Synthesis methods of microporous organic polymeric adsorbents: a review

MOPs can be synthesized in a large variety of ways, which affect their pores and surface area. Variation in synthesis and porosity has a significant effect on their adsorption properties.

Recent advances in sustainable synthesis of N-heterocycles following acceptorless dehydrogenative coupling protocol using alcohols

In this review, we have summarized various aspects of homogeneous and heterogeneously catalyzed recent advancements in the synthesis of heterocycles following the ADC approach.

Atom-efficient synthesis of 2,4,6-trisubstituted 1,3,5-triazines via Fe-catalyzed cyclization of aldehydes with NH4I as the sole nitrogen source

An atom-efficient, straightforward method for the synthesis of 2,4,6-triaryl-1,3,5-triazines via iron-catalyzed cyclization of aldehydes with NH₄I as the sole nitrogen source is demonstrated. This strategy works smoothly under air atmosphere, and affords symmetrical 2,4,6-trisubstituted and unsymmetrical 1,3,5-triazines with yields from 18% to 72%. Compared to other methods, the present protocol provides a straightforward and atom-efficient approach to 2,4,6-trisubstituted 1,3,5-triazines using an inexpensive, easily available ammonium salt as the sole nitrogen source. Research into the preliminary mechanism indicates that N-benzylidenebenzimidamides are involved in this cyclization reaction.

An atom-efficient, straightforward method for the synthesis of 2,4,6-triaryl-1,3,5-triazines via iron-catalyzed cyclization of aldehydes with NH₄I as the sole nitrogen source is demonstrated.

Tandem transformations and multicomponent reactions utilizing alcohols following dehydrogenation strategy

In this review, the progress of tandem transformation of nitro, nitrile and azide functionalities is summarised to develop new C–C and C–N bonds as well as multi-component reactions using alcohols.

Developments towards synthesis of N-heterocycles from amidines via C–N/C–C bond formation

This review focuses on the synthesis of N-heterocycles using amidines as starting materials, with an emphasis on the mechanisms of these reactions via C–N/C–C bond formation.

Crystalline Covalent Triazine Frameworks by In Situ Oxidation of Alcohols to Aldehyde Monomers

Covalent triazine frameworks (CTFs) with aromatic triazine linkages have recently received increasing interest for various applications because of their rich nitrogen content and high chemical stability. Owing to the strong aromatic C=N bond and high chemical stability, only a few CTFs are crystalline, and most CTFs are amorphous. Herein we report a new general strategy to give highly crystalline CTFs by in situ formation of aldehyde monomers through the controlled oxidation of alcohols. This general strategy allows a series of crystalline CTFs with different monomers to be prepared, which are shown to have higher thermal stability and enhanced performance in photocatalysis as compared with the less crystalline or amorphous CTFs. This open-system approach is very simple and convenient, which presents a potential pathway to large-scale industrial production of crystalline CTFs.

Copper-catalyzed ambient-temperature decarboxylative annulation of isatins with amidine hydrochlorides: a facile access to 2-(1,3,5-triazin-2-yl)aniline derivatives

A copper-catalyzed domino protocol for the synthesis of 2-(1,3,5-triazin-2-yl)anilines has been developed from isatins and amidine hydrochlorides at ambient temperature.

iEDDA Reaction of the Molecular Iodine-Catalyzed Synthesis of 1,3,5-Triazines via Functionalization of the sp3 C-H Bond of Acetophenones with Amidines: An Experimental Investigation and DFT Study

The present work reports an inverse electron demand Diels-Alder (iEDDA)-type reaction to synthesize 1,3,5-trizines from acetophenones and amidines. The use of molecular iodine in a catalytic amount facilitates the functionalization of the sp³ C-H bond of acetophenones. This is a simple and efficient methodology for the synthesis of 1,3,5-triazines in good to excellent yields under transition-metal-free and peroxide-free conditions. The reaction is believed to take place via an in situ iodination-based oxidative elimination of formaldehyde. DFT calculations at the M062X/6-31+G(d,p) level were employed to investigate the reaction mechanism. Reaction barriers for the cycloaddition as well as a formaldehyde expulsion steps were computed, and a multistep mechanism starting with the nucleophilic attack by benzamidine on an in situ generated imine intermediate has been proposed. Both local and global reactivity descriptors were used to study the regioselectivity of the addition steps.

Cu-Catalyzed intermolecular [3 + 3] annulation involving oxidative activation of an unreactive C(sp3)–H bond: access to pyrimidine derivatives from amidines and ketones

An efficient approach to pyrimidines through a copper-catalyzed oxidative unreactive C(sp³)–H bond and intermolecular [3 + 3] annulation of amidines and ketones is described.

Elongated and substituted triazine-based tricarboxylic acid linkers for MOFs

New triazine-based tricarboxylic acid linkers were prepared as elongated relatives of triazinetribenzoic acid (TATB). Additionally, functional groups (NO₂, NH₂, OMe, OH) were introduced for potential post-synthetic modification (PSM) of MOFs. Functionalized tris(4-bromoaryl)triazine "cores" (3a,3b) were obtained by unsymmetric trimerization mixing one equivalent of an acid chloride (OMe or NO₂ substituted) with two equivalents of an unsubstituted nitrile. Triple Suzuki coupling of the cores 3 with suitable phenyl- and biphenylboronic acid derivatives provided elongated tricarboxylic acid linkers as carboxylic acids 17 and 20 or their esters 16 and 19. Reduction of the nitro group and cleavage of the methoxy group gave the respective amino and hydroxy-substituted triazine linkers.

Synthesis of quinazolines from 2-aminobenzylamines with benzylamines and N-substituted benzylamines under transition metal-free conditions

This work reports the synthesis of quinazolines from 2-aminobenzylamines with N-substituted benzylamines in the presence of molecular iodine. The developed methodology works smoothly under transition-metal free, additive free and solvent free conditions and the use of O₂ as a green oxidant makes it a greatly economical.