Photophysical, photostability, and ROS generation properties of new trifluoromethylated quinoline-phenol Schiff bases

A new series of ten examples of Schiff bases, namely (E)-2-(((2-alkyl(aryl/heteroaryl)-4-(trifluoromethyl)quinolin-6-yl)imino)methyl)phenols 3, was easily synthesized with yields of up to 91% from the reactions involving a series of 2-(R-substituted) 6-amino-4-(trifluoromethyl)quinolines 1 and 4(5)-R¹-substituted salicylaldehydes 2 - in which alkyl/aryl/heteroaryl for 2-R-substituents are Me, Ph, 4-MeC₆H₄, 4-FC₆H₄, 4-NO₂C₆H₄, and 2-furyl, and R¹-substituents are 5-NEt₂, 5-OCH₃, 4-Br, and 4-NO₂. Complementarily, the Schiff bases showed low to good quantum fluorescence yield values in CHCl₃ (Φ_f = 0.12-0.80), DMSO (Φ_f = 0.20-0.75) and MeOH (Φ_f = 0.13-0.85). Higher values of Stokes shifts (SS) were observed in more polar solvents (DMSO; 65-150 nm and MeOH; 65-130 nm) than in CHCl₃ (59-85 nm). Compounds 3 presented good stability under white-LED irradiation conditions and moderate ROS generation properties were observed.

Novel Alkyl(aryl)-Substituted 2,2-Difluoro-6-(trichloromethyl)-2H-1,3,2-oxazaborinin-3-ium-2-uides: Synthesis, Antimicrobial Activity, and CT-DNA Binding Evaluations

The synthesis, antimicrobial activity evaluations, biomolecule-binding properties (DNA), and absorption and emission properties of a new series of (Z)-1,1,1-trichloro-4-alkyl(aryl)amino-4-arylbut-3-en-2-ones (4, 5) and 2,2-difluoro-3-alkyl(aryl)amino-4-aryl-6-(trichloromethyl)-2H-1,3,2-oxazaborinin-3-ium-2-uides (6, 7) in which 3(4)-alkyl(aryl) = H, Me, iso-propyl, n-butyl, C6H5, 4-CH3C6H4, 4-CH3OC6H4, 4-NO2C6H4, 4-FC6H4, 4-BrC6H4, 2-naphthyl, is reported. A series of β-enaminoketones (4, 5) is synthesized from the O,N-exchange reaction of some amines (3) with (Z)-1,1,1-trichloro-4-methoxy-4-aryl-but-3-en-2-ones (1, 2) at 61-90% yields. Subsequently, reactions of the resulting β-enaminoketones with an appropriate source of boron (BF3.OEt2) gave the corresponding oxazaborinine derivatives (6, 7) at 50-91% yields. UV-Vis and emission properties of biomolecule-binding properties for the DNA of these new BF2-β-enamino containing CCl3 units were also evaluated. Some compounds from the present series also exhibited potent antimicrobial effects on various pathogenic microorganisms at concentrations below those that showed cytotoxic effects. Compounds 4d, 4e, 6e, and 6f showed the best results and are very significant against P. zopfii, which causes diseases in humans and animals.

New 2-(aryl/heteroaryl)-6-(morpholin-4-yl/pyrrolidin-1-yl)-(4-trifluoromethyl)quinolines: synthesis via Buchwald–Hartwig amination, photophysics, and biomolecular binding properties

New 6-(morpholino/pyrrolidino)quinolines displaying interesting photophysical and biomolecular binding properties achieved by Buchwald–Hartwig amination.

Synthesis of novel trifluoromethyl-substituted spiro-[chromeno[4,3-d]pyrimidine-5,1'-cycloalkanes], and evaluation of their analgesic effects in a mouse pain model

