Extension of the Bambus[n]uril Family: Microwave Synthesis and Reactivity of Allylbambus[n]urils

Abstract

Microwave irradiations allow the preparation of unsaturated bambusurils in 85% yield compared to 20% yield under classical reaction conditions. Five new bambusurils were synthesized including unsaturated derivatives Allyl(8)BU[4] and Allyl(12)BU[6] bearing diallylglycoluril units. The reactivity of Allyl(8)BU[4] was tested in a variety of organic reactions showing that this macrocycle acts as a classical double bond-bearing product. The first monofunctionalized bambusuril Allyl(7)HepBU[4] prepared by a cross metathesis reaction is also reported.

Bambusurils Bearing Nitro Groups and Their Further Modifications

“…Finally, we performed the reaction in a microwave reactor, as reported previously for different BU[n]s, [14] which shortened the reaction time from 16 to 4 h and doubled the amount of 7b·I -(46 %). At this stage we decided to investigate synthetic routes for the conversion of all the nitro groups on the prepared bambusuril derivatives into amino functionalities.…”

“…Heck and co-workers decorated BU[n]s with allyl substituents to obtain BU [4]c and BU [6]c (Figure 1). [14] They also explored the possibility of linking neighboring allyl groups by cross metathesis. Another approach came with Reany and co-workers, who modified the BU[n] core by replacing half of the carbonyl groups by thiocarbonyl [4,5] and, subsequently, the thiocarbonyl by imine moieties.…”

A Família Das Bambus[n]urilas

“…Desde a descoberta da MeBU [6], diversos derivados foram reportados contendo resíduos alifáticos e substituintes aromáticos. [33][34][35][36][37] De maneira geral, as glicolurilas dissubstituídas reagem com formaldeído em meio ácido, em condições específicas, produzindo as respectivas BU[n] funcionalizadas (Figura 5). As benzil-bambus [4]urila (BnBU [4]), benzil-bambus [6]urila (BnBU [6]) e propil-bambus [6] urila (PrBU [6]) 34 foram obtidas a partir das 2,4-dibenzilglicolurila ou 2,4-dipropilglicolurila, respectivamente, em solventes apolares, e não em meio aquoso como na síntese da MeBU [6].…”

Structural studies of diaminocyclohexane-containing aza-crown ether macrocycles and their Zn(II) complexes

“…While an impressive variety of functional compounds has been adapted from wellestablished macrocyclic scaffolds including cyclodextrins [11], calixarenes [12], porphyrins [13], macrocyclic peptides [14], and curcubiturils [15]; there is also considerable interest in the de novo design of novel macrocyclic systems [16][17][18][19][20][21], which affords the opportunity to tailor stereochemistry, conformational behavior and functional group composition. Previously, we synthesized a series of chiral, C 2 -symmetrical azacrown macrocycles, including those shown in Fig.…”