Unsymmetrically disubstituted urea derivatives: a potent class of antiglycating agents

Novel acyl hydrazide derivatives of polyhydroquinoline as potent anti-diabetic and anti-glycating agents: Synthesis, in vitro α-amylase, α-glucosidase inhibition and anti-glycating activity with molecular docking insights

In this study, eleven novel acyl hydrazides derivative of polyhydroquinoline were synthesized, characterized and screened for their in vitro anti-diabetic and anti-glycating activities. Seven compounds 2a, 2d, 2i, 2 h, 2j, 2f, and 2 g exhibited notable α-amylase inhibitory activity having IC50 values from 3.51 ± 2.13 to 11.92 ± 2.30 µM. Similarly, six compounds 2d, 2f, 2 h, 2i, 2j, and 2 g displayed potent α-glucosidase inhibitory activity compared to the standard acarbose. Moreover, eight derivatives 2d, 2 g, 2f, 2j, 2a, 2i, 2 g, and 2e showed excellent anti-glycating activity with IC50 values from 6.91 ± 2.66 to 15.80 ± 1.87 µM when compared them with the standard rutin (IC50 = 22.5 ± 0.90 µM). Molecular docking was carried out to predict the binding modes of all the compounds with α-amylase and α-glucosidase. The docking analysis revealed that most of the compounds established strong interactions with α-amylase and α-glucosidase. All compounds fitted well into the binding pockets of α-amylase and α-glucosidase. Among all compounds 2a and 2f were most potent based on docking score -8.2515 and -7.3949 against α-amylase and α-glucosidase respectively. These results hold promise for the development of novel candidates targeted at controlling postprandial glucose levels in individuals with diabetes.

The Different Facets of Triclocarban: A Review

In the late 1930s and early 1940s, it was discovered that the substitution on aromatic rings of hydrogen atoms with chlorine yielded a novel chemistry of antimicrobials. However, within a few years, many of these compounds and formulations showed adverse effects, including human toxicity, ecotoxicity, and unwanted environmental persistence and bioaccumulation, quickly leading to regulatory bans and phase-outs. Among these, the triclocarban, a polychlorinated aromatic antimicrobial agent, was employed as a major ingredient of toys, clothing, food packaging materials, food industry floors, medical supplies, and especially of personal care products, such as soaps, toothpaste, and shampoo. Triclocarban has been widely used for over 50 years, but only recently some concerns were raised about its endocrine disruptive properties. In September 2016, the U.S. Food and Drug Administration banned its use in over-the-counter hand and body washes because of its toxicity. The withdrawal of triclocarban has prompted the efforts to search for new antimicrobial compounds and several analogues of triclocarban have also been studied. In this review, an examination of different facets of triclocarban and its analogues will be analyzed.

Searching for Small Molecules as Antibacterials: Non-Cytotoxic Diarylureas Analogues of Triclocarban

Triclocarban (TCC), a broad-spectrum lipophilic antimicrobial agent, is a diarylurea derivative that has been used for more than 60 years as a major ingredient of toys, clothing, food packaging materials, food industry floors, medical supplies and especially of personal care products, such as soaps, toothpaste and shampoo. In September 2016, the U.S. FDA banned nineteen antimicrobial ingredients, including TCC, in over-the-counter consumer antiseptic wash products, due to their toxicity. Withdrawal of TCC has prompted efforts to search for new antimicrobial compounds. In this paper, we present the synthesis and biological evaluation, as antibiotic and non-cytotoxic agents, of a series of diarylureas, analogues of TCC. These compounds are characterized by an intriguingly simple chemistry and can be easily synthesized. Among the synthesized compounds, 1ab and 1bc emerge as the most interesting compounds as they show the same activity of TCC (MIC = 16 µg/mL) against Staphylococcus aureus, and a higher activity than TCC against Enterococcus faecalis (MIC = 32 µg/mL versus MIC = 64 µg/mL). Moreover, 1ab and 1bc show no cytotoxicity towards the human mammary epithelial cells MCF-10A and embryonic kidney epithelial cells Hek-293, in opposition to TCC, which exhibits a marked cytotoxicity on the same cell lines and shows a good antitumor activity on a panel of cell lines tested.

