The use of anilinodihydrofurans in the synthesis of novel heterocyclic compounds

Abstract

The increasing importance of furano-fused heterocycles as biologically active compounds [1][2][3][4][5] has led to continuing development of new simple procedures for their synthesis. In the light of these findings and our continuing interest in the synthetic importance of the enaminones and synthesis of some functionally substituted heterocycles [6-9], we have investigated the behavior of some furans of the enaminone type towards cinnamonitriles.When arylidenemalononitriles 1a-c [10] were subjected to reaction with alkyl 4-oxo-2-phenylamino-4,5-dihydrofuran-3-carboxylates 2a,b [11] in refluxing 1-propanol in the presence of a catalytic amount of piperidine (Scheme 1), the 1-benzofuran derivatives 5a-c were obtained, instead of the expected furo-[3,2-b]pyrans 4a-c. Similar behavior has been reported previously [12][13][14][15][16].The NMR spectrum of compound 5a exhibited two one-proton singlets at 5.50 (CH benzyl) and  5.60 (OH) ppm. The mass spectrum of compound 5b showed the molecular ion at m/z 584.Formation of compound 5 could be explained by addition of two molecules of compound 1 to compound 2 to form the intermediate 3 via retro Knoevenagel reaction followed by cyclization and elimination of hydrogen cyanide. This reaction represents an interesting method for the construction and functionalization of the 1-benzofuran ring systems. In addition, this method has the advantages of ready accessibility of the reagents, good yields, and experimental simplicity.In view of the above findings and in connection with the present work aiming to explore the synthetic importance of enaminones, we studied the conversion of compound 2a into some new substituted furan derivatives.

2,6-Dicyanoaniline based donor-acceptor compounds: the facile synthesis of fluorescent 3,5-diaryl/hetaryl-2,6-dicyanoanilines

“…3 In addition, the 2,6-dicyanoanilines type of A-D-A system constitutes a part of the molecular framework of many biological important compounds such as quinolines, isoquinolines, tetrahydroisoquinolines, fluorenes, 9-oxofluorenes, benzofurans, naphthalenes, steroids, quinazolines, phenoxazines and coumarins. [4][5][6][7][8][9][10][11][12][13][14][15][16][17] The most studied derivatives of 2,6-dicyanoanilines are 3,5-disubstituted-2,6-dicyanoanilines, and many synthetic procedures and catalyst systems have been used in the synthesis of 3,5-disubstituted-2,6-dicyanoanilines. 3 They are generally obtained from one-pot reaction process via multicomponent domino coupling reaction pathway by using appropriate aldehyde and ketone.…”

CoFe2O4@SiO2‐PA‐CC‐guanidine nanoparticles: A novel, efficient, and recyclable catalyst for the synthesis of 3,5‐disubstituted‐2,6‐dicyanoaniline derivatives

“…Organic dyes consist of donor-acceptor systems and demonstrate various optical properties. [4] In addition, 2,6-dicyanoanilines are found in the structure of various polymers [5] ; light-emitting diodes [6] ; and biological compounds such as benzofurans, [7] fluorenes, [8] 9-oxofluorenes, [9] quinolines, [10] isoquinolines, [11] tetrahydroisoquinolines, [12] indoles, [13] indazoles, [14] imines, [15] 6H-benzo[c]chromenes, [16] steroids, [17] naphthalenes, [18] coumarins, [19] phenoxazines, [20] quinazolines, [15] and dibenzo [b,d]furans. [21] Substituted 2,6-dicyanoanilines, which contain 2,6-dicyanoanilines derivatives in their structures, have biological activities such as anticancer, [22] antimicrobial, [23] antileishmanial, [24] antihyperglycemic, [25] antiamyotrophic lateral sclerosis, [26] and growth-promoting properties.…”

Microwave Assisted Synthesis and Biological Evaluation of 1, 2, 4-Triazolo[1, 5-a]pyrimidines

“…New synthetic conditions recently described involve melting under microwave irradiation, a reaction that is environmental friendly and gives higher yields than conventional heating in solvent 14 . Furthermore, certain lithium 1,3-diketonates have proven to be better synthons than the corresponding diketones 15 .…”