A microwave assisted synthesis of benzoxazoles from carboxylic acids

One-Pot Multicomponent Reaction of Catechols, Ammonium Acetate, and Aldehydes for the Synthesis of Benzoxazole Derivatives Using the Fe(III)-Salen Complex

The Fe(III)-salen complex has been applied successfully as a catalyst for the novel, simple, efficient, and one-pot multicomponent synthesis of benzoxazole derivatives from catechols, ammonium acetate as the nitrogen source, and aldehydes (nontoxic and cheap alternatives of amines) for the first time. Using this procedure, a wide range of benzoxazoles was successfully synthesized in the presence of a catalyst in EtOH under mild conditions, and all products were obtained in excellent yields. To the best of our knowledge, this method is the first example of the multicomponent synthesis of benzoxazole derivatives using these starting materials. The notable features such as the use of air that is considered as a benign oxidant and EtOH as a green solvent, ease of product separation, readily available and inexpensive aldehydes, and mild conditions make our procedure more efficient and practical for organic synthesis. Moreover, the current protocol is successfully applied to synthesize desirable products on a large scale.

Synthesis of benzoxazoles via the copper-catalyzed hydroamination of alkynones with 2-aminophenols

We describe herein the synthetic method to benzoxazole derivatives via the copper-catalyzed hydroamination of alkynones with 2-aminophenols.

Transition-metal-free synthesis of oxazoles: valuable structural fragments in drug discovery

This review article encapsulates the recent developments in the metal-free approaches used to construct oxazole moiety.

Ultrasonic Irradiation: Synthesis, Characterization, and Preliminary Antimicrobial Activity of Novel Series of 4,6-Disubstituted-1,3,5-triazine Containing Hydrazone Derivatives

Novel series of 4,6-disubstituted-1,3,5-triazines containing hydrazone derivatives were synthesized employing ultrasonic irradiation and conventional heating. The ultrasonication gave the target products in higher yields and purity in shorter reaction time compared with the conventional method. IR, NMR (H 1 and C 13), elemental analysis, and LC-MS confirmed the structures of the new products. The antimicrobial and antifungal activities were evaluated for all the prepared compounds against some selected Gram-positive and Gram-negative bacterial strains. The results showed that only two compounds 7i (pyridine derivative) and 7k (4-chlorobenzaldehyde derivative) displayed biological activity against some Gram-positive and Gram-negative bacteria, while the rest of the tested compounds did not display any antifungal activity.

Iron(ii) bromide-catalyzed oxidative coupling of benzylamines with ortho-substituted anilines: synthesis of 1,3-benzazoles

An iron(ii) bromide-catalyzed oxidative coupling of benzylamines with 2-amino/hydroxy/mercapto-anilines has been developed, allowing the synthesis of a diversity of substituted 1,3-benzazoles in good to excellent yields.

Synthesis, spectral characterization and antimicrobial studies of novel s-triazine derivatives

A series of fifteen novel triazinyl derivatives, with various natural nucleobases by mono, di and tri substitution in cyanuric chloride at the 2,4- and/or 6-positions was synthesized. Target molecules were synthesized by stoichiometric addition of various nucleophiles to cyanuric chloride in the presence of suitable base. The structural characterizations of all the compounds were made by spectral and analytical techniques, IR, (1)H NMR, (13)C NMR, and 2D NMR (HSQC, HMBC), mass spectral and elemental analysis. All the synthesized compounds were screened for in vitro antimicrobial activity against a panel of selected bacterial and fungal strains using Streptomycin and Amphotericin B as standards. The minimum inhibition concentration (MIC) results revealed that most of the purine (1a-2a, 1b-2b, and 1c-2c) compounds exhibit excellent activity against selected bacterial and fungal strains.