Triphenylamine-based rhombimine macrocycles with solution interconvertable conformation

Abstract

Three imine macrocycles having rhomboidal shape were synthesized in good yields by [2+2] cyclocondensation reaction between equimolar quantities of (R,R)-1,2-diaminocyclohexane and 4,4'-bisformyl triphenylamine derivatives. The macrocycles structure was assigned by electrospray ionization mass spectrometry (ESI-MS), (1)H-NMR, and elemental analysis. UV, FTIR spectroscopy, and TG measurements were also used to characterize and prove the structure of these compounds. A conformational modification arising out of the rotation of triphenylamine group around the flexible cyclohexane-N bonds was observed in solution by (1)H-NMR and UV spectroscopy for all three macrocycles.

Imine polymers containing chiral nanohoops in the backbone obtained through [2 + 2] cyclocondensation

“…A rhombimine macrocycle ( 3 ), used as model compound for proposed polymers’ structure, was synthesized by [2 + 2] cyclocondensation between 4,4′‐diformyl triphenylamine and (R,R)‐1,2‐diaminocyclohexane (Scheme ). Its macrocyclic structure was unambiguously previously proved . The reaction was carried out at room temperature in chlorinated solvents in presence of catalyst (traces of p‐toluenesulfonic acid) and the compound was soluble in chlorinated solvents, CH 2 Cl 2 , CHCl 3 , or CCl 4 and poor soluble in DMF, THF, or DMAc.…”

“…Cyclic model 3 (2R,3R,17R,18R)‐1,4,10,16,19,25‐hexaaza‐10,25‐di(p‐phenyl)‐(2,3:17,18)‐dibutano‐(6:9,11:14,21:24,26:29)‐tetraetheno‐(2H,3H,17H,18H)‐tetrahydro‐(30)‐annulene, for simplicity we refer shortly as macrocycle ( 3 ) was synthesized by cyclocondensation of equimolar quantities of 4,4‐bisformyl triphenylamine ( 1 ) with (R,R)‐trans‐1,2‐diaminocyclohexane ( 2 ) as previously reported …”

“…Depending on dialdehyde geometry, imine macrocycles with different shapes, such as trianglimines, rhombimines, and rectanglimines were obtained by [2 + 2] or [3 + 3] cyclocondensation. For instance, the condensation of 4,4′‐diformyl triphenylamine with (R,R)‐trans 1,2‐diaminocyclohexane led to macrocycles with rhomboidal shape by [2 + 2] cyclocondensation …”

Solvent‐Mediated Functionalization of Benzofuroxan on Electron‐Rich Ruthenium Complex Platform

“…The simultaneous formation of 2 as amajor product, in addition to the minor product 1 (Scheme 2), extended the impression of nucleophilic attack by the anilido functiono f1 on the in situ generated aldehyde (Scheme 4a)t op rovide the final product 2 via intermediates B-D.E limination of H 2 Of rom B followed by proton removal from the a carbon, with respect to imine (acidic), [16] in C led to negatively charged D,w hich then underwent an Aldol-type addition with A,a nd subsequent eliminationofH 2 Oy ielded final product 2.The 1,4-diazabutadienef ragment of L 2 in 2 adopts the thermodynamically stable s-trans configuration. [17] Moreover,m ethyl substitution at the 5-position of benzofuroxan facilitated nucleophilic attack by D at the para-nitroso group of A,a se videncedb yt he crystal structureo f2b.P referential attack at the nitroso group para to the methyl group could be addressed by considering better charge separation of the N=Of unction, which,i nt urn, enhanced its electrophilicity.T he change in metal oxidation state upon moving from 1 (Ru III )t o2 (Ru II )d uring the course of the reaction favored by the p-accepting feature of L 2 in 2. Furthermore, the observed highera nd negligible yields of 2b (R = Me) and 2c (R = Cl), respectively,s uggested appreciable changes in the nucleophilicity of the anilido group in 1,a sa functiono fv arying Rg roup in the framework of benzofuroxan.…”

Probing the mechanism and dynamic reversibility of trianglimine formation using real‐time electrospray ionization time‐of‐flight mass spectrometry

“…The synthesis of imine macrocycles relies in numerous cases on [n+n]-cyclocondensation reactions of diamines and dialdehydes. [1][2][3][4] In most cases, it involves preorganization of the building blocks with the aid of a template or non-covalent interactions to a predictable geometry. [5][6][7][8] [3+3]-Cyclocondensation reactions have only been discovered in the last decade and promise a new approach for the synthesis of architecturally unique and exciting macrocyclic structures with potential applications.…”