The synthesis of [1]benzothieno[2,3-c]quinolines, [1]benzothieno[2,3-c][1,2,4]triazolo[4,3-a]quinoline,and [1]benzothieno[2,3-c]tetrazolo[1,5-a]quinoline

Photocyclization of 3-chloro-N-phenylbenzo[b]thiophene-2-carboxamide 10 afforded [1]benzothieno[2,3-c]-quinolin-6(5H)-one 11 which was chlorinated to 6-chloro[1]benzothieno[2,3-c]quinoline 12 followed by dechlorination to give [1]benzothieno[2,3-c]quinoline 5 . A series of 6-substituted alkoxy and thioalkoxy[1]benzothieno[2,3-c]quinoline derivatives were prepared along with the N-methyl quaternary salt 13 of 5 . 6-Chloro[1]-benzothieno[2,3-c]quinoline 12 was converted into 6-hydrazino[1]benzothieno[2,3-c]quinoline 23 which upon treatment with formic acid yielded [1]benzothieno[2,3-c][1,2,4]triazolo[4,3-a]quinoline 6 . Treatment of 23 with nitrous acid resulted in [1]benzothieno[2,3-c]tetrazolo[1,5-a]quinoline 7 . Compounds 6 and 7 are novel heterocyclic ring systems.     

Selenium heterocycles. XXXII . Synthesis of [1]benzoxepino[3,4-d]-thiazole, [1]benzothiepino[3,4-d]thiazole, [1]benzoxepino[3,4-d]selenazole,and [1]benzothiepino[3,4-d]selenazole. four novel heterocycles

Starting from the readily available ethyl 2-phenyl-4-methyl-thiazole-5-carboxylate (III), 2-phenyl-4-chloromethyl-thiazole (VIII) and 2-aryl-4-chloromethylselenazole (XIV), 2-phenyl-4,10-dihydro-10-oxo-[1]benzoxepino[3,4-d]thiazole (Ia), 2-phenyl-4,10-dihydro-10-oxo[1]benzothiepino[3,4-d]thiazole (Ib), 2-aryl-4,10-dihydro-10-oxo[1]benzoxepino[3,4-d]selenazoles (IIa-IIe) and 2-aryl-4,10-dihydro-10-oxo[1]benzothiepino[3,4-d]selenazoles (IIf-IIj) were prepared.     

The synthesis of methano-bridged bisdehydro [18]-, -[20]-, -[22]-, and -[24] annulenes

Title annulenes were synthesized by Wittig reaction of cyclohepta-1,3,5-triene-1,6-dialdehyde or its vinylogous dialdehydes with 5-methylpenten-2-yn-4-yltriphenylphosphonium bromide, followed by intramolecular oxidative couplings of the resulting acyclic compounds, and they proved to be diatropic or paratropic, corresponding to the number of peripheral π-electrons.     

Conformational analysis—XIII: Syn and anti [3.2]-, [3.3]-, [4.2]-, and [4.3]-metacyclophanes

While in [3.3]metacyclophane (19) the aromatic rings preferentially adopt the syn arrangement, its lower and higher homologues, i.e. [2,2]-, [3.2]-, [4.2], and [4.3]-metacyclophane (1, 6, 26 and 30), adopt the anti conformation. Substituted [m,n]metacyclophanes do not necessarily behave similarly to the parent hydrocarbons. Substituted compounds exhibiting a different conformation are [3.2]metacyclophane-1,11-dione (7) (syn), [3.3]metacyclophane-2,11-dione (24) and the corresponding bis[propylene thioacetal] (25) (anti), [4.2]metacyclophane-2,12-dione (27) (syn), and [4.3]metacyclophane-2,13-dione (31) (syn). Thus, the solution conformation of an [m.n]metacyclophane is sensitive both to chain length [m.n.] of the bridges and substitution. The ring inversion barriers determined by variable temperature ¹H NMR decrease with increasing length of the bridges and qualitatively correlate with the transanular strain present in the pertinent system.     

Synthesis of a Novel Heterocyclic System, [1,2,4] Triazino[1,2-a]Pyrimido [4,5-e] [1,3,4] Thiadiazines

Substituted 6-chloro-pyrimido[4,5-e][1,3,4] thiadiazine was converted to the corresponding 6-hydrazino derivative by treatment with hydrazine hydrate in DMF/Et ₃ N. The latter was converted to various substituted [1,2,4]triazino[1,2-a] pyrimido[4,5-e][1,3,4]thiadiazines.     

