Reactions in liquid ammonia. Some acetylenic compounds

REACTIONS IN LIQUID AMMONIA. SOME ACETYLENIC COMPOUNDS  

CONDENSATIONS WITH SODAMIDE IN LIQUID AMMONIA Acetylenic compounds are conveniently prepared with the aid of Uquid ammcx as a solvent. The preparation of a simple acetylenic hydrocarbon ( -butylacetylene or 1-hexyne) and also of phenylacetylene is described. Experimental details are also given for two acetylenic carbinols, viz., 1-ethynyl-eyciohoxanul and 4-pentyn-l-ol. It will be noted that the scale is somewhat laige smaller quantities can readily be prepared by obvious modifications of the directions. 

Sodamide is first prepared in situ by the reaction of sodium with Uquid ammonia in the presence of a catalyst  

The catalyst is finely-divided iron and is produced by adding a little crystallised ferric nitrate and a slight excess of sodium to liquid ammonia the reaction is probably  

A solution of mono-sodium acetylide in liquid ammonia is formed by passing excess of acetylene gas into the suspension of sodamide  

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VI,16. REACTIONS IN LIQUID AMMONIA. SOME ACETYLENIC COMPOUNDS ... 

In contrasi to many acetylenes RCsCH, chloroacetylene can be successfully coupled with ketones in liquid ammonia via the lithium compound [80,85], The excellent yield in the reaction with acetone indicates that practically no formation of enolate occurs. Similar good results have been obtained with lithiated ethynyl thioethers, (LiCsCSR), lithiated enyne thioethers, (LiCsCCH=CHSR), lithiated 1,3-diynes (RC=CC=CLi), and lithiated aiylacetylenes (LiCsCAryl)[2], A possible explanation for the small extent of enolization of the ketone is that all these acetylides are less basic due to some stabilization of the anion. 

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