Herein we report the synthesis of twelve 2,5-substituted 4-(trifluoromethyl)-spirochromeno[4,3-d]pyrimidines (7-10), as well as an evaluation of their analgesic effect in a mouse pain model. The nine new chromeno[4,3-d]pyrimidines (7-9) were synthesized from the cyclocondensation reactions of three 2,2,2-trifluoro-1-(4-methoxyspiro[chromene-2,1'-cycloalkane]-3-yl)ethanones (3) containing 5-, 6- and 7-membered spirocycloalkanes, with some well-known amidine salts (4-6) [NH₂CR(NH)]-in which R=Me, Ph, and NH₂-at yields of 60-95%. Subsequently, three new 2-(pyrrol-1-yl)-4-(trifluoromethyl)-chromeno[4,3-d]pyrimidines (10) were obtained through a Clauson-Kaas reaction between the respective 2-(amino)-4-(trifluoromethyl)-chromeno[4,3-d]pyrimidines (9) and 2,5-dimethoxy-tetrahydrofuran. The analgesic evaluation showed that these 4-(trifluoromethyl)chromeno[4,3-d]pyrimidines (100mg/kg, p.o.) and Ketoprofen (100mg/kg, p.o.) significantly reduced capsaicin-induced spontaneous nociception. Moreover, the 2-pyrrolyl-spirocyclohexane derivative 10b (100 and 300mg/kg, p.o.) had an anti-allodynic effect comparable to Ketoprofen (100 and 300mg/kg, p.o.) in the arthritic pain model, without causing locomotor alterations in the mice. These results suggest that the compound 10b is a promising molecule for new analgesic drugs in the treatment of pathological pain, such as in arthritis.

Synthesis of tetra-substituted 5-trifluoromethylpyrazoles via sequential halogenation/palladium-catalyzed C–C and C–N cross-coupling

The assembly of tetra-substituted 5-trifluoromethylpyrazoles is presented, involving palladium-catalyzed Negishi or Buchwald–Hartwig cross-couplings to install carbon or nitrogen-based 4-substituents.

Effect of age and magnesium administration on the performance of SHR in the elevated plus-maze

It is currently accepted that young spontaneously hypertensive rats (SHR) have lower pressure levels than adult SHR in which the hypertension is well established, reaching the highest plateau at about 24 weeks, and that treatment with magnesium initiated during intrauterine life postpones the onset of cardiovascular alterations in SHR to about 90 days. These animals also show many behavioral alterations. The anxiety of SHR was measured in the elevated plus-maze, considering the age of the animals and previous ingestion of food supplemented with 1% magnesium oxide. Both young (1.5-2 months) and adult (5-6 months) SHR showed higher mean ( +/- SEM) percent of entries (48 +/- 3 and 51 +/- 3, respectively) and a longer mean ( +/- SEM) percent of time spent (43 +/- 5 and 55 +/- 5, respectively) in the open arms when compared to the mean ( +/- SEM) percent of entries and time spent in the open arms of young (35 +/- 3 and 20 +/- 4, respectively) and adult (36 +/- 7 and 17 +/- 5, respectively) normotensive Wistar rats. Treatment with magnesium oxide did not alter the performance of SHR in the elevated plus-maze. SHR showed an anxiolytic-like behavior which was neither influenced by age nor by antihypertensive treatment.

Effects of the antihypertensive drugs alpha-methyldopa and hydralazine on the performance of spontaneously hypertensive rats in the elevated plus-maze

The effects of antihypertensive drugs on the performance of spontaneously hypertensive rats (SHR) in the elevated plus-maze were determined. Male SHR (3 months old) were submitted to long-term treatment (15 days) with alpha-methyldopa (alpha MD, 5 g/l, N = 10) and hydralazine (HYD, 100 mg/l, N = 10) given orally, diluted in water. After the drug treatment, the performance of the rats in the plus-maze was observed for 5 min in a single test and mean arterial pressure (MAP) and heart rate (HR) were then measured. The antihypertensive drugs reduced MAP significantly (mean +/- SEM: CON = 176.2 +/- 5.2, alpha MD = 157.8 +/- 4.6 and HYD = 150 +/- 4.4 mmHg) and only alpha MD increased HR significantly (mean +/- SEM: CON = 391.7 +/- 13.8, alpha MD = 453.3 +/- 14 and HYD = 368.8 +/- 18.9 bpm). The alpha MD group presented a lower total number of entries (mean +/- SEM: CON = 12.7 +/- 0.7, alpha MD = 8.7 +/- 0.9 and HYD = 12 +/- 0.9) and spent less time in the open arms than the CON (N = 10) and HYD groups (mean +/- SEM: CON = 0.69 +/- 0.04, alpha MD = 0.48 +/- 0.07 and HYD = 0.65 +/- 0.06 s). alpha-Methyldopa acts centrally and hydralazine acts peripherally. The behavioral change of SHR treated with alpha-methyldopa suggests that hypertension seems to be related to central nervous dysfunctions that are affected by an antihypertensive drug with central noradrenergic action.