Reaction of 6(7)-acyl-and 6(7)-formylperimidines with 1,3,5-triazines in poly-phosphoric acid

Abstract

We have already shown that the 1,3,5-triazine-PPA* system is useful for the acylation and formylation of perimidines [2] and the synthesis of 1,2,3,7-tetraazapyrenes from 1H-naphtho [1,8-de][1,2,3]triazine (1,2,3-triazaphenalene) [3]. The present study is a continuation of our investigation of the synthetic scope of this system. The reaction of this system with 6(7)-acylperimidines 1a-c and 1e and 6(7)-formylperimidine (1d) was studied in present work.Since perimidines [2] and 1,2,3-triazaphenalene [3] undergo, in effect, double electrophilic attack by the system of 1,3,5-triazines 2 in PPA, we might have assumed that perimidines 1 would react analogously. Indeed, 1,3,7-triazapyrenes 3a-d were obtained in 50-65% yield upon heating 1a-d with 1,3,5-triazine (2a) in PPA. N N R N R 1 N H R N O R 1 N N N 1a-e 3a-e + 2a PPA 1, 3 a R = H, R 1 = Ph, b R = Me, R 1 = Ph, c R = R 1 = Ph, d R = R 1 = H, e R = H, R 1 = Me _______ * PPA with 86% P 2 O 5 prepared according to Uhlig [1] was used. __________________________________________________________________________________________

Use of the ring opening reactions of 1,3,5-triazines in organic synthesis (review)

“…An example of such a transformation is the synthesis of 1,2,4-oxadiazoles from nitrile oxides [29]. [4,[30][31][32][33][34][35]. Historically one of the first papers based on the transformation under discussion is the synthesis of 4-aminoquinazolines from the nitriles of anthranilic acids [4].…”

“…For example, the reaction of perimidines containing a carbonyl group at the peri position leads to annulation of the pyridine ring [34]. The examples presented above involved the participation of C-electrophiles.…”

Synthesis and cleavage of 1,3,7-triazapyrene ethers

“…The starting 1,3,7-triazapyrenes 1a,b [19] and 1c [20], and the standards of alkoxy derivatives 2a-d [8] were synthesized by the indicated methods.…”

Synthesis and hydroxylation of 1-alkyl- and 7-alkyl- 1,3,7-triazapyrenium salts

“…We have recently developed a series of synthetic methods for these compounds from perimidines, including the parent of the series [1][2][3][4]. The aim of our work was to study the regioselectivity of the quaternization process for 1,3,7-triazapyrenes and to investigate hydroxylation reactions for the 1,3,7-triazapyrenium salts obtained.…”