The dual diene/1,3-dipolar character of 1-H-imidazole 3-oxide, HIO 1, allows this compound toparticipate in a competitive Diels-Alder (DA)/1,3-dipolar cycloaddition (13DC) reaction toward C=Sdouble bond of the electro-deficient sulfonyl methane SFM 2. The B3LYP/6-311++G(d,p) calculatedrelative Gibbs free energies indicate that among the studied 13DC and DA reactions, former iscompletely preferr...

A series of 1,3-dipolar cycloaddition reactions are carried out using cyclodimers of simple nitrones and various dipolarophiles; substituted isoxazolidines are isolated and identified. It is proved that such cyclodimers, in solution, are in equilibrium with their corresponding nitrones and enamines. It is also concluded that aldocyclodimers are more potent than keto-cyclodimers in establish...

In this protocol, we report a novel approach for the synthesis of a new class of heterocyclic 1H-1,2,3-triazole-modified peptidomimetic compounds. The process consists of an Ugi four-component condensation reaction of amines, an isocyanide, an aldehyde and acids followed by a Huisgen 1,3-dipolar cycloaddition reaction with an azide group in the presence of a catalytic amount of CuSO4</...

1-Sulfonyl-1,2,3-triazoles, which are readily available through copper-catalyzed azide-alkyne cycloaddition, are stable precursors to Rh–azavinyl carbenes, as well as carbene complexes of other metals. Among other transformations, these reactive intermediates can be used for the introduction of a nitrogen atom into various heterocycles that are important in both synthetic and medicinal chemistr...

Diazo compounds, which can be accessed directly from azides by deimidogenation, are shown to be extremely versatile dipoles in 1,3-dipolar cycloaddition reactions with a cyclooctyne. The reactivity of a diazo compound can be much greater or much less than its azide analog, and is enhanced markedly in polar-protic solvents. These reactivities are predictable from frontier molecular orbital energ...

The development of multicomponent reactions (MCRs) designed to produce elaborate biologically active compounds has become an important area of research in organic, combinatorial, and medicinal chemistry. A comparative study of the synthesis of new bis-spiro-oxindolo(pyrrolizidines/pyrrolidines) ring systems by the cycloaddition of azomethine ylides generated by a decarboxylative route from sarc...

Common cases of cycloaddition include concerted (2 + 4) and stepwise (2 + 2) reactions which latter are usually easily recognizable as involving biradicals or dipolar ions. The addition in situ of dichioroketene to 2,4-hexadiene and 2butene is stereospecific, as required by the (2 + 2a) mechanism, but is followed by rapid base-catalysed rearrangement of the resulting 2,2-dichiorocyclobutanones ...

The synthesis and antibacterial activity of the title compounds having an isoxazolidine ring at the C-2 position are described. These derivatives were synthesized by the 1,3-dipolar cycloaddition reaction of nitrone with 2-vinyl carbapenems. This 1,3-dipolar cycloaddition reaction proceeded regioselectively to give diastereomeric isomers of 2(-isoxazolidin-5-yl)carbapenems. It was ascertained t...

the development of multicomponent reactions (mcrs) designed to produce elaborate biologically active compounds has become an important area of research in organic, combinatorial, and medicinal chemistry. a comparative study of the synthesis of new bis-spiro-oxindolo(pyrrolizidines/pyrrolidines) ring systems by the cycloaddition of azomethine ylides generated by a decarboxylative route from sarc...

The copper-catalyzed 1,3-dipolar azide-alkyne cycloaddition (CuAAC) was used for the first time to attach a biologically active carbon monoxide delivery agent to modified nanodiamond (ND) as a highly biocompatible carrier. The [Mn(CO)(3)(tpm)](+) photoactivatable CO-releasing molecule (PhotoCORM) on the surface retained the carbon monoxide release properties of the parent compound as shown with...