— 1 84 — 



camphenilanaldehyde monoacetate C 9 H 14 : CH«0-OC*CH 3 , 

 with the following constants: b. p. 1 13 to n6° (10 mm), d2o° 1,0125, 

 n D 1,4816, mol. refr. found 55,1, calc. f. ester C 12 H 18 2 /~~ 54,61. 

 Oxidation with ozone yielded camp heni lone (b. p. 70 to 8o°, 

 10 mm., d 2 o° 0,970; n D 1,471 ; m. p. of the semicarbazone 223 ). Re- 

 duction with sodium in alcoholic solution gave the hitherto unknown 

 camphenilyl alcohol C 10 H 18 O (b.p. io5toio6°, 10 mm.; m. p. 58 

 to 5Q°, not very clearly defined). This body belongs to camphenil- 

 analdehyde. The corresponding chloride of the alcohol possessed the 

 following constants: b. p. 83 to 85 (10 mm.), d2o° 0,9909, n D 1,4862. 

 The oxidation as well as the reduction proved the unsaturated character 

 of enol-camphenilanaldehyde acetate. 



As two aliphatic aldehydes, oenanthic aldehyde and octylic aldehyde, 

 when boiled with acetic acid anhydride, also react in the enolic form, 

 Semmler 1 ) regards it as probable that all aldehydes with CH 2 -group 

 vicinal to the C HO- group give this reaction. It is true that phenyl 

 acetaldehyde (which had already been examined previously), also 

 possesses a CH 2 - group which is adjacent to the aldehyde-group, but 

 it is not impossible that the phenyl-radical 2 ) may have an "activating" 

 influence upon the CH 2 -group. 



Oenanthic aldehyde(b.p. 42 to 43 , 10mm.; d 2 o° 0,8250; 1^1,41655; 

 m. p. of the semicarbazone 106 to 107 from methyl alcohol) yielded, 

 besides the di-acetate, enol-n-heptanal monoacetate with the 

 following constants: b. p. 76 to 79 (10 mm), d2o° 0,888, n D 1,43258, 

 mol. refr. found 45,6 calc. for the ester C 9 H 16 2 /~45,o. 



Octylic aldehyde supplied by us (b. p. 60 to 61 °, 9 mm.; d2o° 0,82 1 1 ; 

 n D 1,4 1 955 ; b. p. of the oxime 1 1 1 to 1 1 2 , 9 mm. ; m. p. of the oxime 6o°, 

 from dilute alcohol; m. p. of the semicarbazone 101 ) yielded enol- 

 n-octanal-monoacetate CH 3 «(CH 2 ) 5 «CH :CH-0*CH 3 , with the 

 following constants: b. p. 90 to 94 (10 mm.), d 2 oo 0,88, n D 1,43256, 

 mol. refr. found 50,1, calc. for the ester C 10 H ls O 2 ^ 49,6. Only a 

 little di-acetate had been formed in addition. 



Aldehydes with a ramified chain also react in the enolic form 

 when boiled with acetic anhydride 3 ). 



isovaleric aldehyde (b. p. 92 , 760 mm.; d 2 o° 0,8089; ^1,30,488) 

 gave enol- aw valeric aldehyde monoacetate, with the following con- 

 stants: b. p. 127 to 133 (760 mm.), d 2 o° 0,8818, n D 1,41655. Here 

 also diacetate was formed in addition. 



Citronellal (b.p. 83,5 to 87,5° [10 mm.]; d 2 o° 0,8627; Md +io°; 

 &d 1,45262) likewise gave, together with diacetate, enoi-citronellal 

 monoacetate (b.p. no to 115 [10 mm.]; d 2 o<> 0,900; Md — 1°; 



*) Berl. Berichte 42 (1909), 1161. 



2 ) Berl. Berichte 42 (1909), 584; Report April 1909, 128. 



8 ) Berl. Berichte 42 (1909), 2014. 



