Synthesis of 6H-pyrazolo[2,3-a][1,3,5]benzotriazepines

Treatment of 5-amino-1-(2-aminophenyl)-1H-pyrazole-4-carbonitrile ( 15 ) with triethyl orthoformate produces 6H-pyrazolo[2,3-a][1,3,5]benzotriazepine-3-carbonitrile ( 16 ). Other members of this novel ring system result from treating 15 with triethyl orthoacetate and triethyl orthopropionate. These latter reactions, which yield homologs 17 and 19 , respectively, of 16 , also produce acyclic Schiff bases. These Schiff bases are useful in determining the position of the triazepine double bond in pyrazolobenzotriazepines 16 , 17 and 19 , using ¹³C nmr spectroscopy.