(6S,7S,8S,8aS)-6-Ethyl-7,8-dihy­droxy-1,5,6,7,8,8a-hexa­hydro­indolizin-3(2H)-one monohydrate

The absolute configuration of the title compound, C10H17NO3·H2O, was assigned from the synthesis. In the mol­ecular structure, the central six-membered ring of the indolizine moiety adopts a chair conformation, with two atoms displaced by −0.578 (2) and 0.651 (1) Å from the plane of the other four atoms [maximum deviation 0.019 (2) Å] The conformation of the fused oxopyrrolidine ring is close to that of a flat envelope, with the flap atom displaced by 0.294 (1) Å from the plane through the remaining four atoms. In the crystal, one of the hy­droxy groups is hydrogen-bonded to two water mol­ecules, while the other hy­droxy group exhibits an inter­molecular hydrogen bond to the carbonyl O atom, resulting in a chain parallel to the b axis

(7R,8S,8aS)-8-Hydr­oxy-7-phenyl­perhydro­indolizin-3-one

In the title compound, C14H17NO2, the six-membered ring of the indolizine system adopts a chair conformation. In the crystal, mol­ecules form chains parallel to the b axis via inter­molecular O—H⋯O hydrogen bonds. The absolute mol­ecular configuration was assigned from the synthesis

Boron-doped diamond as the new electrode material for determination of heavy metals

Abstract Nowadays, the new material -boron-doped diamond represents the perspective electrode material which exhibits wide potential range, lower noise and residual current and can be applied in the various solvents, with good resistance to passivation and high chemical stability. The important part of this paper was the study of Zn(II)/Zn redox system using cyclic voltammetry and optimizing of stripping analysis parameters (deposition potential and time). The low limit of detection (3×10 -9 mol L -1 ) and quantification (1×10 -8 mol L -1 ) indicate that differential pulse anodic stripping voltammetry is a highly sensitive electrochemical method suitable for samples with trace amounts of Zn and other heavy metals. This work also builds on the current trend in the development of new electrode materials and electrochemical study of the environmental samples

(3aR,8aS,9S,9aR)-9-Hydroxy­perhydro­furo[3,2-f]indolizin-6-one

In the title compound, C10H15NO3, the central six-membered ring of the indolizine system adopts a chair conformation, while the oxopyrrolidine and hydro­furan rings attached to the indolizine ring system have envelope conformations. In the crystal, the mol­ecules form chains parallel to the b axis via inter­molecular O—H⋯O hydrogen bonds. The absolute configuration was assigned from the synthesis

(7R,8R,8aS)-8-Hydr­oxy-7-phenyl­per­hydro­indolizin-3-one

The absolute configuration of the title compound, C14H17NO2, was assigned from the synthesis. There are two mol­ecules in the asymmetric unit. Their geometries are very similar and corresponding bond lengths are almost identical [mean deviation for all non-H atoms = 0.015 (2) Å]. The six-membered ring of the indolizine system adopts a chair conformation. In the crystal structure, mol­ecules form chains parallel to the a axis via inter­molecular O—H⋯O hydrogen bonds, which help to stabilize the crystal structure

(8aS)-7,8,8a,9-Tetra­hydro­thieno[3,2-f]indolizin-6(4H)-one

In the mol­ecular structure of the title compound, C10H11NOS, the central six-membered ring of the indolizine unit adopts an envelope conformation, the maximum deviations from the mean plane of the ring being 0.533 (2) Å. The fused thieno ring is nearly coplanar [mean deviation = 0.007 (2) Å]. The conformation of the fused oxopyrrolidine ring is close to that of a flat-envelope, with a maximum deviation of 0.339 (3) Å. The crystal structure is stabilized by C—H⋯O hydrogen bonds

Application of Screen Printed Diamond Electrode, Coupled with “Point-of-Care” Platform, for Nanomolar Quantification of Phytonutrient Pterostilbene in Dietary Supplements: An Experimental Study Supported by Theory

