Construction of Electrochemical Aptamer Sensor Based on Pt-Coordinated Titanium-Based Porphyrin MOF for Thrombin Detection

In this work, a Pt-coordinated titanium-based porphyrin metal organic framework (Ti-MOF-Pt) was prepared by embedding single-atom Pt through strong interactions between the four pyrrole nitrogen atoms in the rigid backbone of the porphyrin. The synthesized Ti-MOF-Pt was characterized by TEM, XRD, FTIR and BET. Then, the Ti-MOF-Pt has been used for glassy carbon electrode surface modification and consequently used for construction of a thrombin aptamer sensor. The high surface area provides by MOF and excellent electrochemical property provided by Pt enhance the sensing performance. After optimization of amount of aptamer, hybridization time and specific reaction time, the fabricated aptamer sensor exhibited a linear relationship with the logarithm of the thrombin concentration in the range of 4 pM to 0.2 μM. The detection limit can be calculated as 1.3 pM.

Bis(1-methylimidazole)[meso-α,α,α,α-tetrakis(o-nicotinamidophenyl)porphinato]iron(II)–1-methylimidazole–tetrahydrofuran (1/1/1.5)

In the title compound, [FeII(C68H44N12O4)(C4H6N2)2]·C4H6N2·1.5C4H8O, the central FeII ion is coordinated by four pyrrole N atoms of the porphyrin core and two N atoms of the 1-methylimidazole ligands in the axial sites. One 1-methylimidazole and one and a half tetrahydrofuran solvent molecules are also present in the asymmetric unit. The complex exhibits a near planar porphyrin core conformation, in which the iron centre is slightly displaced towards the hindered porphyrin side (0.01 Å). The average Fe—Np (Np refers to the pyrrole nitrogen atoms in the porphyrin) bond length is 1.990 (9) Å, and the axial Fe—NIm (NIm refers to the imidazole nitrogen atoms) bond lengths are 1.993 (3) and 2.004 (3) Å. The dihedral angle between the two coordinated 1-methylimidazole planes is 56.6 (2)°. The dihedral angles between the 1-methylimidazole planes and the planes of the closest Fe—Np vector are 16.8 (2) and 39.8 (2)°. N—H...N and N—H...O interactions are observed in the crystal structure.

Benzofuran and pyrrole derivatives as cannabinoid receptor modulators with in vivo efficacy against ulcerative colitis

Aim: Highlighting the need for effective therapies for the treatment of ulcerative colitis, novel series of potential CB2 modulators (benzofuran and pyrrole carboxamides) were developed and tested for their functional activities on CB1/CB2 receptors. Results: In the benzofuran series, the cannabinoid (CB) receptor selectivity and the functional profile were dependent on the nature of the amide substituent and the position of the methoxy group, meanwhile the pyrrole derivatives, displayed an exclusive selectivity to the CB2 receptor and a functionality that is controlled by the nature of the pyrrole nitrogen substituent. Conclusion: Remarkably, we succeeded to develop potent and selective pyrrole-based CB2 receptor agonists, represented by compound 25a, which also demonstrated an exquisite anti-inflammatory effect in a dextran sodium sulfate-induced colitis model in mice.

IR/Raman characterization of Au-mercaptotriazole crystals

The aim of this study was a characterization of the crystals of gold complexes based on mercaptotrazole, obtained from solutions with different pH values (2, 4, 7, and 9), using the methods of infrared (IR) and Raman spectroscopy. Both methods provided very useful information on the investigated systems and signalized existence of the Au-S bond in the complexes obtained at pH = 2 and 9. Recorded spectra clearly illustrated the changes that occur in the systems as a consequence of pH change. At the same time, the results also showed that the pyrrole nitrogen atoms stay protonated at pH = 9, which is not in favor of the assumption evolved from the previous UV-vis analysis of possible additional coordination between Au and possible deprotonated nitrogen atoms at this particular pH. Keywords: synthesis; gold-mercaptotriazole (Au-MT); IR and Raman spectroscopy

Regioselective Synthesis of 2,5-Disubstituted Pyrroles via Stepwise Iododesilylation and Coupling Reactions

A new protocol has been developed for the regioselective preparation of 2,5-disubstituted pyrroles. This approach is based on a stepwise iododesilylation and a subsequent coupling reaction, involving a 6-step pathway starting from the simplest pyrrole. A variety of 2,5-disubstituted pyrrole derivatives are accessible in moderate to good yields. In this study, the protection group for the pyrrole nitrogen is carefully chosen and N,N-dimethylaminosulfonyl is the final choice, which facilitates the subsequent double lithiation and makes the pyrrole moiety more stable. However, the attempted removal of this group fails under several different conditions. Instead, unexpected dimethylaminosulfonyl migration to the β-position of the pyrrole ring in the presence of tetrabutylammonium fluoride is observed.