A Switch in the Hydrophobic/Hydrophilic Gas-Adsorption Character of Prussian Blue Analogues: An Affinity Control for Smart Gas Sorption

Porous coordination polymers are molecule-based materials presenting a high degree of tunability, which offer many advantages for targeted applications over conventional inorganic materials. This work demonstrates that the hydrophilic/hydrophobic character of Prussian blue analogues having a lipophilic feature may be tuned to optimize the gas adsorption properties. The role of the coordinatively unsaturated metal sites is emphasized through a combination of theoretical and experimental study of water, ethanol, and n-hexane adsorption.     

A novel methodology for the synthesis of 1-desoxy-Δ-tetrahydrocannabinol (THC) analogues

A versatile and efficient sequence was developed for the synthesis of 1-desoxy-Δ⁸-THC analogues and is demonstrated by the synthesis of sulfonamide analogues with an acetylene group at the C-2^′ position in the side chain. In this procedure the 1-desoxy-Δ⁸- THC ring structure is built first and the synthesis of the side chain is then developed.     

Electronic structure and vibrational spectra of cis-diammine(orotato)platinum(II), a potential cisplatin analogue: DFT and experimental study

Orotic acid (vitamin B₁₃) is a key intermediate in biosynthesis of the pyrimidine nucleotides in living organisms, moreover, it may serve as the biological carrier for some metal ions. cis-Diammine(orotato)platinum(II), cis-[Pt(C₅H₂N₂O₄)(NH₃)₂] can be considered as a new potential cisplatin analogue. The FT-Raman and FT-IR spectra of the title complex are reported, for the first time. The molecular structure, vibrational frequencies, and the theoretical infrared and Raman intensities have been calculated by the density functional mPW1PW91 method. The detailed vibrational assignment has been made on the basis of the calculated potential energy distribution. The theoretically predicted IR and Raman spectra show very good agreement with experiment. Natural bond orbital (NBO) analyses were performed for cisplatin, carboplatin and the title complex. The results provided new data on the nature of platinum–ligand bonding in these compounds. Strong intramolecular hydrogen bond between the orotate ligand and the coordinated ammonia group stabilizes the structure of the platinum(II) complex. Thus, it is suggested that the orotate ligand in the title complex is more inert to the substitution reactions than the chloride ligands in cisplatin.     

Metal–Nitrosyl complexes as a source of new vasodilators: Strategies derived from systematic chemistry and nitrosyl ligand reactivity

A series of nitrosyl complexes of empirical formula K_n[M(CN)₅NO], where M = V, Cr, Mn and Co and n = 3, or M = Mo and n = 4, have been prepared which are notional analogues of the widely used vasodilator sodium nitroprusside. Their reactivity towards common nucleophiles (OH^?, NH₂R, NHR₂, HS^? and RS^?), acid and photolysis has been investigated to elucidate the desired properties required of new metal nitrosyls which may have some potential as new non-cyanide-based vasodilators.     

Synthesis and luminescence properties of lanthanide(III) chelates with polyacid derivatives of thienyl-substituted terpyridine analogues

Two new polyacid derivative ligands of thienyl-substituted terpyridine analogues, N,N,N¹,N¹-[4′-(2?-thienyl)-2,2′:6′,2″-terpyridine-6,6″-diyl]bis(methylenenitrilo) tetrakis(acetic acid) (TTTA) and N,N,N¹,N¹-[2,6-bis(3′-aminomethyl-1′-pyrazolyl)-4-(2″-thienyl)pyridine] tetrakis(acetic acid) (BTTA), were synthesized, and the luminescence properties of their Eu³⁺ and Tb³⁺ chelates were investigated. The Eu³⁺chelates of the two ligands are strongly luminescent having luminescence quantum yields of 0.150 (TTTA-Eu³⁺) and 0.114 (BTTA-Eu³⁺), and lifetimes of 1.284 ms (TTTA-Eu³⁺) and 1.352 ms (BTTA-Eu³⁺), whereas their Tb³⁺ chelates are weakly luminescent. The TTTA-Eu³⁺ chelate was used for streptavidin (SA) labeling, and the labeled SA was used for time-resolved fluoroimmunoassay of insulin in human sera. The method gives the detection limits of 33 pg ml⁻¹.     

Access to Paullone Analogues by Intramolecular Heck Reaction

The syntheses of paullone ( 1a ) and three paullone derivatives, including a sulfur analogue ( 2a ), a tricyclic derivative ( 2b ), and a ring‐enlarged variant ( 2c ), are described, Pd‐catalyzed intramolecular Heck reaction being the key step. The kinase‐inhibitory properties of the novel paullone analogues were investigated.     

Oligonucleotide Analogues with Integrated Bases and Backbone. Part 14

The self‐complementary tetrameric propargyl triols 8, 14, 18 , and 21 were synthesized to investigate the duplex formation of self‐complementary, ethynylene‐linked UUAA, AAUU, UAUA, and AUAU analogues with integrated bases and backbone (ONIBs). The linear synthesis is based on repetitive Sonogashira couplings and C‐desilylations (34–72% yield), starting from the monomeric propargyl alcohols 9 and 15 and the iodinated nucleosides 3, 7, 11 , and 13 . Strongly persistent intramolecular H‐bonds from the propargylic OH groups to N(3) of the adenosine units prevent the gg‐type orientation of the ethynyl groups at C(5′). As such, an orientation is required for the formation of cyclic duplexes, this H‐bond prevents the formation of duplexes connected by all four base pairs. However, the central units of the UAUA and AAUU analogues 18 and 14 associate in CDCl₃/(D₆)DMSO 10 : 1 to form a cyclic duplex characterized by reverse Hoogsteen base pairing. The UUAA tetramer 8 forms a cyclic UU homoduplex, while the AUAU tetramer 21 forms only linear associates. Duplex formation of the O‐silylated UUAA and AAUU tetramers is no longer prevented. The self‐complementary UUAA tetramer 22 forms Watson–Crick‐ and Hoogsteen‐type base‐paired cyclic duplexes more readily than the sequence‐isomeric AAUU tetramer 23 , further illustrating the sequence selectivity of duplex formation.     

Toward breast cancer resistance protein (BCRP) inhibitors: design, synthesis of a series of new simplified fumitremorgin C analogues

In this study, we report the design and synthesis of a series of new simplified fumitremorgin C analogues. The preliminary biological study indicated some of these simplified fumitremorgin C might be developed into breast cancer resistance inhibitors.     

Affinity Chromatography of Insulin with a Heptapeptide Ligand Selected from Phage Display Library

A heptapeptide phage display library was screened with insulin to find its ligands for affinity chromatography. The peptide was synthesized and coupled to EAH Sepharose 4B (5.4 mol mL^–1 bed). Then, insulin chromatography was carried out with mobile phases of different pH values and by the addition of urea and ethylene glycol. It was found that electrostatic interactions were predominant for the affinity binding, and hydrogen bonding might also contribute somewhat to the affinity. Finally, frontal analysis was performed and the dynamic binding capacity of the affinity column for insulin at 50% breakthrough was estimated at 60.6 mg mL^–1 bed, which was about two times higher than the theoretical binding capacity of the monomeric insulin. The result suggests that insulin was bound in dimer state in a stoichiometric relationship with the coupled peptide, indicating the high binding efficiency of the peptide ligand for insulin.