2-Acetyl-5-bromothiophene

white to light yellow crystal powder

2-acetylthiophene (1.08 mL, 10 mmol) and N-bromosuccinimide (NBS) (1.78 g, 30 mmol) were mixedwith acetic anhydride (3.78 mL, 40 mmol) in a dry 25 mL round bottom flask fitted with a guard tube and acetic acid (0.40 mL) were added to it. Then the mixture was stirred at 50 C in a dark place for 1hour. The colour of the solution changes from colourless to light yellow. Then it was cooled to roomtemperature and poured into 100 ml of water and stirred until the acetic anhydride was totallyhydrolyzed. White crystals of 2-bromo-5-acetylthiophene were appeared. Then it was filtered andwashed portion wise with 50 ml of water to get 82percent yield. mp 92-94 °C (acetone). 1H NMR (300MHz, CDCl3): δ 7.40 (d, J = 3.9 Hz, 1H), 7.08 (d, J = 3.9 Hz, 1H), 2.48 (s, 3H).Add in a 100ml eggplant bottle2-bromothiophene (2.00 g, 12.3 mmol), Acetic anhydride (2.51 g, 24.6 mmol), Perchloric acid (3.71 g, 36.9 mmol) was slowly added dropwise under ice bath.0.5h plus to remove the ice bath, Stir at room temperature.After 6 h, TLC showed no residue of starting material.Add ice water, Adjust the pH to neutral with sodium carbonate, Extracted with ethyl acetate (25ml × 3), Combine the organic phase, Wash twice with saturated saline solution, Dry over anhydrous MgSO4.The solvent was distilled off under reduced pressure.Crude column chromatography (PE: EA = 50:1), It has a pale yellow oil of 2.03g.The yield was 80.6percent.In a 1, 000 ml four-necked flask equipped with a stirrer and a thermometer, 25.8 g (158.4 mmol) of the compound (23-1a) was placed under an argon atmosphere, 500 ml of anhydrous methylene chloride, And 11 ml of acetyl chloride were added, followed by cooling with a water bath.42.2 g of aluminum chloride was gradually added while maintaining the temperature in the reaction system, And the mixture was stirred at room temperature overnight.The reaction solution was added to a 6N hydrochloric acid aqueous solution, separated, washed and concentrated to obtain 31 g of a crude product. Methanol was added to the crude product, followed by filtration, The obtained filtrate was concentrated to dryness, 15 g of compound (23-1b) was obtained as white crystals

Molecular Weight:205.07
XLogP3:2.6
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:1
Exact Mass:203.92445
Monoisotopic Mass:203.92445
Topological Polar Surface Area:45.3
Heavy Atom Count:9
Complexity:126
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes