ZrOCl2/nano TiO2 as an Efficient Catalyst for the One Pot Synthesis of Naphthopyranopyrimidines Under Solvent-free Conditions

Abstract

ZrOCl 2 /nano-TiO 2 has been used as an efficient catalyst for the preparation of naphtho[1',2':5,6]pyrano[2,3-d]pyrimidine derivatives by the three-component reaction of aldehydes, β-naphthol and 1,3-dimethylbarbituric acid. The advantages of the reaction are solvent-free conditions, short reaction times, easy workup, good to excellent yields, and cost-effective and reusable catalyst.

Acid‐Mediated One‐Pot Three‐Component Tandem Cyclization: Access to Some New Series of Benzo[5,6]chromeno[2,3‐d]pyrimidine Derivatives

“…A common route for the synthesis of benzo [5,6]chromeno [2,3-d]pyrimidine derivatives is a three-component coupling reaction of naphthols, aldehydes and barbituric acid/1,3-dimethylbarbituric acid/thiobarbituric acid/1,3-dimethyl-2-thiobarbituric acid/6-amino-1,3dimethyluracil. To date, various conditions have been applied to promote this reaction in the presence of both homogeneous and heterogeneous catalysts such as InCl 3 , [12] I 2 , [13] KAl(SO 4 ) 2 .12H 2 O, [14] sulfated tin oxide, [15] HCOOH, [16] Lactic acid, [17] potassium phthalimide-N-oxyl (PPINO), [18] p-TSA, [19] cetylpyridinium chloride (CPC), [20] HClO 4 -SiO 2 , [21] H 3 PO 4 /Al 2 O 3 , [22] ZnO, [23] ([HMIm][HSO 4 ]) or Fe 3 O 4 @MCM-48-SO 3 H, [24] ZrOCl 2 /nano-TiO 2 , [25] cellulose sulfuric acid, [26] ZnAl 2 O 4 , [27] perlite NPs@IL/ ZrCl 4 , [28] MWCNTs@NHBut/PTA, [29] LaMo 0.1 Fe 0.9 O 3 , [30] PATDBP)(HSO 4 ) 2 @HNT, [31] MWCNTs@SiO 2 /MSA, [32] Nd 2 O 3 @g-C 3 N 4 , [33] H 4 [SiW 12 O 40 ], [34] L-proline, [35] and Al(H 2 PO 4 ) 3 . [36] Recently, one review article has been published based on the synthesis of naphthopyranopyrimidine derivatives.…”