Condensed pyridine bases synthesis of some benzo[b]furo[2,3-c]-, benzo[b]- thieno[2,3-c]-, and benzo[b]selenopheno[2,3-c]-quinolines

Summary Condensation of benzo[b]furan-3(2H-one, benzo[b]thiophen-3(2H)-one and benzo[b]selenophen-3(2H)-one with dimedone gives 2-(3-heteryl)dimedones. Acylation of the latter leads to the corresponding tetracyclic pyrylium salts, from which condensed quinolines are obtained. Some condensed quinoline derivatives are obtained by reaction of 1-oxo-1,2,3,4-tetrahydroheterene[2,3-c]quinolines with sodium borohydride, hydrazine, and hydroxylamine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 321–326, March, 1994.     

One-pot synthesis of imidazo[1,2-b]pyrazole,imidazo[1,2-b]-1,2,4-triazole,imidazo[1,2-a]pyridine,imidazo[1,2-a]pyrimidine,imidazo[1,2-a]benzimidazole,and 1,2,4-triazolo[4,3-a]benzimidazole derivatives

Hydrazonoyl bromides 1a-c react with 5-amino-3-phenyl-1H-pyrazole, 5-amino-1H-1,2,4-triazole, 2-aminopyridine, and 2-aminobenzimidazole to afford the corresponding imidazol[1,2-b]pyrazoles 10, imidazo[1,2-b]-1,2,4-triazoles 11, imidazo[1,2-a]pyridines 16, imidazo[1,2-a]pyrimidines 17, and imidazo[1,2-a]benzimidazoles 20, respectively. Compounds 1a-c reacted also with 2-methylthiobenzimidazole to give 1,2,4-triazolo[4,3-a]benzimidazole derivatives 21. © 1997 John Wiley & Sons, Inc.     

Symmetric,Unsymmetrical, and Asymmetric [7]‐, [10]‐, and [13]Helicenes

Fully aromatic helicenes with more than one pitch‐length are illustrious synthetic targets with potential applications in advanced optical devices and nano‐electronics. The task of extending the length of fully conjugated helicenes past one pitch length is challenging. Now, the synthesis of a series of azaoxa[7]‐, [10]‐, and [13]helicenes is described. The synthesis is based on iterative oxidative furan formation between 3,6‐dihydroxycarbazoles and/or 2‐naphthols. The flexibility of the presented method allows the convenient and scalable synthesis of symmetric, unsymmetrical, and asymmetric homo‐chiral structures. The [13]helicenes can be synthetically functionalized both at the termini and the periphery. The full range of helicenes were characterized using NMR and optical spectroscopy (UV/Vis, fluorescence, and CD) along with single‐crystal X‐ray crystallography. The enantiomers of the [13]helicenes are the longest optically pure helicenes isolated to date.     

Symmetric,Unsymmetrical, and Asymmetric [7]‐, [10]‐, and [13]Helicenes

Fully aromatic helicenes with more than one pitch‐length are illustrious synthetic targets with potential applications in advanced optical devices and nano‐electronics. The task of extending the length of fully conjugated helicenes past one pitch length is challenging. Now, the synthesis of a series of azaoxa[7]‐, [10]‐, and [13]helicenes is described. The synthesis is based on iterative oxidative furan formation between 3,6‐dihydroxycarbazoles and/or 2‐naphthols. The flexibility of the presented method allows the convenient and scalable synthesis of symmetric, unsymmetrical, and asymmetric homo‐chiral structures. The [13]helicenes can be synthetically functionalized both at the termini and the periphery. The full range of helicenes were characterized using NMR and optical spectroscopy (UV/Vis, fluorescence, and CD) along with single‐crystal X‐ray crystallography. The enantiomers of the [13]helicenes are the longest optically pure helicenes isolated to date.     

