— 13° — 



ations, came to the conclusion that "piperonal dichloride", from 

 piperonal and chloride of sulphur 1 ) is, in fact, composed in accordance 

 with the formula expressed by Delange, and not according to the 

 old formula, which had also been adopted by us at the time. Pauly 

 was able to afford direct proof that when reducing "piperonal dichloride" 

 made in accordance with the patent above referred to, and purified by 

 him by a special process, with zinc- dust in glacial acetic acid solution 

 at a temperature not exceeding 55 to 6o°, he did not recover piperonal, 

 but instead there of the cyclic carbonic acid ester (m. p. 34 ) of 

 methyl pyrocatechol, CO : 2 : C 6 H 3 • CH 3 , from which, by saponific- 

 ation with a 50 per cent, pyridin solution, free methyl pyrocatechol, 

 (HO) 2 • C 6 H 3 • CH 3 , was obtained. This possessed a melting point 

 of 65 , whereas up to the present 51 has been stated. The only 

 inference to be drawn from this result is that in the course of the 

 action of sulphur chloride on piperonal there is formed primarily a 

 piperonal dichloride of the old formula, but that, possibly, this body, 

 under the formation of sulphurous intermediary compounds, is con- 

 verted into the cyclical carbonate of methyl pyrocatechol dichlorinated 

 in the side-chain. According to Pauly, the circumstance that when 

 piperonal dichloride obtained in this manner is worked up, larger or 

 smaller quantities of protocatechuic aldehyde carbonate are produced, 

 affords confirmation of his theory. 



In connection with Pauly's communication, Barger 2 ), points out 

 that very soon after the publication of Delange's paper, he ranged 

 himself on the side of that investigator 3 ) in consequence of the results 

 obtained when acting with thionyl chloride upon combinations with 

 the methylenedioxy-group. Barger was able to show that with thionyl 

 chloride, piperonal at a relatively low temperature yields piperonal 

 dichloride, from which piperonal could be regenerated with formic acid. 

 At 180 , however, the CH 2 2 - group was also attacked, resulting in 

 the formation of "piperonal dichloride", CO : 2 : C 6 H 3 • CHC1 2 , while 

 the excess of thionyl chloride was reduced to chloride of sulphur. 



Homopiperonal. To the already known reactions for dis- 

 tinguishing propenyl from allyl compounds, such as the different be- 

 haviour of these compounds towards acetate of mercury 4 ) or towards 

 concentrated formic acid 5 ), F. W. Semmler and K. Bartelt 6 ) have 

 added a new one. This process deals with the action of ozone 



x ) German Patent 165727 of Schimmel & Co. 



2 ) Berl. Berichte 42 (1909), 763. 



8 ) Journ. chem. Soc. 93 (1908), 563, 735. 



4 ) Berl. Berichte 35 (1902), 2995; 36 (1903), 3575; Report April 1903, 83; 

 April 1904, 100; April 1906, 100. 



5 ) Berl. Ber. 41 (1908), 2185; Report November 1908, 51. 



6 ) Berl. Ber. 41 (1908), 2751. 





