Visible-light induced cascade radical cyclization of sulfinic acids and o-(allyloxy)arylaldehydes towards functionalized chroman-4-ones

An efficient method for the synthesis of functionalized chroman-4-ones induced by visible light via the radical cyclization reaction of sulfinic acids and o-(allyloxy)arylaldehydes at room temperature was described.The corresponding products were isolated with moderate to good yields.Radical mechanism was proposed fo r this trans formation.Anti-microbial activity of some desired compounds we re screened.

Expedient chemoselective and catalyst-free synthesis of 3,3-difluorochroman-4-ones from o-hydroxyarylenaminones and Selectfluor

An expedient and mild strategy for the synthesis of unconventional 2-（dimethylamino）-3,3-difluorochroman-4-one derivatives from o-hydroxyarylenaminones and Selectfluor was developed at room temperature under catalyst-free conditions. This method showed excellent chemoselectivity and great functional groups tolerance.

Highly efficient synthesis of 2,3-dihydroquinazolin-4(1H)-ones catalyzed by heteropoly acids in water

Heteropoly acids efficiently catalyzed the cyclocondensation reaction of anthranilamide with aldehydes in water at ambient temperature and afforded the corresponding 2,3-dihydro-4（1H）-quinazolinones compounds in good to excellent yields.This method provides mild reaction conditions and clean reaction profiles,using a small quantity of catalyst and a simple workup procedure.

A new isochroman-4-one derivative from the peel of Musa sapientum L.and its total synthesis

A new isochroman-4-one, 7,8-dihydroxy-3-methylisochroman-4-one was isolated from water soluble fraction of Musa sapientum L. Its structure was determined by spectroscopic evidences and its total synthesis has also been reported. The compound showed potent antihypertensive activity.

7-Deazapurines:Synthesis of new pyrrolo[2,3d]pyrimidin-4-onescatalyzed by a Brφnsted-acidic ionic liquid as a green and reusable catalyst

Some new 2-aryl-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-ones have been prepared through cyclocondensation of 2-amino 1H-pyrrole-3-carboxamides with aromatic aldehydes followed by air oxidation in the presence of 3-methyl-1-（4-sulfonic acid）butylimidazolium hydrogen sulfate[（CH;）;SO;HMIM][HSO;],a Br（?）nsted-acidic ionic liquid,as a green and reusable catalyst in solvent-free conditions.

New Facile Synthesis of 2-Aryloxy-5-(2-furfurylidene)- 4H-imidazolin-4-ones

Novel 2-aryloxy-5-(2-furfurylidene)-4H-imidazolin-4-ones 6 were synthesized by aza-Wittig reaction of vinyliminophosphorane 4 with phenyl isocyanate and subsequent condensation with Various substituted phenols in the presence of catalytic amount of potassium carbonate. The products are confirmed by H-1 NMR, MS, IR and elementary analysis.

Synthesis of some new 3-[5-(2-oxo-2H-3-chromenyl)-1,3-oxazol-2-yl]-1,3-thiazolan-4-ones as antimicrobials

A series of some new 2-imino-5-[（Z）-1-（4-methylphenyl）methylidene]-3-[5-（2-oxo-2H-3-chromenyl）-1,3-oxazol-2-yl]-1,3- thiazolan-4-ones 5a-j has been synthesized and assayed for their antibacterial activity against Gram-positive bacteria viz.Bacillus subtilis（ATCC 6633）,Staphylococcus aureus（ATCC 6538p） and Micrococcus luteus（IFC 12708）,and Gram-negative bacteria viz. Proteus vulgaris（ATCC 3851）.Salmonella typhimurium（ATCC 14028） and Escherichia coli（ATCC 25922）.Among the screened compounds,5d,5e,5f,5g,and 5j exhibited potent inhibitory activity compared to standard drug,and emerged as potential molecules for further development.

Efficient Synthesis of 3,5,6,7-Tetrahydro-4H-cyclopenta [4,5] thieno [2,3-d] Pyrimidin-4-ones

The title compounds 3,5,6,7-tetrahydro-4H-cyclopenta[4,5]thieno[2,3-d]pyrimidin-4-ones（6） were synthesized by base catalytic reactions of secondary amines with carbodiimides 4, which were obtained from the aza-Wittig reaction of iminophosphoranes（3） with aromatic isocyanates.

