Reaction #72871

Reaction equation

guanidine hydrochloride

ethyl-6-[(dimethylamino)methylene]-1-methyl-7-oxo-4,5,6,7-tetrahydro-1H-indazole-3-carboxylate

→

Ethyl 8-amino-1-methyl-1H-pyrazolo[4,3-h]quinazoline-3-carboxylate

Yield 85.0%

Solvents

sodium ethylate

ethanol

Conditions

Workup

1. 1
   Temperatureat reflux for 12 hours
2. 2
   OtherThe solvent was then evaporated
3. 3
   workup.DISSOLUTIONthe residue redissolved with dichloromethane
4. 4
   Washwashed with water
5. 5
   DryingThe organic layer was then dried over anhydrous Na2SO4
6. 6
   Concentrationconcentrated
7. 7
   OtherThe residue was triturated with diethyl ether
8. 8
   Filtrationthe product collected by filtration (85% yield as a white solid)

Procedure

16.00 g (0.06 mol) of ethyl-6-[(dimethylamino)methylene]-1-methyl-7-oxo-4,5,6,7-tetrahydro-1H-indazole-3-carboxylate were dissolved in 600 mL of ethanol and 3.90 g of sodium ethylate, and 5.44 g of guanidine hydrochloride were added consecutively. The solution was stirred at reflux for 12 hours. The solvent was then evaporated, the residue redissolved with dichloromethane and washed with water. The organic layer was then dried over anhydrous Na2SO4 and concentrated. The residue was triturated with diethyl ether and the product collected by filtration (85% yield as a white solid).

Source