Synthesis of Coumarin Derivatives from 4-Oxo-4H-1-benzopyran-3-carboxaldehyde via 3-(Arylaminomethylene)chroman-2,4-dione

3-(Bromoacetyl)coumarins: unraveling their synthesis, chemistry, and applications

This review emphasizes recent developments in synthetic routes of 3-(bromoacetyl)coumarin derivatives. Also, chemical reactions of 3-(bromoacetyl)coumarins as versatile building blocks in the preparation of critical polyfunctionalized heterocyclic systems and other industrially significant scaffolds are described. Recent advances of 3-(bromoacetyl)coumarins as attractive starting points towards a wide scale of five and six-membered heterocyclic systems such as thiophenes, imidazoles, pyrazoles, thiazoles, triazoles, pyrans, pyridines, thiadiazins as well as fused heterocyclic systems have been reported. Additionally, this review covers a wide range of analytical chemistry, fluorescent sensors, and biological applications of these moieties, covering the literature till May 2021.

Reactivity of [1]Benzopyrano[4,3-c][1,5]Benzodiazepin-7(8H)-Ones Towards Some N-Binucleophiles

The behaviour of [1]benzopyrano[4,3- c][1,5]benzodiazepin-7(8 H)-ones 1a–c towards some N-binucleophiles have been studied. With non-aromatic hydrazines the reaction carried out in acidic medium led exclusively to the unexpected [1]benzopyrano[4,3- c]pyrazol-4-ones 4 and 5. Compounds 1 reacted under less drastic conditions with variously substituted amidines and guanidines to give 5 H-[1]benzopyrano[4,3- d]pyrimidin-5-ones (10a–d). A general mechanism is proposed to explain the formation of the obtained heterocycles.

One-Pot Synthesis of 2-Alkyl/Arylamino-4-oxo-4H-1-Benzopyran-3-Carboxaldehyde from 4-oxo-4H-1-Benzopyran-3-Carboxaldehyde

Zn/NH4Cl–mediated reactions of aldehyde 1 with nitro compounds 2 afford 2-( N-alkyl/arylamino)-3-formylchromones 4, which on heating with 70% H2SO4 produces 9a-d and 11e-h from 4a-d and 4e-h, respectively.

A one-pot three-component reaction involving 2-aminochromone in aqueous micellar medium: a green synthesis of hexahydrochromeno[2,3-b]quinolinedione

An efficient and green synthesis of hitherto unreported 11-(chromen-3-yl)-8,8-dimethyl-8,9-dihydro-6H-chromeno[2,3-b]quinoline-10,12(7H,11H)-dione has been accomplished by a three-component reaction involving 2-aminochromone, chromone-3-carbaldehyde, and 5,5-dimethyl-1,3-cyclohexanedione (dimedone) in 0.5 M aqueous SDS solution. The mechanism of the reaction has been studied by isolating the reaction intermediate. This methodology features eco-friendly reaction conditions, a simple working procedure, high atom-economy and high efficiency in product formation.

One-pot synthesis of chromenylfurandicarboxylates and cyclopenta[b]chromenedicarboxylates involving zwitterionic intermediates. A DFT investigation on the regioselectivity of the reaction

The reaction of 1:1 zwitterionic intermediates generated in situ from either tert-butylisocyanide or cyclohexylisocyanide and acetylenedicarboxylates with 3-formylchromones is described, whereupon either chromenylfurandicarboxylates or cyclopenta[b]chromenedicarboxylates are formed, depending on the nature of the chromone 6-position substituent and also on the acetylene ester group. In addition, from the reaction with a 1:2 zwitterionic intermediate, cyclohepta[b]chromenetetracarboxylates are isolated. The regioselectivity of the reaction was also investigated by DFT calculations. The geometries of the reactants, intermediate zwitterions, transition structures, and intermediate products, leading to the final products, were optimized using the B3LYP functional with the 6-31G(d) basis set. The structures of the products were elucidated by 1D and 2D NMR experiments. Full assignment of all (1)H and (13)C NMR chemical shifts has been achieved. Plausible mechanistic schemes are provided.

Antibacterial, antifungal and cytotoxic properties of novel N-substituted sulfonamides from 4-hydroxycoumarin

A new series of 4-({[2, 4-dioxo-2H-chromen-3 (4H)-ylidene] methyl} amino) sulfonamides have been obtained by the condensation reaction of 4-hydroxycoumarin with various sulfonamides (sulfanilamide, sulfaguanidine, p-aminomethyl-sufanilamide, p-aminoethylsufanilamide, sulfathiazole, sulfamethoxazole, sulfamethazine and 4-[(2-amino-4-pyrimidinyl) amino] benzenesulfonamide) in the presence of an excess of ethylorthoformate. These compounds were screened for their in-vitro antibacterial activity against four Gram-negative (E. coli, S. flexneri, P. aeruginosa and S. typhi) and two Gram-positive (B. subtilis and S. aureus) bacterial strains and for in-vitro antifungal activity against T. longifusus, C. albicans, A. flavus, M. canis, F. solani and C. glaberata. Results revealed that a significant antibacterial activity was observed by compounds (4) and (5), (6) and (8) against two Gram-negative, (P. aeruginosa and S. typhi) and two Gram-positive (B. subtilis and S. aureus) species, respectively. Of these (4) was found to be the most active. Similarly, for antifungal activity compounds (3) and (8) showed significant activity against M. canis and, (6) and (8) against F. solani. The brine shrimp bioassay was also carried out to study their in-vitro cytotoxic properties and only two compounds, (4) and (8) possessing LD50 = 2.9072 x 10(-4) and 3.2844 x 10(-4) M, respectively, displayed potent cytotoxic activity against Artemia salina

Synthesis of coumarin derivatives with cytotoxic, antibacterial and antifungal activity

The synthesis and selective biological screening of 7-hydroxy-4-methyl-2H-chromen-2-one (2), 7-hydroxy-4,5-dimethyl-2H-chromen-2-one (15) and some of their derivatives were carried out. Compound 13 was found to be most potent cytotoxic agent with LD50 = 126.69 microg/ml. In antibacterial assay the compounds showed a broad spectrum of activities. Compound 11 exhibited a very high degree of plant growth inhibition at three levels of concentration. Compound 4 showed very promising antifungal activity against Candida albicans. Compounds 12 and 13 demonstrated excellent antioxidant activity.

Synthesis, antifungal, and phytotoxic effects of some benzopyrone derivatives

Syntheses of benzopyrones 1, 13, and their derivatives, as well as their phytotoxic (in vitro) and antifungal (in vitro) screening was carried out. Compounds 2, 7, 8, and 10 showed significant phytotoxic activity, whereas 3, 8, 10, and 12 exhibited significant antifungal (in vitro) activity.