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ChemicalBook CAS DataBase List 1-BROMO-2-BUTYNE
3355-28-0

1-BROMO-2-BUTYNE synthesis

6synthesis methods
1-bromo-2-butyne is obtained by reacting 2-butyn-1-ol and organic solvent, pyridine.First react bromoethane with metal magnesium in THF to prepare Grignard reagent, then add paraformaldehyde to Grignard reagent for Grignard reaction, separate and recover after Grignard reaction 2-butyn-1-ol, then mix 2-butyn-1-ol with organic solvent and pyridine, add phosphorus tribromide dropwise for bromination reaction, separate and recover the product after bromination reaction.
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Yield:3355-28-0 11.0 g (58%)

Reaction Conditions:

with pyridine in (2S)-N-methyl-1-phenylpropan-2-amine hydrate;pentane;

Steps:

2.a (a)

(a) 1-Bromo-2-butyne To a stirred solution of 2-butyne-1-ol (10.0 g, 0.143 mol) in 30 ml of ether at 0° C. is added pyridine (4.84 g, 0.06 mol, 0.43 eq) at once followed by careful dropwise addition of phosphorous tribromide (26.3 g, 0.097 mol, 0.68 eq) over a 30 minute period. An additional 10 ml of ether was added to facilitate stirring and the contents warmed to reflux for 2 hours. The reaction mixture is cooled in ice bath, treated cautiously with 70 ml of ice water and extracted with ether (2*150 ml). The combined ether extracts are washed with saturated brine (2*25 ml), the combined aqueous washings extracted with ether (1*50 ml) and the combined organic extracts dried over anhydrous sodium sulfate. The filtrate is concentrated on a rotary evaporator while keeping the water bath temperature less than 10° C. Twice the contents are diluted with 100 ml of pentane and reconcentrated as before. The heterogenous looking oil is dissolved in 300 ml of pentane, dried over anhydrous magnesium sulfate and reconcentrated as before to obtain 11.0 g (58%) of 1-bromo-2-butyne.

References:

US4486598,1984,A US4628110,1986,A US4533749,1985,A

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