Mr Ruhemann, The Dihydrotetrazines. 317 



but the iodide C 4 H n N 4 I which is formed from dimethyltetrazoline 

 does not give such a reaction. 



Ruhemann and Merriman (loc. cit.) have stated that the 

 alcoholic solution of the mixture of dimethyltetrazoline and 

 benzaldehyde does not deposit a solid even on standing with 

 piperidine for many days. I have since found that a condensa- 

 tion-product is indeed formed which is very soluble in alcohol, 

 but the yield is so small that I have not yet examined this 

 compound. More promptly dimethyltetrazoline condenses with 

 salicylic aldehyde, but the compound, which is formed, differs 

 from the one which is produced by the action of salicylic alde- 

 hyde on tetrazoline. It has the composition CuH ]2 ON 4 , H 2 0, 

 and therefore possesses one mol. of water of crystallisation which 

 it loses at 100°; this substance, moreover, is sparingly soluble in 

 cold dilute hydrochloric acid, and this solution does not give a 

 precipitate with platinic chloride, whereas o-hydroxybenzylidene- 

 tetrazoline as well as the other condensation-products of tetrazoline 

 with aldelrydes, are readily soluble in hydrochloric acid, and with 

 platinic chloride, form chloroplatinates. These facts therefore 

 lead to the conclusion that, although the condensation-products 

 of dimethyltetrazoline with aldehydes are most probably to be 

 expressed by the formula 



N— -N. 

 CH,.C CH.RC.CHj, 



the corresponding compounds from tetrazoline have a different 

 constitution which is probably the one suggested by Ruhemann 

 and Merriman. 



Bisdiazomethane, like its isomeride tetrazoline, reacts with 

 aldehydes, i.e. ?7i-nitrobenzaldehyde or salicylic aldehyde, to yield 

 compounds which, no doubt, are to be represented by the symbol 



y N = N\ • 

 R.CH:C< >CH 2 . 



These substances are hydrolysed readily by boiling water and 

 differ from the condensation-products of tetrazoline with alde- 

 hydes inasmuch as they do not yield precipitates with platinic 

 chloride. 



