Advances in Indole Chemistry: Regiodivergent Annulations and Bridged Azacycle Synthesis

An important aspect for the research and development of new drug therapies is the ability to use modular synthetic methods to rapidly access structurally diverse drug-like building blocks. Nitrogen-containing heterocycles represent one of the most prevalent structural motifs found in pharmaceutical agents and biologically active natural products. However, despite their ubiquity, existing methods for accessing these structures often remain limited in scope, efficiency, and structural diversity, particularly when targeting densely functionalized or sterically demanding scaffolds from simple starting materials. To address this problem, the research described in this dissertation focuses on the design and development of (3+2) annulation reactions for the direct synthesis of diverse cyclohexa-fused indoline compounds This reaction technology enables rapid and regioselective construction of indoline cores with unique substitution patterns that would be challenging or cannot be easily accessed with existing methods. Key to this approach is the use of mechanistically informed reaction design to control regiochemical outcomes under mild conditions with a broad substrate scope. Moreso, using previously published methodologies by our lab, these annulative products serve as highly functionalized intermediates amenable to further structural elaboration. In particular, they can be modified to incorporate bridged azacycles within the gross structure; thereby expanding the accessible chemical space and enabling the exploration of novel three-dimensional architectures. This capacity for modular diversification aligns with the broader goal of generating compound libraries with maximized structural diversity, favorable for drug discovery. Overall, the methodologies described herein not only expand the synthetic toolbox for nitrogen heterocycle construction but also invite new opportunities for accessing molecular architectures that are both challenging to prepare and relevant to pharmaceutical research. By enabling the streamlined synthesis of complex, stereochemically rich scaffolds from simple starting materials, these strategies contribute to the efficient exploration of underrepresented regions of biologically relevant chemical space

Liraglutide, a once-daily human GLP-1 analogue, added to a sulphonylurea over 26 weeks produces greater improvements in glycaemic and weight control compared with adding rosiglitazone or placebo in subjects with Type 2 diabetes (LEAD-1 SU)

Aim: To compare the effects of combining liraglutide (0.6, 1.2 or 1.8 mg/day) or rosiglitazone 4 mg/day (all n ≥ 228) or placebo (n = 114) with glimepiride (2-4 mg/day) on glycaemic control, body weight and safety in Type 2 diabetes. Methods: In total, 1041 adults (mean ± sd), age 56 ± 10 years, weight 82 ± 17 kg and glycated haemoglobin (HbA1c) 8.4 ± 1.0% at 116 sites in 21 countries were stratified based on previous oral glucose-lowering mono : combination therapies (30 : 70%) to participate in a five-arm, 26-week, double-dummy, randomized study. Results: Liraglutide (1.2 or 1.8 mg) produced greater reductions in HbA1c from baseline, (-1.1%, baseline 8.5%) compared with placebo (+0.2%, P < 0.0001, baseline 8.4%) or rosiglitazone (-0.4%, P < 0.0001, baseline 8.4%) when added to glimepiride. Liraglutide 0.6 mg was less effective (-0.6%, baseline 8.4%). Fasting plasma glucose decreased by week 2, with a 1.6 mmol/l decrease from baseline at week 26 with liraglutide 1.2 mg (baseline 9.8 mmol/l) or 1.8 mg (baseline 9.7 mmol/l) compared with a 0.9 mmol/l increase (placebo, P < 0.0001, baseline 9.5 mmol/l) or 1.0 mmol/l decrease (rosiglitazone, P < 0.006, baseline 9.9 mmol/l). Decreases in postprandial plasma glucose from baseline were greater with liraglutide 1.2 or 1.8 mg [-2.5 to -2.7 mmol/l (baseline 12.9 mmol/l for both)] compared with placebo (-0.4 mmol/l, P < 0.0001, baseline 12.7 mmol/l) or rosiglitazone (-1.8 mmol/l, P < 0.05, baseline 13.0 mmol/l). Changes in body weight with liraglutide 1.8 mg (-0.2 kg, baseline 83.0 kg), 1.2 mg (+0.3 kg, baseline 80.0 kg) or placebo (-0.1 kg, baseline 81.9 kg) were less than with rosiglitazone (+2.1 kg, P < 0.0001, baseline 80.6 kg). Main adverse events for all treatments were minor hypoglycaemia (< 10%), nausea (< 11%), vomiting (< 5%) and diarrhoea (< 8%). Conclusions: Liraglutide added to glimepiride was well tolerated and provided improved glycaemic control and favourable weight profile. Diabet. Med. 26, 268-278 (2009)

Graphene quantum dots from chemistry to applications

Graphene quantum dots (GQDs) have been widely studied in recent years due to its unique structure-related properties, such as optical, electrical and optoelectrical properties. GQDs are considered new kind of quantum dots (QDs), as they are chemically and physically stable because of its intrinsic inert carbon property. Furthermore, GQDs are environmentally friendly due to its non-toxic and biologically inert properties, which have attracted worldwide interests from academic and industry. In this review, a number of GQDs preparation methods, such as hydrothermal method, microwave-assisted hydrothermal method, soft-template method, liquid exfoliation method, metal-catalyzed method and electron beam lithography method etc., are summarized. Their structural, morphological, chemical composition, optical, electrical and optoelectrical properties have been characterized and studied. A variety of elemental dopant, such as nitrogen, sulphur, chlorine, fluorine and potassium etc., have been doped into GQDs to diversify the functions of the material. The control of its size and shape has been realized by means of preparation parameters, such as synthesis temperature, growth time, source concentration and catalyst etc. As far as energy level engineering is concerned, the elemental doping has shown an introduction of energy level in GQDs which may tune the optical, electrical and optoelectrical properties of the GQDs. The applications of GQDs in biological imaging, optoelectrical detectors, solar cells, light emitting diodes, fluorescent agent, photocatalysis, and lithium ion battery are described. GQD composites, having optimized contents and properties, are also discussed to extend the applications of GQDs. Basic physical and chemical parameters of GQDs are summarized by tables in this review, which will provide readers useful information

Synthesis of Functionalized Hexahydrocarbazoles by Beckmann Elimination and Nucleophile-Intercepted Beckmann Fragmentation

The Beckmann elimination and nucleophile-intercepted Beckmann fragmentation (NuBFr) of oximes starting from regioisomeric indolinyl bicyclic ketones lead to products that are subjected to further synthetic manipulations and ultimately result in the stereospecific formation of densely functionalized hexahydrocarbazoles. The Pd-catalyzed Suzuki–Miyaura cross-coupling reaction of a key alkenyl bromide intermediate with various boronic acids gives arylated products