performed in aqueous media, have become increasingly useful tools for the synthesis of chemically and biologically important compounds because of their environmentally friendly atom economy and green characteristics [1][2][3][4][5][6][7].Among the wide variety of heterocycles that have been explored for developing potential pharmacologically active compounds, pyrazoles fused with different heterocycles that are known to contribute to various chemotherapeutic effects have emerged as antimicrobial [8,9], antifungal [10], and antiviral agents [11]. In addition, some fused pyrazole derivatives were reported to induce various antileukemic [12], antitumor [13,14], and antiproliferative [15,16] activities.The benzopyrano[2,3-d]pyrimidines are organic compounds which are constructed from two fused benzopyran and pyrimidine rings which exhibit extremely diverse biological and pharmaceutical activities [17][18][19][20][21][22][23][24][25][26][27][28]. The benzopyrans (4H-chromene) have shown a wide range of biological activities such as anti-HBV, cytotoxic [17], antibacterial [18], antioxidant [19], antigenotoxic [20], ATP sensitive potassium channel openers [21], and antiangiogenic activity [22]. On the other hand, pyrimidine scaffold is the base of many bioactive molecules such as antitubercular [23], antibacterial [24], antitumor [25], antiinflammatory [26], antifungal [27], and antileishmanial agent [28]. Consequently, synthetic methodologies for the synthesis of novel benzopyrano[2,3-d]pyrimidine [28] are of particular interests to organic and medicinal chemists.Recently, we described the synthesis of alkyl-1H-chromeno[2,3-d]pyrimidine-5-carboxamides via a new three-component reaction of isocyanide, barbituric acid, and a salicylaldehyde in the presence of acetic acid in ethanol/water mixture at 75 °C [29]. Herein, we aim to expand the versatility of the reaction using pyrazolones instead of isocyanides. Therefore, we examined the reaction between the salicylaldehydes 1, barbituric acid 2, and pyrazolones 3 Abstract A new three-component reaction between salicylaldehydes, barbituric acid, pyrazolones, in the presence of para-toluenesulfonic acid, efficiently provides pyrazolchromeno[2,3-d]pyrimidine-ones derivatives in good yields in ethanol/water at 70 °C. This multicomponent reaction showed high atom economy.
Graphical Abstract
