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A new, convenient and efficient method for the construction of a new polycyclic condensed system containing an azepine and pyrazolophthalazine has been developed in the form of a two-step protocol comprising the condensation reaction of hydroxylamine with 1H-indazolo[1,2-b]phthalazine-1,6,11-trione derivative, followed by a Beckman rearrangement reaction using polyphosphoric acid (PPA) as catalyst. Various substituted substrates were successfully used, affording the azepino phthalazine hybrids in good yields and in short reaction times. [ABSTRACT FROM AUTHOR]

In this work, we studied the corrosion protection efficiency of three pyridinium salts on steel (API 5L Gr.B) in 0.5 M H2SO4 solution. Gravimetric and electrochemical methods were employed. We conducted investigations at various concentrations of the studied inhibitors and experiment temperature. The morphological of the steel surface was accomplished using scanning electron microscopy. Weight loss shows that an increase in the concentration of inhibitors A and C does not have any notable influence on the inhibition efficiency from 0.5 mM. However, the inhibition efficiency increases significantly with the increase of inhibitor B concentration. The values of (IE%) determined from EIS for these inhibitors follow the order: A ≈ C > B and the most excellent inhibition efficiencies are 97.88%, 86.96%, and 97.65%, respectively at 5 mM and all studied inhibitors are mixed-type inhibitors. In addition, the adsorption of the inhibitor molecules on the steel surface is reliable on the Langmuir adsorption isotherm model and the adsorption mechanism occurs through the combination of three aspects of interactions (physisorption, chemisorptions and retro-donation). IE% values of A, B and C inhibitors determined from EIS increase very slightly with temperature increase; the protective properties are excellent even at 55 °C (98.37% for A, 92.18% for B and 98.78% for C). This investigation is completed by a theoretical calculation of some quantum chemical parameters using the Gaussian09 program. The order of IE determined from experimental measurements is successfully supported by surfaces analysis and the obtained results confirmed an excellent concordance between potentiodynamic polarization, weight loss, EIS and theoretical study. [ABSTRACT FROM AUTHOR]

A new route is described for tetrahydroisoquinoline (THIQ) alkaloids involving the alkylation of [alpha]-aminonitrile as a key step, where the latter compound is prepared by anodic cyanation of the corresponding tertiary amine. The syntheses of ([plusmn])-carnegine, ([plusmn])-norlaudanosine and ([pulsmn])-O,O-dimethylcoclaurine are achieved.

A novel compound, methyl 3-(quinolin-2-yl)indolizine-1-carboxylate (2) has been synthesized by cycloaddition reaction of 1-(quinolin-2-ylmethyl)pyridinium ylide (1) with methyl propiolate in presence of sodium hydride in THF. The structure of this compound was established by IR, ¹H-NMR, 13C-NMR and MS data [ABSTRACT FROM AUTHOR]

The title compound, C21H16N2O3, consists of an indazolone moiety, bearing a phenyl group, fused to a phthalazine ring system (r.m.s. deviation = 0.018 Å). The phenyl ring is almost normal to the mean plane of the five-membered ring of the indazolone moiety, making a dihedral angle of 89.64 (7)°. The six-membered ring of the indazolone moiety has an envelope conformation, with the central methyl-ene C atom as the flap. In the crystal, mol-ecules are linked via C-H⋯O hydrogen bonds, forming slabs parallel to the bc plane. The slabs are linked via C-H⋯π and π-π inter-actions [the shortest inter-centroid distance involving rings of pyrazolo-phthalazine moieties is 3.6430 (8) Å], forming a three-dimensional structure.

In the title compound, C22H18N2O4, the three fused rings of the pyrazolo-phthalazine moiety are coplanar (r.m.s. deviation = 0.027 Å). The cyclo-hexene ring fused to the pyrazolidine ring, so forming the indazolophthalazine unit, has a half-chair conformation. The benzene ring is almost normal to the mean plane of the pyrazolo-phthalazine moiety, with a dihedral angle of 87.21 (6)° between their planes. In the crystal, mol-ecules are linked by pairs of C-H⋯O hydrogen bonds forming inversion dimers. The dimers are linked via C-H⋯π inter-actions, forming slabs parallel to (100). Between the slabs there are weak π-π inter-actions [shortest inter-centroid distance = 3.6664 (9) Å], leading to the formation of a three-dimensional structure.

In the title mol-ecule, C15H12O3, the C atoms bearing the hy-droxy group and the phenyl ring are disordered over two sets of sites with refined occupancies of 0.573 (7) and 0.427 (7). There is also disorder of the phenyl ring but the hy-droxy group was refined as ordered. The dihedral angles between the benzene ring of the chromane ring system and the phenyl ring are 89.7 (2)° for the major component of disorder and 72.1 (3)° for the minor component. Both disorder components of the the di-hydro-pyran ring are in a half-chair conformation. In the crystal, mol-ecules are linked by pairs of O-H⋯O hydrogen bonds, forming inversion dimers with an R 2 (2)(10) graph-set motif. Weak C-H⋯π inter-actions link these dimers into ladders along [001].

In the cation of the title compound, C10H13N2O(+)·I(-), all non-H atoms, with the exception of the O atom, are essentially coplanar, with a maximum deviation of 0.04 (1) Å. In the crystal, the cations and anions are arranged in layers parallel to (100). The cations are connected to the anions via an O-H⋯I hydrogen bond and there are significant π-π stacking inter-actions between cation layers, with centroid-centroid distances in the range 3.606 (5)-3.630 (5) Å. A weak intra-molecular C-H⋯O hydrogen bond is also observed. The crystal studied was an inversion twin with refined components of 0.52 (5) and 0.48 (5).

The crystal packing of the title salt, C6H11N2O(+)·I3 (-), can be described as consisting of alternating layers of cations and anions parallel to the (100) plane along the a-axis direction. The components are linked by O-H⋯I, C-H⋯I and C-H⋯O interactions, generating a three-dimensional network. The O atom deviates from the imidazol ring by 0.896 (2) Å.