24706-50-1Relevant articles and documents
Tailoring of spectral response and intramolecular charge transfer in β-enaminones through band gap tuning: Synthesis, spectroscopy and quantum chemical studies
Misra, Ramprasad,Chakraborty, Pushkin,Roy, Subhas C.,Maity,Bhattacharyya
, p. 36811 - 36822 (2016)
In this paper, we investigate the synthetic tailoring of the spectral response and intramolecular charge transfer (ICT) of β-enaminones through bandgap modulation. Two donor/acceptor substituted β-enaminones, namely, 3-(4-methoxyphenylamino)-2-cyclohexen-1-one (OACO) and 3-(4-nitrophenylamino)-2-cyclohexen-1-one (NACO) have been synthesized along with their unsubstituted counterpart, 3-(phenylamino)-2-cyclohexen-1-one (PACO). Steady state as well as time resolved spectroscopic techniques with picosecond resolution are used to record their spectral responses. Substitution of the donor group (-OCH3) mildly enhances the charge transfer from the phenyl ring to the enaminone moiety, while substitution of the acceptor group (-NO2) jeopardizes the charge transfer through mutual electron withdrawing effects of PNA and enaminone moieties. Combined experimental and quantum chemical investigations reveal that the ground state photophysics of OACO and NACO in water are controlled by both microscopic and macroscopic solvation with dominant contribution from the former. Time dependent density functional theory (TDDFT) calculations predict that the HOMO to [LUMO+1] transition gives rise to the absorption spectra of OACO in water, while the absorption by the enaminone moiety of NACO arises as a result of a HOMO to LUMO transition. A crossing between the first (S1) and the second excited (S2) states takes place in the microclusters of PACO, OACO and NACO with water. The intersystem crossing (ISC) has been found to be the major reason for low quantum yields in these molecules. The band gap modulation through waxing and waning of the conjugation strength is expected to throw light on many ICT-driven processes and provides means of tuning the properties depending on it.
Intermolecular Multiple Dehydrogenative Cross-Couplings of Ketones with Boronic Acids and Amines via Copper Catalysis
Wang, Tianzhang,Chen, Guowei,Lu, Yu-Jing,Chen, Qian,Huo, Yanping,Li, Xianwei
supporting information, p. 3886 - 3892 (2019/07/19)
An efficient and versatile oxidative coupling reaction was developed for the synthesis of valuable β-functionalized unsaturated ketones and meta-substituted phenols. In the case of intramolecular reactions, achieving rapid molecular complexity through multiple dehydrogenative couplings is already a well-established strategy. Herein, we report an intermolecular multiple dehydrogenative coupling between ketones and nucleophilic amines or boronic acids using inexpensive copper(I) oxide as a catalyst. This method provides a facile access to highly desirable chemical products such as α,β-unsaturated ketones, enaminones, and synthetically relevant meta-substituted phenols. (Figure presented.).
Hypervalent Iodine(III)-Mediated Counteranion Controlled Intramolecular Annulation of Exocyclic β-Enaminone to Carbazolone and Imidazo[1,2-a]pyridine Synthesis
Bhattacherjee, Dhananjay,Ram, Shankar,Chauhan, Arvind Singh,Yamini,Sheetal,Das, Pralay
supporting information, p. 5934 - 5939 (2019/04/08)
A highly efficient and flexible protocol for intramolecular annulation of exocyclic β-enaminones has been disclosed for the synthesis of carbazolones and imidazo[1,2-a]pyridines through a counter-anion-controlled free-radical mechanism promoted by hypervalent iodine(III). The cooperative behavior of HTIB and AgSbF6 plays a crucial role in the intramolecular annulation process through C?C and C?N bond formation to give the desired products. The mechanistic insights suggest that the two competitive reactions involved in the system are guided by the nature of the counteranion, which determines the formation of the final products. A wide variety of carbazolones and imidazo[1,2-a]pyridine molecules have been prepared and isolated in good to excellent yields.
