Strategies for the synthesis of HBGl3 , a glutamic acid derived ligand bearing phenolic and azacarboxylate donor groups at the nitrogen atom

Abstract

(2017) 'Strategies for the synthesis of HBGl3, a glutamic acid derived ligand bearing phenolic and azacarboxylate donor groups at the nitrogen atom. ', Tetrahedron., 73 (45). pp. 6410-6420. Further information on publisher's website: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.

Resonance Assisted Hydrogen Bonding Phenomenon Unveiled through Both Experiments and Theory: A New Family of Ethyl N‐Salicylideneglycinate Dyes

“…[52] In the literature only ah andful structurally characterized Nsalicylidene a-amino acid esters, exhibiting both enol-imine and keto-enamine structures, are known( Figure 1). [46,[52][53][54][55] However,its till remains unclear which factorsdetermine the stability of tautomers:w hether it is defined by the nature of an ester group or as ubstituent at the benzene ring of salicylaldehyde or at the a-position of an amino acid moiety.Equally important is that theses ystems contain extra stabilization stemming from p-electrons delocalization, the so-called resonance-assisted hydrogen bonding( RAHB),w hich might influencef ormation of varioust automeric forms.A lthought his effect is well recognized in the literature, its fundamentalm echanism and impact on photophysical properties are not well understood. [56][57][58][59][60][61][62][63][64][65][66][67][68] With all this in mind, we have directed our attention to a new family of N-salicylidene aniline derivatives 1-4 differing in donor-acceptor properties and their luminescence activity, which are fabricated from the ethyl ester of glycine and corresponding salicyladehyde derivatives (Scheme 1).…”

“…Diagrams of the reported crystal structures of N-salicylidene aamino acid esters. [45,[51][52][53][54] Scheme1.Possible tautomeric forms of 1 (X = H), 2 (X = OMe), 3 (X = Br), 4 (X = NO 2 ). presenceo fc atalytic amountso fs ubstituted salicylaldehydes.…”

“…In the literature only a handful structurally characterized N‐salicylidene α‐amino acid esters, exhibiting both enol‐imine and keto‐enamine structures, are known (Figure ) . However, it still remains unclear which factors determine the stability of tautomers: whether it is defined by the nature of an ester group or a substituent at the benzene ring of salicylaldehyde or at the α‐position of an amino acid moiety.…”

“…Diagrams of the reported crystal structures of N-salicylidene aamino acid esters. [45,[51][52][53][54] noted that for N-salicylideneglycinates the additional tautomerism between the CH 2 C(O)OR keto-and CHC(OH)OR enol forms can be assumed (Scheme 1). This is indicated by smooth racemization of enantio-enriched a-amino acid esters in the presence of catalytic amounts of substituted salicylaldehydes.…”

“…[52] In the literature only a handful structurally characterized Nsalicylidene a-amino acid esters, exhibiting both enol-imine and keto-enamine structures, are known (Figure 1). [46,[52][53][54][55] However, it still remains unclear which factors determine the stability of tautomers: whether it is defined by the nature of an ester group or a substituent at the benzene ring of salicylaldehyde or at the a-position of an amino acid moiety. Equally important is that these systems contain extra stabilization stemming from p-electrons delocalization, the so-called resonance-assisted hydrogen bonding (RAHB), which might influence formation of various tautomeric forms.…”