Crystal structure, Hirshfeld surface analysis and DFT calculations of 7-bromo-2,3-di-hydro-pyrrolo[2,1-b]quinazolin-9(1H)-one.

The mol-ecular structure of the title compound, C11H9BrN2O, is almost planar. The benzene and pyrimidine rings are essentially coplanar, with r.m.s. deviations of 0.0130 Å, and the largest displacement is for the flap atom of the di-hydro-pyrrole moiety [0.154 (7) Å]. Hirshfeld surface analyses revealed that the crystal packing is dominated by H⋯H, Br⋯H/H⋯Br and O⋯H/H⋯O inter-actions, and Br⋯Br inter-actions in the crystal structure are also observed. Theoretical calculations using density functional theory (DFT) with the B3LYP functional basis set gave numerical parameters for the frontier molecular orbitals.

Crystal structure and Hirshfeld surface analysis of bis-(6,7,8,9-tetra-hydro-11H-pyrido[2,1-b]quinazolin-5-ium) tetra-chlorido-zincate.

The title compound, (C12H15N2)2[ZnCl4], is a salt with two symmetrically independent, essentially planar heterocyclic cations and a slightly distorted tetra-hedral chloro-zincate dianion. N-H⋯Cl hydrogen bonds link these ionic constituents into a discrete aggregate, which comprises one formula unit. The effect of hydrogen bonding is reflected in the minor distortions of the [ZnCl4]2- moiety: distances between the cation and chlorido ligands engaged in classical hydrogen bonds are significantly longer than the others. Secondary inter-actions comprise C-H⋯π hydrogen bonding and weak π-π stacking. A Hirshfeld surface analysis indicates that the most abundant contacts in packing stem from H⋯H (47.8%) and Cl⋯H/H⋯Cl (29.3%) inter-actions.

Structural insight from intermolecular interactions and energy framework analyses of 2-substituted 6,7,8,9-tetrahydro-11H-pyrido[2,1-b]quinazolin-11-ones.

The crystal structures of three mackinazolinone derivatives (2-amino-6,7,8,9-tetrahydro-11H-pyrido[2,1-b]quinazolin-11-one at room temperature, and 2-nitro-6,7,8,9-tetrahydro-11H-pyrido[2,1-b]quinazolin-11-one and N-(11-oxo-6,8,9,11-tetrahydro-7H-pyrido[2,1-b]quinazolin-2-yl)benzamide at 100 K) are explored using X-ray crystallography. To delineate the different intermolecular interactions and the respective interaction energies in the crystal architectures, energy framework analyses were carried out using the CE-B3LYP/6-31G(d,p) method implemented in the CrystalExplorer software. In the structures the different molecules are linked by C-H...O, C-H...N and N-H...O hydrogen bonds. Together with these hydrogen bonds, C-H...π and C-O...π interactions are involved in the formation of a three-dimensional crystal network. A Hirshfeld surface analysis allows the visualization of the two-dimensional fingerprint plots and the quantification of the contributions of H...H, H...C/C...H and H...O/O...H contacts throughout the different crystal structures. To obtain additional information on the intrinsic properties of our targets and to compare the experimental crystal structures with their respective conformations in the gas phase, quantum chemical calculations at the B3LYP-D3BJ/6-311++G(d,p) level of theory, including Grimme's D3 correction term and BJ damping functions, were carried out to account for intramolecular dispersion interactions. The identified energy gaps between the highest occupied and the lowest unoccupied molecular orbitals (HOMO-LUMO gap) of our targets in the gas phase and in two implicit solvents (methanol and dimethyl sulfoxide) allow us to quantify the impact of different substituents on the reactivity of mackinazolinone derivatives.

(E)-6-(Furan-2-yl-methyl-idene)-6,7,8,9-tetra-hydro-pyrido[2,1-b]quinazoline-11-thione.

A quinazolinthione, C17H14N2OS, was synthesized by the condensation reaction of 6,7,8,9-tetra-hydro-11H-pyrido[2,1-b]quinazolin-11-thione with furfural. The mol-ecule crystallizes in the monoclinic system (Cc space group) and has an E configuration with respect to the exocyclic C=C bond. In the crystal, mol-ecules are linked through C-H⋯π(furan) inter-actions, forming zigzag chains propagating along the [001] direction.

