3-Chloro-1-propyne → Methyl 2-hydroxy-4-propargyloxybenzoate

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Reaction Steps

A mixture of 11 g of 2,3-diaminopyrazine (IIa), 20.6 g of 2-methoxy-4-propargyloxybenzoic acid [m.p. 142°; obtainable by reacting methyl 2,4-dihydroxybenzoate with propargyl chloride to give methyl 2-hydroxy-4-propargyloxybenzoate (m.p. 100°), reacting the latter with methyl iodide to give methyl 2-methoxy-4-propargyloxybenzoate (m.p. 88°), and hydrolysing the latter] and 300 ml of POCl3 is boiled for 2 hours. The mixture is evaporated to dryness, ice-water is added to the residue, and the mixture is rendered alkaline with K2CO3 solution. The precipitated 2-(2-methoxy-4-propargyloxyphenyl)-1,3,4,7-tetraazaindene is filtered off. M.p. 189°-190°.

Provenance & Evidence