o-(2-Thienyl)vinylarene as an Alternative Synthetic Motif for Porphyrinoids: o-Arene-Connected Porphyrinoids.

o-Arene-connected porphyrinoids were synthesized with o-(2-thienyl)vinylarene motif as a new building block for porphyrinoids. This motif can replace meso-aryl-substituted dipyrromethene and serve as a command key arranging o-connectivity of porphyrinoid. While 6a (benzene version) is very weak, 6b (pyridine version) shows a substantial amount of diatropic ring current due to reduced steric hindrance (without H23) and rigidified Pd-6a became more aromatic than 6b.

Isolation of a Melanoblast Stimulator from Dimocarpus longan, Its Structural Modification, and Structure-Activity Relationships for Vitiligo.

A novel melanoblast stimulator (1) was isolated from Dimocarpus longan. Its analogs were also synthesized to support a new furan-based melanoblast stimulator scaffold for treating vitiligo. Isolated 5-(hydroxymethyl)furfural (HMF, 1) is a well-known compound in the food industry. Surprisingly, the melanogenic activity of HMF (1) was discovered here for the first time. Both HMF and its synthetic analog (16) promote the differentiation and migration of melanoblasts in vitro. Typically, stimulator (1) upregulated MMP2 expression, which promoted the migration of melanoblasts in vitro.

Tuned Cd2+ Selectivity: Showcase of Electronic and Regio-Effect of π-Extended Di-2-Picolylamine-Substituted Quinoline-Based Tolans.

π-Extended di-2-picolylamine (DPA)-substituted 8-hydroxyquinoline (8-HQ) tolans (2) were synthesized for testing electronic and regio-effects. The electron-poor CN-tolan (2b) showed clear selectivity for Cd2+ (>>Zn2+) over other metal ions via turn-on fluorescence, while the electron-rich MeO-tolan (2a) displayed no clear metal selectivity. Furthermore, considering that there was no significant energy difference between the Cd2+ complexes of 1 and 2b, the intended regio-effect (7- vs. 5-substituted effect) did not induce steric hindrance. Thus, the regio-effect is mainly electronic. Considering the above, 2a and 2b constitute a complete showcase in which electronic and regio-effects modulate the metal selectivity. The fluorescence titration of 2b (10 mM) with Cd2+ showed that the limit of detection (LOD) of the Cd2+-selective 2b was 158 nM in PBS (phosphate-buffered saline) (10 mM, pH 7.2) containing 50% MeOH.

Systematic Modifications of a Simple Tolan: Another Category of Viscosity Sensor.

The first tolan derivative-based viscosity sensor (5d) has been synthesized, and its fluorescence intensity and lifetime increase when the viscosity of the solvent increases in methanol-glycerol mixtures. Phthalide (5d) was selected among structurally diverse tolan derivatives through systematic modifications of a simple tolan. To test 5d as a viscosity sensor, fluorescence lifetime imaging (FLIM) images of HeLa cells were obtained upon treatment with 5 µM of 5d to map the viscosity of the HeLa cells.

A facile approach for the synthesis of C13-C24 fragments of maltepolides A, C and D.

A linear, chiron approach for the synthesis of C13-C24 fragments of cytostatic maltepolides A, C and D consisting of a tetrahydrofuran subunit and a chiral alkenyl/alkyl substituent is achieved from (+)-diethyl l-tartrate. The other chiral stereocenters were generated by employing key reactions such as Crimmins aldol, alkynylation and CeCl3·7H2O mediated Luche reduction reactions.