Synthesis of some new bis-3,4-dihydropyrimidin-2(1H)-ones by using silica-supported tin chloride and titanium tetrachloride

Silica-supported tin chloride and titanium tetrachloride were prepared by the reaction of tin chloride and titanium tetrachloride with activated silica gel in refluxing toluene.These solid acids have been employed as the catalysts for the synthesis of bisdihydropyrimidin -2(1H)-ones from aromatic dialdehydes,1,3-dicarbonyl compounds and urea at 90℃under solvent-free conditions.

A Selective Synthesis of 2-Alkylamino-5, 6, 7, 8-tetrahydro-benzothieno[2, 3-d]pyrimidin-4(3H)-ones

Alkylamino-5, 6, 7, 8-tetrahydrobenzothieno [2, 3-d] pyrimidin-4(3H)-ones 7 weresynthesized by a new selective synthetic method, which includes aza-Wittig reaction of imino-phosphorane 4 with aromatic isocynate to give carbodiimide 5 and subsequent reaction of 5 withvarious aliphatic primary amine in the presence of EtO-Na+.

A rapid synthesis of isoxazolo[5,4-d]pyrimidin-4(5H)-ones under microwave irradiation with solid acid catalysis in solvent-free conditions

A rapid and efficient method for the synthesis of isoxazolo[5,4-d]pyrimidin-4（5H）-ones has been developed through cyclocondensation of 5-aminoisoxazole-4-carboxamides with orthoesters under conventional heating and solvent-free microwave irradiation with solid acid catalysis. In comparison, the reactions are faster and the yields are higher under microwave irradiation.

Synthesis, Structural Characterization and Antimicrobial Activity of a Novel Cobalt(II) Complex Based on 3-Methyl-1-Phenyl-4-(2-Thienoyl)-Pyrazol-5-One

New cobalt(II) complex, [Co(O2C15H11N2S)2(OH2)2]∙2H2O (1∙2H2O), has been synthesized upon reaction of cobalt chloride hexahydrate (Co(Cl)2∙6H2O) with 3-methyl-1-Phenyl-4-(2-thienoyl)-pyrazol-5-one (referred as HL) in ethanol at room temperature. Single crystal X-ray diffraction (XRD), spectroscopic methods, and microelemental analyses were used to characterize 1∙2H2O. Compound 1∙2H2O crystallizes in the orthorhombic crystal system with a Pbca space group and with the cobalt atom being pseudo-octahedral coordinated. The broth microdilution technique was used to screen the free ligand (HL) and the complex (1∙2H2O) for antimicrobial activities. HL has a low activity (MIC > 100 μg/mL) on all microorganisms, whereas compound 1∙2H2O displayed moderate activity (10 ∙2H2O exhibited bactericidal and fungicidal activity respectively on all the bacteria and yeasts tested. These findings reveal that the antimicrobial activity of HL was enhanced upon coordination to Co(II) ion against all microorganisms (bacteria and fungus).

Efficient synthesis of 5,6-dihydrothieno[3′,2′:4,5]-thieno[2,3-d]pyrimidin-4(3H)-ones via an iminophosphorane

5,6-Dihydrothieno[3＇,2＇：4,5]thieno[2,3-d]pyrimidin-4（3H）-ones 6 were synthesized in yields of 71-87% by a consecutive method, which includes aza-Wittig reaction of iminophosphorane 3 with aromatic isocynate to give carbodiimide 4 and subsequent reaction of 4 with various amines, phenols or alcohols in the presence of catalytic amount of sodium ethoxide or solid potassium carbonate. 2009 Ming Wu Ding. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Synthesis, Structural Characterization and Antimicrobial Activity of a Novel Cobalt(II) Complex Based on 3-Methyl-1-Phenyl-4-(2-Thienoyl)-Pyrazol-5-One

New cobalt(II) complex, [Co(O2C15H11N2S)2(OH2)2]∙2H2O (1∙2H2O), has been synthesized upon reaction of cobalt chloride hexahydrate (Co(Cl)2∙6H2O) with 3-methyl-1-Phenyl-4-(2-thienoyl)-pyrazol-5-one (referred as HL) in ethanol at room temperature. Single crystal X-ray diffraction (XRD), spectroscopic methods, and microelemental analyses were used to characterize 1∙2H2O. Compound 1∙2H2O crystallizes in the orthorhombic crystal system with a Pbca space group and with the cobalt atom being pseudo-octahedral coordinated. The broth microdilution technique was used to screen the free ligand (HL) and the complex (1∙2H2O) for antimicrobial activities. HL has a low activity (MIC > 100 μg/mL) on all microorganisms, whereas compound 1∙2H2O displayed moderate activity (10 ∙2H2O exhibited bactericidal and fungicidal activity respectively on all the bacteria and yeasts tested. These findings reveal that the antimicrobial activity of HL was enhanced upon coordination to Co(II) ion against all microorganisms (bacteria and fungus).

