179 



For the preparation of tliis 2-keto-R-hexeiie d'.'rivative, one mole- 

 cule (6 gr. ) of benzoin is dissolved in boiling al)solute ethyl alcohol 

 (lOOcc. ), and to this solution is added one molecule (5.32 gr. ) of euminal- 

 acetone. Tliis mixture is treated with an alcoholic solution (4cc. ) of 

 sodium-ethylate (.5 gr. sodium in 3()cc. absolute ethyl alcoliol). The mix- 

 ture becomes deep red in color and upon standing in a cool place for two 

 hours deposits clusters of needle-like crystals. The crystalline mass is 

 filtered off and after washing witli absolute ethyl alcohol is recrystallized 

 twice from glacial acetic acid. Clusters of long, fine, white needles result 

 w'hicli melt at 231°. It is insoluble in ligroin (40-60), ether, and cold alco- 

 hol, but dis.solves readily in liot benzene, glacial acetic acid and chloro- 

 form . 



If a mixture of one molecule each of cumiuol (4.2 gr.) and pure acet- 

 one (1.7 gr. ) is used instead of tlie cuminalacetone, it has been established 

 by several comparable experiments that it is necessary that the reaction 

 shall be carried on at the temperature of the water bath for fifteen min- 

 utes. Upon the cooling of tlie mixture, the /\2-keto-R-liexene derivative 

 separates in a relatively pure condition. By repeated additions of 4cc. of 

 sodium ethylate at a time, additional quantities of tlie substance are ob- 

 tained whicli make the yield almost quantitative. Experiments were 

 made using the total quantity of sodium ethylate solution (12cc.) required 

 for the quantitative completion of the reaction, and it was found that the 

 reaction took an entirely different course, resulting in the formation of 

 the sodium ethylate addition product of benzoin*'. 



The condensation takes place readily when 15 grs. of a 10% solution of 

 sodium hydroxide are used in place of the 4cc. of sodium ethylate solution. 



O.ri^n of S-4-dli)hf)nj1-n-(-umiil-4-(}.i-ii-\^^-krto-Tl-hcr('ne. 



CH .CeH^ .CH. (CHa)^ 



CoHb . C.(OH). 



CgHb 



Dissertation, Chicago, 1897. p. 4. 



ICH. 



C = NOH 



CH 



