Reaction #215813

Reaction equation

ethyl 7-ethoxy-4-(4-methoxyanilino)-1,8-naphthyridine-3-carboxylate hydrochloride

→

ethyl 4-[4-methoxyanilino]-7-oxo-7,8-dihydro-1,8-naphthyridine-3-carboxylate

Solvents

sodium hydroxide

Conditions

Workup

1. 1
   Temperaturewas heated on a steam bath for 4 hours
2. 2
   TemperatureThe mixture was cooled
3. 3
   Filtrationfiltered
4. 4
   workup.DISSOLUTIONThe residue was dissolved in IMS
5. 5
   Otherhydrogen chloride gas bubbled through this solution
6. 6
   workup.ADDITIONEther was added
7. 7
   Othercrystallisation
8. 8
   Filtrationthe mixture was filtered

Procedure

A mixture of ethyl 7-ethoxy-4-(4-methoxyanilino)-1,8-naphthyridine-3-carboxylate hydrochloride (2.6 g) and 5M sodium hydroxide solution (60 ml) was heated on a steam bath for 4 hours. The mixture was cooled and filtered. The residue was dissolved in IMS and hydrogen chloride gas bubbled through this solution. Ether was added to induce crystallisation and the mixture was filtered to give ethyl 4-[4-methoxyanilino]-7-oxo-7,8-dihydro-1,8-naphthyridine-3-carboxylate 0.3 hydrochloride hemihydrate, m.p. 243°-246° C.

Source