中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
—— | methylxanthoroccellin | 94514-45-1 | C20H18N2O2 | 318.375 |
A reinvestigation of the reduction of 3,6-dibenzylidenepiperazine-2,5-dione (1) with zinc and acetic acid established that this reaction gave (Z)-6-benzyl-3-benzylidenepiperazine-2,5-dione (10). When a mixture of acetic acid and hydrochloric acid was used in the reduction, a mixture of trans- (12) and cis-3,6-dibenzylpiperazine-2,5-dione (5) was obtained. Direct catalytic reduction of 3,6-di(2-chloro- benzy1idene)piperazine-2,5-dione (2) to (�)-cis-3,6-di(2-chlorobenzyl)piperazine-2,5-dione (6) was also accomplished.
The trans- and (�) cis-isomers of 1,4-dimethyl-and 1,4-diacetyl-3,6-dibenzylpiperazine-2,5-dione were synthesized. The hydriodic acid reduction of 3,6-dibenzylidene-1,4-dimethylpiperazine-2,5-dione gave (�)-cis-3,6-dibenzyl-1,4-dimethylpiperazine-2,5-dione although this product has previously been assigned the trans-geometry. The unknown isolated from the permanganate oxidation of (�)-cis- 1,4-diacetyl-3,6-dibenzylpiperazine-2,5- has been identified as the corresponding trans-isomer.
Quinoid single molecules are regarded as promising materials for electronic applications due to their tunable chemical structure-driven properties. A series of three single bio-inspired quinoid materials containing para-azaquinodimethane (p-AQM) moiety were designed, synthesized and characterized. AQM1, AQM2 and AQM3, prepared using aldehydes derived from almonds, corncobs and cinnamon, respectively, were studied as promising quinoid materials for optoelectronic applications. The significance of facile synthetic procedures is highlighted through a straightforward two-step synthesis, using Knoevenagel condensation. The synthesized molecules showed molar extinction coefficients of 22,000, 32,000 and 61,000 L mol−1 cm−1, respectively, for AQM1, AQM2 and AQM3. The HOMO-LUMO energy gaps were calculated experimentally, theoretically showing the same trends: AQM3 < AQM2 < AQM1. The role of the aryl substituent was studied and showed an impact on the electronic properties. DFT calculations show planar structures with quinoidal bond length alternation, in agreement with the experimental results. Finally, these bio-based materials showed high thermal stabilities between 290 °C and 340 °C and a glassy behavior after the first heating–cooling scan. These results highlight these bio-based single molecules as potential candidates for electronic or biomedical applications.