Preparation Of Novel Kind Of AIE Materials And Synthesis Of Thiazepine, Indolizine Derivatives

Heterocyclic chemistry plays important roles in modern organic chemistry; it is one of the most active fields in synthetic chemistry. Nitrogen-and Sulphur-containing compounds are numerous and wildly existed in nature, their bioactivities and functional abilities have shown great value to human. Nitrogen-and Sulphur-containing molecular have been wildly applied for OLED materials, bio-probe, depressant and anti-tumor reagents. We have been focusing on the development of direct synthesis of heterocyclic systems using tandem reactions.Part 1 Novel kind of Aggreation Induced Emission MaterialsFluorescent materials have a long history. But AIE luminophors were new kind of materials.This new kind of luminophors have plenty of advantages, unlike tradational photophysical materials, the fluorescence emission was enhanced rather than quenched after aggregation. Traditional fluorenscent compounds have large π-conjugated frameworks like plates. After molecules aggregated, the fluorescence quenched. It is widely known as aggregation-caused quenching (ACQ) effect, this effect has greatly limited the practical application of luminescent materials.To avoid ACQ effect, two common methods were used:adding big blocking groups or diluting the molecules in electricity conducting polymers. But it either increased the synthetic difficulty or reduced the efficiency. AIE (aggregation-induced emission) material was first reported by Tang’s group at 2001. Different from traditional methodologies, AIE structure was proved to be a promising way to elminate ACQ (aggregation-caused quenching) effect perfectly. So it has been wildly used in all kinds of areas, such as organic lihgting-emitting diodes (OLEDs), Chemosensors (CO2, HSO3- detection) and bioprobe (DNA, RNA analysis). Base on an accident discover, novel kind of AIE material was synthsized and applied as HSO3- and cysteine bioprobe.Chaptor 1:Bisulfite is usually used as preservative for foods, beverages, and pharmaceutical products. It acts like antioxidant, antimicrobial agent and enzyme inhibitor during production and storage. But recent research discovered that certain concentration levels of bisulfite can cause asthmatic attacks, oculonasal symptoms, and allergic reaction in some sulfite-sensitive individuals. Therefore, it is very important to develop a quick, low cost, sensitive and selective method for bisulfite determination.Herein, we reported the design and synthesis of 2-phenylisothiazolo [5,4-b]pyridin-3(2H)-one which can act as a high sensitive and selective sensor for rapid and efficient detection of bisulfite in water.Chapter 2:A facile and efficient method was developed for the synthesis of isothiazolo[5,4-b]pyridin-3(2H)-one derivatives. This new type of AIE materials were studied through photophysical analysis, X-ray and theoretical calculations. At last, based on a ring-opening reaction, we found a useful application of this material on cysteine detection.Part 2:One-pot synthesis of thiazolinone derivatives through Smiles rearrangementsPyridazinone moiety is widely used because of its biological and medicinal properties. Many pyridazinone derivatives are analgesic, antimicrobial, herbicidal, anti-inflammatory, antihypertensive, and antitumor.The traditional methods for the synthesis of pyridazinopyrido [3,2-f][1,4]thiazepine-diones proceeded through several steps and involved tedious treatment. Herein, we report an efficient and convergent approach to assemble thiazepine-dione derivatives with commercially available and prepared starting materials. To construct the tricyclic system, a method of tandem reaction via coupling/Smiles rearrangement/cyclization is developed.Chapter 1:A transition metal-free methodology for the synthesis of pyridazinopyrido[3,2-f][1,4]thiazepine-diones was studied. The construction of this tricyclic system went through a one-pot coupling/Smiles rearrangement/cyclization process. The high yields of pure products were obtained through simple recrystallization.Chapter 2:A series of 1,4-thiazepin-5(4H)-one derivatives were synthesized via a transition metal-free one-pot Smiles rearrangement process at room temperature. Regioselective seven-membered heterocycles were constructed in good to excellent yields. To get an in-depth understanding of the S-N type SR (Smiles Rearrangement) mechanism, a theoretical study was also performed by quantum chemistry calculations.Part 3 New routes for the synthesis of indolizines through tandem reactions.A series of transition metal-free tandem reactions for the synthesis of indolizines and 6,7-dihydroindolizin-8(5H)-ones by 4-bromobut-2-enoate ramifications reacted with 2-acetyl pyrrole derivatives are described. As the a-carbon changed from CH3, CH2CI, CHCl2, to CCl3, different kinds of tandem reactions were observed. These tandem reactions could be used to synthesize fused indolizine and indolizidine scaffolds under mild and green conditions.