Sodium Hydroxide → Methyl 3-bromo-4-hydrazinylbenzoate

Temperature

-10 °C

Methyl-4-amino-3-bromobenzoate (32 g, 139 mmol) is combined with 250 mL conc. hydrochloric acid and cooled to −10° C. A solution of sodium nitrite (10.2 g, 146 mmol) in 120 mL water is added dropwise such that the temperature does not exceed −5° C. After 40 min stirring at −10° C. a solution of tin(II)chloride dihydrate (128 g, 556 mmol) in 130 mL conc. hydrochloric acid is added dropwise to the suspension, while the reaction temperature does not exceed −5° C. The thick liquid suspension is stirred for 1.5 h at RT, before being adjusted to pH 10 with NaOH (12 N). The reaction mixture is combined with 500 mL dichloromethane and water and after 30 min stirring it is filtered. The filter cake is combined with 300 mL dichloromethane and 100 mL water and refluxed for 30 min. After filtration the filtrate is extracted with chloroform. The combined organic phases are dried on magnesium sulphate, filtered and evaporated to dryness. Yield: 34 g.

1. customdoes not exceed −5° C
2. additionis added dropwise to the suspension, while the reaction temperature
3. customdoes not exceed −5° C
4. stirringstirring it
5. filtrationis filtered
6. temperaturerefluxed for 30 min
7. filtrationAfter filtration the filtrate
8. extractionis extracted with chloroform
9. customThe combined organic phases are dried on magnesium sulphate
10. filtrationfiltered
11. customevaporated to dryness

ORD record

ord-72d2a2dc6d30429b80e2b572cfc35e20

Source dataset

uspto-grants-2011_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07902183B2