13125-68-3

Upstream product

• 24171-78-6 m-bromophenylhydroxylamine 
• 591-19-5 m-Bromoaniline 
• 585-79-5 m-nitrobromobenzene 

Downstream Products

• 1416273-44-3 dibutyl 5,5'-bis[(E)-(3-bromophenyl)diazenyl]biphenyl-3,3'-dicarboxylate 
• 1416273-61-4 nonyl 3',5-bis[(E)-(3-bromophenyl)diazenyl]-5'-{(4-[(triisopropylsilyl)ethynyl]phenoxy)-methyl}-[1,1'-biphenyl]-3-carboxylate 
• 3652-90-2 2-bromo-9H-carbazole 
• 59506-74-0 6-Brom-2,3-dihydro-1H-pyrrolo<1,2-a>benzimidazol 

Relevant academic research and scientific papers

Affinity modulation of photoresponsive hosts for fullerenes: Light-gated corannulene tweezers

Six azobenzene derivatives bearing polyaromatic fragments have been prepared and their reversible photoisomerization has been assessed. Corannulene-functionalized molecules have demonstrated excellent switchable hosting abilities towards fullerenes in which an interesting range of affinities has been found. The success of this design relies upon the reversible formation and destruction of tweezer-like structures.

Synthesis of 4-substituted azopyridine-functionalized Ni(II)-porphyrins as molecular spin switches

We present the synthesis and the spin switching efficiencies of Ni(II)-porphyrins substituted with azopyridines as covalently attached photoswitchable ligands. The molecules are designed in such a way that the azopyridines coordinate to the Ni ion if the azo unit is in cis configuration. For steric reasons no intramolecular coordination is possible if the azopyridine unit adopts the trans configuration. Photoisomerization of the azo unit between cis and trans is achieved upon irradiation with 505 nm (trans→cis) and 435 nm (cis→trans). Concurrently with the isomerization and coordination/decoordination, the spin state of the Ni ion switches between singlet (low-spin) and triplet (high-spin). Previous studies have shown that the spin switching efficiency is strongly dependent on the solvent and on the substituent at the 4-position of the pyridine unit. We now introduced thiol, disulfide, thioethers, nitrile and carboxylic acid groups and investigated their spin switching efficiency.

Rh(III)-Catalyzed bilateral cyclization of aldehydes with nitrosos toward unsymmetrical acridines proceeding with C-H functionalization enabled by a transient directing group

A Rh(iii)-catalyzed bilateral cyclization was developed for the efficient construction of acridines proceeding with C-H functionalization whereby in situ formation and removal of an imino transient directing group in the presence of catalytic amount of BnNH2 are achieved. In this transformation, a sequential Rh(iii)-catalyzed C-H amination, cyclization, and aromatization process was involved.

Ni(II)porphyrins as pH dependent light-driven coordination-induced spin-state switches (LD-CISSS) in aqueous solution

A water-soluble Ni(II)-porphyrin substituted with a covalently attached azopyridine ligand was synthesized. Upon irradiation with violet and green light, the azo unit performs a reversible cis-trans isomerization. This geometry change triggers a coordinat

Photoswitchable Magnetic Resonance Imaging Contrast by Improved Light-Driven Coordination-Induced Spin State Switch

We present a fully reversible and highly efficient on-off photoswitching of magnetic resonance imaging (MRI) contrast with green (500 nm) and violet-blue (435 nm) light. The contrast change is based on intramolecular light-driven coordination-induced spin state switch (LD-CISSS), performed with azopyridine-substituted Ni-porphyrins. The relaxation time of the solvent protons in 3 mM solutions of the azoporphyrins in DMSO was switched between 3.5 and 1.7 s. The relaxivity of the contrast agent changes by a factor of 6.7. No fatigue or side reaction was observed, even after >100 000 switching cycles in air at room temperature. Electron-donating substituents at the pyridine improve the LD-CISSS in two ways: better photostationary states are achieved, and intramolecular binding is enhanced.

