Heteroaromatization with 4-phenyldiazenyl-1-naphthol. Part I: Synthesis of some new naphthopyrans and naphthopyranopyrimidines

Reaction of 4-phenyldiazenyl /or 4-(p-tolyldiazenyl)-1-naphthol (1) with various substituted α-cyanocinnamonitriles (2a-h) and ethyl α-cyanocinnamates (2i-p) afforded 2-amino-4-(aryl)-6-(phenyldiazenyl /or p-tolyldiazenyl)-4H-naphtho[1,2-b]pyrano-3-carbonitrile (3a-h) and ethyl 2-amino-4-(aryl)-6-(phenyldiazenyl /or p-tolyldiazenyl)-4H-naphtho[1,2-b]pyrano-3-carboxylate (3i-p). Reaction of compound 3a with Ac2O or PhCOCl and formic acid afforded N-acetylamino or N,N-dibenzoylamino and naphthopyranopyrimidine derivatives (4-8), respectively. The structures of these compounds were established on the basis of IR, UV, 1H NMR, 13C NMR, and MS data

Heteroaromatization with 4-phenyldiazenyl-1-naphthol. Part II: Synthesis of some new benzochromens, benzochromenopyrimidines, benzochromenotriazolopyrimidines, benzochromenopyrimidotriazepine and antimicrobial activities

Synthesis of several new of benzochromenes (4-7), benzochromenopyrimidines (8 and 9), 14-(4-chlorophenyl)-12-(phenyldiazenyl)-14H-benzo[7,8]chromeno[3,2-e][1, 2, 4]triazolo[1, 5-c]pyrimidines, 4-amino-16-(4-chlorophenyl)-14-(phenyldiazenyl)-16H-benzo[7', 8']chro-meno[2',3':4,5]pyrimido[1,6-b][1,2,4]triazepine-3-carbonitrile (10a-e, 13) and 9-(benz-ylideneamino)-7-(4-chlorophenyl)-5-(phenyldiazenyl)-7, 9-dihydro-8H-benzo[7,8]chromeno [2,3-d]pyrimidin-8-imine (12), form starting from 2-amino-4-(p-chlorophenyl)-6-phenyl-diazenyl-4H-benzochromene-3-carbonitrile (3). The structure of these new compounds was confirmed using IR, 1H NMR and 13C NMR as well as MS spectroscopy. The structure activity relationship studies of the target compounds in agreement with the in vitro essays and confirmed higher potent antimicrobial activity against some of the tested microorganisms. The structure-activity relationship study revealed that the antimicrobial activity of benzochromenopyrimido triazepine nucleus was more beneficial than benzochromeno-triazolopyrimidine nucleus for antimicrobial activity

The synthesis and properties of liquid crystals with bulky terminal groups for bookshelf geometry ferroelectric mixtures

The area of liquid crystals has received a substantial research effort over the last century, particularly when the beneficial applications such as Liquid Crystal Displays (LCDs) were realised and developed. The changes to the molecular structure of liquid crystals can have a significant effect upon their mesomorphism and ferroelectric properties. Most of the research in liquid crystal for display applications concentrates on the design and synthesis of novel mesogenic cores to which straight terminal alkyl or alkoxy chains are attached. However, little is known about the effects upon the mesomorphism and ferroelectric properties of varying the terminal chains. The synthesis and mesomorphic properties of a systematic range of ortho difluoroterphenyls with a bulky terminal chain are detailed. The bulky terminal chain consists of either a tertiarybutyl group or a trimethylsilyl unit, each separated from the core by a short (dimethylene) chain, with the other terminal chain being either octyloxy or heptyl. Unusually for liquid crystals with bulky terminal chains, the smectic phase stability (particularly smectic C) is upheld by more than the nematic phase stability, and in most cases the smectic C phase stability is actually higher than comparable analogues with conventional unbranched terminal chains. It is postulated that the surprisingly high smectic C phase stability results from a phase separation effect due to the incompatibility of the spherical bulky group and the conventional unbranched terminal chain, hence implying that the smectic 'layers' are well defined, and such definition of the layers bodes well for bookshelf geometry in ferroelectric mixtures. Two mono- and four trifluoroterphenyls with a bulky terminal chain were prepared in this work to study the effect on the mesomorphic behaviour of varying the degree of fluoro substituents upon the multi-ring system. Two chiral ortho difluoro-substituted terphenyl compounds were prepared also in this work for future ferroelectric mixtures

