Peroxynitrite is a highly reactive oxidant that has been implicated in a number of serious human diseases including cardiopathy, acute inflammation and cancer. The decomposition of peroxynitrite can be promoted efficiently by metalloporphyrins and are therefore important to detoxify the cytotoxic oxidant as therapeutic agents. A novel cobalt porphyrin was synthesized to investigate the scavenging effect on peroxynitrite decomposition. Kinetics of peroxynitrite decomposition in the presence of cobalt porphyrin was studied by UV-Vis spectrophotometer and stopped flow instrument. The kinetic experiments reveal that cobalt porphyrin could accelerate the decomposition of peroxynitrite and the catalytic ability is improved with the increasing concentration of cobalt porphyrin. The study is helpful to develop more effective scavengers of peroxynitrite in order to treat related diseases.
Numerous electrophilic thiocyano oxyfunctionalization reactions of alkenes have been achieved using N-thiocyano-dibenzenesulfonimide, which is a new electrophilic thiocyanation reagent and could be easily prepared in two steps from dibenzenesulfonimide. This approach provides efficient, simple, and modular methods for the formation of SCN-containing heterocycles such as lactones, tetrahydrofurans, dihydrofurans, and dihydrobenzofurans in moderate to excellent yields. Meanwhile, diverse oxa-quaternary centers were rapidly constructed. Additionally, this protocol is free of transition metals and features broad substrate toleraance and mild reaction conditions.
A tandem dearomative electrophilic thiocyanation/cyclization/acylation of indoles was developed for the first time, which is enabled by acyl chloride. A variety of 3-SCN pyrroloindolines were obtained with moderate to excellent yields. Interestingly, following replacement of acyl chloride with methanesulfonic acid, 2-SCN tryptamines were obtained using the same starting substrates and reagents. Furthermore, catalytic enantioselective manner of thiocyanation/cyclization/acylation reaction was also studied. An enantiomer self-disproportionation effect of 3-SCN pyrroloindolines was discovered. A series of chiral 3-SCN pyrroloindolines were obtained with high enantioselectivities.
A new set of ciprofloxacin (CPFX)‐isatin‐1 H ‐1,2,3‐triazole hybrids 6a – l with greater lipophilicity compared with the parent CPFX was designed, synthesized, and assessed for their in vitro anti‐mycobacterial activity against Mycobacterium tuberculosis (MTB) H 37 Rv as well as cytotoxicity in VERO cell line. The preliminary results showed that all hybrids (MIC: 0.39–50 μg/mL) exhibited promising activities against MTB H 37 Rv, and six of them (MIC: 0.39–1.56 μg/mL) were more active than the parent CPFX (MIC: 3.12 μg/mL). In particular, the most active conjugate 6h (MIC: 0.39 μg/mL) was comparable with RIF (MIC: 0.39 μg/mL), and eight times more potent than CPFX. All conjugates (CC 50 : 4–64 μg/mL) were more toxic than the parent (CC 50 : 128 μg/mL) in VERO cell lines, and the most active hybrids, which also displayed the highest cytotoxicity, should be further optimized.
Four metal tetracarboxyl phthalocyanines were synthesized and characterized by elemental analysis and mass spectrometry. p-Nitrobenzoic acid was efficiently prepared in high yield from bromide-free and acetic acid-free aerobic oxidation of p-nitrotoluene using metal phthalocyanines as catalysts under mild conditions in alkali−methanol solution. Up to 88.8% isolated yield of p-nitrobenzoic acid was obtained with the catalysis of tetracarboxyl phthalocyanine cobalt (0.13 mol %, based on the moles of p-nitrotoluene) optionally combined with a small amount of dimethylformamide in the presence of 2.0 MPa dioxygen at 30−60 °C. The effect on catalytic performance of a carboxyl group introduced into the phthalocyanine ring was further discussed on the basis of metal coordination chemistry theory.
An electrophilic thiocyano semipinacol rearrangement of allylic alcohols has been achieved for the first time by using N-thiocyano-dibenzenesulfonimide (NTSI). This approach provides a direct, simple, and efficient strategy for the formation of thiocyano carbonyl compounds with moderate to excellent yields. Meanwhile, an all-carbon quaternary center was rapidly constructed. In addition, an asymmetric version of this tandem reaction was preliminarily investigated.
An efficient method for the preparation of chiral sulfenylated lactones was described based on Lewis base-catalyzed enantioselective sulfenylation of alkenes.
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