Efficient Synthesis of 2-Substituted Quinolino[7',8':5,6]pyrano-[2,3-d]pyrimidin-4(3H)-ones via Tandem Aza-Wittig Reaction

An efficient method is described for the synthesis of 2-substituted quinolino[7＇,8＇：5~6]pyrano[2,3-d] pyrimidin-4（3H）-ones（6） via a tandem aza-Wittig annulation process. The iminophosphorane（3） reacted with aromatic isocyanates, followed by heterocyclization on the addition of secondary amines, phenols or alcohols to give the corresponding guanidine intermediates（5）, which were cyclized in the presence of a catalytic amount of a base to tetracyclic compounds 6 in good yields. The corresponding carbodiimide（4） and guanidine-type intermediate compounds 5 need not be isolated.

Solid Phase Synthesis of 4H-Pyrimido[2,1-b] Benzothiazol-4-ones from Resin-Bound Cyclic Malonic Ester

The solid phase synthesis of 4H-pyrimido[2,1-b] benzothiazol-4-ones has been reported.

Efficient Synthesis of 3,5,6,8-Tetrahydro-4H-thiopyrano[4′,3′:4,5]· thieno[2,3-d]pyrimidin-4-ones via an Iminophosphorane

3,5,6,8-Tetrahydro-4H-thiopyrano[4＇,3＇：4,5]thieno[2,3-d]pyrimidin-4-ones（7） were synthesized via the base catalytic reactions of amines or phenols with carbodiimides（5）, which were obtained from the aza-Wittig reac tions of iminophosphoranes（4） with aromatic isocyanates.

Synthesis and antimicrobial activity of 2-（3＇, 5＇-disubstituted-indoly-2＇-yl）-4H-3, 1-benzoxazin-4-ones and their derivatives

As benzoxazin-4-ones and quinazolines linked to indole nucleus acting as a good pharmacophore, the synthesis of these compounds has significant meaning. The key intermediates 2-（2＇, 5＇-disubstituted-indol-2＇-yl）-4H-3, 1-benzoxazin-4-ones （3） were synthesized from cyclocondensation of indole-2-carbonyl chlorides （2） and anthranilic acid. Compound （3） on reaction with thiosemicarbazide and o-phenylene diamine afforded the compound （4） and （6） respectively. Compound （4） subjected to intramolecular cyclization under thermal conditions above its melting point afforded the compound （5）. Similarly compound （3） on fusion with o- phenylene diamine gave compound （7）. Structures of these compounds were confirmed by their spectral studies. The compounds were screened for their antimicrobial activity and the results were reported.

H_3PMo_(12)O_(40) catalyzed three-component one-pot synthesis of 4,6-diarylpyrimidin-2(1H)-ones under solvent-free conditions

4,6-Diarylpyrimidin-2(1H)-one derivatives have been synthesized from three-component one-pot condensation of acetophe-none derivatives,aldehydes and urea in the presence of trimethylsilyl chloride and a catalytic amount of HPMoOunder solvent-free conditions.

3-Phenyl/Pyridinyl Derivatives of <i>Trans</i>-2-(aryl/heteryl)vinyl-3<i>H</i>-quinazolin-4-ones: Synthesis and Fluorescent Properties

Novel 3-phenyl/pyridinyl-trans-2-(aryl/heteryl)vinyl-3H-quinazolin-4-ones 3a,b, 4a, 5a, 7a and their 6,7-difluoro de- rivatives 3c,d, 4b, 5b, 7b have been obtained by condensation of the correspondent 2-methylquinazolin-4-ones 1, 6 with aromatic (heterocyclic) aldehydes in the presence of ZnCl2 (AcONa) or by the reaction of 2-methyl-3,1-benzoxazin-4- ones 2 with the Shiff bases. Effects of aryl(heteryl) substituents on photophysical properties of (aryl/heteryl) quinazolinylethenes have been studied.