A green and efficient synthesis of [1,3]oxazines has been achieved via a three-component, one-pot condensation of 4-hydroxycoumarin, potassium selenocyanate and acyl chlorides in the presence of N-methylimidazole under solvent-free conditions at ambient temperature.
AbstractEfficient syntheses of 3,4-dihydropyrimidin-2-(1H)-ones and the corresponding thioxo derivatives using 1,3-dibromo-5,5-dimethylhydantoin (DBH) catalysis of a one-pot three-component Biginelli reaction of aldehydes, ethyl acetoacetate, and urea or thiourea under microwave irradiation are described. The advantages of this method are its short reaction times, high yields of the products, inexpensive and commercially available catalyst, and solvent-free conditions. Typical isolated yields exceed 70 % for arylaldehydes (9 examples) and aliphatic aldehydes (2 examples).
A simple and efficient synthesis of 3-(2'-benzothiazolyl)-2,3-dihydro quinazolin-4(1H)- ones has been accomplished by the one-pot condensation of isatoic anhydride, aldehyde and 2-aminobenzothiazole under solvent-free conditions in the presence of Zr(HSO4)4.
Two efficient and direct procedures have been developed for the preparation of 1-amidoalkyl-2-naphthols by a one-pot condensation of aldehydes, 2-naphthol, and amides in the presence of trichloroacetic acid or cobalt (II) chloride as catalyst. The reactions were carried out under solvent-free media. High yields, short reaction times, easy workup of the catalyst are advantages of these procedures.
An efficient method for the synthesis of secondary and primary dialkyl α-aminophosphonates under solvent-free conditions by one-pot reaction of aldehydes/ketones, amines/ammonium acetate and trialkyl/diethyl phosphite in the presence of a low catalytic amount of [ Cu (3,4-tmtppa)]( MeSO 4)4(0.16 mol%) as a highly stable and reusable catalyst, is described. By this method, aromatic, aliphatic, cyclic and heterocyclic aldehydes, hindered and cage ketones are converted into their corresponding α-aminophosphonates in good to excellent yields.
Herein, the catalytic activity of a novel synthesized Fe3O4/HT-SMTU-ZnII nanocatalyst, in the green and efficient synthesis of acridinediones, is described.
An efficient synthesis of 1,2,3-functionalized imidazoles and dimethyl-2-[(alkoxycarbonyl)- anilino]-2-butenedioate derivatives via one-pot reactions between N-methylimidazole, dimethyl acetylenedicarboxylate and N-phenylcarbamates under solvent-free conditions is described. The mild reaction conditions and good yields exhibit the synthetic advantage of this method.
Zr(HSO4)4: An Efficient Catalyst for the Synthesis of 3-(2'- Benzothiazolyl)-2,3-dihydroquinazolin- 4(1H)-ones