ADVANCES IN TETRAZOLE CHEMISTRY IN RUSSIA

V.A. Ostrovskii (all other questions, proposals or information) , Michael Yudintceff (web-master)

The Cycle Formation

3. 1,5-Disubstituted Tetrazoles by Schmidt Reaction

The rate constants for reaction of ketones with hidrogen azide in H₂SO₄ and for imidoyl azide cyclization (cycle formation) have been obtained in a wide range of medium acidity. The suitable kinetics equations (1,2) are solved in variable assosiated with medium acidity and basicity of reagents and intermediate.

k¹_obs. = k¹h_o / (K₁ + h_o)^.(1+h_o/K₂+h_oh₊/K₂K₃); k²_obs. = k²h_o/K₄+ho;

k¹_obs. , k¹_, k²_obs., k² - the observed and actual rate constants of ketone-HN₃ interaction (1) and unprotonated imidoylazide cyclization (2); ho,h+ - the medium acidity for neutral (o) and charged (+) bases; K₁,K₂,K₃,K₄ - basicity constants for the ketone, HN₃, H₂N₃⁺ and imidoyl azide respectively; F= c_A/c_T = K (f_H2O c_H2O/f_HN3 c_HN3 a ); K -k_A/k_T; f_H2O, c_H2O, f_HN3 , c_HN3 - activity coefficients and concentrates of water and hidrogen azide in H₂SO₄ .

1. G.I. Koldobskii, V.A.Ostrovskii, B.V.Gidaspov, Application of Schmidt reaction for synthesis of tetrazoles(Review), Khim.Geterotsikl.Soedin., # 6, 723-735 (1975).

2. A.S.Enin, G.I. Koldobskii, V.A.Ostrovskii, L.I.Bagal, Zh.Org.Khim., 8, # 9, 1895-1901 (1972).

3.V.A.Ostrovskii, A.S.Enin, G.I. Koldobskii, Zh.Org.Khim., 9, # 4, 802-806 (1973).

4. G.I. Koldobskii, A.S.Enin, V.N.Naumov, V.A.Ostrovskii, Zh.Org.Khim., 8, # 1, 242-245 (1972).