2-(2-Br-phenyl)-8-methoxy-benzoxazinone (HPW-RX2), a direct thrombin inhibitor with a suppressive effect on thromboxane formation in platelets

Design, synthesis, and in vitro evaluation of 4-aminoalkyl-1(2H)-phthalazinones as potential multifunctional anti-Alzheimer's disease agents

A series of 4-aminoalkyl-1(2H)-phthalazinone derivatives was designed and synthesized as potential multifunctional agents for Alzheimer's disease (AD) treatment. In vitro biological assay results demonstrated that most synthesized compounds exhibited significant AChE inhibition, moderate to high MAOs inhibitory potencies and good anti-platelet aggregation abilities. Among them, compound 15b exhibited the highest inhibitory potencies towards MAO-B and MAO-A (IC₅₀ = 0.7 µM and 6.4 µM respectively), moderate inhibition towards AChE (IC₅₀ = 8.2 µM), and good activities against self- and Cu²⁺-induced Aβ_1-42 aggregation and platelet aggregation. Moreover, 15b also displayed antioxidant capacity, neuroprotective potency, anti-neuroinflammation and BBB permeability. These excellent results indicated that compound 15b could be worthy of further studies to be considered as a promising multifunctional candidate for the treatment of AD.

NIS-mediated intramolecular oxidative α-functionalization of tertiary amines: transition metal-free synthesis of 1,2-dihydro-(4H)-3,1-benzoxazin-4-one derivatives

A novel method for direct α-functionalization of tertiary amines via NIS-mediated oxidative C–O bond formation, where NIS serves as both an oxidant and an iodination reagent, has been developed.

Antiplatelet Aggregation Effects of Phenanthrenes from Calanthe arisanensis

Three phenanthrenes (1–3), four indole alkaloids (4–7) and one steroid (8) were isolated from the leaves of Calanthe arisanensis for the first time. In the antiplatelet aggregation assay, phenanthrenes 1 and 2 showed potential antiplatelet activity. We have reported and discussed here the antiplatelet aggregation properties of the eleven naturally-occurring phenanthrenes (1–2 and 9–17) isolated from the underground part of the plant and eighteen chemically synthesized phenanthrenes (18–35). Overall, our data demonstrated that 1,4-phenanthrenequinones 20, 21 and 22 (collagen, IC50 0.2, 0.2, 0.1 μg/mL; thrombin, IC50 0.8, 1.0, 1.1 μg/mL, respectively) could be promising lead candidates for further cardiovascular disease studies.

Antiplatelet, Antithrombotic, and Fibrinolytic Activities of Campomanesia xanthocarpa

In a previous work based on popular belief, Campomanesia xanthocarpa Berg., popularly known as “guavirova”, showed to have a potential effect in the control of a number of conditions associated with cardiovascular diseases. The aim of the present work was to investigate the effects of C. xanthocarpa extract (CXE) on antiplatelet, antithrombotic and fibrinolytic activities in mice and in human blood. Mice were treated orally for 5 days with CXE or acetylsalicylic acid and at the end of the treatment period animals were challenged for bleeding, acute thromboembolism and ulcerogenic activity. In addition, we have assessed the prothrombin time and activated partial thromboplastin time (aPTT) after oral administration. In in vitro assays, antiplatelet effects of CXE was evaluated on platelet aggregation, and fibrinolytic activity of the extract was observed by mice or human artificial blood clot degradation. Platelet citotoxicity of the extract was also determined by the LDH assay. Results demonstrated that CXE has a significant protective effect on thrombosis. It also inhibits platelet aggregation without demonstrating cytotoxicity on platelets. CXE slightly prolonged aPTT and showed no ulcerogenic activity after oral administration. In addition, CXE showed a fibrinolytic activity. Thus, C. xanthocarpa showed antiplatelet, antithrombotic and fibrinolytic activities in mice.

