DFT and FT-IR analyses of hydrogen bonding in 3-substistuted-3-oxo-arylhydrazonopropanenitriles

Ab initio calculations, FT-IR and X-ray crystal analysis, indicated that the most stable configuration of 3-oxo-2-(phenylhydrazono)-3-(thien-2-yl)-propionitrile is the anti phenylhydrazone structure 1. Stability of such a conformation, over the possible E-form, 2, that would be stabilized by intramolecular hydrogen bonding, is due to interaction between electron-pair domains of the N, S and O atoms. However, the simulated and experimental IR frequency data indicated intermolecular hydrogen bonding between NH and CN, the latter being lowered to 2214 cm(-1). Studies on 3-oxo-3-phenyl-2-(phenylhydrazono)-propionitrile showed the same result, as well as, another intramolecular hydrogen association of the type N-H...O. This was clearly indicated by the absorbance of the carbonyl stretch at 1605 cm(-1). These data indicated the existence of a bifurcated hydrogen bond in 1a and a single intermolecular association in 1b.     

An exceptionally simple and efficient synthesis of 6-methyl-6-vinylfulvene, and its oxidative transformations

A new efficient synthesis of 6-methyl-6-vinylfulvene was developed, starting from the 6-(2-hydroxyethyl)-6-methylfulvene. With larger quantities of the title compound in hand, its photooxygenation with singlet oxygen was studied. Cyclization of the cyclopropanone intermediate to both vinyl moieties in the unsaturated system was observed, whereas the saturated endoperoxide gave mostly the cyclopentenone derivative. m-CPBA attacks exclusively the endocyclic double bonds and gives the 3-cyclopentenones via the unstable epoxides.     

cis-β-Bromostyrene derivatives from cinnamic acids via a tandem substitutive bromination-decarboxylation sequence

cis-β-Bromostyrene derivatives were synthesized stereospecifically from cinnamic acids through β-lactone intermediates. The synthetic sequence did not require the purification of the β-lactone intermediates although they were found to be stable and readily purified in most cases.     

C12H12 interconversions: Two non-pyrolytic syntheses of tricyclo[5.3.2.04,8]dodeca-2,5,9,11-tetraene

Herein, we describe two independent and non-pyrolytic syntheses of an important C₁₂H₁₂ hydrocarbon which had been prepared previously by gas phase thermolysis of compound 6. The first method is based on an unusual dipolar cycloaddition of dichloroketene onto bullvalene. After reductive dechlorination, a Shapiro-Heath reaction of the tosylhydrazone gave the title compound. Alternatively, compound 13 is also obtained from its isomer 6 by a Ag⁺ catalyzed reaction.     

Doubly Reflected Backward Stochastic Differential Equations in the Predictable Setting

Journal of Theoretical Probability - In this paper, we introduce a specific kind of doubly reflected backward stochastic differential equations (in short DRBSDEs), defined on probability spaces...     

Facile protic hydration of acetonitrile to protonated acetamide at oxygen mediated by chloroauric acid: insights from experimental and calculations

Research on Chemical Intermediates - Chemical transformations such as nitrile hydration or carbon–oxygen bond formation reactions under gentle conditions are important in the pharmaceutical...     

Bioreducible cationic random copolymer for gene delivery

Cationic polymers have been widely investigated for gene delivery, although their low transfection efficiency and high cytotoxicity limit their application. We synthesized a bioreducible cationic random copolymer, poly(cystamine bisacylamide‐aminoethyl piperazine)‐co‐poly(cystamine bisacylamide‐histamine) (denoted as CBA‐AEP‐His) from N,N′‐cystamine bis acrylamide (CBA) with aminoethyl piperazine (AEP) and histamine (His). CBA‐AEP‐His copolymer possesses disulfide linkages that endow it with redox‐responsivity to the intracellular environment. This polymer efficiently condenses pZNF580 into complexes with the size of 160 ± 4 nm to 280 ± 5 nm and positive zeta potential of 20 ± 0.3 mV to 30 ± 0.4 mV. The gel‐retardation assay shows that CBA‐AEP‐His can retard pZNF580 even at a low mass ratio of 1/1. The gene complexes were triggered to release pZNF580 when exposed to the reducing environment of dithiothreitol (DTT). CBA‐AEP‐His random copolymer presented higher buffer capacity owing to its His moieties, which protected pZNF580 from DNase degradation. The gene transfection results reveal that CBA‐AEP‐His can efficiently deliver pZNF580 and transfect EA. Hy926 cells. The MTT assay indicates that CBA‐AEP‐His and its complexes exhibit lower cytotoxicity than PEI25KDa. These results illustrate that CBA‐AEP‐His had promising properties for gene delivery, which may provide a suitable platform for the development of a non‐viral gene carrier.