A toolbox of molecular photoswitches to modulate the CXCR3 chemokine receptor with light

We report a detailed structure–activity relationship for the scaffold of VUF16216, a compound we have previously communicated as a small-molecule efficacy photoswitch for the peptidergic chemokine GPCR CXCR3. A series of photoswitchable azobenzene ligands was prepared through various synthetic strategies and multistep syntheses. Photochemical and pharmacological properties were used to guide the design iterations. Investigations of positional and substituent effects reveal that halogen substituents on the ortho-position of the outer ring are preferred for conferring partial agonism on the cis form of the ligands. This effect could be expanded by an electron-donating group on the para-position of the central ring. A variety of efficacy differences between the trans and cis forms emerges from these compounds. Tool compounds VUF15888 (4d) and VUF16620 (6e) represent more subtle efficacy switches, while VUF16216 (6f) displays the largest efficacy switch, from antagonism to full agonism. The compound class disclosed here can aid in new photopharmacology studies of CXCR3 signaling.

Continuous Flow Synthesis of Azoxybenzenes by Reductive Dimerization of Nitrosobenzenes with Gel-Bound Catalysts

In the search for a new synthetic pathway for azoxybenzenes with different substitution patterns, an approach using a microfluidic reactor with gel-bound proline organocatalysts under continuous flow is presented. Herein the formation of differently substituted azoxybezenes by reductive dimerization of nitrosobenzenes within minutes at mild conditions in good to almost quantitative yields is described. The conversion within the microfluidic reactor is analyzed and used for optimizing and validating different parameters. The effects of the different functionalities on conversion, yield, and reaction times are analyzed in detail by NMR. The applicability of this reductive dimerization is demonstrated for a wide range of differently substituted nitrosobenzenes. The effects of these different functionalities on the structure of the obtained azoxyarenes are analyzed in detail by NMR and single-crystal X-ray diffraction. Based on these results, the turnover number and the turnover frequency were determined.

Understanding Mechanistic Differences between 3-Diazoindolin-2-Imines and N-Sulfonyl-1,2,3-Triazoles in the Rh2(II)-Catalyzed Reactions with Nitrosoarenes

The employment of α-iminometallocarbenes to construct valuable N-containing compounds has attracted significant research interest. Herein, the nucleophilic addition of nitrosoarenes with the α-imino rhodium carbene species (I), which is derived from Rh2(II)-catalyzed denitrogenation of 3-diazoindolin-2-imines, to produce synthetically useful 2-iminoindolin-nitrones is described. Mechanistically, the N-attack of nitrosoarenes with the carbene site of I is proposed. For the analogous Rh2(II)-catalyzed reaction of nitrosoarenes with N-sulfonyl-1,2,3-triazoles reported by Li and co-workers (Org. Lett. 2014, 16, 6394), however, the O-attack of nitrosoarenes with the carbene site of α-imino rhodium carbene species (II) is more favorable to occur than the N-attack. The subsequent transformation to yield the product of N-acylamidines is rationalized based on computational studies. The mechanistic differences for the reactions of nitrosoarenes with α-imino rhodium carbene species I and II are discussed.

Active ester functionalized azobenzenes as versatile building blocks

Azobenzenes are important molecular switches that can still be difficult to functionalize selectively. A high yielding Pd-catalyzed cross-coupling method under mild conditions for the introduction of NHS esters to azobenzenes and diazocines has been established. Yields were consistently high with very few exceptions. The NHS functionalized azobenzenes react with primary amines quantitatively. These amines are ubiquitous in biological systems and in material science.

Enantioselective Oxidative Coupling of β-Ketocarbonyls and Anilines by Joint Chiral Primary Amine and Selenium Catalysis

An enantioselective primary amine-catalyzed total N-selective nitroso aldol reaction (N-NA) was achieved through the oxidation of primary aromatic amines to the corresponding nitrosoarenes catalyzed by selenium reagents and 30% H2O2. This protocol provides a facile and highly efficient access to α-hydroxyamino carbonyls bearing chiral quaternary centers under exceedingly mild and green reaction conditions with high chemo-and enantiocontrol.