Traceless solid-phase synthesis of heteroannulated 1,3-oxazin-6-ones

A microwave-assisted solid-phase synthesis of heteroannulated 1,3-oxazin-6-ones has been developed. Significant rate enhancement was observed for all steps carried out under microwave irradiation, and the overall reaction time was dramatically shortened when compared to the conventional procedures. A representative set of 20 bi- and tricyclic heteroannulated 1,3-oxazin-6-ones was prepared. Key steps in the synthesis are (i) five-member heterocycle formation, (ii) acylation of amine, and (iii) ring closure to give the heteroannulated 1,3-oxazin-6-one.

Silica-bound benzoyl chloride mediated the solid-phase synthesis of 4H-3,1-benzoxazin-4-ones

The solid-phase synthesis of 4H-3,1-benzoxazin-4-ones was achieved using silica-bound benzoyl chloride (SBBC) as dehydrating agent in reaction with 2-acylaminobenzoic acids. The silica-grafted reagent (SBBC) was simply recovered after reaction and reused several times.

Uses of Piperonal in the Synthesis of Novel Prop-2-Enoyl Amides, Esters, Heterocyclic Systems and Study of their Antibacterial Activities

Novel ( E)-3-(benzo[d][1,3]dioxol-5-yl)-2-cyanoacryloyl chloride 4 was condensed with several mono-; 1,2-; 1,3- and 1,4-bi-nucleophilic reagents containing nitrogen and oxygen to give new 2-propenoylamide and ester derivatives. Some of these amides cyclised under the reaction conditions and/or with POCl3 to give new derivatives of heterocyclic systems. Antibacterial activities were tested for nine of these products.

Synthesis and pharmacological evaluation of novel beta-nitrostyrene derivatives as tyrosine kinase inhibitors with potent antiplatelet activity

Protein tyrosine kinases have been known to be involved in regulation of platelet aggregation, suggesting a potential target for antiplatelet therapy. Our previous study showed that 3,4-methylenedioxy-beta-nitrostyrene (MNS) prevented platelet aggregation caused by various stimulators, and this action was accompanied by inhibition of tyrosine kinases. In the present study, in order to examine the structural determinants required for the actions of MNS and to develop more potent tyrosine kinase inhibitors and antiplatelet agents, a new series of beta-nitrostyrene derivatives were synthesized and pharmacologically characterized. The beta-nitrostyrene derivatives inhibited thrombin- or collagen-induced human platelet aggregation, ATP secretion, GPIIb/IIIa activation and protein tyrosine phosphorylation. In recombinant enzyme assay, some beta-nitrostyrene derivatives also demonstrated potent inhibition of Src and/or Syk kinase activity. Furthermore, there was a good correlation between the inhibitory potency of these compounds on tyrosine kinases and on platelet activation/aggregation. Among them, a benzoyl ester derivative (compound 10) possess up to 8-fold greater potency than MNS and over two orders of magnitude greater potency than genistein or tyrphostin A47 in inhibiting platelet responses to thrombin. Our data suggest that beta-nitrostyrenes may represent a new class of tyrosine kinase inhibitors with potent antiplatelet activity.

The evaluation and structure–activity relationships of 2-benzoylaminobenzoic esters and their analogues as anti-inflammatory and anti-platelet aggregation agents

Forty-seven 2-benzoylaminobenzoic esters were synthesized and evaluated in anti-platelet aggregation, inhibition of superoxide anion generation, and inhibition of neutrophil elastase release assays. Most 2-benzoylamino-4-chlorobenzoic acid derivatives showed selective inhibitory effects on arachidonic acid (AA)-induced platelet aggregation. Among them, compounds 6b and 7b exhibited more potent inhibitory effects (ca. 200-fold) than aspirin. Additionally, compounds 1a and 5a showed strong inhibitory effects on neutrophil superoxide generation with IC(50) values of 0.65 and 0.17 microM, respectively. However, compounds 6d and 6e exhibited dual inhibitory effects on platelet aggregation and neutrophil elastase (NE) release; therefore, these two compounds may be new leads for development as anti-inflammatory and anti-platelet aggregatory agents.

CO2 Incorporation Reaction Using Arynes: Straightforward Access to Benzoxazinone

A zwitterion, generated from an aryne and an imine, has been demonstrated to serve as an excellent molecular scaffold for capturing CO2, which results in the straightforward formation of diverse benzoxazinones.