A Highly Selective Fluorescent Probe for Hydrogen Sulfide and its Application in Living Cell.

A new Near-infrared fluorescent probe for hydrogen sulfide detection was synthesized by employing dicyanoisophorone based fluorescence dye as a fluorophore and methyl 3-(2-(carbonyl)phenyl)-2-cyanoacrylate group as the response unit. The Probe DCI-H2S showed a long emission wavelength (λem = 674 nm). Based on the H2S-induced addition-cyclization of deprotecting methyl 3-(2-(carbonyl)phenyl)-2-cyanoacrylate group, the probe DCI-H2S showed high selectivity, sensitivity and response speed toward hydrogen sulfide under room temperature. These numerous advantages of the probe DCI-H2S make it to potentially detect endogenous hydrogen sulfide in living organisms.

CuBr/NHPI co-catalyzed aerobic oxidative [3 + 2] cycloaddition-aromatization to access 5,6-dihydro-pyrrolo[2,1-a]isoquinolines.

An efficient and enviromentally friendly CuBr/NHPI co-catalyzed aerobic oxidative [3 + 2] cycloaddition-aromatization cascade was realized with N-substituted tetrahydroisoquinolines and electron-deficient olefins. Under the mild conditions, the reaction proceeded smoothly and displayed excellent functional group tolerance, affording 5,6-dihydro-pyrrolo[2,1-a]isoquinolines in good to high yields. This protocol exhibits a broad substrate scope to both N-alkyl tetrahydroisoquinolines and dipolarophile substrates.

Chemical constituents from Ginkgo biloba leaves and their cytotoxicity activity.

One novel neoligan glucoside, Ginkgoside B (1), and one new glucose ester, 6-O-(4-hydroxyhydrocinnamoyl)-D-glucopyranose (2), along with nine known compounds (3-11) were isolated from the ethanol extract of Ginkgo biloba leaves. Their structures were elucidated by combination of spectroscopic analyses and alkaline methanolysis. The absolute configuration of compound 1 was determined by single-crystal X-ray diffraction. All the isolated compounds were evaluated for their cytotoxicity activities, and compound 11 exhibited IC50 values of 36.20 and 58.95 µM against 5637 and HeLa cell lines, respectively.

Isolation, structure elucidation, tyrosinase inhibitory, and antioxidant evaluation of the constituents from Angelica dahurica roots.

Two undescribed phenolic compounds, angelicols A (1) and B (2) and one undescribed coumarin rhamnoside, angelicoside A (3), together with 17 known compounds (4-20) were isolated from the roots of Angelica dahurica. Their structures were characterized by physical data analyses such as NMR, HRESIMS, and X-ray diffraction. Compounds 2, 3, 5, 6 and L-ascorbic acid (positive control) exhibited obvious DPPH radical scavenging activities with IC50 values of 0.36 mM, 0.43 mM, 0.39 mM, 0.44 mM, 0.25 mM, respectively. At a concentration of 25 µM, all compounds showed weaker tyrosinase inhibition activities (%inhibition < 5%) than kojic acid (26.00 ± 0.67%, IC50 = 44.29 ± 0.06 µM).

An ESIPT-Based Fluorescent Probe for Hydrazine Detection in Aqueous Solution and its Application in Living Cells.

A new fluorescent probe based on "protection-deprotection" sequence and the excited-state intramolecular proton transfer (ESIPT) effect was designed and synthesized. The probe responds rapidly and high selectively toward hydrazine at room temperature, and exhibits a low detection limit of 0.016 µM (0.512 ppb), which is well below the safety level (10 ppb) as regulated by EPA. Moreover, it can be applied for the imaging of hydrazine in living cells.

6-Benz-yloxy-2-phenyl-pyridazin-3(2H)-one.

In the title compound, C(17)H(14)N(2)O(2), the central pyridazine ring forms dihedral angles of 47.29 (5) and 88.54 (5)° with the benzene rings, while the dihedral angle between the benzene rings is 62.68 (6)°. In the crystal, molecules are linked by two weak C-H⋯O hydrogen bonds and three weak C-H⋯π inter-actions.

rac-Ethyl 4-hy-droxy-4-trifluoro-methyl-6-(2,4,5-trimeth-oxy-phen-yl)-2-thio-1,3-diazinane-5-carboxyl-ate.

In the title compound, C(17)H(21)F(3)N(2)O(6)S, the hexa-hydro-pyrimidine ring adopts a half-chair conformation: the mean plane formed by the ring atoms excluding the C atom bonded to the eth-oxy-carbonyl group has an r.m.s. deviation of 0.0427 Šand forms a dihedral angle of 66.41 (5)° with the benzene ring. The mol-ecular conformation is stabilized by an intra-molecular hydroxyl O-H⋯O(carbox-yl) hydrogen bond, generating an S(6) ring. In the crystal, pairs of N-H⋯S and N-H⋯O hydrogen bonds give rise to the formation of two-dimensional networks lying parallel to the ab plane, which incorporate graph-set motifs R(2) (2)(8) and R(2) (2)(16), respectively.

2-Benzyl-6-benz-yloxypyridazin-3(2H)-one.

In the title compound, C(18)H(16)N(2)O(2), the central pyridazine ring forms dihedral angles of 77.08 (5)° and 84.62 (5)° with the two benzene rings. The dihedral angle between the two benzene rings is 68.18 (4)°. A very weak intra-molecular C-H⋯N hydrogen bond and an intra-molecular C-H⋯π inter-action occur. The crystal structure is stabilized by weak inter-molecular C-H⋯O hydrogen bonds and weak C-H⋯π and π-π stacking inter-actions [centroid-centroid distance = 3.6867 (10) Å].

1,3-Bis(4-meth-oxy-benz-yl)-6-methyl-pyrimidine-2,4(1H,3H)-dione.

The title compound, C(21)H(22)N(2)O(4), was prepared by reaction of 6-methyl-pyrimidine-2,4(1H,3H)-dione and 1-chloro-methyl-4-meth-oxy-benzene. In the title mol-ecule, the central pyrimidine ring forms dihedral angles of 62.16 (4) and 69.77 (3)° with the two benzene rings. In the crystal, weak inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into chains.

6-Hy-droxy-4-(pyridin-3-yl)-5-(2-thienyl-carbon-yl)-6-trifluoro-meth-yl-3,4,5,6-tetra-hydro-pyrimidin-2(1H)-one.

In the title compound, C(15)H(12)F(3)N(3)O(3)S, the pyrimidine ring adopts a half-chair conformation with the mean plane formed by the ring atoms excluding the C atom bonded to thio-phene-2-carbonyl group lying nearly perpendicular to the pyridine and thio-phene rings, making dihedral angles of 84.91 (4) and 87.40 (5)°, respectively. The dihedral angle between the pyridine and thio-phene rings is 54.44 (5)°. The crystal structure is stabilized by inter-molecular O-H⋯O and N-H⋯N hydrogen bonds and weak C-H⋯O inter-actions further consolidate the structure.