Toward a 6π+6π Zwitterion or a Bioinhibitors‐Related OH‐Substituted Aminoquinone: Identification of a Key Intermediate in Their pH Controlled Synthesis

Abstract

Their pH-controlled reactivity places the N,N'-dialkyl-2-amino-5-lithium alcoholate-1,4-benzoquinonemonoimines [C(6)H(2)(NHCH(2)R') (=NCH(2)R')(=O)(OLi)] 7 (R'=tBu) and 8 (R'=p-C(6)H(4)-tBu) at the crossroads of a new versatile strategy for the preparation of two very different classes of substituted quinones. We describe new 2-(N-alkyl)amino-5-hydroxy-1,4-benzoquinones, which are parent molecules to biologically active substituted aminobenzoquinones, for which changes of the N-substituent will become readily possible. The results of the first X-ray structural determination of such compounds ([C(6)H(2)(NHCH(2)tBu)(OH)(=O)(2)] 13) are also reported and we compare the influence of the number of N-substituents of the C(6) ring on the supramolecular networks resulting from self-assembling of 13, zwitterionic N,N'-dineopentyl-2-amino-5-alcoholate-1,4-benzoquinonemonoiminium [C(6)H(2)(=NHCH(2)tBu)(2)(=O)(2)] 9 and N,N',N",N"'-tetraneopentyl-2,5-diamino-1,4-benzoquinone diimine [C(6)H(2)(NHCH(2)tBu)(2)(=NCH(2)tBu)(2)] 15.

Tunable N‐substitution in Zwitterionic Benzoquinonemonoimine Derivatives: Metal Coordination, Tandemlike Synthesis of Zwitterionic Metal Complexes, and Supramolecular Structures

“…Interestingly, hydroxybenzoquinone derivatives, related to 17 ,7 react with amines to afford quinonemonoimine derivatives; this represents an important step in enzyme‐catalyzed deamination reactions 18c,d. We anticipated that reaction of 17 with n‐ butylamine could afford the unsymmetrical zwitterion C (Scheme ).…”

“…Such quinonoids display interesting supramolecular structural properties,5, 6a, 7 and appear very attractive in organic chemistry,6a, 7 color chemistry,8 and coordination chemistry6a, 9 owing to their remarkable chemical and physical properties: 1) as zwitterions they are strongly dipolar (electrostatic interactions), 2) they possess two hydrogen‐donor sites and two hydrogen‐acceptor sites (hydrogen‐bonding interactions), 3) they have a conjugated π system (π–π interaction), and 4) it is possible to vary the nature of the N‐substituent (tuning of the steric properties and introduction of heteroatoms and/or hydrogen‐donor and ‐acceptor sites).…”

Reactions of Amines with Zwitterionic Quinoneimines: Synthesis of New Anionic and Zwitterionic Quinonoids

“…[20] The presence of multiple hydrogen-bond donors and acceptors results in crystal packings dominated by these interactions. In zwitterions 4a, 4c·1/2C 6 H 7 N, and 4e but also in monoanionic 6c and 6d·H 2 O, couples of molecules are connected as shown, for example, in Figure 6, through double NH···O hydrogen bonds.…”

“…[38] A more efficient synthesis was subsequently developed, which involved acylation of diaminoresorcinol followed by reduction with LiAlH 4 and aerobic work up. [20,38] However, only -NCH 2 R substituted derivatives could be obtained by using this procedure. This prompted us to develop a more versatile synthetic pathway for this new class of molecules.…”

Selective Reduction of Carbonyl Amides: Toward the First Unsymmetrical Bischelating N‐Substituted 1,2‐Diamino‐4,5‐di­amidobenzene

“…[1,[3][4][5][6][7][8][9][10][11] Class III derivatives (3) contains all other 1,4-benzoquinonediimines (X = or ϶ Y, but both are different from N). [1] The second class of quinonediimines is the largest owing to easy access to symmetrical systems (R 1 = R 2 = R 3 ) and a high stability, which have allowed their use in different fields ranging from hair coloring [12] and biosensors [13] to supramolecular [14] and coordination chemistry. [15] This high stability is explained by the coupling principle [16,17] of the 12π-electron system of the quinoid skeleton, which is best described as being constituted of two 6π-electron subunits chemically connected by two single C-C bonds but each unit is electronically independent (no conjugation).…”