Efficient Lactic Acid-catalyzed Route to Naphthopyranopyrimidines under Solvent-free Conditions

An efficient method for the synthesis of 2,4,5-trisubstituted imidazoles using lactic acid as promoter

“…Lactic acid is obtained from fermentation of carbohydrates, it is easy to handle and readily available. Lactic acid is reported as organocatalyst in several organic reactions [39][40][41][42][43][44][45][46][47][48]. In the present method we are reporting lactic acid for the synthesis of 2,4,5-trisubstituted imidazole compounds from an aromatic aldehyde, benzil, and ammonium acetate under milder reaction conditions (160 °C) ( Fig.…”

Importance of Hybrid Catalysts toward the Synthesis of 5H-Pyrano[2,3-d]pyrimidine-2-ones/2,4-diones (Thiones)

“…105 Some of them were acquired either from nature or synthesized in the laboratory. As organocatalyst inexpensive, natural, nontoxic, efficient, commercially available, 106 their use in organic synthesis increase in recent years.…”

Recent advancements in the multicomponent synthesis of heterocycles integrated with a pyrano[2,3-d]pyrimidine core

“…Thus, following the same previous reaction sequence of the reactants, b-naphthol reacted with aryl aldehydes, and (thio) barbituric acids in a one-pot multicomponent procedure under catalytic, free-solvent, and heating conditions giving the appraised naphthopyranopyrimidine derivatives 53a-q in 82-92% yields. Most of the compounds prepared in this example using the molybdenum-doped LaFeO 3 nanocatalyst were previously prepared under other catalytic conditions, for example, iodine, lactic acid, and Fe 3 O 4 @MCM-48-SO 3 H. [125][126][127] The LaMo 0.1 Fe 0.9 O 3 nano-catalyst was prepared from La(NO 3 ) 3 $6H enabled its reusability, ease of product separation, and relatively worthy yields. The procedure has a drawback in the difficulty of nanocatalyst preparation although this method provided improved product yields by the green protocol than the preceding method.…”

“…Thus, following the same previous reaction sequence of the reactants, β-naphthol reacted with aryl aldehydes, and (thio)barbituric acids in a one-pot multicomponent procedure under catalytic, free-solvent, and heating conditions giving the appraised naphthopyranopyrimidine derivatives 53a–q in 82–92% yields. Most of the compounds prepared in this example using the molybdenum-doped LaFeO 3 nanocatalyst were previously prepared under other catalytic conditions, for example, iodine, lactic acid, and Fe 3 O 4 @MCM-48–SO 3 H. 125–127 The LaMo 0.1 Fe 0.9 O 3 nano-catalyst was prepared from La(NO 3 ) 3 ·6H 2 O in deionized water, Fe(NO 3 ) 3 ·9H 2 O, and (NH 4 ) 6 Mo 7 O 24 ·4H 2 O under stirring for 10 min followed by the addition of citric acid with continuous stirring at 80 °C. The product was calcified at 750 °C for 3 h. The use of this catalyst enabled its reusability, ease of product separation, and relatively worthy yields.…”