Hydrochloric Acid → HCID 178516421, compound

N′-(3,4-Dichlorophenyl)hydrazine was liberated from its hydrochloride (8.7 g, 40.6 mmol) by partitioning the solid between dilutes Na2CO3 solution and ethyl acetate. The aqueous layer was extracted 2 more times with AcOEt, dried over Na2SO4 and the solvent removed in vacuo. The residue is taken up in t-butyl alcohol (60 ml) and, in a dry nitrogen atmosphere, the ethyle propionate (4.6 ml, 44.66 mmol) was dropwise added. The mixture was ice-cooled and potassium t-butoxide (10.5 g, 81.2 mmol) was slowly added over the time of 1 hr. The resulting mixture was stirred overnight at room temperature. The solvent was evaporated in vacuo and ice-water was added. The resulting aqueous solution is extracted with dichloromethane and acidified to pH 6 with acetic acid. The solid precipitated was filtered off, dried and crystallized from ethyl acetate yielding 2.4 g of brown solid. The mother liquors were evaporated to dryness and the crude residue was column chromatographied on silica gel (petroleum ether/AcOEt 9:1) another fraction of 1 g was obtained (total yield 37%)

1. customby partitioning the solid between dilutes Na2CO3 solution and ethyl acetate
2. extractionThe aqueous layer was extracted 2 more times with AcOEt
3. dry with materialdried over Na2SO4
4. customthe solvent removed in vacuo
5. temperaturecooled
6. customThe solvent was evaporated in vacuo and ice-water
7. additionwas added
8. extractionThe resulting aqueous solution is extracted with dichloromethane
9. customThe solid precipitated
10. filtrationwas filtered off
11. customdried
12. customcrystallized from ethyl acetate yielding 2.4 g of brown solid
13. customThe mother liquors were evaporated to dryness
14. customwas obtained (total yield 37%)

ORD record

ord-c07e6761176046059bcea2626abe8929

Source dataset

uspto-grants-2012_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08293740B2