Ethyl 2-chloroacetoacetate → Chloro-(5-bromo-2-but-3-ynyloxyphenylhydrazono)acetic acid ethyl ester

Temperature

0 °C

2-Chloro-3-oxo-butyric acid ethyl ester (1.94 g, 11.2 mmol) and sodium acetate (1.45 g, 17.8 mmol) were stirred in IMS (100 mL) to give a clear solution, then cooled to 0° C. Separately, 5-bromo-2-but-3-ynyloxy-phenylamine (2.68 g, 11.2 mmol) in 6M hydrochloric acid (6.8 mL) was cooled to 0° C. and a solution of sodium nitrite (0.77 g, 11.2 mmol) in water (11.2 mL) was added dropwise with stirring, keeping the temperature below 5° C. The aqueous acidic solution was added to the IMS solution, washed in with a little water, keeping the temperature below 5° C. After 1 h at 0-5° C., the mixture was diluted with water and extracted several times with ethyl acetate. The combined organic extracts were washed with water, dried (Na2SO4), filtered and concentrated in vacuo to give Chloro-(5-bromo-2-but-3-ynyloxyphenylhydrazono)acetic acid ethyl ester as a pale brown solid (3.96 g, 95%). LCMS: RT=4.97 min, [M+Na]+=395/397/399.

1. customto give a clear solution
2. customthe temperature below 5° C
3. washwashed in with a little water
4. customthe temperature below 5° C
5. additionthe mixture was diluted with water
6. extractionextracted several times with ethyl acetate
7. washThe combined organic extracts were washed with water
8. dry with materialdried (Na2SO4)
9. filtrationfiltered
10. concentrationconcentrated in vacuo

ORD record

ord-56f06394b92149a0b13ab971361c266f

Source dataset

uspto-grants-2012_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08242104B2