Amidrazones. VII. Formation of s‐triazines by thermolysis of N1‐benzyl‐substituted amidrazone ylides

Abstract The preparation of ylides of the general structure magnified image is described. Thermolysis of 14a (R = CH 3 , R' = H, Ar = C 6 H 5 ) gave dimethylamine and 2,4‐dimethyl‐6‐phenyl‐ s ‐triazine. Thermolysis of ylides 14b (R = C 6 H 5 ; R' = CH 3 , Ar = C 6 H 5 ) and 14c (R = C 6 H 5 , R' = CH 3 , Ar = p ‐tolyl) gave dimethylamine, ArCH = NCH 3 and 1‐methyl‐2‐Ar‐4,6‐diphenyl‐1,2‐dihydro‐ s ‐triazines ( 19a,b ). Triazines 19a and 19b were also prepared by condensation of N ‐methylbenzamidine with benzaldehyde and p ‐tolualdehyde, respectively. Thermolysis of 14d (R = C 6 H 5 , R 1 = CH 2 C 6 H 5 ,Ar = C 6 H 5 ) gave 1‐benzyl‐2,4,6‐triphenyl‐1,2‐dihydro‐ s ‐triazine ( 19c ) and N ‐benzylidenebenzylamine. Mechanistic aspects of these reactions are discussed.