New Potential Biologically Active Compounds: Synthesis and Characterization of Urea and Thiourea Derivativpes Bearing 1,2,4-oxadiazole Ring

Background:

Urea, thiourea, and 1,2,4-oxadiazole compounds are of great interest due to their different activities such as anti-inflammatory, antiviral, analgesic, fungicidal, herbicidal, diuretic, antihelminthic and antitumor along with antimicrobial activities.

Objective:

In this work, we provide a new series of potential biologically active compounds containing both 1,2,4-oxadiazole and urea/thiouprea moiety.

Materials and Methods:

Firstly, 5-chloromethyl-3-aryl-1,2,4-oxadiazoles (3a-j) were synthesized from the reaction of different substituted amidoximes (2a-j) and chloroacetyl chloride in the presence of pyridine by conventional and microwave-assisted methods. In the conventional method, 1,2,4-oxadiazoles were obtained in two steps. O-acylamidoximes obtained in the first step at room temperature were heated in toluene for an average of one hour to obtain 1,2,4-oxadiazoles. The yields varied from 70 to 96 %. 1,2,4-oxadiazoles were obtained under microwave irradiation in a single step in a 90-98 % yield at 160 °C in five minutes. 5-aminomethyl-3-aryl-1,2,4- oxadiazoles (5a-j) were obtained by Gabriel amine synthesis in two steps from corresponding 5-chloromethyl-3- aryl-1,2,4-oxadiazoles. Finally, twenty new urea (6a-j) and thiourea (7a-j) compounds bearing oxadiazole ring were synthesized by reacting 5-aminomethyl-3-aryl-1,2,4-oxadiazoles with phenyl isocyanate and isothiocyanate in tetrahydrofuran (THF) at room temperature with average yields (40-70%).

Results and Discussions:

An efficient and rapid method for the synthesis of 1,2,4-oxadiazoles from the reaction of amidoximes and acyl halides without using any coupling reagent under microwave irradiation has been developed, and twenty new urea/thiourea compounds bearing 1,2,4-oxadiazole ring have been synthesized and characterized.

Conclusion:

We have synthesized a new series of urea/thiourea derivatives bearing 1,2,4-oxadiazole ring. Also facile synthesis of 3,5-disubstituted 1,2,4-oxadiazoles from amidoximes and acyl chlorides under microwave irradiation was reported. The compounds were characterized using FTIR, 1H NMR, 13C NMR, and elemental analysis techniques.

Synthesis of new phenolic compounds and biological evaluation as antiproliferative agents

New series of phenolic azomethine compounds in addition to 5-arylidene thiazolidinones are synthesized and screened for their anticancer activity against the brain cancer cell line SNB-75 and non-small lung cancer cells HOP-92. The azomethine derivative 12b is the most active compound against SNB-75 displaying an IC50value of 0.14 μM. Compounds 7b, 16a and 27d display submicromolar activity against the HOP-92 cell line with IC50values of 0.73, 0.74 and 0.81 μM, respectively. Moreover, studying the cytotoxic effects of the most active compounds against normal lung cells WI-38 revealed that compounds 7b, 16a and 27d showed high safety profiles as anticancer agents.

Direct Conversion of Carboxylic Acids to Various Nitrogen-Containing Compounds in the One-Pot Exploiting Curtius Rearrangement

Herein we report, a single-pot multistep conversion of inactivated carboxylic acids to various N-containing compounds using a common synthetic methodology. The developed methodology rendered the use of carboxylic acids as a direct surrogate of primary amines, for the synthesis of primary ureas, secondary/tertiary ureas, O/S-carbamates, benzoyl ureas, amides, and N-formyls, exploiting the Curtius reaction. This approach has a potential to provide a diversified library of N-containing compounds, starting from a single carboxylic acid, based on the selection of the nucleophile.

Chemoselective isocyanide insertion into the N–H bond using iodine–DMSO: metal-free access to substituted ureas

A chemoselective metal-free method for isocyanide insertion into amines is developed to synthesize symmetrical and unsymmetrical ureas.

