Reacción #164618

Ecuación de reacción

product 63

Ethyl 2-bromo-6-formyl-4-methyl-4H-thieno[3,2-b]pyrrole-5-carboxylate

hydrazine monohydrate

product 62

Ethyl 2-bromo-6-formyl-4H-thieno[3,2-b]pyrrole-5-carboxylate

→

pyridazinone

Rendimiento 94.0%

2-Bromo-4-methyl-4H-thieno[3,2-b]pyrrole[3,2-d]pyridazinone

Rendimiento 94.0%

Disolventes

2-ethoxyethanol

2-ethoxyethanol

2-ethoxyethanol

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturato reflux for additional 1 hr
2. 2
   Otrowas removed under reduced pressure
3. 3
   FiltraciónThe precipitate was filtered
4. 4
   Lavadowashed with 2-ethoxyethanol

Procedimiento

The N-methylated product 63 (420 mg, 1.33 mmol) was dissolved in warm 2-ethoxyethanol (26 mL). To a refluxed solution of hydrazine monohydrate (1 mL, 31.9 mmol) and 2-ethoxyethanol (5 mL) under nitrogen was added prepared N-methylated product 62 solution dropwise over a 2 hr period and the solution continued to reflux for additional 1 hr. After cooling to room temperature, about half of the 2-ethoxyethanol was removed under reduced pressure and the remaining solution was refrigerated at −20° C. overnight. The precipitate was filtered and washed with 2-ethoxyethanol to give desired pyridazinone 64 (354 mg, 94%) as a white solid.

Fuente