Chemistry of 1,2,3-thiadiazole. IV. Synthesis of [1]benzoxepino-[3,4-d][1,2,3]thiadiazole, [1]benzothiepino-[3,4-d][1,2,3]thiadiazole, [1]benzoxepino[4,3-d][1,2,3]thiadiazole, [1]benzoxepino[4,3-d]oxazole and [1]benzoxepino[4,3-d]oxazole. Four novel heterocycles

Starting from the readily available 4-bromomethy-5-carbethoxy 1,2,3-thiadiazole (V), 5-bromomethy-4-carbethoxy-1,2,3-thiadiazole (IX) and ethyl 2-aryl-5-bromomethyloxazole-4-carboxylate (XIV), 4,10-dihydro-10-oxo[1]benzoxepino[3,4-d][1,2,3]thiadiazole (Ia), 4,10-dihydro-10-oxo[1]benzothiepino[3,4-d][1,2,3]thiadiazole (Ib), 4,10-dihydro-4-oxo[1]benzothiepino[4,3-d] [1,2,3]thiazole (II), 2-aryl-4,10-dihydro-4-oxo[1]benzoxepino[4,3-d]oxazoles (XIXa-XIXc) and 2-aryl-4,10-dihydro-4-oxo[1]benzothiepino[4,3-d]oxazoles (XIXd-XIXf) were prepared.     

Self-assembly of Novel Hetero[3]rotaxane,[2]Rotaxanes and [2]Catenane

One linear template 13 and one cyclophane template 15, both incorporating two electron rich 1,4-dialkoxybenzene units and one diamide unit, have been synthesized. By utilizing donor-acceptor interaction and/or intermolecular hydrogen bonding assembling principles, one novel hetero[3]rotaxane 22·4Cl, possessing one neutral and one tetracationic ring components, has been synthesized from 13, through neutral [2]rotaxane 21 as intermediate. With 15 as template, tetracationic [2]catenane 23·4PF6 was assembled by using donor-acceptor interaction, but no neutral [2]rotaxane could be obtained under the typical conditions of hydrogen bonding assembling principle. The interlocked supramolecular compounds have been characterized and their spectral properties are investigated.     

Novel polycyclic heterocycles. XI. Synthesis of 11,12-dihydropyrido[2,1-b] [1,3]benzodiazepines, 6H-pyrido[1,2-c] [1,3,5]benzoxadiazepines,and 6H-Pyrido[1,2-c] [1,3,5]benzothiadiazepines

An unusually facile dehydrobromination, involving the ortho-bromine atom and the = NH proton of a 2-imino-1-(phenethyl)-, 2-imino-1-(phenoxymethyl)-, or 2-imino-1-(phenylthiomethyl)-pyridine ( 2a-e ) has led to the synthesis of three novel bridgehead nitrogen tricyclic systems: 11,12-dihydropyrido[2,1-b] [1,3]benzodiazepines ( 3a,b ), 6H-pyrido[1,2-c] [1,3,5]benzoxadiazepines ( 3c,d ) and 6H-pyrido[1,2-c][1,3,5]benzothiadiazepines ( 3e ). As anticipated, these cyclizations required a base, e.g., potassium carbonate, and a catalyst, e.g., copper bronze. What was unusual, was that these reactions occurred in methanol or n-propanol, under reflux, either under anhydrous conditions, or in the presence of large amounts of water. The pmr spectra of these compounds are discussed.     

Synthetic and structural studies of [6]-, [7]- and [10]metacyclophanes

A new preparative sequence from 2,3-polymethylene-2-cyclopentenone 5 to 2,6-polymethylenebromobenzenes 3 (n = 6, 7, 10) and 2,6-polymethylenephenyllithiums 6 has been found. The reaction of 6 with various electrophiles produces a number of new compounds to disclose the unique reactivity of the aryl C-Li moiety surrounded by the polymethylene chain. Photolysis of 3a and 3b provides transannular products 8, 10 and 11, all arising from the proximity between the aromatic bromine and the aliphatic hydrogen intraannularly opposed to be removed as HBr. Spectrometric study gives quantitative data of the dependence of the molecular geometry upon the chain length and the aromatic substituents. The energy barriers ΔG_c^≠ of the conformational flipping are 17·4 kcal/mol (T_c 76·5°) for [6]metacyclophane (7a), 11·5 kcal/mol (T_c ?28°) for [7]metacyclophane (7b), ·8 kcal/mol for [10]metacyclophane (7c). The lower-energy process of the aliphatic chain in [6]metacyclophane derivatives is the pseudorotation with substituent-dependent barrier ΔG_c^≠ 11·1 kcal/mol (T_c ?31·5°) for 7a, 12·4 kcal/mol (T_c ?4·5°) for 3a and 12·7 kcal/mol (T_c 1·0°) for 12a. The rather large rotational barrier is attributed to the compressed structure of each system. The benzene ring distortion of the cyclophanes is deduced from the bathochromic shift of the B-band and the diamagnetic shift of the benzene proton signals in the PMR.