Methyl 4-bromo-2-butenoate

Compound 25 (1.525 g, 9.24 mmol) and anhydrous methanol (10 ml) were added to a 50 ml three-necked flask, stirred at 0° C. until dissolved, and SoCl2 (5.49 g, 46.19 mmol, 5 ml) was slowly added dropwise to generate bubbles. After completion, the temperature was raised to room temperature, stirring was continued for 15 hours, and the reaction was completed by TLC. The solvent was evaporated to dryness, and the mixture was extracted with ethyl acetate/water. The product was in the organic phase, and the liquid was separated. The organic phase was collected and dried over Na 2 SO 4 . The solvent was removed by spin-drying to give a crude product, which was purified by column chromatography. Petroleum ether: ethyl acetate = 8 The elution of: 1 gave a red oily liquid of compound 26, 1.54 g, yield: 93.1percent.The compound crotonic acid methyl ester (20 g, 200 mmol) was added to a 500 ml single-necked flask, Treated with carbon tetrachloride (200 ml)A mixture of azobisisobutyronitrile (AIBN) (66 mg, 0.4 mmol)And N-bromosuccinimide (NBS) (39.1 g, 220 mmol)The reaction solution was allowed to react for 6 hours under reflux, cool down, The solid was removed by filtration, The filtrate was washed with water (20 ml x 3), dried over anhydrous Na2SO4, Filtration by spinning gave a yellow oil 4-bromocrotonic acid methyl ester (34 g)The compound was used directly in the next step without purification.

Molecular Weight:179.01
XLogP3:1.1
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:3
Exact Mass:177.96294
Monoisotopic Mass:177.96294
Topological Polar Surface Area:26.3
Heavy Atom Count:8
Complexity:98.6
Undefined Bond Stereocenter Count:1
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes