1- ETHOXY-l-BUTYNE

Some studies seeking preferred conditions for this reaction have been reported. Optimum yields of 1-ethoxy-1-propyne and 1-ethoxy-l-butyne are found when the product is worked up before allowing the ammonia solvent to evaporate, as the product evidently volatilizes with the ammonia. An experiment with 1-ethoxy-1-propyne showed a marked increase in yield when ammonia predried over calcium hydride was used instead of ammonia directly from the cylinder. A twofold excess of ethyl bromide is required to obtain a good yield of l-ethoxy-l-but5me, since elimination apparently competes with alkylation in this case. 

Ethoxy-l-btttyne (5, 592). The preparation of 1-ethoxy-l-butyne from chloroacetaldehyde diethyl acetal has been published. ... 

SAFETY PROFILE A poison by intravenous route. Moderately toxic by ingestion, intraperitoneal, and subcutaneous routes. Human systemic effects heart changes, cyanosis, flaccid paralysis with appropriate anesthesia. An experimental teratogen. Mutadon data reported. Potentially explosive reaction when heated with ethoxyethynyl alcohols (e.g., 1-ethoxy-3-methyl-l-butyn-3-ol). When heated to decomposition it emits toxic fumes of SOx. See also SULFATES. 

As above, conjugated addition of 2-butyn-l-ol onto the triple bond of 1 was accomplished in 12 hours in the presence of a catalytic amount of DBU at room temperature (40%). However, its homologe 3-pentyn-l-ol behaved in a very different way. Under the same experimental conditions, a new complex was obtained as red crystals after flash chromatography on silica (hexane dichloromethane 4 1). Its infrared spectrum evidenced the presence of the M(CO)5 unit. In addition, the NMR spectrum showed the existence of an ethoxy group bonded to the metal... 

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