1.2.4- Triazolo cinnolines

Chloroperoxidase catalysis by, 58, 302 in chlorination of pyrazoles, 57, 337 Chlorophyll, thioaldehyde synthetic intermediate to, 55, 3 Chlorosulfonyl isocyanate, reaction with 2-arylhydrazono-3-oxobutanoate, 59, 148 Chromatography, of [l,2,4]triazolo[l,5-a]-pyrimidines, 57, 106 Chrom-3-enes, see 2//-l-Benzopyrans Chromium tricarbonyl complexes of 3,5-diphenyl-l-(alkyl- or oxido-)-thiabenzenes, 59, 206, 227 indoles, lithiation of, 56, 181, 184 of pyridine, 58, 160 pyridines, lithiation of, 56, 230, 239 of 2f/-thiopyrans, 59, 227 Chromones, see l-Benzopyran-4-ones Cinnamonitrile, a-cyano-, condensations with thio-, seleno-amides, 59, 184, 186 Cinnoline, nitration, MO calculation, 59, 302... 

Tetrahydro-[l,2,4]triazolo[4,3-h]cinnolines have been prepared from 3-hydrazino-5,6,7,8-tetrahydrocinnolines and the reagents just described for (17) (71BSF3043), and also by condensing 2-hydroxymethylenecyclohexanone with 4-amino-1,2,4-triazole (79JCS(P1)3085). 

Under this heading, the synthesis of l,2,4-triazolo[4,3-fe]pyridazines (255) as well as the closely related and medicinally very important 1,2,4-triazolo[3,4-a]phthalazines (256), in addition to l,2,4-triazolo[4,3-( ]-cinnolines (257), will be discussed. 

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