Mode of action of 2-(diethylamino)-7-ethoxychromone on human platelets

One-pot five-component synthesis of spirocyclopenta[b]chromene derivatives and their acid-catalyzed rearrangement

The reaction of the zwitterionic intermediate, generated in situ from either tert-butylisocyanide or cyclohexylisocyanide and acetylenedicarboxylates, with 3-cyanochromones is described, whereupon spirochromenofuran derivatives 5 or 6 were obtained in good yields. The subsequent acid-catalyzed rearrangement of the isolated 2-imino-spirochromenofurans 5 to 2-amino-spirochromenofurans 7 has also been studied. Rational mechanistic schemes for the formation of compounds 5, 6, and 7 are proposed. The structure elucidation of the products was accomplished by 1D and 2D NMR experiments and confirmed by X-ray crystallographic analysis. Full assignment of all (1)H and (13)C NMR chemical shifts has been unambiguously achieved with the aid of DFT/GIAO calculations.

Pseudo-five-component reaction between 3-formylchromones, meldrum's acid, isocyanides and primary arylamines: diversity-oriented synthesis of novel chromone-containing peptidomimetics

An efficient and practical method has been developed for the diversity-oriented synthesis of chromone-containing tripeptides via pseudo-five-component reaction between 3-formylchromones, Meldrum's acid, isocyanides and primary aromatic amines for the generation of a wide range of structurally interesting and pharmacologically significant compounds at ambient temperature. It is worth mentioning that in the course of this reaction, five new bonds (two C-C bonds, two C-N bonds and one C═O bond) are formed. In the present reaction three amide bonds are newly formed.

Synthesis, identification and antiplatelet evaluation of 2-morpholino substituted benzoxazines

A number of 2-morpholino substituted benzoxazines have been prepared in order to test their effectiveness against ADP and collagen induced platelet aggregation. The reaction of 2-thio-1,3-benzoxazines with morpholine has been generalised to enable the use of substituted benzoxazines. Two separate methods were used to prepare 7-O-2-morpholino substituted benzoxazines from 7-hydroxy-2-morpholino benzoxazines. Antiplatelet testing was carried out on 15 of the title compounds. 7-(2-Chloroethoxy)-8-methyl-2-morpholin-4-yl-4H-1,3-benzoxazin-4-one 15d and 7-[2-(4-methylpiperazin-1-yl)ethoxy]-8-methyl-2-morpholin-4-yl-4H-1,3-benzoxazin-4-one 16d showed potent activity against ADP and collagen induced platelet aggregation. The structures of the newly prepared compounds were confirmed by microanalysis as well as the analysis of IR, (1)H and (13)C NMR.

Synthesis, antiplatelet activity and comparative molecular field analysis of substituted 2-amino-4H-pyrido[1,2-a]pyrimidin-4-ones, their congeners and isosteric analogues

2-(1-Piperazinyl)-4H-pyrido[1,2-a]pyrimidin-4-one (5a) is a recently described in vitro inhibitor of human platelet aggregation which specifically inhibits the activity of high affinity cAMP phosphodiesterase. A number of substitution derivatives, isosteres, and analogues of 5a were now synthesized and tested in vitro for their inhibitory activity on human platelet aggregation induced in platelet-rich plasma by ADP, collagen, or the Ca2+ ionophore A23187. Among the most effective compounds, the 6-methyl, 8-methyl and 6,8-dimethyl derivatives of 5a resulted nearly as active as the lead when platelet aggregation was induced by ADP or A23187, but less active when collagen was the inducer. On the basis of present results and those previously obtained by us in this and 2-aminochromone structural fields, we have developed a statistically significant 3-D QSAR model, using comparative molecular field analysis (CoMFA), describing the variation of the antiplatelet activity in terms of molecular steric and electrostatic potential changes.

N,N-dialkylaminosubstituted chromones and isoxazoles as potential anti-inflammatory agents

The ability of some N,N-dialkylaminosubstituted chromones and isoxazoles to inhibit the protein kinase C (PKC) dependent signal transduction pathway was tested. As a cellular model, human neutrophils stimulated with either phorbol myristate acetate (PMA) or formylmethionine-leucine-phenylalanine (f-MLF) were used. The efficiency of the compounds was established by their capacity to reduce the O2- production by activated human neutrophils. Compounds carrying a 3-bis(2-methoxyethyl)amino group, a substituent found active in previously tested tricyclic compounds, do not show significant anti-PKC activity in this study. On the other hand, substitution with a 1-piperidinyl group leads all tested compounds to a high biological activity against stimulated neutrophils.