Herein, a screen–printed diamond electrode (SPDE) coupled with a “point-of-care” platform (30 µL-drop concepts, single-drop-detection approach) was successfully applied for the electrochemical determination of pterostilbene (PTS). Cyclic voltammetry identified irreversible oxidation of PTS, where oxidation peak was shown to be strongly dependent on the pH of the working environmental. Although the proposition of the detailed electrochemical oxidation mechanism of PTS goes out of the scope of the present research, we have determined the most probable reactive site of our analyte, by utilizing DFT-based reactivity descriptors (Fukui functions). For electrochemical quantification of PTS, oxidation peak at 0.32 V (vs. Ag/AgCl) was followed in presence of 0.5 mol L−1 of Briton–Robinson buffer solution (pH = 9). Coupled with the optimized parameters of differential pulse voltammetry (DPV), SPDE detected PTS in two linear ranges (first range was from 0.011 to 0.912 µmol L−1; second range was from 0.912 to 4.420 µmol L−1), providing the LOD and LOQ on a nanomolar level (3.1 nmol L−1 and 10.0 nmol L−1, respectively). The selectivity of the optimized DPV method was found to be excellent, with the current changes of less than 7%, in the presence of ten times higher concentrations of the certain interferences. The practical applicability of the SPDE and single-drop-detection approach in dietary supplements (with a declared PTS content of 50 mg/tablet), with the recovery values ranging from 95 to 102%, shows that the developed method has high potential for precise and accurate PTS detection, as well as exceptional miniaturization possibilities of relevant equipment for on-site sensing

Application of Screen Printed Diamond Electrode, Coupled with “Point-of-Care” Platform, for Nanomolar Quantification of Phytonutrient Pterostilbene in Dietary Supplements: An Experimental Study Supported by Theory

Herein, a screen–printed diamond electrode (SPDE) coupled with a “point-of-care” platform (30 µL-drop concepts, single-drop-detection approach) was successfully applied for the electrochemical determination of pterostilbene (PTS). Cyclic voltammetry identified irreversible oxidation of PTS, where oxidation peak was shown to be strongly dependent on the pH of the working environmental. Although the proposition of the detailed electrochemical oxidation mechanism of PTS goes out of the scope of the present research, we have determined the most probable reactive site of our analyte, by utilizing DFT-based reactivity descriptors (Fukui functions). For electrochemical quantification of PTS, oxidation peak at 0.32 V (vs. Ag/AgCl) was followed in presence of 0.5 mol L−1 of Briton–Robinson buffer solution (pH = 9). Coupled with the optimized parameters of differential pulse voltammetry (DPV), SPDE detected PTS in two linear ranges (first range was from 0.011 to 0.912 µmol L−1; second range was from 0.912 to 4.420 µmol L−1), providing the LOD and LOQ on a nanomolar level (3.1 nmol L−1 and 10.0 nmol L−1, respectively). The selectivity of the optimized DPV method was found to be excellent, with the current changes of less than 7%, in the presence of ten times higher concentrations of the certain interferences. The practical applicability of the SPDE and single-drop-detection approach in dietary supplements (with a declared PTS content of 50 mg/tablet), with the recovery values ranging from 95 to 102%, shows that the developed method has high potential for precise and accurate PTS detection, as well as exceptional miniaturization possibilities of relevant equipment for on-site sensing

(4R,6S,7S,8S,8aS)-6-Ethyl-7,8-dihy­droxy-4-methyl-1,2,3,5,6,7,8,8a-octa­hydro­indolizin-4-ium iodide

The title compound, C11H22NO2 +·I−, is a chiral mol­ecule with five stereogenic centres. The absolute configuration was assigned from the synthesis and confirmed by the structure determination. The central six-membered ring of the indolizine system adopts a chair conformation, with two atoms displaced by −0.690 (2) and 0.550 (2) Å from the plane of the other four atoms. The conformation of the pyrrolidine ring is close to that of an envelope, with the flap atom displaced by 0.563 (2) Å from the plane of the remaining four atoms. In the crystal, there are two O—H⋯I hydrogen bonds

(11R,11aS)-11-Hydr­oxy-1,5,11,11a-tetra­hydro-1-benzothieno[2,3-f]indolizin-3(2H)-one

The absolute configuration of the title compound, C14H13NO2S, was assigned from the synthesis and confirmed by the structure determination. The central six-membered ring of the indolizine system adopts an envelope conformation, the greatest deviation from the mean plane of the ring being 0.459 (2) Å for the N atom. The benzothieno system is planar [mean deviation = 0.009 (2) Å]. In the crystal structure, mol­ecules form chains parallel to the b axis via inter­molecular O—H⋯O hydrogen bonds