Ryan and Egan — The Action of Nitrous Acid ^ Sfc, on Urcthunes. lf)9 



alcohol, and. carbon tetrachloride were mixed with butyl nitrite and acetic or 

 hydrochloric acid and allowed to remain at the temperature of the room for 

 periods varying from seven weeks to thi-ee months. Yellow oily products 

 were obtained in each case, but from these no crystalline substances were 

 isolated. , 



III. o-Tolylurethane. 



(a) Nitrous Acid, — 1. Six molecular amounts of butyl nitrite were added 

 to a solution of 5 grams of o-tolylurethaiie in 100 grams of glacial acetic acid. 

 The mixture was allowed to remain at the temperature of the room for two 

 months, but from it the only substance isolated was unchanged o-tolylurcthane. 



The urethane was also recovered unchanged in a somewhat similar 

 experiment (but at a lower temperature), in which the butyl nitrite was 

 replaced by sodium nitrite. 



2. The urethane was also unaffected when its alcoholic solution, to which 

 butyl nitrite and hydrochloric acid had been added, was allowed to remain 

 for nine weeks at the ordinary tempei^ature. 



3. To a solution of 2*5 grams of o-tolylurethane in 50 grams of carbon 

 tetrachloride, 6 moleculorr amounts of butyl nitrite and 8 molecular amounts 

 of glacial acetic acid were added. After one month the solution had acquired 

 a reddish colour, and after two months, colourless crystals and some oily 

 matter floated on the surface. When the mixture had remained for three 

 months at the temperature of the room, it was examined. The crystals 

 melted at 132°-134° C, and since a mixture of them with 4.-nitro-o-toly- 

 lurethane melted at the same temperature the two substances must have 

 been identical. 



The carbon tetrachloride layer was neutralized with barium carbonate 

 filtered and distilled. The reddish oily residue solidified on standing. It 

 was freed from unchanged o-tolylurethane by warm petroleum ether, and 

 then dissolved in hot alcohol. After boiling the alcoholic solution with 

 animal charcoal, filtering and cooling, a good j'ield of ^-nitro-o-tolylurethane 

 was obtained. 



4. As in the case of phenylurethane, a solution of o-tolylurethane in 

 carbon tetrachloride, which had been treated with nitrons acid for a shorter 

 time, about fourteen days, contained ^-nitro-o-tolylurethane mixed with 

 unchanged o-iolylurcihane. 



(6) Nitrous fumes. — Dry nitrous fumes were passed for thirty minutes 

 through a well-^cooled solution of 1 gram of o-tolylurethane in 10 c.cs. of 

 carbon tetrachloride. The yellow oil which separated solidified after some 

 days. The product wa,s recrystallised from carbon tetrachloride, and melted 