Synthesis of 2-(2-hydroxyethyl)-1-(2-hydroxyphenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline and pseudosymmetry in its crystal structure.

Natural and synthetic isoquinoline alkaloids display a wide variety of potent biological activities. The title 1-aryl-2-hydroxyethyl-1,2,3,4-tetrahydroisoquinoline, C19H23NO4, crystallizes with two molecules in the asymmetric unit related by pseudo-translation but differing only slightly in conformation. The pseudosymmetry is also reflected in the diffraction pattern. The subset of reflections corresponding to the smaller cell and average structure are on average twice as intense as those subtending the larger cell. Tentative refinement in the subcell leads to a disordered structural model with satisfactory agreement factors and, after appropriate use of restraints, acceptable molecular geometry but significantly larger and more anisotropic displacement parameters. In the correct unit cell, the independent molecules differ with respect to the orientation of the hydroxyethyl group. Intramolecular hydrogen bonding occurs between the hydroxyphenyl group and the N atom.

Crystal structure of 2,3-dimeth-oxy-5,6,7,8,13,13a-hexa-hydro-6a,8-di-aza-indeno-[2,1-b]phenanthrene methanol monosolvate.

The asymmetric unit of the title solvate, C21H22N2O2·CH3OH, contains one methanol solvent mol-ecule and one mol-ecule of the heterocycle that is built up by the fusion of four six-membered rings A, C, D, E and one five-membered ring B. The indole moiety (rings A and B) is essentially planar, with an r.m.s. deviation of 0.013 Å, whereas rings C and D adopt a twisted conformation with a trans-ring junction. In the crystal, two heterocyclic mol-ecules are associated with two methanol mol-ecules through mutual N-H⋯O and O-H⋯N hydrogen bonds, forming a centrosymmetric dimer.

Crystal structure of anagyrine perchlorate.

The title mol-ecular salt, C15H21N2O(+)·ClO4 (-), crystallizes with four cations (A, B, C and D) and four anions in the chiral unit cell (space group P21). The alkaloid was isolated from the aerial parts of Genista Hispanica collected in the Samarkand region of Uzbekistan. Each cation is protonated at the N atom that bridges the alkaloid rings C and D. In each cation, ring A is almost planar and ring B adops a sofa conformation with the methyl-ene group bridging to the C ring as the flap. Rings C and D adopt chair conformations with a cis ring junction in all four cations. In the crystal, A+B and C+D dimeric pairs linked by pairs of N-H⋯O hydrogen bonds are observed, which generate R 2 (2)(16) loops in each case. The dimers are consolidated by weak aromatic π-π stacking inter-actions between the A rings [centroid-centroid distances = 3.913 (3) and 3.915 (3) Å].

2,3-Tri-methyl-ene-7,8-di-hydro-pyrrolo-[1,2-a]thieno[2,3-d]pyrimidin-4(6H)-one.

The title mol-ecule, C12H12N2OS, is planar, with an r.m.s. deviation of 0.04 Å. In the crystal, the N atom adjacent to the carbonyl group is sp (2)-hybridized. The crystal structure is stabilized by π-π stacking inter-actions observed between thio-phene and pyrimidinone rings of c-glide-related mol-ecules [centroid-centroid distance = 3.9554 (13) Å] and by C-H⋯π inter-actions, forming an infinite chain along the c-axis direction.

3-Methyl-2-(3,3,3-tri-chloro-2-hy-droxy-prop-yl)quinazolin-4(3H)-one.

The title mol-ecule, C12H11Cl3N2O2, contains planar quinazolin-4(3H)-one (r.m.s. deviation = 0.0257 Å) and propyl fragments, forming a dihedral angle of 10.4 (2)°. An intra-molecular O-H⋯N hydorgen bond occurs. In the crystal, O-H⋯O hydrogen bonds link the mol-ecules into an infinite chain running parallel to the b axis.

(-)-Norfluoro-curarine ethanol monosolvate.