Crystal structure of 1,1-dimethyl-3-(4-methylphenyl)urea, C10H14N2O

C10H14N2O, monoclinic, Cc (no. 9), a = 6.8354(9) Å, b = 13.8221(17) Å, c = 10.2905(12) Å, β = 90.625(11)°, V = 972.2(2) Å3, Z = 4, R gt(F) = 0.0526, wR ref(F 2) = 0.1335, T = 296(2) K.

Biphenyl urea derivatives as selective CYP1B1 inhibitors

Herein, we report the discovery of ‘biphenyl ureas’ as selective CYP1B1 inhibitors.

One-pot synthesis of trisubstituted ureas from α-chloroaldoxime O-methanesulfonates and secondary amines

Trisubstituted ureas can be synthesized in a one-pot fashion from bench-stable α-chloroaldoxime O-methanesulfonates and secondary amines under mild reaction conditions.

Small molecule regulation of self-association and catalytic activity in a supramolecular coordination complex

Herein, we report the synthesis and characterization of the first weak-link approach (WLA) supramolecular construct that employs the small molecule regulation of intermolecular hydrogen bonding interactions for the in situ control of catalytic activity. A biaryl urea group, prone to self-aggregation, was functionalized with a phosphinoalkyl thioether (P,S) hemilabile moiety and incorporated into a homoligated Pt(II) tweezer WLA complex. This urea-containing construct, which has been characterized by a single crystal X-ray diffraction study, can be switched in situ from a rigid fully closed state to a flexible semiopen state via Cl(-) induced changes in the coordination mode at the Pt(II) structural node. FT-IR and (1)H NMR spectroscopy studies were used to demonstrate that while extensive urea self-association persists in the flexible semiopen complex, these interactions are deterred in the rigid, fully closed complex because of geometric and steric restraints. Consequently, the urea moieties in the fully closed complex are able to catalyze a Diels-Alder reaction between cyclopentadiene and methyl vinyl ketone to generate 2-acetyl-5-norbornene. The free urea ligand and the semiopen complex show no such activity. The successful incorporation and regulation of a hydrogen bond donating catalyst in a WLA construct open the doors to a vast and rapidly growing catalogue of allosteric catalysts for applications in the detection and amplification of organic analytes.

N-nitrourea derivatives as novel potential fungicides against Rhizoctonia solani: synthesis, antifungal activities, and 3D-QSAR

A series of N-nitrourea derivatives bearing various aryl substituents were conveniently obtained via three steps including nitration, carbamic chlorination, and aminolysis reactions. The structures of all newly synthesized compounds were characterized and confirmed by IR, ¹H-NMR, MS, and elemental analysis. The preliminary bioassays indicate that five compounds possess sufficient fungicidal activity against Rhizoctonia solani. Structure-activity relationship (SAR) is also discussed based on the experimental data, and the further quantitative structure-activity relationship (QSAR) was analyzed using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA).

Evaluation of new chalcone derivatives as polyphenol oxidase inhibitors

A newly series of 4-(phenylurenyl)chalcone (4a-j) and 4'-(phenylurenyl/thiourenyl)chalcone (9a-l) derivatives were synthesized and their inhibitory effects on the diphenolase activity of banana tyrosinase were evaluated. Tyrosinase has been purified from banana on an affinity gel comprised of Sepharose 4B-l-tyrosine-p-aminobenzoic acid. The result showed that 4a-j inhibited the PPO enzyme activity. Conversely, 9a-h and 9i-l showed activator effect on tyrosinase enzyme activity.

Urea/thiourea derivatives of quinazolinone-lysine conjugates: synthesis and structure-activity relationships of a new series of antimicrobials

Synthesis of a series of urea/thiourea/acetamide/sulphonamide derivatives of quinazolinones conjugated lysine has been reported. Structures of the products have been determined by standard spectroscopical studies. All the compounds have been screened for their antibacterial studies and structure-activity relationship has been developed. The activity profile revealed that the compounds containing urea and thiourea functionalities along with fluoro group have exerted a highly potent activity. Thus, the title compounds represent a novel class of potent antimicrobial agents.