A concise, efficient and versatile synthesis of amino-substituted benzo[b]pyrimido[5,4-f]azepines: synthesis and spectroscopic characterization, together with the molecular and supramolecular structures of three products and one intermediate

2018 ◽  
Vol 74 (3) ◽  
pp. 312-320 ◽  
Author(s):  
Lina M. Acosta Quintero ◽  
Isidro Burgos ◽  
Alirio Palma ◽  
Justo Cobo ◽  
Christopher Glidewell
Keyword(s):  
Mass Spectrometry ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Spectroscopic Characterization ◽  
Supramolecular Structures ◽  
Boat Conformation ◽  
Reaction Intermediates ◽  
A Chain ◽  
Related Compounds ◽  
C Nmr

A concise, efficient and versatile synthesis of amino-substituted benzo[b]pyrimido[5,4-f]azepines is described: starting from a 5-allyl-4,6-dichloropyrimidine, the synthesis involves base-catalysed aminolysis followed by intramolecular Friedel–Crafts cyclization. Four new amino-substituted benzo[b]pyrimido[5,4-f]azepines are reported, and all the products and reaction intermediates have been fully characterized by IR,1H and13C NMR spectroscopy and mass spectrometry, and the molecular and supramolecular structures of three products and one intermediate have been determined. In each ofN,2,6,11-tetramethyl-N-phenyl-6,11-dihydro-5H-benzo[b]pyrimido[5,4-f]azepin-4-amine, C22H24N5, (III), 4-(1H-benzo[d]imidazol-1-yl)-6,11-dimethyl-6,11-dihydro-5H-benzo[b]pyrimido[5,4-f]azepine, which crystallizes as a 0.374-hydrate, C21H19N5·0.374H2O, (VIIIa), and 6,7,9,11-tetramethyl-4-(5-methyl-1H-benzo[d]imidazol-1-yl)-6,11-dihydro-5H-benzo[b]pyrimido[5,4-f]azepine, C24H25N5, (VIIIc), the azepine ring adopts a boat conformation, but with a different configuration at the stereogenic centre in (VIIIc), as compared with (III) and (VIIIa). In the intermediate 5-allyl-6-(1H-benzo[d]imidazol-1-yl)-N-methyl-N-(4-methylphenyl)pyrimidin-4-amine, C22N21N5, (VIIb), the immediate precursor of 4-(1H-benzo[d]imidazol-1-yl)-6,8,11-trimethyl-6,11-dihydro-5H-benzo[b]pyrimido[5,4-f]azepine, (VIIIb), the allyl group is disordered over two sets of atomic sites having occupancies of 0.688 (5) and 0.312 (5). The molecules of (III) are linked into chains by a C—H...π(pyrimidine) hydrogen bond, and those of (VIIb) are linked into complex sheets by three hydrogen bonds, one of the C—H...N type and two of C—H...π(arene) type. The molecules of the organic component in (VIIIa) are linked into a chain of rings by two C—H...π(arene) hydrogen bonds, and these chains are linked into sheets by the water components; a single weak C—H...N hydrogen bond links molecules of (VIIIc) into centrosymmetricR22(10) dimers. Comparisons are made with some related compounds.

A concise and versatile route to tetrahydro-1-benzazepines carrying [a]-fused heterocyclic units: synthetic sequence and spectroscopic characterization, and the molecular and supramolecular structures of one intermediate and two products

2019 ◽  
Vol 75 (2) ◽  
pp. 168-177
Author(s):  
Sergio A. Guerrero ◽  
Juan E. Ramírez ◽  
Alirio Palma ◽  
Justo Cobo ◽  
Christopher Glidewell
Keyword(s):  
Mass Spectrometry ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Spectroscopic Characterization ◽  
Chair Conformation ◽  
Supramolecular Structures ◽  
Target Product ◽  
Target Compound ◽  
Synthetic Sequence ◽  
C Nmr

