Facile heterocyclic synthesis and antimicrobial activity of polysubstituted and condensed pyrazolopyranopyrimidine and pyrazolopyranotriazine derivatives

Reaction of 6-amino-3-methyl-4-(substituted phenyl)-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile (1) with triethylorthoformate followed by treatment with hydrazine hydrate, formic acid, acetic acid, phenylisocyanate, ammonium thiocyanate and formamide afforded the corresponding pyranopyrimidine derivatives 2–6. Cyclocondensation of 1 with cyclohexanone afforded pyrazolopyranoquinoline 7. One-pot process of diazotation and de-diazochlorination of 1 afforded pyrazolopyranotriazine derivative 8, which upon treatment with secondary amines afforded 9 and 10a-c. Condensation of 2 with aromatic aldehyde gave the corresponding Schiff bases 11a,b, the oxidative cyclization of the hydrazone with appropriate oxidant afforded 11-(4-fluorophenyl))-2-(4-substitutedphenyl)-10-methyl-8,11-dihydropyrazolo-[4\u27,3\u27:5,6]pyrano[3,2-e][1,2,4]triazolo[1,5-c]pyrimidines (12a,b). Structures of the synthesized compounds were confirmed by spectral data and elemental analysis. All synthesized compounds were evaluated for antibacterial and antifungal activities compared to norfloxacin and fluconazole as standard drugs. Compounds 9, 10c, 12a and 15 were found to be the most potent antibacterial agents, with activity equal to that of norfloxacin. On the other hand, compound 5 exhibited higher antifungal activity compared to fluconazole

Ethyl 2-amino-4-(4-fluoro­phen­yl)-6-meth­oxy-4H-benzo[h]chromene-3-carboxyl­ate

In the title compound, C23H20FNO4, the fluoro-substituted benzene ring is approximately perpendicular to the mean plane of the 4H-benzo[h]chromene ring system [maximum deviation = 0.264 (1) Å], with a dihedral angle of 83.79 (6)°. The pyran ring adopts a flattened boat conformation. The meth­oxy group is slightly twisted from the attached benzene ring of the 4H-benzo[h]chromene moiety [C—O—C—C = −2.1 (2)°]. An intra­molecular N—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, mol­ecules are linked by N—H⋯O and N—H⋯F hydrogen bonds into a layer parallel to the bc plane. The crystal packing also features C—H⋯π inter­actions

Priprava derivata 4-aminofeniloctene kiseline s antimikrobnim djelovanjem

Condensation of 4-APAA with phthalic anhydride gave (dioxoisoindolin-2-yl)phenylacetic acid 1, which is employed as key intermediate in the synthesis of title compounds 2-8. The products have been characterized by analytical and spectral data (IR, 1H NMR, 13C NMR and mass spectra). Antimicrobial activities were also studied and some of these compounds gave promising results.Kondenzacijom 4-APAA s anhidridom ftalne kiseline dobivena je (dioksoizoindolin-2-il)feniloctena kiselina 1, koja je upotrebljena kao ključni intermedijer u sintezi spojeva 2-8. Produkti su karakterizirani analitičkim i spektroskopskim metodama (IR, 1H NMR, 13C NMR i MS). Neki od sintetiziranih spojeva ima značajno antimikrobno djelovanje

The chemical reactivity of naphthols and their derivatives toward α-cyanocinnamonitriles and ethyl α-cyanocinnamates: A review of synthesis, reactions and applications of naphthopyrano

This review deals with synthesis and reactions of some naphthopyrano derivatives and their applications. The main purpose of this review is to present a survey of literatures on the reactivity of naphthols and their derivatives toward α-cyanocinnamonitrile or ethyl α-cyanocinnamate derivatives and the reactions of β-enaminonitriles and β-enaminoesters with different electrophiles followed by nucleophilic reagents. Some of these reactions have been applied successfully to the synthesis of biologically important compounds

7,7′,8,8′-Tetra­meth­oxy-4,4′-dimethyl-3,5′-bichromene-2,2′-dione

In the title mol­ecule, C24H22O8, the mean planes of the two coumarin units are inclined to each other at a dihedral angle of 79.93 (3)°. The attached meth­oxy groups form torsion angles of 7.65 (19) and 78.36 (14)° with respect to one coumarin unit, and angles of 9.01 (16) and 99.08 (11)° with respect to the other coumarin unit. In the crystal structure, weak inter­molecular C—H⋯O hydrogen bonds connect pairs of mol­ecules to form dimers, generating R 2 2(16) and R 2 2(18) rings; the dimers are linked by further weak inter­molecular C—H⋯O hydrogen bonds, forming extended chains. Additional stabil­ization is provided by weak C—H⋯π inter­actions

Antifungal activity of a novel chromene dimer

The activity on Aspergillus spp. growth and on ochratoxin A production of two novel chromene dimers (3) was evaluated. The results of the bioassays indicate that the chromene dimer 3a inhibited mycelia growth by approximately 50% (EC50) at 140.1 μmol L−1 for A. niger, 384.2 μmol L−1 for A. carbonarius, 69.1 μmol L−1 for A. alliaceus and 559.1 μmol L−1 for A. ochraceus. When applied at concentrations of 2 mmol L−1, 3a totally inhibited the growth of all Aspergillus spp. tested. Furthermore, ochratoxin A production by A. alliaceus was reduced by about 94% with a 200 μmol L−1 solution of this compound. A moderate inhibitory effect was observed for the analogous structure 3b on ochratoxin A production but not in mycelia growth. No inhibition was registered for compounds 2a and 2b, used as synthetic precursors of the dimeric species 3.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/ 11228/2002

The Antioxidant Activity of New Coumarin Derivatives

The antioxidant activity of two synthesized coumarins namely, N-(4,7-dioxo-2- phenyl-1,3-oxazepin-3(2H,4H,7H)-yl)-2-(2-oxo-2H-chromen-4-yloxy)acetamide 5 and N-(4-oxo-2-phenylthiazolidin-3-yl)-2-(2-oxo-2H-chromen-4-yloxy)acetamide 6 were studied with the DPPH, hydrogen peroxide and nitric oxide radical methods and compared with the known antioxidant ascorbic acid. Compounds 5 and 6 were synthesized in a good yield from the addition reaction of maleic anhydride or mercaptoacetic acid to compound 4, namely N′-benzylidene-2-(2-oxo-2H-chromen-4-yloxy)acetohydrazide. Compound 4 was synthesized by the condensation of compound 3, namely 2-(2-oxo-2H-chromen-4-yloxy) acetohydrazide, with benzaldehyde. Compound 3, however, was synthesized from the addition of hydrazine to compound 2, namely ethyl 2-(2-oxo-2H-chromen-4-yloxy)acetate, which was synthesized from the reaction of ethyl bromoacetate with 4-hydroxycoumarin 1. Structures for the synthesized coumarins 2–6 are proposed on the basis of spectroscopic evidence