Pyran derivatives. XX. 2-Aminochromone benzo-fused derivatives with antiproliferative properties

Synthesis of linear and angular aryl-morpholino-naphth-oxazines, their DNA-PK, PI3K, PDE3A and antiplatelet activity

To continue our study of 2-morpholino-benzoxazine based compounds, which show useful activity against PI3K family enzymes or antiplatelet activity, we designed and synthesized a series of linear 6.7-fused, 5,6-angular fused and 7,8-angular fused-aryl-morpholino-naphth-oxazines. The compounds were prepared from substituted 2-hydroxynaphthoic acid to give the corresponding thioxo analogues 8, 9, 15 and 19. The thioxo products were then converted to the morpholino substituted analogue. The aryl group was introduced by Suzuki coupling of bromo precursors. The products were evaluated for activity at PI3K family enzymes and as platelet aggregation inhibitors and compared to reported unsubstituted analogues. The linear 6.7-fused product 13a and 13b were moderated potent but selective PI3Kδ isoform inhibitors (IC₅₀=7.7 and 5.61μM). Good antiplatelet activity was noticed for the angular 7,8-fused compounds 22a, b, k and l with IC₅₀=3.0,14.0, 2.0 and 5.0μM respectively. The antiplatelet activity is independent of PDE3.

Synthesis of 3-Substituted 2-Aminochromones via Sn(IV)-Promoted Annulation of Ynamides with 2-Methoxyaroyl Chlorides

A Sn(IV)-promoted annulation reaction of ynamides is described for the efficient synthesis of 3-substituted 2-aminochromones under mild conditions. This novel method allows for a concomitant construction of C-C and C-O bonds between ynamides and 2-methoxyaroyl chlorides by a tandem Friedel-Crafts acylation/oxo-Michael addition/elimination strategy.

Synthesis of Tetracyclic 8-Aza-Naphthalen-9-Ones and Oxa-Naphthalen-9-One

Bromination of 1-methylbenzo[f]chromen-3-one with N-bromosuccinimide gives 2-bromo-1-methylbenzo[f]chromen-3-one which, on condensation with different primary aromatic amines, gives tetracyclic aza-naphthalen-9-ones. Condensation of 2-bromo-1-methylbenzo[f]chromen-3-one with different secondary cyclic amines also gives tetracyclic oxa-naphthalen-9-one. The formation of 8-aza-naphthalen-9-one and 7,8-dioxa-naphthalen-9-one is confirmed by their single crystal analyses.

Pyran derivatives

The N-substituted tricyclic 2-aminochromone derivatives 1a, 2a, and 2b were obtained by treating the corresponding (methylthio) or (methylsulfinyl) derivatives 10, 11, or 12, respectively, with an excess of the proper amines. Compound 2c was synthesized through the reaction of 2-naphthol with the ethyl N,N-diphenylmalonamate/POCl(3) reagent 14. The N-substituted 4-aminocoumarin bicyclic and tricyclic derivatives 5-8 were prepared by treating the corresponding chloro derivatives with the excess suitable amines. Compounds 1, 2, 5-8 were tested in vitro for their antiproliferative activity (DNA synthesis inhibition in Ehrlich cells) and cytotoxicity (MTT test in HeLa cells). The inhibitory properties of three selected compounds (5c, 5e, 7c) on protein and RNA syntheses in Ehrlich cells were also evaluated. Among the 27 compounds tested, 10 4-aminocoumarin derivatives (5-8) and two 2-aminochromone derivatives (1a and 2a) showed an appreciable antiproliferative activity (IC(50) range: 1.74-13.8 microM), whereas only four compounds 5-8 exhibited a comparable cytotoxic activity (IC(50) range: 4.95-12.9 microM).

Coumarin, chromone, and 4(3H)-pyrimidinone novel bicyclic and tricyclic derivatives as antiplatelet agents: synthesis, biological evaluation, and comparative molecular field analysis

As a further part of our chemical and biological studies in this field, we describe the multistep preparations of the properly substituted 2-(1-piperazinyl)chromone 1b, 4-(1-piperazinyl)coumarins 5c-h, their linear benzo-fused analogues 4a,b and 8a,b, bicyclic (15e-g) and tricyclic (15h,i) fused derivatives of 6-(1-piperazinyl)pyrimidin-4(3H)-one, and of the 4H-pyrido[1,2-a]pyrimidine derivatives 9b,c. The in vitro evaluation of their inhibitory properties towards human platelet aggregation induced in platelet-rich plasma by ADP, collagen, or the Ca (2+)ionophore A23187 showed the high activity of compounds 5d-g and 15f,g,i, among which the coumarins 5g and 5d proved to be, in that order, the most effective in vitro antiplatelet agents until now synthesized by us. Thus, in order to consider also the 4-aminocoumarin structural class, we developed a new statistically significant 3-D QSAR model, more general than the one previously obtained, through a further CoMFA study based on the antiplatelet activity data and molecular steric and electrostatic potentials of both the previously studied and herein described compounds.

7-Hydroxy-2-substituted-4-H-1-benzopyran-4-one derivatives as aldose reductase inhibitors: a SAR study

On the basis of the results of molecular modelling studies performed on the aldose reductase (ALR2) inhibitor 7-hydroxy-2-(4'-hydroxybenzyl)-4H-1-benzopyran-4-one (compound A) bound at the active site of the enzyme, we synthesised and tested on bovine and human ALR2 several derivatives modified at position 2 of the benzopyran moiety, in order to confirm the hypothesised binding mode of this compound. The substitution of the methylene bridge with the isosteric sulphur substituent gives an active derivative, while substitution with a polar NH causes a decrease in inhibitory activity; this is in accordance to the previously reported structure in which the methylene linker was found to be adjacent to a hydrophobic aminoacid (Leu300). Among the substituents at 4' position examined, the most favourable for inhibitory activity are those able to act as hydrogen bond donors, supporting the hypothesis of the importance of the interaction with Thr113 for the inhibition of the enzyme.