A concise, efficient and versatile route from simple starting materials to tricyclic tetrahydro-1-benzazepines carrying [a]-fused heterocyclic units is reported. Thus, the easily accessible methyl 2-[(2-allyl-4-chlorophenyl)amino]acetate, (I), was converted, via (2RS,4SR)-7-chloro-2,3,4,5-tetrahydro-1,4-epoxy-1-benzo[b]azepine-2-carboxylate, (II), to the key intermediate methyl (2RS,4SR)-7-chloro-4-hydroxy-2,3,4,5-tetrahydro-1H-benzo[b]azepine-2-carboxylate, (III). Chloroacetylation of (III) provided the two regioisomers methyl (2RS,4SR)-7-chloro-1-(2-chloroacetyl)-4-hydroxy-2,3,4,5-tetrahydro-1H-benzo[b]azepine-2-carboxylate, (IVa), and methyl (2RS,4SR)-7-chloro-4-(2-chloroacetoxy)-2,3,4,5-tetrahydro-1H-benzo[b]azepine-2-carboxylate, C14H15Cl2NO4, (IVb), as the major and minor products, respectively, and further reaction of (IVa) with aminoethanol gave the tricyclic target compound (4aRS,6SR)-9-chloro-6-hydroxy-3-(2-hydroxyethyl)-2,3,4a,5,6,7-hexahydrobenzo[f]pyrazino[1,2-a]azepine-1,4-dione, C15H17ClN2O4, (V). Reaction of ester (III) with hydrazine hydrate gave the corresponding carbohydrazide (VI), which, with trimethoxymethane, gave a second tricyclic target product, (4aRS,6SR)-9-chloro-6-hydroxy-4a,5,6,7-tetrahydrobenzo[f][1,2,4]triazino[4,5-a]azepin-4(3H)-one, C12H12ClN3O2, (VII). Full spectroscopic characterization (IR, 1H and 13C NMR, and mass spectrometry) is reported for each of compounds (I)–(III), (IVa), (IVb) and (V)–(VII), along with the molecular and supramolecular structures of (IVb), (V) and (VII). In each of (IVb), (V) and (VII), the azepine ring adopts a chair conformation and the six-membered heterocyclic rings in (V) and (VII) adopt approximate boat forms. The molecules in (IVb), (V) and (VII) are linked, in each case, into complex hydrogen-bonded sheets, but these sheets all contain a different range of hydrogen-bond types: N—H...O, C—H...O, C—H...N and C—H...π(arene) in (IVb), multiple C—H...O hydrogen bonds in (V), and N—H...N, O—H...O, C—H...N, C—H...O and C—H...π(arene) in (VII).

Nine closely related tetrahydro-1,4-epoxy-1-benzazepines carrying pendant heterocyclic substituents: hydrogen-bonded supramolecular assembly in zero, one and two dimensions

2012 ◽  
Vol 68 (3) ◽  
pp. o131-o140 ◽  
Author(s):  
Maria C. Blanco ◽  
Alirio Palma ◽  
Justo Cobo ◽  
Christopher Glidewell
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Supramolecular Assembly ◽  
Two Dimensions ◽  
Specific Interactions ◽  
Space Groups ◽  
Racemic Mixtures ◽  
Sheet Structure ◽  
A Chain ◽  
Related Compounds

The structures are reported of nine closely related tetrahydro-1,4-epoxy-1-benzazepines carrying pendant heterocyclic substituents, namely: 2-exo-(5-nitrofuran-2-yl)-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C14H12N2O4, (I), 7-fluoro-2-exo-(1-methyl-1H-pyrrol-2-yl)-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C15H15FN2O, (II), 7-fluoro-2-exo-(5-methylfuran-2-yl)-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C15H14FNO2, (III), 7-fluoro-2-exo-(3-methylthiophen-2-yl)-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C15H14FNOS, (IV), 7-fluoro-2-exo-(5-methylthiophen-2-yl)-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C15H14FNOS, (V), 7-chloro-2-exo-(5-methylfuran-2-yl)-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C15H14ClNO2, (VI), 2-exo-(5-methylfuran-2-yl)-7-trifluoromethoxy-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C16H14F3NO3, (VII), 2-exo-(3-methylthiophen-2-yl)-7-trifluoromethoxy-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C16H14F3NO2S, (VIII), and 2-exo-(5-nitrofuran-2-yl)-7-trifluoromethoxy-2,3,4,5-tetrahydro-1,4-epoxy-1H-1-benzazepine, C15H11F3N2O5, (IX). All nine compounds crystallize in centrosymmetric space groups as racemic mixtures with configuration (2RS,4SR). There are no direction-specific interactions between the molecules in (V). The molecules in (III), (IV), (VI) and (VII) are linked into simple chains, by means of a single C—H...O hydrogen bond in each of (III), (VI) and (VII), and by means of a single C—H...π(arene) hydrogen bond in (IV), while the molecules in (VIII) are linked into a chain of rings. In each of (I) and (II), a combination of one C—H...O hydrogen bond and one C—H...π(arene) hydrogen bond links the molecules into sheets, albeit of completely different construction in the two compounds. In (IX), the sheet structure is built from a combination of four independent C—H...O hydrogen bonds and one C—H...π(arene) hydrogen bond. Comparisons are made with some related compounds.

