Inhibitory effect of novel pyrimidines on ATP and ADP hydrolysis in synaptosomes from rat cerebral cortex

Chemoselective O-Alkylation of 4-(Trifluoromethyl)pyrimidin-2(1H)-ones Using 4-(Iodomethyl)pyrimidines

This study reports two strategies for preparing O-alkyl derivatives of 6-substituted-4-(trifluoromethyl)pyrimidin-(1H)-ones: a linear protocol of alkylation, using a CCC-building block followed by [3 + 3]-type cyclocondensation with 2-methylisothiourea sulfate and a convergent protocol based on direct alkylation, using 4-(iodomethyl)-2-(methylthio)-6-(trihalomethyl)pyrimidines. It was found that the cyclocondensation strategy is not feasible; thus, the direct chemoselective O-alkylation was performed, and 18 derivatives of the targeted pyrimidines were obtained in 70-98% yields. The structure of the products was unambiguously determined via single crystal X-ray analyses and two-dimensional nuclear magnetic resonance experiments.

Ultrasound-assisted synthesis of pyrimidines and their fused derivatives: A review

The pyrimidine scaffold is present in many bioactive drugs; therefore, efficient synthetic routes that provide shorter reaction times, higher yields, and site-selective reactions are constantly being sought. Ultrasound (US) irradiation has emerged as an alternative energy source in the synthesis of these heterocyclic scaffolds, and over the last ten years there has been a significant increase in the number of publications mentioning US in either the construction or derivatization of the pyrimidine core. This review presents a detailed summary (with 140 references) of the effects of US (synergic or not) on the construction and derivatization of the pyrimidine core through classical reactions (e.g., multicomponent, cyclocondensation, cycloaddition, and alkylation reactions). The main points that were taken into consideration are as follows: chemo- and regioselectivity issues, and the results of conventional heating methods compared to US and mechanistic insights that are also presented and discussed for key reactions.

Selective nucleoside triphosphate diphosphohydrolase-2 (NTPDase2) inhibitors: nucleotide mimetics derived from uridine-5'-carboxamide

Ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDases, subtypes 1, 2, 3, 8 of NTPDases) dephosphorylate nucleoside tri- and diphosphates to the corresponding di- and monophosphates. In the present study we synthesized adenine and uracil nucleotide mimetics, in which the phosphate residues were replaced by phosphonic acid esters attached to the nucleoside at the 5'-position by amide linkers. Among the synthesized uridine derivatives, we identified the first potent and selective inhibitors of human NTPDase2. The most potent compound was 19a (PSB-6426), which was a competitive inhibitor of NTPDase2 exhibiting a K i value of 8.2 microM and selectivity versus other NTPDases. It was inactive toward uracil nucleotide-activated P2Y 2, P2Y 4, and P2Y 6 receptor subtypes. Compound 19a was chemically and metabolically highly stable. In contrast to the few known (unselective) NTPDase inhibitors, 19a is an uncharged molecule and may be perorally bioavailable. NTPDase2 inhibitors have potential as novel cardioprotective drugs for the treatment of stroke and for cancer therapy.

Physiology and pathophysiology of purinergic neurotransmission

This review is focused on purinergic neurotransmission, i.e., ATP released from nerves as a transmitter or cotransmitter to act as an extracellular signaling molecule on both pre- and postjunctional membranes at neuroeffector junctions and synapses, as well as acting as a trophic factor during development and regeneration. Emphasis is placed on the physiology and pathophysiology of ATP, but extracellular roles of its breakdown product, adenosine, are also considered because of their intimate interactions. The early history of the involvement of ATP in autonomic and skeletal neuromuscular transmission and in activities in the central nervous system and ganglia is reviewed. Brief background information is given about the identification of receptor subtypes for purines and pyrimidines and about ATP storage, release, and ectoenzymatic breakdown. Evidence that ATP is a cotransmitter in most, if not all, peripheral and central neurons is presented, as well as full accounts of neurotransmission and neuromodulation in autonomic and sensory ganglia and in the brain and spinal cord. There is coverage of neuron-glia interactions and of purinergic neuroeffector transmission to nonmuscular cells. To establish the primitive and widespread nature of purinergic neurotransmission, both the ontogeny and phylogeny of purinergic signaling are considered. Finally, the pathophysiology of purinergic neurotransmission in both peripheral and central nervous systems is reviewed, and speculations are made about future developments.

Synthesis and antimicrobial activity of new (4,4,4-trihalo-3-oxo-but-1-enyl)-carbamic acid ethyl esters, (4,4,4-trihalo-3-hydroxy-butyl)-carbamic acid ethyl esters, and 2-oxo-6-trihalomethyl-[1,3]oxazinane-3-carboxylic acid ethyl esters

This work presents a three-step synthesis of a new series of 4-substituted 2-oxo-6-trihalomethyl-[1,3]oxazinane-3-carboxylic acid ethyl esters, from beta-alkoxyvinyl trihalomethyl ketones of general formula X3C-C(O)-CH=C(R)-OR(1), where R = H, Me, Ph, and 4-Me-Ph; R(1) = Me and Et; and X = F and Cl. The Michael addition-substitution of the ethyl carbamate on beta-alkoxyvinyl trihalomethyl ketones furnished the corresponding (4,4,4-trihalo-3-oxo-but-1-enyl)-carbamic acid ethyl esters. These compounds underwent reduction with NaBH4 leading to the respective (4,4,4-trihalo-3-hydroxy-butyl)-carbamic acid ethyl esters. The 3-hydroxy-butyl carbamates were submitted to cyclization reaction with triphosgene to give a series of 4-substituted 2-oxo-6-trihalomethyl-[1,3]oxazinane-3-carboxylic acid ethyl esters. The in vitro antimicrobial activity, of some of the three new series of the title compounds, was assessed against a panel of microorganisms including yeast like fungi, bacteria, and algae, and their minimal inhibitory concentration and minimal fungicidal, bactericidal, and algacidal concentrations were determined. Some of the analyzed carbamates exhibited significant in vitro antimicrobial activity.