I. V. Borovlev

Heterocyclic Analogs of Pleiadiene: LXXIV. peri-Cyclizations in the Perimidine Series. Synthesis of 1,3-Diazapyrene Derivatives

Reactions of perimidines and perimidin-2-ones with α,β-unsaturated carbonyl compounds gave various 1,3-diazapyrene derivatives. Acylation of 1-methylperimidine, perimidin-2-one, and 1-methylperi-midin-2-one with cinnamoyl chloride in the presence of AlBr3 is accompanied by peri-fusion at the 6,7-position and dearylation of the intermediate product. Under analogous conditions, 1,3-dimethyl-2,3-dihydroperimidine gave rise to 6-cinnamoyl-1,3-dimethyl-2,3-dihydroperimidine. Reactions of perimidin-2-ones with 1,3-di-phenyl-2-propenone in polyphosphoric acid resulted in peri-fusion at the 6,7-position, and with acetylacetone, at the 1,9-position.

Formylation of perimidine derivatives in a system 1,3,5-triazine-polyphosphoric acid

The application of compound II in the role of formylating agent is well known [2]. In the classical version the reaction is carried out without catalyst or in the presence of Lewis acids. We demonstrated that under these conditions the perimidine formylation did not occur. Therefore another combination of reagents was used as formylating agent: 3-fold excess of 1,3,5-triazine II in 80% polyphosphoric acid (PPA) at 55–60°C. The yield of aldehydes IV under these conditions was 83–91%.

Heterocyclic Analogs of Pleiadene. 71. Synthesis of 1,3-Diazapyrene

The reaction of perimidine and 2-R-perimidines with α,β-unsaturated carbonyl compounds in polyphosphoric acid has yielded the previously unknown 1,3-diazapyrene and its 6,8-di- and also 2,6,8-trisubstituted derivatives. Their spectroscopic parameters are discussed.

Investigations in the region of 2,3′-biquinolyl 5. Investigation of the reaction of stabilized C-nucleophiles with 1-alkyl-3-(2-quinolyl)-quinolinium halides

The regioselectivity of the nucleophilic addition of stabilized C-nucleophiles to 1-alkyl-3-(2-quinolyl)quinolinium halides was investigated. The reaction of the latter with enolates, indolesodium, and cyanide ion leads to 4′-substituted 1′-alkyl-1′, 4′-dihydro-2,3′-biquinolyls.

Acid hydrolysis of amines and cleavage of 1,3,7-triazapyrene ethers

Acid hydrolysis of 6-amino derivatives of 1,3,7-triazapyrene affords the corresponding 6-oxo-6,7-dihydro-1,3,7-triazapyrenes. In the case of 6,8-bis(dialkylamino)-1,3,7-triazapyrenes depending on their structure products of hydrolysis of one or two dialkylamino groups are obtained. 6-Alkoxy-8-dialkylamino-1,3,7-triazapyrenes were synthesized. Conditions were found providing a possibility to cleave an ether bonds in the presence of amino group in the 1,3,7-triazapyrene structure and also to perform the hydrolytic substitution of both functional groups.

Synthesis of 1,3-diazapyrenes by vinylformylation of perimidines

Several methods for the synthesis of 1,3-diazapyrene derivatives have been reported previously [1 5]. However, these methods suffer from poor yields and lack of general character. In the present communication we describe a procedure that is free from the above disadvantages. The procedure is based on the vinylformylation of heterocyclic compounds, which has been developed relatively recently [6]. We have found that perimidines Ia Ic react with 3-(Nmethyl-N-phenylamino)acrolein in dichloroethane in the presence of POCl3 to give the corresponding 1,3diazapyrenes IIIa IIIc in 42 56% yields.

Direct oxidative SNH amidation of 1,3,7-triazapyrene

6-Acylamino-1,3,7-triazapyrenes have been synthesized for the first time by direct oxidative nucleophilic substitution of hydrogen.

Amides of 1,3,7-triazapyrene series: synthesis by nucleophilic substitution of alkoxy groups

The treatment of 6,8-dialkoxy-1,3,7-triazapyrenes with sodium acylamides in DMSO at room temperature resulted in ipso substitution of one alkoxy group with amide group, giving 8-acylamino-6-alkoxy-1,3,7-triazapyrenes. The reaction at 65–70°C proceeded as a tandem SNAripso–SN2 process, leading to the formation of 8-acylamino-6-oxo-6,7-dihydro-1,3,7-triazapyrenes.

1,3,7-Triazapyrene: the first case of hetarylation of benzene and its analogs

The reactions of heteroaromatic cations with neutral aromatic compounds is an important method for the introduction of heterocyclic substituents into the molecules of organic compounds. Depending on the nature of the substrate, similar processes are known as electrophilic hetarylation of arenes or nucleophilic arylation of hetarenes; such reactions are well known for various azines [1-5]. Generally azaheterocycles are activated by N-acylation, N-protonation, or N-alkylation, but π-rich arenes or hetarenes (phenols, arylamines, their O- and N-alkyl derivatives, pyrrole, indole, etc.) are used as the aromatic reagents. This process has found use for the construction of new heterocyclic systems [6, 7]. During a study of the nucleophilic substitution of hydrogen in a series of 1,3,7-triazapyrenes [8-11] we observed a reaction unusual for azines, namely, arylation by benzene and its homologs. The reaction occurred in a polyphosphoric acid (PPA) medium containing 86% P2O5 [12]. The reaction of 1,3,7-triazapyrene (1) with a large excess of benzene occurred at the boiling point of the latter, and in the case of toluene or o-xylene at 100-110°C. The process was accompanied by the development of a deep red coloration that is characteristic of the dihydrotriazapyrene structure. However, we were unable to isolate the intermediate products resulting from the nucleophilic addition of arenes – the σ-adducts 2a-c – since on alkalinization they underwent oxidative dehydroaromatization in the presence of air oxygen with the formation of 6-phenyl- (3a), 6-p-tolyl- (3b), and 6-(3,4-dimethylphenyl)-1,3,7-triazapyrene (3c), respectively.

SNH Arylation of 1,3,7-triazapyrenes in acidic aqueous solution

The reaction of 1,3,7-triazapyrenes with π-electron rich arenes in concentrated hydrochloric acid yielded the corresponding 6-aryl-1,3,7-triazapyrenes. An example of double arylation of 1,3,7-triaza-pyrene was found.