Synthesis, antibacterial activities, and theoretical studies of dicoumarols

Abstract

Four dicoumarols (DC, 2-PyDC, 3-PyDC and 4-PyDC) were synthesized and characterized via IR, (1)H NMR, HRMS, and single crystal X-ray crystallography. Two classical intramolecular O-H···O hydrogen bonds (HBs) stabilized their structures. The total HB energies in DC, 2-PyDC, 3-PyDC and 4-PyDC were calculated with the density functional theory (DFT) [B3LYP/6-31G*] method. The in vitro antibacterial activity of DC, 2-PyDC, 3-PyDC and 4-PyDC against Staphylococcus aureus (S. aureus ATCC 29213), methicillin-resistant S. aureus (MRSA XJ 75302), vancomycin-intermediate S. aureus (Mu50 ATCC 700699), and USA 300 (Los Angeles County clone, LAC) was evaluated by observing the minimum inhibitory concentration and time-kill curves. The results showed that among all the compounds, 2-PyDC exhibited the most potent antibacterial activity.

Crystal structure of 2-amino-5-oxo-4-(3,5-bis(trifluoromethyl)phenyl)-4H,5H-pyrano [3,2-c]chromene-3-carbonitrile, C21H10F6N2O3

“…Pyrans possess diverse pharmacological and biological activities such as antitumor, analgesic and ulcerogenic, anti-in ammatory, anticoagulant, phototriggering, and fungicidal properties, and can act as anticoagulants in the production of pesticides [2,3]. In particular, the antitumor activity of pyran compounds has received considerable attention among researchers because of their cytotoxic activity against numerous types of cancers, including malignant melanoma, leukemia, renal cell carcinoma, prostate and breast cancer cell progression [4,5].…”

Going Round in Circles with N→S Acyl Transfer

“…60 An increasing number of researchers are employing the acyl hydrazide as a thioester precursor because of its stability, relative ease of synthesis and greater flexibility in terms of synthetic strategy and tactics. 23,61 Once formed, 4 can be converted to a thioester via diazotisation and thiolysis of an acyl azide intermediate (5). Indeed, the thioester need not be isolated at all and the diazotisation and subsequent NCL can be conducted in one pot, minimising the opportunity for thioester hydrolysis.…”

“…Initially this was based around finding efficient methods for the synthesis of the required thioester and cysteinyl components 14,17,18,19 but as the methodology developed the emphasis shifted towards performing multiple ligation reactions sequentially in one pot, and minimising handling steps. 20 These streamlining processes typically comprise one pot kinetically controlled ligations, 21,22 combined with in-situ removal of protecting groups 22,23 and desulfurisation. 24 The desire to conduct in-situ desulfurisation was prompted by the rapid growth, and effective use, of mercapto amino acid derivatives capable of performing NCLreactions, 25 yet are reverted to non-cysteinyl amino acids upon reduction under mild conditions (Scheme 2a).…”

Fe3O4@SiO2@Im‐bisethylFc [HC2O4] as a novel recyclable heterogeneous nanocatalyst for synthesis of bis‐coumarin derivatives

“…These derivatives have been found useful in an extensive range of biological and pharmaceutical actions, including enzyme inhibitors, anticoagulants, antioxidants, antitumor drugs, anti‐diabetic (α‐glucosidase inhibitors) urease inhibitors, anticancers, antibacterials, inhibit c‐Met phosphorylation in BaF 3 /TPR‐Met and EBC‐1 NSCLC cell lines, antimicrobial, antiviral, proliferation inhibition of K‐562 and inhibit HIV‐1 . Recently, several methods have been reported for the synthesis of bis‐coumarin by the reaction of 4‐hydroxycoumarin and various aldehydes in the presence of various homogeneous and heterogeneous catalysts and under various reaction conditions, such as tetrabutylammonium bromide (TBAB), molecular iodine, [bmin] BF 4 , SO 3 H‐functionalized IL, sodium dodecyl sulfate, piperidine, n‐dodecylbenzene sulfonic acid (DBSA), [pyridin‐SO 3 H]Cl, TrBr and [Fe 3 O 4 @SiO 2 @(CH 2 ) 3 ‐Im‐SO 3 H]Cl, MNPs‐PSA and Fe 3 O 4 @SiO 2 @(CH 2 ) 3 semicarbazide‐SO 3 H/HCl . Although all the procedures for the synthesis of corresponding bis‐coumarin have their merits, the main disadvantages of these methods are often tedious work‐up procedures, low yields, harsh reaction conditions, and the use of toxic, corrosive and expensive catalysts, and the recovery of these catalysts are often difficult.…”