Sodium Carbonate → 3-Amino-4-bromo-6-chloropyridazine

To a stirred mixture of 6-chloropyridazin-3-amine (D-1) (52.0 g, 0.4 mol, 1.0 eq) and sodium carbonate (84.8 g, 0.8 mol, 2.0 eq) in MeOH (500 mL) at RT, bromine (70.6 g, 0.44 mol, 1.1 eq) is added dropwise and the resulting mixture is stirred overnight. The reaction mixture is filtered and the filter cake is washed with ethyl acetate. The filtrate is concentrated in vacuo and the residue is poured into water (300 mL). The resulting mixture is extracted with ethyl acetate (2×300 mL). The combined organic layers are dried over Na2SO4 and filtered. The filtrate is concentrated in vacuo and the residue is purified by flash column chromatography on silica gel (0-50% ethyl acetate-petroleum ether) to afford the product, 4-bromo-6-chloropyridazin-3-amine (D-2).

1. filtrationThe reaction mixture is filtered
2. washthe filter cake is washed with ethyl acetate
3. concentrationThe filtrate is concentrated in vacuo
4. additionthe residue is poured into water (300 mL)
5. extractionThe resulting mixture is extracted with ethyl acetate (2×300 mL)
6. dry with materialThe combined organic layers are dried over Na2SO4
7. filtrationfiltered
8. concentrationThe filtrate is concentrated in vacuo
9. customthe residue is purified by flash column chromatography on silica gel (0-50% ethyl acetate-petroleum ether)

ORD record

ord-220a67c37e614aba914e7bea436e9321

Source dataset

uspto-grants-2014_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08901133B2