Propargyl bromide
# Propargyl bromide

Propargyl bromide, also known as 3-bromo-prop-1-yne, is an organic compound with the chemical formula $HC≡CCH_2Br.$ A colorless liquid, it is a halogenated organic compound consisting of propyne with a bromine substituent on the methyl group. It has a lachrymatory effect, like related compounds. The compound is used as a reagent in organic synthesis.

## Applications and production

Propargyl bromide can also be used as an intermediate for the synthesis of organic compounds, including agrochemicals and pharmaceuticals. In the 1960s, it was used in a soil fumigant called Trizone.

Propargyl bromide may be produced by the treatment of propargyl alcohol with phosphorus tribromide.

## Reactions

Propargyl bromide is an alkylating agent. With dimethylsulfide, it reacts to give the sulfonium salt:

    $HCCCH_2Br$ + $S(CH_3)_2$ → $[HCCCH_2S(CH_3)_2]Br$

It also alkylates even weakly basic amines such as aniline.

Aldehydes react with propargyl bromide in a Barbier-type reaction to yield alkynyl alcohols:

At low temperatures, upon treatment with magnesium, propargyl bromide gives the Grignard reagent formally derived from allenyl bromide, i.e., $CH_2=C=CHMgBr.$

## Safety

Propargyl bromide is a lachrymator and an alkylating agent.

