Trifluoroacetyl substituted pyrazolotriazines: synthesis and pathways of formation

Non-aromatic azolo[5,1-c][1,2,4]triazines: a pot, atom and step economic (PASE) synthesis, mechanistic insight and fluorescence properties

“…Earlier formyl derivatives of type B were obtained in the reaction of salts 1 with β-amino α,β-enones and fully characterized. 32 Isolation of extremely active intermediate 4-( N , N -dimethylamino)-3-(4-methoxycarbonylthiadiazol-5-yl)-1-(4-ethoxycarbonylpyrazol-5-yl)-1,2-diazabuta-1,3-diene ( 9 ) in the reaction of β-hetaryl enamines 3 with 5-diazoazoles 5 completely excludes the 1,7-cycloaddition mechanism, which was previously considered as the main one. 4,6,8 In our opinion, the key process in this interaction is 1,3-dipolar cycloaddition realized through intermediates E and A to give non-aromatic derivatives D (Scheme 2).…”