Efficient Approaches to S-Alkyl-N-alkylisothioureas: Syntheses of Histamine H3 Antagonist Clobenpropit and Its Analogues

Incorporating Thiourea into Fluorescent Probes: A Reliable Strategy for Mitochondrion-Targeted Imaging and Superoxide Anion Tracking in Living Cells

Three aggregation-induced emission active fluorescent compounds, TPA-Pyr-Octane, TPA-Pyr-Br, and TPA-Pyr-Thiourea (TPA = triphenylamine pyridinium), are synthesized; their tiny differences in chemical structures result in a huge difference in cell-imaging applications. Especially, incorporating thiourea into fluorescent probes is found as a reliable strategy for mitochondrion-targeted imaging and superoxide anion tracking in living cells, which is possibly due to the presence of hydrogen bonding between thiourea and mitochondrion proteins. This finding is very useful for the design of biosensors and delivery carriers in disease treatment.

Development of New Synthetic Reactions Using Hetero-Heavy Atoms and Their Application to Synthesis of Biofunctional Molecules

Novel reactions using hetero-heavy atoms (P, S, Si, Se, and Sn) were developed and applied to the synthesis of biofunctional molecules and some medicine-candidates, in which the following items are covered. 1) Development of introduction of C₁-unit using cyanophosphates (CPs). 2) Carbene-generation under neutral condition from CPs and its application to organic synthesis. 3) [3,3]Sigmatropic rearrangement-ring expansion reactions of medium-sized cyclic thionocarbonates containing a sulfur atom and their application to natural product synthesis. 4) Stereoselective synthesis of novel β-imidazole C-nucleosides via diazafulvene intermediates and their application to investigating ribozyme reaction mechanism. 5) Developments of novel histamine H₃- and H₄-receptor ligands using new synthetic methods involving Se or Sn atoms.

Synthesis of anti-allergic drugs

Histamine is formed by the decarboxylation of histidine catalyzed by enzymes. It is an endogenous biologically active substance involved in multiple complex physiological processes as an important chemical transmitter. Histamine receptors have four subtypes, H₁, H₂, H₃ and H₄, all of which are G protein coupling receptors (GPCRs) with different physiological functions. Histamine plays an important role in the pathophysiological mechanism of allergic diseases, and the antagonistic effect of histamine has become an important way to study anti-allergic drugs, wherein the anti-allergic drugs used in clinical practice are mainly H₁ receptor antagonists. Currently, there are many varieties of H₁ receptor antagonists in clinical applications, which can be divided into ethylenediamine antagonists, amino ether antagonists, propylamine antagonists, tricyclic antagonists, piperazine antagonists and piperidine antagonists depending on their chemical structures. This article mainly reviews the research progress of allergic reactions with histamine H₁ receptor antagonists and expounds the important aspects of the design and synthesis of various new compounds.

Histamine is formed by the decarboxylation of histidine catalyzed by enzymes. It is an endogenous biologically active substance involved in multiple complex physiological processes as an important chemical transmitter.

A greener approach for impressive removal of As(iii)/As(v) from an ultra-low concentration using a highly efficient chitosan thiomer as a new adsorbent

Contamination of ground water with arsenic is a serious problem all over the world.

A green and highly efficient sulfur functionalization of starch

An innovative green approach to achieve thiol functionalization of starch with a degree of substitution ≥ 2.

Synthetic applications of hypophosphite derivatives in reduction

The purpose of this review is to collect the applications in fine synthesis of hypophosphite derivatives as reducing agents.

Synthesis of Closo-1,7-Carboranyl Alkyl Amines

Of the three closo-carborane isomers (C(2)B(10)H(12)), closo-1,2-carborane has been used most widely in the synthesis of carboranyl amines. However, closo-1,2-carboranes are prone to deboronation to nido-7,8-carborane under various conditions including attack by basic amino groups. In order to overcome this problem, closo-1,7-carboranyl ethyl-, propyl-, and butylamine were synthesized, which should be more stable towards basic deboronation than their closo-1,2-carboranyl counterparts. These closo-1,7-carboranyl amines (5, 18 and 19) were synthesized using two different methods, both starting from the corresponding closo-1,7-carboranyl alkyl iodides (3, 14 and 15). One of the carboranyl alkyl amine (5) was conjugated with folic acid to form a closo-1,7-carborane-folic acid bioconjugate (20).