Design, Synthesis, and Antimicrobial Evaluation of Novel Pyrazoles and Pyrazolyl 1,3,4-Thiadiazine Derivatives

A novel series of pyrazolyl 1,3,4-thiadiazines 5a–c, 8a–c, 12, 15a–c, 17a–c, and 20 was prepared from the reaction of pyrazole-1-carbothiohydrazide 1a,b with 2-oxo-N′-arylpropanehydrazonoyl chloride, 2-chloro-2-(2-arylhydrazono)acetate, and 3-bromoacetylcoumarin. Moreover, the regioselective reaction of 5-pyrazolone-1-carbothiohydrazide 1a with 4-substituted diazonium salts and 4-(dimethylamino)benzaldehyde gave the corresponding hydrazones 21a–c and 22. The newly prepared compounds were characterized by spectroscopy and elemental analysis. Many new synthesized compounds showed considerable antimicrobial activity against tested microorganisms. Hydrazones 21a–c and 22 showed remarkable antibacterial and antifungal activities. 4-(2-(p-tolyl)hydrazineylidene)-pyrazole-1-carbothiohydrazide 21a displayed the highest antibacterial and antifungal activities with minimum inhibitory concentration (MIC) values lower than standard drugs chloramphenicol and clotrimazole, in the range of 62.5–125 and 2.9–7.8 µg/mL, respectively

Ecofriendly and simple synthesis of pyrano[3,2-c]quinolone in water via an efficient one-pot three-component reaction

Pyrano[3,2-c]quinolones are commonly found in alkaloids, manifesting diverse biological activities. In this work, 2-amino-6-methyl-5-oxo-4-substituted-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carbonitriles and ethyl 2-amino-4-(substituted)-6-methyl-5-oxo-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carboxylates have been synthesized efficiently from reaction of 4-hydroxy-1-methylquinolin-2(1H)-one, aldehydes and active methylene nitriles in one-pot three component reaction in aqueous medium, containing catalytic amount of ethanolamine resulting in 70-95% yields

Noble Metals Deposited LaMnO₃ Nanocomposites for Photocatalytic H₂ Production

Due to the growing demand for hydrogen, the photocatalytic hydrogen production from alcohols present an intriguing prospect as a potential source of low-cost renewable energy. The noble metals (Ag, Au, Pd and Pt) deposited LaMnO3 nanocomposites were synthesized by a non-conventional green bio-reduction method using aqueous lemon peel extract, which acts as both reducing and capping agent. The successful deposition of the noble metals on the surface of LaMnO3 was verified by using powder XRD, FTIR, TEM, N2-physisorption, DR UV-vis spectroscopy, and XPS techniques. The photocatalytic activity of the synthesized nanocomposites was tested for photocatalytic H2 production under visible light irradiation. Different photocatalytic reaction parameters such as reaction time, pH, catalyst mass and reaction temperature were investigated to optimize the reaction conditions for synthesized nanocomposites. Among the synthesized noble metal deposited LaMnO3 nanocomposites, the Pt-LaMnO3 nanocomposite offered superior activity for H2 production. The enhanced photocatalytic activity of the Pt-LaMnO3 was found as a result from low bandgap energy, high photoelectrons generation and enhanced charge separation due to deposition of Pt nanoparticles. The effective noble metal deposition delivers a new route for the development of plasmonic noble metal-LaMnO3 nanocomposites for photocatalytic reforming of aqueous methanol to hydrogen

Ecofriendly and simple synthesis of pyrano[3,2-c]quinolone in water via an efficient one-pot three-component reaction

Pyrano[3,2-c]quinolones are commonly found in alkaloids, manifesting diverse biological activities. In this work, 2-amino-6-methyl-5-oxo-4-substituted-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carbonitriles and ethyl 2-amino-4-(substituted)-6-methyl-5-oxo-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carboxylates have been synthesized efficiently from reaction of 4-hydroxy-1-methylquinolin-2(1H)-one, aldehydes and active methylene nitriles in one-pot three component reaction in aqueous medium, containing catalytic amount of ethanolamine resulting in 70-95% yields