The title compound, C19H20N2O·C2H5OH, is an ethanol solvate of an indol alkaloid which was extracted from the plant Vinca erecta. The fused piperidine ring adopts an approximate boat conformation and the pyrrolidine ring an envelope conformation with one of the methyl-ene C atoms at the flap. An intra-molecular N-H⋯O hydrogen bond forms an S6 ring motif. In the crystal, norfulorocurarine and ethanol mol-ecules are linked into a chain along the c-axis direction through N-H⋯O and O-H⋯N hydrogen bonds.

5,7-Dihy-droxy-2-(3-hy-droxy-4,5-dimeth-oxy-phen-yl)-6-meth-oxy-4H-chromen-4-one.

The title compound, C18H16O8, was isolated from the plant Artemisia baldshuanica Krasch et Zarp. The mol-ecule is approximately planar, with the exception of the terminal methyl groups, the C atoms of which devitate from their attached ring planes by 1.243 (5) and 1.168 (5) Å. The dihedral angle between the substituted benzopyran and benzene rings is 5.8 (1)°; this near planarity could be due to conjugation or a packing effect. Intra-molecular O-H⋯O and C-H⋯O hydrogen bonds occur. In the crystal, mol-ecules are connected by O-H⋯O hydrogen bonds involving the hy-droxy and carbonyl groups, forming hydrogen-bonded chains along [001] and [1-10]. The chains are linked by C-H⋯O inter-actions.

Diaqua-dichloridobis[quinazolin-4(1H)-one-κN(3)]nickel(II).

In the title complex, [NiCl(2)(C(8)H(6)N(2)O)(2)(H(2)O)(2)], the Ni(II) ion is located on an inversion center and is six-coordinated by two N atoms of 1H-quinazolin-4-one ligands, two chloride ions and two water mol-ecules. The water mol-ecules are involved in intra- and inter-molecular O-H⋯O and O-H⋯Cl hydrogen bonding. Inter-molecular N-H⋯O and N-H⋯Cl hydrogen bonds are formed between ligands. In addition, weak π-π inter-actions are observed between the benzene rings of the ligands [centroid-centroid distance = 3.580 (3) Å]. The inter-molecular hydrogen bonds and π-π inter-actions lead to the formation of a three-dimensional supra-molecular network.

2,3-Dihydro-pyrrolo-[2,1-b]quinazoline-9(1H)-thione.

In the crystal, mol-ecules of the title compound, C(11)H(10)N(2)S, are connected by C-H⋯N inter-actions around threefold axes. Furthermore, they form stacks along the c axis showing π-π inter-actions between pyrimidine rings [centroid-centroid distance = 3.721 (1) Å]. The central ring is essentially planar with an r.m.s. deviation of 0.007 Å. The five-membered ring adopts an envelope conformation with the flap atom deviating by 0.241 (4) Šfrom the mean plane (r.m.s. deviation = 0.002 Å) through the other four ring atoms.

(4-Nitrophenyl)(1,2,3,9-tetrahydro-pyrrolo[2,1-b]quinazolin-3-yl)methanol monohydrate.

In the crystal structure of the title compound, C(18)H(17)N(3)O(3)·H(2)O, the mol-ecules are linked by O-H⋯O and O-H⋯N hydrogen bonds, resulting in a chain along the a axis. The crystal structure is stabilized by weak inter-molecular C-H⋯π (ring) hydrogen bonds and aromatic π⋯π stacking inter-actions [centroid-centroid distance = 3.902 (1) Å] between the pyrimidino rings of the quinazoline system. The tricyclic quinazoline fragment is almost planar (rms deviation = 0.0139 Å) with the two methylene C atoms of the pyrrolo ring deviating by 0.148 (2) and -0.081 (3) Šfrom the plane through the other atoms. The 4-nitrophenyl ring makes a dihedral angle of 12.55 (7)° with the tricyclic ring system.

2-Methyl-4-oxo-6,7,8,9-tetrahydro-thieno[2',3':4,5]pyrimidino-[1,2-a]pyridine-3-carboxylic acid.

