Hydrazine hydrate (1:1) → Hydralazine

Temperature

2.5 °C

A 2 L, 3-necked, round-bottomed flask fitted with a temperature probe and condenser, and was charged 375 mL of hydrazine hydrate; the solution was then cooled to 0 to 5° C. About 75 g of 1-chlorophthalazine salt was added in portions at a rate to maintain the solution temperature at 0 to 5° C. After addition, the solution was stirred at 20 to 25° C. for about 24 hrs. The reaction mixture was then cooled to 0 to 5° C. and 150 mL of methanol was added, the solution stirred for 3 hrs, and the resulting solid material was filtered, washed with 150 mL of cold methanol, and dried under vacuum at 35° C. Yield 99%.

1. customA 2 L, 3-necked, round-bottomed flask fitted with a temperature probe and condenser
2. temperatureto maintain the solution temperature at 0 to 5° C
3. additionAfter addition
4. temperatureThe reaction mixture was then cooled to 0 to 5° C.
5. stirringthe solution stirred for 3 hrs
6. filtrationthe resulting solid material was filtered
7. washwashed with 150 mL of cold methanol
8. customdried under vacuum at 35° C

ORD record

ord-35f0bfb01b28422585845fb955d5cc72

Source dataset

uspto-grants-2009_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07531653B2