Nitroazines. 8. Reactions of 6-nitroazolo[1,5-a]pyrimidines with pyrroles

✍ Scribed by T. L. Pilicheva; V. L. Rusinov; A. A. Tumashov; O. N. Chupakhin

• Publisher: Springer US
• Year: 1988
• Tongue: English
• Weight: 384 KB
• Volume: 24
• Category: Article
• ISSN: 0009-3122
• DOI: 10.1007/bf00474050

✦ Synopsis

The reactions of 6-nitroazolo[l,5-a]pyrimidines with pyrroles have been examined, and the influence of substitution in the azole moiety of the substrate on the course of the reaction studied~ The format&on of two isomeric sigma-" adducts has been established by spectroscopy.

We have previously reported [2] the direct introduction of the indole residue into 6-nitroazolo[l,5-a]pyrimidines to give stable sigma-adducts.

Some of these compounds have hypotensive activity [3].

In order to establish the scope of this reaction, and in a search for biologically active compounds, we here report the reaction of pyrrole (Ia) and N-methylpyrrole (Ib) with 6-nitro-l,2,4-triazolo[l,5-a]pyrimidines (II)-(VII) and 6-nitropyrazolo[l,5-a]pyrimidine (VIII)-(XII), which have a variety of substituents in the azole moiety of the molecule.

Pyrrole and N-methylpyrrole add readily to most of these 6-nitroazolo[l,5-a]pyrimidines. From the reaction mixtures there were isolated 6-nitro-7-(2'-pyrrolyl)-4,7-dihydro-1,2,4-triazolo-[l,5-a]pyrimidines (XIII) and (XIVa, b), (XV) and (XVIa), and 6-nitro-7-(2'-pyrrolyl)-4,7-dihydropyrazolo[l,5-a]pyrimidines (XVIIa, b), (XVIII), and (XIXa).