反应详情

A mixture of 0.5 g of N-isopropyl-4-aminopyridine-3-sulfonamide (Preparation 7) and 0.5 g of paraformaldehyde in 15 cm3 of isopropanol to which 50 drops of ethyl acetate saturated with gaseous HCl have been added is brought to reflux for 24 hours. After this lapse of time, the solvent is removed under partial vacuum. The residue is redissolved in 20 cm3 of methanol. The possible insoluble material is removed by filtration. The filtrate, treated with 40 cm3 of water and stored for 2 hours at +4° C., produces a precipitate of the isopropoxymethylenated derivative of Preparation 7. It is collected on a filter, washed with water, dried and recrystallized from a CHCl3 /petroleum ether (40°-60° C.) (1/2) mixture. The dry product is introduced into an open round-bottomed flask and brought to a temperature of 180°-190° C. After 15 to 30 minutes, the molten mass solidifies. It is then cooled and then dissolved in a small volume of chloroform. The addition of 1 volume of petroleum ether (40°-60° C.) causes precipitation of crystals of the title compound. They are collected on a filter, washed with petroleum ether (40°-60° C.) and dried.

1. additionhave been added
2. temperatureto reflux for 24 hours
3. customAfter this lapse of time, the solvent is removed under partial vacuum
4. dissolutionThe residue is redissolved in 20 cm3 of methanol
5. customThe possible insoluble material is removed by filtration
6. additionThe filtrate, treated with 40 cm3 of water
7. customproduces
8. customa precipitate of the isopropoxymethylenated derivative of Preparation 7
9. customIt is collected on a filter
10. washwashed with water
11. customdried
12. customrecrystallized from a CHCl3 /petroleum ether (40°-60° C.) (1/2) mixture
13. additionThe dry product is introduced into an open round-bottomed flask
14. custombrought to a temperature of 180°-190° C
15. waitAfter 15 to 30 minutes
16. temperatureIt is then cooled
17. dissolutiondissolved in a small volume of chloroform
18. additionThe addition of 1 volume of petroleum ether (40°-60° C.)
19. customprecipitation of crystals of the title compound
20. customThey are collected on a filter
21. washwashed with petroleum ether (40°-60° C.)
22. customdried