scholarly journals Twelve 4-(4-methoxyphenyl)piperazin-1-ium salts containing organic anions: supramolecular assembly in one, two and three dimensions

2019 ◽  
Vol 75 (10) ◽  
pp. 1494-1506 ◽  
Author(s):  
Haruvegowda Kiran Kumar ◽  
Hemmige S. Yathirajan ◽  
Sabine Foro ◽  
Christopher Glidewell
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Supramolecular Assembly ◽  
Organic Anions ◽  
Three Dimensions ◽  
Space Group ◽  
Dimensional Array ◽  
A Chain ◽  
Related Compounds

Twelve 4-(4-methoxyphenyl)piperazin-1-ium salts containing organic anions have been prepared and structurally characterized. The monohydrated benzoate, 4-fluorobenzoate, 4-chlorobenzoate and 4-bromobenzoate salts, C11H17N2O+·C7H5O2 −·H2O (I), C11H17N2O+·C7H4FO2 −·H2O (II), C11H17N2O+·C7H4ClO2 −·H2O (III), and C11H17N2O+·C7H4BrO2 −·H2O (IV), respectively, are isomorphous and all exhibit disorder in the 4-methoxyphenyl unit: the components are linked by N—H...O and O—H...O hydrogen bond to form chains of rings. The unsolvated 2-hydroxybenzoate, pyridine-3-carboxylate and 2-hydroxy-3,5-dinitrobenzoate salts, C11H17N2O+·C7H5O3 − (V), C11H17N2O+·C6H4NO2 − (VI) and C11H17N2O+·C7H3N2O7 − (VII), respectively, are all fully ordered: the components of (V) are linked by multiple N—H...O hydrogen bonds to form a chain of rings; those of (VI) are linked into a three-dimensional framework by a combination of N—H...O, C—H...O and C—H...N hydrogen bonds and those of (VII), where the anion has a structure reminiscent of the picrate anion, are linked into a three-dimensional array by N—H...O and C—H...O hydrogen bonds. The hydrogensuccinate and hydrogenfumarate salts, C11H17N2O+·C4H5O4 − (VIII) and C11H17N2O+·C4H3O3 − (IX), respectively, are isomorphous, and both exhibit disorder in the anionic component: N—H...O and O—H...O hydrogen bonds link the ions into sheets, which are further linked by C—H...π(arene) interactions. The anion of the hydrogenmaleate salt, C11H17N2O+·C4H3O3 − (X), contains a very short and nearly symmetrical O...H...O hydrogen bond, and N—H...O hydrogen bonds link the anions into chains of rings. The ions in the trichloroacetate salt, C11H17N2O+·C2Cl3O2 − (XI), are linked into simple chains by N—H...O hydrogen bonds. In the hydrated chloranilate salt, 2C11H17N2O+·C6Cl2O4 2−·2H2O (XII), which crystallizes as a non-merohedral twin, the anion lies across a centre of inversion in space group P21/n, and a combination of N—H...O and O—H...O hydrogen bonds generates complex sheets. Comparisons are made with the structures of some related compounds.

