fe f 
arte > ae : ; ‘ 3 
Pg oe . 147 
. 4g Sao th Ws 4 
‘mful than benzalde ryde and ‘the Aaa were so B devately injured that it was difficult 
9 differentiate is effects in the different solutions. | 
From the pot and field. trials it was found that salicylaldehyde and vanillin had 
#y esi: action on well- drained, good productive soils in a high state of cultivation, 
a which, when examined in the laboratory, were found to possess good oxidising power. 
| urt er in these soils, the aldehydes disappeared. The soils in which the aldehydes were 
found. to have a harmful effect had a lower. crop-producing power and their general 
3 1anz gement had not been so good. The aldehydes remained in these soils. In these 
1. atter soils. lime and manganese ‘salts greatly aided in lessening the effects of both 
aldehydes, phosphates | ameliorated the harmfulness of salicylaldehyde and nitrate, of 
4 vanillin. Unfertile soils, poor owing to the presence of aldehydes, can be made produc- 
tive by good drainage and by the use of lime and certain fertilisers. 
| The piperylhydrazones of some s cdetites ot special interest for us have been tescrihed 
by A-Weinhagen’). The piperylhydrazine employed was prepared by reducing nitroso- | 
piperidine *). The hydrazones were obtained by heating the aldehydes with the requisite 
amount- of piperylhydrazine in alcoholic solution faintly acidified with acetic acid. The. 
piperylhydrazone of piperonal melted at 65 to 67°, of. salicylaldehyde at'71to 729 )of % 
benzaldehyde at 68 to 69° (Knorr giving 62 to 63°, and Forster?) 68°), and of anisic 
ie aldehyde at 54°. When preparing the last-named hydrazone, a reddish-violet impurity 
was formed which, however, was insoluble in light penoleun and could be easily 
removed from the reaction-mixture by extraction with that solvent, in which the hydrazone 
ay soluble. 
| abet i iManavenasot in an extensive Siblieation’)) one on the condensation of 
pit al with ethyl acetoacetate. The condensation — passes olf with | elimination of water, 
cording to the experimental conditions by union of equal molecules of citral and 
wo molecules of ester, forming citrylidene bis-acetoacetic ester. | | 
_Isomerism as with y-ionone and ionone is not observed when' starting from 
a lidene ethyl acetoacetate. The product obtained by Sehler®) by rearrangement of 
ci -ylidene ethyl acetoacetate with strong acids which he regarded to bea cyclic ester 
ind termed «-ester, was no pure body, neither was Stétzner’s®) a-ester pure. Both 
ithors had not borne in mind that the primary Condensation-product from equal mole- 
es of citral and ethyl acetoacetate, during praenet heating, and d parually even on 
distilling, suffers a rearrangement. 
_ By means of careful investigations, Knoevenagel established the difference of the — 
peeinal condensation-product from citral and ethyl acetoacetate (in whose preparation 
fl heating was avoided) from the ester obtained by several hours’ heating with exclusion 
) f water. The primary ester was now termed «ester, the one resulting from rearrange- 
ent by heat, f-ester. In the various reactions to which the ¢ and the §-derivatives 
were subjected, additional rearrangements took placé; the bodies resulting wee were 
ermed by Knoevenagel « and (-iso or -pseudo compounds. 
a _a-Citrylidene acetoacetic ester, the primary condensation-product positing from a 
ixture of equal molecules of citral and ethyl acetoacetate on addition of piperidine 
fter aa standing in the cold, viride, on treatment according to Tiemann, no 
a | 
a! 
8 
=e 
~ 
h 
x 2) Journ. chem. Soc. 118 (1918), 585. — 4) Liebig’s Annalen 221 (1883), 304. — 8) Journ. chem. Soc. 107 
915), 207. — *) Journ. f. prakt. Chem. 97 fase 288. — 5) Inaug.-dissert., Heidelberg 1897. — *) Inaug- 
lisser ie eal 1900. : OP ea ee 
10* 
es ster, with formation of citrylidene acetoacetic ester, or of one molecule of citral with | ee 
