Rubber Chemicals Derived from Conjugate Addition. II. Synthesis of a Novel Class of Benzoquinone Diimines

Abstract

Various 2-alkylthio-5-amino- and 2,5-diamino-1,4-phenylenediamines were prepared by treatment of N-(1,3-dimethylbutyl)- N′-phenyl-1,4-quinonediimine with thiols and amines using air as an oxidizing agent. Key 2-alkylthio-1, 4-benzoquinone diimines were prepared via Ag2O oxidation of the corresponding 1,4-phenylenediamines.

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

“…Solvents were distilled under an atmosphere of argon prior to use and dried by standard methods. 1 H and 13 C NMR spectra were recorded in CDCl 3 , [D 6 ]acetone, and [D 6 ]DMSO with a AC250 Bruker spectrometer operating at 250 MHz. Chemical shifts are reported in δ units in parts per million (ppm).…”

“…The solid in suspension was isolated by filtration and washed with diethyl ether (3 mL) to afford 13 (0.06 g, 30 % yield) as a white solid. 1 …”

“…[1,2] They can be classified under three major categories, namely, I, II, and III. [1] Class I molecules (1) contain no substituent attached to the benzoquinoid ring and have been described mainly with electron-withdrawing R groups that stabilize the systems. [2] Class II (2) contains amino substituents at the 2-and 5-positions of the benzoquinoid ring (R 1 = or ϶ R 2 = or ϶ R 3 ).…”

“…[2] Class II (2) contains amino substituents at the 2-and 5-positions of the benzoquinoid ring (R 1 = or ϶ R 2 = or ϶ R 3 ). [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.…”

“…[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).…”