A Macrocyclic Azo Dye

✍ Scribed by Dipl.-Ing. J. Jarkovský; Dr. Z. J. Allan

• Book ID: 101549712
• Publisher: John Wiley and Sons
• Year: 1963
• Tongue: English
• Weight: 231 KB
• Volume: 2
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.196306872

✦ Synopsis

ether is c y c l k d to I-phenyl-1,2,4-triazol-5-one (4) (yield: 81 %). 1,2,4-Triazol-5-one results directly from (2) and hydrazine in 60 7; yieid. (31, Y = NH2 or (4). Y = OH 4CsNHNH> r -y T' I CSHS .s-Triazines are not only obtained from open-chain amidines; N-cc-pyridyl-N'-ethoxycarbonylformamidine, which is prepared almost quantitatively by heating cc-aminopyridine with (2) to approx. IOO"C, is converted on addition to boiling diphenyl ether into pyrido[ I ,2u]s-triazin -4one in 41 % yield.

In contrast to tautomerizable enamines, such as $-aminocrotonic ester (5) or I ,3-dimethyl-4-aminouracil (6), which react directly with (2) at 100 -120°C to yield pyrimid-4-ones [(7) in 40% yield, (8) in 86 yield], aromatic primary amines react with (2) to yield formamidines; their cyclization to quinazol-4-ones requires heating in diphenyl ether.

H O Y N B

A r = P-CloH7; X = COzR The yields are sometimes satisfactory (Ar = a-naphthyl, 51 %,;

(3-naphthyl, 89 x ; 2-anthry1, 94 x), but occasionally poor (Ar = C6H5, 10 7:); now and then merely decomposition of the formamidine is observed.