Greener Approach for Synthesis of δ-MnO2 Nanoparticles: Access to Pharmaceutically Important Pyrimidines and their Antimicrobial Activity Studies

A sustainable approach for pharmaceutically important pyrimidine derivatives is achieved by using biogenically produced single-phase δ-MnO2 NPs under external ligand-free conditions. The phytochemicals that comprise the extract of Areca Nut Husk (ANH) have been discovered to serve as reducing agents. The role of phytochemicals is not only to aid in the reduction of Mn(VII) into Mn(IV), but they also have an important role in stabilizing the catalyst. The establishment of δ-MnO2 NPs was confirmed inveterate by FE-SEM, p-XRD, ICP-OES (Mn content = 43.17% w/w), EDX, and with an active Mn content of 43.17% w/w. A series of pyrimidine derivatives were prepared in good yields using a one-pot multicomponent synthesis approach under atmospheric conditions. In addition, hot filtration tests, control experiments, gram-scale synthesis, and mechanistic investigations were demonstrated. Additionally, antimicrobial activity studies of δ-MnO2 NPs and pyrimidine derivatives against the Gram-negative bacteria E. coli, growth curve and minimum inhibitory concentration were studied.

Green synthesis of C5–C6-unsubstituted 1,4-DHP scaffolds using an efficient Ni–chitosan nanocatalyst under ultrasonic conditions

A heterogeneous and magnetically recyclable Ni–chitosan nanocatalyst was synthesized and thoroughly characterized by powder Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray (EDX) spectroscopy, etc. It was effectively utilized in the eco-friendly synthesis of new C5–C6-unsubstituted 1,4-DHPs under ultrasonic irradiation. The important focus of the methodology was to develop an environmentally friendly protocol with a short reaction time and a simple reaction procedure. The other advantages of this protocol are a wide substrate scope, a very good product yield, the use of an eco-friendly solvent and a recyclable nanocatalyst, as well as reaction at room temperature.

Iron-Catalyzed Alkyne-Based Multicomponent Synthesis of Pyrimidines under Air

An iron-catalyzed sustainable, economically affordable, and eco-friendly synthetic protocol for the construction of various trisubstituted pyrimidines is described. A wide range of trisubstituted pyrimidines were prepared using a well-defined, easy to prepare, bench-stable, and phosphine-free iron catalyst featuring a redox-noninnocent tridentate arylazo pincer under comparatively mild aerobic conditions via dehydrogenative functionalization of alcohols with alkynes and amidines.

Metal-free cascade synthesis of unsymmetrical 2-aminopyrimidines from imidazolate enaminones

A convenient metal-free synthesis of unsymmetrical 2-aminopyrimidines from imidazolate enaminones has been developed. In this procedure, various structural 2-aminopyrimidines, as well as 4,5-dihydroisoxazol-5-ols and pyrazoles were synthesized in moderate to excellent yields. A plausible mechanism was also proposed for the cascade reaction. This method represents an effective strategy towards the synthesis of unsymmetrical 2-aminopyrimidines.

A convenient metal-free synthesis of unsymmetrical 2-aminopyrimidines from imidazolate enaminones has been developed.

Polysubstituted Pyrimidines as Potent Inhibitors of Prostaglandin E2 Production: Increasing Aqueous Solubility

Water solubility is one of the key features of potential therapeutic agents. In order to enhance the low water solubility of the parent 5-butyl-4-(4-methoxyphenyl)-6-phenylpyrimidin-2-amine, a potent inhibitor of prostaglandin E₂ (PGE₂ ) production, we synthesized and evaluated a new series of derivatives in which the butyl group at the C5 position of the pyrimidine ring was replaced with a less lipophilic substituent, preferably with a hydrophilic aliphatic moiety. Except for the 5-cyanopyrimidine derivative, all target compounds exhibited increased (2.7 - 87-fold) water solubility relative to the parent compound. Although nontoxic in mouse peritoneal cells, the prepared compounds were either equipotent or weaker inhibitors of PGE₂ production than the parent compound. The most promising compound from the series was found to be the 5-(2,5,8,11-tetraoxadodecyl)pyrimidine derivative (with three polyethylene glycol units at the C5 position), which exhibited 32-fold higher water solubility and only slightly weaker inhibitory activity (22 % of remaining PGE₂ production) compared with the parent compound (15 % of remaining PGE₂ production).

Ethyl (S)-2-Benzamido-5-[(4,6-dimethylpyrimidin-2-yl)amino]pentanoate

Pyrimidines are compounds with a wide range of biological activities, and the synthesis of pyrimidine derivatives—useful in chemical and medicinal applications—is important in medicinal chemistry. This work shows the synthesis under microwave irradiation of the novel compound ethyl (S)-2-benzamido-5-[(4,6-dimethylpyrimidin-2-yl)amino]pentanoate (3) from (S)-N-α-benzoyl-l-arginine ethyl ester hydrochloride (1) and acetylacetone (2). Compound 3 was easily purified, obtained in moderate yield (70%), and fully characterized by UV-Vis, FTIR-ATR spectroscopy, 1H-NMR, 13C-NMR, HRMS, and EI-MS.

Novel triazole-modified chitosan@nickel nanoparticles: efficient and recoverable catalysts for Suzuki reaction

The synthesis of triazole-modified chitosan@nickel catalyst through the click reaction of azide-functionalized chitosan with an alkynated imino-thiophene ligand for Suzuki–Miyaura coupling reactions.

DABCO-functionalized silica–copper(i) complex: a novel and recyclable heterogeneous nanocatalyst for palladium-free Sonogashira cross-coupling reactions

Nano-CuI stabilized in a functionalized-DABCO silica matrix was prepared, characterized and evaluated as a new heterogeneous nanocatalyst in copper-catalyzed Sonogashira coupling reactions.