Iodo-nitroarenesulfonamides: interplay of hard and soft hydrogen bonds, I...O interactions and aromatic π...π stacking interactions

2001 ◽  
Vol 58 (1) ◽  
pp. 94-108 ◽  
Author(s):  
Craig J. Kelly ◽  
Janet M. S. Skakle ◽  
James L. Wardell ◽  
Solange M. S. V. Wardell ◽  
John N. Low ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Stacking Interactions ◽  
Asymmetric Unit ◽  
Space Group ◽  
Rotation Axes ◽  
Π Stacking ◽  
Structural Database ◽  
A Chain

Molecules of N-(4′-iodophenylsulfonyl)-4-nitroaniline, 4-O2NC6H4NHSO2C6H4I-4′ (1), are linked by three-centre I...O2N interactions into chains and these chains are linked into a three-dimensional framework by C—H...O hydrogen bonds. In the isomeric N-(4′-nitrophenylsulfonyl)-4-iodoaniline, 4-IC6H4NHSO2C6H4NO2-4′ (2), the chains generated by the I...O2N interactions are again linked into a three-dimensional framework by C—H...O hydrogen bonds. Molecules of N,N-bis(3′-nitrophenylsulfonyl)-4-iodoaniline, 4-IC6H4N(SO2C6H4NO2-3′)2 (3), lie across twofold rotation axes in space group C2/c and they are linked into chains by paired I...O=S interactions: these chains are linked into sheets by a C—H...O hydrogen bond, and the sheets are linked into a three-dimensional framework by aromatic π...π stacking interactions. In N-(4′-iodophenylsulfonyl)-3-nitroaniline, 3-O2NC6H4NHSO2C6H4I-4′ (4), there are R^2_2(8) rings formed by hard N—H...O=S hydrogen bonds and R^2_2(24) rings formed by two-centre I...nitro interactions, which together generate a chain of fused rings: the combination of a C—H...O hydrogen bond and aromatic π...π stacking interactions links the chains into sheets. Molecules of N-(4′-iodophenylsulfonyl)-4-methyl-2-nitroaniline, 4-CH3-2-O2NC6H3NHSO2C6H4I-4′ (5), are linked by N—H...O=S and C—H...O(nitro) hydrogen bonds into a chain containing alternating R^2_2(8) and R^2_2(10) rings, but there are no I...O interactions of either type. There are two molecules in the asymmetric unit of N-(4′-iodophenylsulfonyl)-2-nitroaniline, 2-O2NC6H4NHSO2C6H4I-4′ (6), and the combination of an I...O=S interaction and a hard N—H...O(nitro) hydrogen bond links the two types of molecule to form a cyclic, centrosymmetric four-component aggregate. C—H...O hydrogen bonds link these four-molecule aggregates to form a molecular ladder. Comparisons are made with structures retrieved from the Cambridge Structural Database.

Conformational preferences in 2-nitrophenylthiolates: interplay between intra- and intermolecular forces; structures of (E)-1-(4-methyl-2-nitrobenzenethiolato)-2-phenylethene, S-(2-nitrophenyl)benzenecarbothiolate and 1-(2-nitrophenylthio)-2,5-pyrrolidinedione

2000 ◽  
Vol 56 (1) ◽  
pp. 58-67 ◽  
Author(s):  
John N. Low ◽  
Emily J. Storey ◽  
Mary McCarron ◽  
James L. Wardell ◽  
George Ferguson ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Nitro Group ◽  
Intermolecular Forces ◽  
Aryl Ring ◽  
Local Energy Minimum ◽  
Conformational Preferences ◽  
A Chain ◽  
Related Compounds ◽  
Scf Calculations ◽  
Intramolecular Forces

In (E)-1-(4-methyl-2-nitrobenzenethiolato)-2-phenylethene, C15H13NO2S (1) (orthorhombic Pbca), the nitro group is almost coplanar with the adjacent aryl ring, but the dihedral angles between the nitro-aryl and styryl fragments is ∼121°. The molecules are linked by paired C—H...O hydrogen bonds in a chain of rings. In S-(2-nitrophenyl)benzenecarbothiolate, C13H9NO3S (2) (monoclinic P21/a), the nitro group is rotated by 33.0 (2)° out of the plane of the adjacent aryl ring and the thiobenzoate group is strongly twisted away from the plane of the disubstituted aryl ring. The molecules of (2) are linked into chains by C—H...O hydrogen bonds, and each chain is linked to two neighbouring chains by means of aromatic π...π stacking interactions. In 1-(2-nitrophenylthio)-2,5-pyrrolidinedione, C10H8N2O4S (3) (monoclinic P21/a), the nitro group is again almost coplanar with the adjacent aryl ring, but the pyrrolidinedione unit is almost orthogonal to the O2NC6H4SN plane. There are three types of C—H...O hydrogen bond in the structure, and these link the molecules into a two-dimensional net. The conformations of these molecules have been investigated by SCF calculations and two energy minima have been identified for each: the molecules of (1) and (3) adopt conformations in their crystals which are close to those at the overall energy minima calculated for isolated molecules, while molecules of (2) adopt a conformation in the crystal close to that calculated for the local energy minimum. Comparisons are made with the structures of some related compounds and it is concluded that, while the nature of the two conformational minima is determined by intramolecular forces, the choice between them is determined primarily by intermolecular forces.

