Application of SBA-Pr-SO3H in the synthesis of benzoxazole derivatives

Three-component synthesis of pyrano[2,3-d]-pyrimidine dione derivatives facilitated by sulfonic acid nanoporous silica (SBA-Pr-SO3H) and their docking and urease inhibitory activity

“…The nanoporous compound SBA-15 was synthesized and functionalizaed according to our previous report and the modified SBA-15-Pr-SO 3 H was used as nanoporous solid acid catalyst in the following reactions [40-43]. …”

Versatile imidazole synthesis via multicomponent reaction approach

“…Japp and Radziszewski reported the first MCR for the synthesis of imidazole. [52] The synthesis of 2,4,5-trisubstituted imidazoles are normally carried out by the reaction of 1,2-diketone, α-hydroxy/silyloxyketone/acetoxy, or 1,2-ketomonoxime with an CH 3 COONH 4 (Ammonium acetate) and Aldehyde (Route I in Figure 4A) in different reaction condition like using simply HOAc [53][54][55] or solid supported acids, [56][57][58][59][60][61][62][63] ionic liquids, [64,65] under microwave [66] or ultrasonic [67] irradiation, under conventional method of central heating in the existence of metal catalytic agent [68][69][70][71][72][73][74] or by the help of solar heating condition, [75] (b) in the presence of various Lewis acid catalysts (Route II), [76] (c) Ni-catalyzed cyclotrimerization of aromatic nitriles (under pressure range of not <60 and not more than 120 psi and high level of temperature which approximately ranges from 180-230 C) hydrogenation condition aimed at long (48 h) (refer Route III in scheme I) [67] ; or Pd-catalyzed one single phase synthesis from imine and chlorides of acids via the formation of Münchnones (Route IV, Figure 4A). [68][69][70][71][72][73][74][75][76][77][78]…”

“…[81] Mohammadi Ziarani et al synthesized 1,2,4, 5-tetrahedrally-substituted imidazoles by reacting benzil, aromatic aldehydes, and ammonium acetate in the presence of water as the solvent for about 10 min with yield ranging from 85 to 98%, as depicted in Figure 5A. [56] Mekheimer et al also suggested a reaction actively involved in preparing tetrasubstituted imidazole by using high surface area SiO 2 as a catalyst. The reaction was induced by solar thermal energy.…”

“…The phosphonite PPh(catechyl) mediate the reaction, and the reaction proceeds via regioselective cycloaddition with an in situ produced phosphate-Münchnone 1,3-dipole (54). Phosphate-Münchnone 1,3-dipole were made from imines, acid chlorides, and PHP(catechyl) (55) to form a regioselective imidazole nucleus (56). (Figure 13B).…”

CuNiFe a Magnetic Nano‐Catalyst: an Efficient Catalyst for the Selective Synthesis of Benzoxazoles

“…Nitrogen containing heterocycles such as benzoxazole and its derivatives are important building blocks for the synthesis of pharmaceutical products, agrochemical compounds and functional materials . Traditionally, benzoxazoles have been synthesized by (i) condensation of 2‐aminophenols with carboxylic acids, aldehydes, benzyl alcohols, and benzyl amines,, (ii) transition metal‐catalyzed intramolecular cyclization of 2‐haloanilides or their analogs,, (iii) tandem cyclization of 2‐halophenol with amidines, (iv) intermolecular cross‐coupling of 1,2‐dihaloarenes with primary amides …”