Synthesis and Fluorescence Properties of Donor-Acceptor-Substituted Novel Dipyrazolo[3,4-<Emphasis Type="Italic">b</Emphasis>:3′,4′-<Emphasis Type="Italic">d</Emphasis>]Pyridines (DPP)

A rapid and efficient method for the synthesis of novel dipyrazolo[3,4-b:3′,4′-d]pyridines (DPP) from pyrazolo[3,4-b]pyridine was successfully developed. The DPP derivative was further N-alkylated (6, 8) as well as N-linked with amino acids (13) and their photophysical properties were studied along with N-aryl DPP 4 and observed that the chromophores at C₄ position in the aryl ring changed the absorption and emission λ_max.     

Neutravidin micropatterning by deep UV irradiation

We describe a novel approach for directly patterning neutravidin protein by exposure to deep UV irradiation. Neutravidin is physically absorbed onto the glass or quartz substrate, dehydrated in acetone and air-dried. Dry neutravidin-coated samples are patterned either by top-side or back-side exposure to 185 nm UV. Subsequent introduction of fluorescent biotinylated proteins clearly demonstrates binding to the masked neutravidin regions and no binding to exposed areas. Patterned samples retain their protein affinity for at least three months of storage at room temperature.     

A novel synthesis of 3-((benzo[d]thiazol-2-ylamino)(phenyl)methyl)-4-hydroxy-1-methylquinolin-2(1H)-one via consecutive C–C and C–N bond formation in water

Research on Chemical Intermediates - A simple, efficient, and eco-friendly protocol has been developed for the synthesis of novel...     

Novel and Efficient Synthesis of Pyrimidine Derivatives

A new series of 1-alkyl-2-oxo-1,2-dihydro-pyrimidine-5-carboxalic acid amides is described. The reaction of N-((E)-3-(dimethylamino)-2-formylacryloyl) formamidine, an intermediate obtained by Vilsmeier–Haack formylation of acetonitrile with various mono-substituted ureas, provides such compounds in good yields.     

Synthetic utility of a heterocyclic o-aminoaldehyde: synthesis of pyrazolopyridopyrimidines, pyrazolonaphthyridines, and pyrazolopyrimidonaphthyridinones

Abstract  

A series of various polysubstituted pyrazolo[3,4-h][1,6]naphthyridines, benzo[b]pyrazolo[3,4-h][1,6]naphthyridines, and pyrazolo[4′,3′:5,6]pyrido[4,3-d]pyrimidines were synthesized by Friedl?nder condensation of 4-amino-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carbaldehyde (o-aminoaldehyde) with active methylene compounds. The o-aminoaldehyde was functionalized to o-aminonitrile and o-aminocarboxamide with malononitrile and cyanoacetamide, respectively, which on condensation with monosubstituted ureas and acetic anhydride, respectively, afforded pyrazolo[3,4-h]pyrimido[4,5-b][1,6]naphthyridines.     

Silica-supported tungstic acid (STA): A recyclable catalyst for the synthesis of 1H-indazolo [1,2-b]phthalazine-trione and spiro-triazolo[1,2-a]indazole-tetraone derivatives under solvent-free condition

Abstract

An efficient one-pot synthesis of 1?H-indazolo[1,2-b]phthalazine-trione and spiro-triazolo[1,2-a]indazole-tetraone derivatives via three-component condensation reaction of phthalhydrazide or 4-phenylurazole, aldehydes or isatins and dimedone in the presence of a catalytic amount of silica-supported tungstic acid (STA), as a heterogeneous solid acid catalyst under solvent-free conditions is presented. This ecofriendly protocol offers several advantages such as a cost-effective procedure with excellent yields, short reaction time, simple workup, recovery and reusability of catalyst with broad scope of usable substrates. This has made the protocol sustainable and economic.     

Transition metal complexes of novel tridentate S,N,O donor ligands

Summary Complexes of chromium(III), iron(III), cobalt(III), nickel(II) and copper(II) with salicylaldehyde N(1-piperidyl) thiocarbonyl hydrazone (spthH₂), salicylaldehyde N-(1-morpholyl) thiocarbonyl hydrazone (smthH₂), 2-hydroxy 4-methyl acetophenone N-(1-piperidyl) thiocarbonyl hydrazone (apthH₂) and 2-hydroxy 4-methyl acetophenone N-(1-morpholyl) thiocarbonyl hydrazone (amthH₂) have been prepared and characterized by analytical, spectral and magnetic measurements. Mixed ligand complexes of Cu^II-thiocarbonyl hydrazones and heterocyclic bases have been isolated. Depending on the nature of the metal salts used and the reaction conditions the thiocarbonyl hydrazones act as neutral or dibasic tridentate ligands.     

Simultaneous Densitometric Determination of Aspirin and Omeprazole by High-Performance Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - A new, simple, accurate, and precise high-performance thin-layer chromatographic (HPTLC) method has been developed for the...