Tetrahydro-4H-chromene-3-carbonitrile derivatives 4a-c where prepared from the reaction of 1,4-cyclohexane dione (1), malononitrile (2) and either benzaldehyde (3a), 2-chlorobenzaldehyde (3b) or 4-methoxybenzaldehyde (3c) in ethanol containing triethylamine. Compound 4b was used to prepare pyrazole, pyrimidine thiazole derivatives. Moreover, tetrahydrobenzo[d]thiazole derivative 18 (1) with ele...

In the presence of triethylamine as catalyst, the one-pot four-component reactions of arylamines, methyl propiolate, isatin and malononitrile afforded the functionalized spiro[indoline-3,4'-pyridine] derivatives in good yields. Similar reactions with ethyl cyanoacetate successfully afforded the functionalized spiro[indoline-3,4'-pyridines] and spiro[indoline-3,4'-pyridinones] as the main produc...

new macrocyclic polyether-diester ligands (3-5) containing the 4h-pyran-4-one subcyclic unit have been prepared by treating various glycols with dimethyl chelidonate (10). in the reaction of compound 10 with ethylene glycol and diethylene glycol, two noncyclic diester and tetraester (6-9) were produced in each case. the new marcocyclic ligand 4 formed stable complexes with benzylammonium perchl...

a novel rice-husk-silica supported n-propyl bipyridinium chloride (rhprbpcl) has been prepared. due to the basicity of rhprbpcl, it was decided to evaluate its catalytic activity in the one-pot preparation of tetrahydrobenzo[b]pyran, dihydropyrano[3,2-c]chromene and dihydropyrano[4,3-b]pyran derivatives. the catalyst was characterized by ft-ir, sem and tga analyses. this methodology offers seve...

The crystal structure of the title compound, C(30)H(38)N(2)O(5)Si, has been investigated to establish the relative stereochemistry at the spiro ring junction and the two anomeric centres. Each of the O atoms in the tetra-hydro-pyran rings adopts an axial position on the neighbouring ring. This bis--diaxial conformation is adopted, thus gaining maximum stablization from the anomeric effect. The ...

tetrahydrobenzo[b]pyran derivatives 1 were utilized for the synthesis of several new pyrano[2,3-d]pyrimidine derivatives 2. compound 2 was obtained in the presence of ac2o/h2so4 (as a catalyst) and was confirmed by spectroscopic data such as ir, 1h nmr and 13c nmr. ab initio calculation was carried out to study geometric optimization, thermodynamic parameters, aromaticity and dynamic process of...

Introduction: Due to the cell labeling potentials of various metal-maltol complexes, the idea of developing a possible cell labeling imaging agent using single photon emission computed chromatography (SPECT) with[111In]-maltolate complex has been investigated. Methods: [111In] labeled 3-hydroxy-2-methyl-4H-pyran-4-onate ([111In]-maltolate) was prepared using f...