%0 Journal Article
%T Kinetics of Cyclization of 2-(N-B-Bromoethyl)-amino-5-substituted Benzophenones into 1,4-Benzodiazepines
%A Decorte
%A E.
%A Kajfe£¿
%A F.
%A Klasinc
%A L.
%A Kuftinec
%A J.
%A Mihali£¿
%A M.
%A £¿unji£¿
%A V.
%J -
%D 1978
%X Sa£¿etak The overall pseudo-first order cyclization rates of 2-N-/J-bro moethylamino-5-substituted benzophenones 1-3 into 1,4-benzodiazepines 7-9, determined in 60/o ethanolic ammonia at 100 ¡ãc, 115 ¡ãc, and 125 ¡ãc respectively, were found to range between 1.0 X 10-£¿ and 8.33 X 10-£¿ s-1 for 1, between 1.6 X 10-4 and 5.83 X 10-£¿ s¡¤1 for 2 and between 6.66 X 10-5 and 3.16 X 10-£¿ s-1 for 3. Rate values calculated from the rising concentrations of cyclization products 7-9 were lower indicating the formation of stable intermediates. It is assumed that these are protonated aziridine derivatives 4-6, since compounds 4 and 5 were identified as intermediates by TLC and GLC. The formation rate for the model compound 2-amino-5-chlorobenzophenone imine was found to be only 5.8 x 10-7 s-1 at 125 ¡ãC, which eliminates imine (C=NH) derivatives of 1-3 as possible intermediates. The ammonolysis rates of 3-phenylpropylbromide between 110 ¡ãc and 125 ¡ãc, were found to range from 1.5 X 10-4 to 4.16 X 10-£¿ s¡¤1£¿ These values revealed that the ~-participation of the N(2)-atom, being a relatively rapid equilibrium, does not enhance the overall cyclization rate. The following parameters characterize the overall cyclization process; l'i H=I= = 50.0 ¡À 4.0 kJ mo1-1 and l'i S=I= = -156 ¡À 5 J mo1-1 K-1 for 1, /'i H=I= = 89.9 ¡À.4.0 kJ moP K 1 for 2, l'i H=I= = = 75.3 ¡À 4.0 kJ moi-1 and l'i S=I= = -89 ¡À 4 J moi-1 K' for 3
%U https://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=288875