scholarly journals Synthesis and crystal structures of a bis(3-hydroxy-cyclohex-2-en-1-one) and two hexahydroquinoline derivatives

2020 ◽  
Vol 76 (2) ◽  
pp. 125-131
Author(s):  
Scott A. Steiger ◽  
Chun Li ◽  
Christina Gates ◽  
Nicholas R. Natale
Keyword(s):  
Hydrogen Bonds ◽  
Title Compound ◽  
Crystal Packing ◽  
Structural Features ◽  
Boat Conformation ◽  
Two Dimensional ◽  
Aryl Group ◽  
Dimensional Network ◽  
A Chain ◽  
Intramolecular Hydrogen

The title compound I, 2,2′-[(2-nitrophenyl)methylene]bis(3-hydroxy-5,5-dimethylcyclohex-2-enone), C23H27NO6, features a 1,3-ketone–enol conformation which is stabilized by two intramolecular hydrogen bonds. The most prominent intermolecular interactions in compound I are C—H...O hydrogen bonds, which link molecules into a two-dimensional network parallel to the (001) plane and a chain perpendicular to (1\overline{1}1). Both title compounds II, ethyl 4-(4-hydroxy-3,5-dimethoxyphenyl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate, C23H29NO6, and III, ethyl 4-(anthracen-9-yl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate, C29H29NO3, share the same structural features, such as a shallow boat conformation of the dihydropyridine group and an orthogonal aryl group attached to the dihydropyridine. Intermolecular N—H...O bonding is present in the crystal packing of both compound II and III.

scholarly journals (Z)-3-(1-Chloroprop-1-enyl)-2-methyl-1-phenylsulfonyl-1H-indole

2013 ◽  
Vol 69 (12) ◽  
pp. o1781-o1781 ◽  
Author(s):  
M. Umadevi ◽  
V. Saravanan ◽  
R. Yamuna ◽  
A. K. Mohanakrishnan ◽  
G. Chakkaravarthi
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Phenyl Ring ◽  
Three Dimensional ◽  
Ring System ◽  
Indole Ring ◽  
Compound C ◽  
Dimensional Network ◽  
A Chain

In the title compound, C18H16ClNO2S, the indole ring system forms a dihedral angle of 75.07 (8)° with the phenyl ring. The molecular structure is stabilized by a weak intramolecular C—H...O hydrogen bond. In the crystal, molecules are linked by weak C—H...O hydrogen bonds, forming a chain along [10-1]. C—H...π interactions are also observed, leading to a three-dimensional network.

Crystal structure of rivastigmine hydrogen tartrate Form I (Exelon®), C14H23N2O2(C4H5O6)

2016 ◽  
Vol 31 (2) ◽  
pp. 97-103 ◽  
Author(s):  
James A. Kaduk ◽  
Kai Zhong ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Powder Diffraction ◽  
Density Functional ◽  
Carbonyl Oxygen ◽  
Strong Hydrogen Bond ◽  
Hydroxyl Groups ◽  
A Chain ◽  
Tartrate Anion

The crystal structure of rivastigmine hydrogen tartrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Rivastigmine hydrogen tartrate crystallizes in space group P21 (#4) with a = 17.538 34(5), b = 8.326 89(2), c = 7.261 11(2) Å, β = 98.7999(2)°, V = 1047.929(4) Å3, and Z = 2. The un-ionized end of the hydrogen tartrate anions forms a very strong hydrogen bond with the ionized end of another anion to form a chain. The ammonium group of the rivastigmine cation forms a strong discrete hydrogen bond with the carbonyl oxygen atom of the un-ionized end of the tartrate anion. These hydrogen bonds form a corrugated network in the bc-plane. Both hydroxyl groups of the tartrate anion form intramolecular O–H⋯O hydrogen bonds. Several C–H⋯O hydrogen bonds appear to contribute to the crystal energy. The powder pattern is included in the Powder Diffraction File™ as entry 00-064-1501.

