I 



322 ] 



XIV. 



THE CONDENSATION OF ALDEHYDES WITH BUTYL- 

 ACETOACETIC ESTEE. 



By HUGH EYAN, D.Sc, 



AND ■ 



MAEY J. SHANNON, M.Sc, 

 University College, Dublin. 



[Read FEBurAuv 25. Published Septemhek 15, 1924.] 



In 1915, H. Evan and J. M. Dunlea [Proc. R.I.A., xxx ii, B, 1915, p. 62] by 

 the action of benzaldehyde on dimethyl-aeetylacetone, in the presence of 

 alcoholic hydrochloric acid, obtained a crystalline compound melting at 

 169°G. This body, which was regarded as the beuzylidene derivative of a 

 tetrahydropyrone, was afterwards prepared by U. Eyau and P. Eyan [Proc. 

 E.I. A., xxxiii, B, 1917, p. 107] by the condensation of benzaldehyde with 

 methylisopropyl-ketone. The mode of formation of the substance, as 

 well as its behaviour towards bromine and hydroxylamine respectively, 

 indicated that it is a benzylidene-diphenyldimethyl-tetrahyropyroue having 

 the formula : — 



o 



H.Ce-HC 



r YH-C^H^ 



H3C.C 



,^^^C = CH.CgH5 



^3^ 



CO 



An attempt was made by H. Eyan and A. Devine [Proc. E.I. A., xxxii, B, 

 1916, p. 208] to obtain a similar body by the action of benzaldehyde on 

 methylethyl-ketone. In the presence of alkali these two substances inter- 

 acted to form the diphenylmethyl-tetrahydropyrone : — 



C^H^ CH 



O 3 



CO 



previously described by C. Harries and G. H. Miiller [Ber. Dtsch. Cliem. 

 Ges., XXXV, 1902, p. 96S]. Tliis substance reacted, indeed, with benzaldehyde; 



