Diazo groups have broad and tunable reactivity. That and other attributes endow diazo compounds with the potential to be valuable reagents for chemical biologists. The presence of diazo groups in natural products underscores their metabolic stability and anticipates their utility in a biological context. The chemoselectivity of diazo groups, even in the presence of azido groups, presents many o...

Aryldiazo substituents were used in nucleophilic aromatic substitution reactions of halogens. The Ph-N=N- group activates ortho fluorine atoms toward alkylthiolation under mild conditions. In contrast, the Me(2)N-C(6)H(4)-N=N- group has virtually no activation effect in nucleophilic aromatic substitution, and serves as a "neutral" mask for the amino group. The Ph-N=N- group was efficiently intr...

The presence of cholinesterase at the myoneural junction of intercostal muscle has been demonstrated in both light and electron microscopic preparations. A new simultaneous diazo coupling technique using alpha-naphthyl acetate as substrate and "hexazonium pararosanilin" as coupler has been applied to cold formalin-fixed tissues. After postfixation in buffered osmium tetroxide the sites of ester...

The diazo group has attributes that complement those of the azido group for applications in chemical biology. Here, we use computational analyses to provide insights into the chemoselectivity of the diazo group in 1,3-dipolar cycloadditions. Dipole distortion energies are responsible for ∼80% of the overall energetic barrier for these reactions. Here, we show that diazo compounds, unlike azides...

A gold-catalyzed intramolecular coupling of diazo compounds to produce cyclic olefins has been well established. The medium and large sized membered olefins were obtained in moderate to good yields. Notably, the Z/E selectivity of the olefins highly depended on the ring size. Furthermore, this investigation indicated that the structure of the phosphorous ligand binding to the gold centre played...

A novel copper-catalyzed [3+2] cycloaddition reaction of secondary amines with α-diazo compounds has been developed via a cross-dehydrogenative coupling process. The reaction involves a sequential aerobic oxidation/[3+2] cycloaddition/oxidative aromatization procedure and provides an efficient method for the construction of 1,2,3-triazoles in a single step in an atom-economic manner from readil...

α-Diazo arylketones are well-known substrates for Wolff rearrangement to phenylacetic acids through a ketene intermediate by either thermal or photochemical activation. Likewise, α-substituted p-hydroxyphenacyl (pHP) esters are substrates for photo-Favorskii rearrangements to phenylacetic acids by a different pathway that purportedly involves a cyclopropanone intermediate. In this paper, we sho...

Kaolin-SO3H nanoparticles were prepared via reaction of kaolin and chlorosulfonic acid and characterized by FT-IR, XRD, FESEM, TEM, XRF, EDS, BET and TGA. The activity of this green catalyst was probed by the synthesis of aryl diazonium salts as the starting reactant and then, their diazo coupling with  2-naphthol to form azo dyes in a solvent-free medium at room temperature...

We introduce a stabilized diazo group as a reporter for chemical biology. ManDiaz, which is a diazo derivative of N-acetylmannosamine, is found to endure cellular metabolism and label the surface of a mammalian cell. There its diazo group can undergo a 1,3-dipolar cycloaddition with a strained alkyne, providing a signal comparable to that from the azido congener, ManNAz. The chemoselectivity of...