Secondary Interactions in Gold(I) Complexes with Thione Ligands, 3. Three Ionic Dimesylamides [1, 2]

2004 ◽  
Vol 59 (11-12) ◽  
pp. 1429-1437 ◽  
Author(s):  
Friedrichsa Friedrichsa ◽  
Peter G. Jones
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Layer Structure ◽  
Chain Structure ◽  
Hydrogen Bond Donor ◽  
Weak Hydrogen Bonds ◽  
Ribbon Structure ◽  
A Chain ◽  
Aurophilic Interactions ◽  
Short Contacts

Three structures of the form bis(thione)gold(I) di(methanesulfonyl)amide [thione = imidazolidine- 2-thione, 1; 1-methyl-imidazolidine-2-thione, 2; thiazolidine-2-thione, 3] were determined; all crystallize with one formula unit in the asymmetric unit. Each N-H hydrogen bond donor forms one classical two-centre hydrogen bond with an anion acceptor. Compound 1 thereby forms a complex layer structure with a layer thickness of 10.17 Å ; the packing may be analysed in terms of thinner subunit layers consisting of interlinked, hydrogen-bonded chains and rings. Compound 2 forms a chain structure consisting of a series of “hairpin bends”, a common feature in the gold complexes of 1-alkyl-imidazolidine-2-thiones. Compound 3 forms a corrugated ribbon structure in which the central region consists of parallel S-Au-S axes linked by aurophilic interactions; the anions exercise a “clamping” function by forming hydrogen bonds at the periphery of the ribbons. Further short contacts can be classed as weak hydrogen bonds C-H ··· X, with X = N, O, S or Au.

A concise and efficient concurrent synthesis of 6,11-dihydrodibenzo[b,e]azepines and 5,6,11,12-tetrahydrodibenzo[b,f]azocines and their conversion to 4-oxo-8,13-dihydro-4H-benzo[5,6]azepino[3,2,1-ij]quinoline-5-carboxylates and N-acetyl-5,6,11,12-tetrahydrodibenzo[b,f]azocines: synthetic sequence, spectroscopic characterization and the structures of two products

2019 ◽  
Vol 75 (6) ◽  
pp. 650-656
Author(s):  
Lina M. Acosta Quintero ◽  
Alirio Palma ◽  
Justo Cobo ◽  
Christopher Glidewell
Keyword(s):  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Spectroscopic Characterization ◽  
Boat Conformation ◽  
Framework Structure ◽  
Molar Ratios ◽  
Boat Form ◽  
Synthetic Sequence ◽  
Time Form ◽  
Twist Boat

Reaction of 2-allyl-N-benzyl-4-fluoroaniline or 2-allyl-N-benzyl-4-chloroaniline with 98% sulfuric acid leads to the concurrent formation of halogeno-substituted 11-ethyl-6,11-dihydrodibenzo[b,e]azepines, (II), and halogeno-substituted 11-methyl-5,6,11,12-tetrahydrodibenzo[b,f]azocines, (III), in each case in (II):(III) molar ratios of ca 2:1. Further reaction of (II) leads to ethyl 13-ethyl-2-halogeno-4-oxo-8,13-dihydro-4H-benzo[5,6]azepino[3,2,1-ij]quinoline-5-carboxylate, while acetylation of (III) gives the corresponding N-acetyl derivatives. The dibenzo[b,e]azepine and dibenzo[b,f]azocine ring systems are of importance in forming the core of a variety of bioactive compounds. In ethyl 13-ethyl-2-fluoro-4-oxo-8,13-dihydro-4H-benzo[5,6]azepino[3,2,1-ij]quinoline-5-carboxylate, C22H20FNO3, (IVa), the azepine ring adopts a conformation close to the twist-boat form, and the molecules are linked into a three-dimensional framework structure by a combination of C—H...O and C—H...π(arene) hydrogen bonds. The azocine ring in 5-acetyl-2-chloro-11-methyl-5,6,11,12-tetrahydrobenzo[b,f]azocine, C18H18ClNO, (Vb), adopts the boat–boat conformation and the molecules are again linked by C—H...O and C—H...π(arene) hydrogen bonds, but this time form a sheet structure.

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