions while stirring at 45°-50° C. After the addition is completed, the mixture is stirred at about 50° C. for a further 4 hours and thereafter at room temperature for about 20 hours. The resulting precipitate is collected by filtration, washed with water and dried. The dried solids are then extracted with boiling ethanol (three portions of 250 ml, 100 ml, and 100 ml, respectively) and filtered hot. The combined filtrates are evaporated in vacuo and the residue is crystallized by trituration with 50% aqueous ethanol (100 ml). The material is collected by filtration, washed with cold 50% ethanol and dried. After recrystallization from aqueous ethanol, 4-benzoyl-5-nitro-3-thiocyanobenzoic acid is obtained with a melting point of 183.5°-184.5° C.

1. additionis added in portions
2. additionAfter the addition
3. stirringthe mixture is stirred at about 50° C. for a further 4 hours
4. filtrationThe resulting precipitate is collected by filtration
5. washwashed with water
6. customdried
7. extractionThe dried solids are then extracted with boiling ethanol (three portions of 250 ml, 100 ml, and 100 ml
8. filtrationrespectively) and filtered hot
9. customThe combined filtrates are evaporated in vacuo
10. customthe residue is crystallized by trituration with 50% aqueous ethanol (100 ml)
11. filtrationThe material is collected by filtration
12. washwashed with cold 50% ethanol
13. customdried
14. customAfter recrystallization from aqueous ethanol