There are two independent mol-ecules in the asymmetric unit of the title compound, C(12)H(12)N(2)O(3)S. With the exception of the methyl-ene groups, a mean plane fitted through all non-H atoms of each mol-ecule has an r.m.s. deviation of 0.035 Šfor one mol-ecule and 0.120 Šfor the second. In one of the independent mol-ecules, the methyl-ene groups was refined using a disorder model with an occupancy ratio of 0.53:0.47 (14). Each molecule features an intra-molecular O-H⋯O hydrogen bond, which generates an S(7) ring.

(E)-3-Propoxymethyl-idene-2,3-dihydro-1H-pyrrolo[2,1-b]quinazolin-9-one monohydrate.

The title compound, C(15)H(16)N(2)O(2)·H(2)O, was synthesized via the alkyl-ation of 3-hydroxy-methyl-idene-2,3-dihydro-1H-pyrrolo[2,1-b]quinazolin-9-one with n-propyl iodide in the presence of sodium hydroxide. The organic mol-ecule and the water mol-ecule both lie on a crystallographic mirror plane. In the crystal structure, inter-molecular O-H⋯O and O-H⋯N hydrogen bonds link the components into extended chains along [100].

9-Furfuryl-idene-2,3-dimethyl-6,7,8,9-tetrahydro-4H--thieno[2',3':4,5]pyrimidino[1,2-a]pyridin-4-one.

The title compound, C(17)H(16)N(2)O(2)S, was obtained by condensation of 2,3-dimethyl-thieno[2',3':4,5]pyrimidino[1,2-a]pyridin-4-one with furfural in the presence of sodium hydroxide. One of the methyl-ene groups of the tetra-hydro-pyrido ring is disordered over two positions in a 0.87 (1):0.13 (1) ratio. The thieno[2,3-d]pyrimidin-4-one unit and the furan ring are both planar (r.m.s. deviation = 0.535 Å), and coplanar with each other, forming a dihedral angle of 5.4 (1)°. Four weak inter-molecular hydrogen bonds (C-H⋯O and C-H⋯N) are observed in the structure, which join mol-ecules into a network parallel to (101).

11-(2-Oxopyrrolidin-1-ylmeth-yl)-1,2,3,4,5,6,11,11a-octa-hydro-pyrido[2,1-b]quinazolin-6-one dihydrate.

In the crystal structure of the title compound, C(17)H(21)N(3)O(2)·2H(2)O, water mol-ecules are mutually O-H⋯O hydrogen bonded and form infinite chains propagating along the b axis. Neighboring chains are linked by the quinazoline mol-ecules by means of O-H⋯O=C hydrogen bonds, forming a two-dimensional network.

(E)-3-[4-(Dimethyl-amino)-benzyl-idene]-2,3-di-hydro-1H,9H-pyrrolo-[2,1-b]quinazolin-9-one.

The title compound, C(20)H(19)N(3)O, was obtained by condensation of 2,3-dihydro-1H,9H-pyrrolo-[2,1-b]quinazolin-9-one (alkaloid de-oxy-vasicinone, isolated from Peganum Harmala) with 4-(dimethyl-amino)-benzaldehyde in the presence of sodium methoxide. The 2,3-dihydro-1H,9H-pyrrolo-[2,1-b]quinazolin-9-one part of the mol-ecule is roughly planar (r.m.s. deviation = 0.0178 Å) and is essentially coplanar with the benzil-idene ring (r.m.s. deviation = 0.0080 Å), forming a dihedral angle of 5.0 (1)°. The crystal structure is stabilized by two aromatic π-π stacking inter-actions observed between the benzene rings of neighboring mol-ecules [centroid-centroid distance = 3.7555 (19) Å.

(1-Phenyl-1H-1,2,3-triazol-4-yl)methyl pyridine-3-carboxyl-ate.

In the title compound, C(15)H(12)N(4)O(2), the dihedral angle between the planes of the nicotino-yloxy fragment and triazole ring is 88.61 (5)°. The dihedral angle between the planes of triazole and benzene rings is 16.54 (11)°. The crystal structure is stabilized by inter-molecular C-H⋯N, C-H⋯O and C-H⋯π(triazole) hydrogen bonds and aromatic π-π stacking inter-actions between the benzene and triazole rings [centroid-centroid distance = 3.895 (1) Å].