The reaction of phenols with fluoro-2,4-dinitrobenzene, clean and quick when catalyzed by triethylamine in dimethylformamide, is shown to be ideal for the characterization of phenols. The resulting 2,4-dinitrophenyl ethers crystallize well and can be used in spectrophotometric and colorimetric q...

Phosphomonoesterase (PMEase) activity plays a key role in nutrient cycling and is a potential indicator of soil condition and ecosystem stress. We compared para-nitrophenyl phosphate (pNPP) and 4-methylumbelliferyl phosphate (MUP) as substrate analogues for PMEase in 7 natural ecosystem soils an...

Schiff base condensation of 2-nitrobenzaldehyde with (para-substituted phenyl)hydrazine in the presence of CH3COONa in EtOH at 80 °C produces (E)-1-(para-substituted phenyl)-2-(2-nitrobenzylidene)hydrazines [−OCH3 (1), −CH3 (2), −H (3), −Br (4), −Cl (5), −F (6)]. CuCl catalyzed olefination of 1...

Hydrolyses of m- and p-nitrophenyl acetates by 6-deoxy-6-alkylthio-β-cyclodextrins and the corresponding sulfoxides were studied to show that the small chemical conversion from the sulfides to the sulfoxides led to a change of meta/para-selectivity in the hydrolysis of the β-cyclodextrin moiety.

Ingestion of hypoglycin A (HGA) in maple seeds or alkaloids produced by symbiotic fungi in pasture grasses is thought to be associated with various syndromes in grazing animals. This article describes analytical methods for monitoring long-term exposure to HGA, its metabolite MCPA-carnitine, as ...

The endophyte fungus Neotyphodium lolii is associated with perennial ryegrass (Lolium perenne L) and can lead to the production of tremorgenic mycotoxins like lolitrem B, which is responsible for “Ryegrass staggers”, a disease in sheep, cattle and horses. We present a new simple, rapid, sensit...

The indole diterpenoid toxin lolitrem B is a tremorgenic agent found in the common grass species, perennial ryegrass (Lolium perenne). The toxin is produced by a symbiotic fungus Epichloë festucae (var. lolii) and ingestion of infested grass with sufficient toxin levels causes a movement disorde...

Condensation of α-acetoxynitro compounds 4a-f with isocyanoacetonitrile (5) using DBU in THF afforded 2-cyano-3,4-substituted pyrroles 6a-f, in good yield. Porphobilinogen (PBG, 12), the key building block for the preparation of tetrapyrrolic natural products, was synthesized from 2-cyano-3,4-s...

In the present work we studied the effect of adenosine and various analogues on cAMP level in guinea pig coronary endothelial cells of microvascular origin. The tested adenosine agonists mediate a concentration-dependent increase in cAMP level. The rank order of potency was 5′-N-ethylcarboxamid...

The involvement of purine salvage in the accumulation of current trypanocidal drugs is important for the treatment of African sleeping sickness. The substrate specificity of essential nucleoside transporters is therefore of physiological and pharmacological interest. With the intention to contri...

A new series of 32 pyrimido- and 5 tetrahydropyrazino[2,1-f]purinediones was obtained and evaluated for their adenosine receptors (ARs) affinities. The 1,3-dibutyl derivative of 9-(4-(2-(dimethylamino)ethoxy)phenyl)-6,7,8,9-tetrahydropyrimido[1,2-f]purine-2,4(1H,3H)-dione was found to be the mos...

The thermal [3 + 2] cycloaddition reaction of N-iminoquiazoline ylides with allenoates worked efficiently under mild reaction conditions to provide a variety of tetrahydropyrazoloquinazoline derivatives in good to excellent yields and moderate to excellent diastereoselectivities.

We herein report the general, versatile, and convenient method for the synthesis of 2-arly/alkyl-5-bromo-7-methoxy benzofurans from easily available o-Vanillin in five steps. These benzofurans was successfully converted into biological active natural products Egonol, Homoegonol, and analogous on...

Two series of 5-substituted 2-amino-4-(3-trifluoromethylphenyl)thiophenes were prepared and evaluated as allosteric enhancers at the A1 adenosine receptor (A1AR). In the 3-benzoyl series, a 5-phenyl group was found to confer the greatest potency (9a: ED50 = 2.1 μM, AE score = 18%). However, the...

A novel series of inhibitors for mitogen activated protein kinase-activated protein kinase 2 (MK-2) are reported. These squarate based inhibitors were identified via a high-throughput screen. An MK2 co-structure with the starting ligand was obtained and a structure based approach was followed to...

Background/aimPyrimidine is found as a core structure in a large variety of compounds that exhibit important biological activity. Specifically, 2,4,5,6-tetrasubstituted dihydropyrimidines have shown potent antimycobacterial activity. The use of combinatorial approaches toward the synthesis of dr...

In the present study an investigation of the structure–activity relationships in 9-ethylpurine derivatives, aimed at preparing A1, A2A, A2B, and A3 selective adenosine receptor antagonists, was undertaken. Our synthetic approach was to introduce various substituents (amino, alkoxy and alkynyl g...

The activation of the human A3 adenosine receptor (AR) by a wide range of N6-substituted adenosine derivatives was studied in intact CHO cells stably expressing this receptor. Selectivity of binding at rat and human ARs was also determined. Among N6-alkyl substitutions, small N6-alkyl groups wer...

Nine C2-substituted adenosine analogues that are potent and selective for the A2-adenosine receptor were tested for their ability to induce relaxations of the guinea pig aorta. Compounds tested were 2-phenylethoxyadenosine (PEA), 2-phenylethoxy-5′- N-ethylcarboxamidoadenosine (PENECA), 2-cycloh...

SummaryA quantitative structure-activity relationship (QSAR) analysis of a series 2-alkyloxy-, 2-aryloxy- and 2-aralkyloxy-adenosines has been performed. Various theoretical 3-D electronic and topological descriptors encoding their molecular structure were estimated and the structure-activity co...