A novel synthesis of dibenzo[b,f] [1,4]thiazepin-11(10H)one 5,5-dioxides

Treatment of thioxanthen-9-one 10,10-dioxides with sodium amide in liquid ammonia provided a novel one-step conversion to dibenzo[b,f][1,4]thiazepin-11(10H)one 5,5-dioxides. Some limitations and a possible mechanism for the reaction are discussed.     

Denitrocyclization in synthesis of dibenzo[b,f][1,4]thiazepin‐11(10h)‐ones and their derivatives

A convenient synthesis of the novel dibenzo[b,f][1,4]thiazepin‐11(10H)‐ones is reported. As a key step, the synthetic route includes intramolecular aromatic denitrocyclization of 2‐(2,4‐dinitro‐phenylsulfanyl)‐benzoic acid amides. Efficient procedures for denitrocyclization in the presence of different bases are developed. Reduction of the nitro group in the obtained heterocycles resulted in formation of primary amines, which were transformed into amides by acylation with different carboxylic acids. The synthesized compounds have a great potential of bioactivity and are useful objects for biomedicinal screening.     

Synthesis of 2‐formyl‐1‐aza‐dibenzo[e,h]azulenes

Synthesis of a novel heterocyclic class of compounds, 1‐aza‐dibenzo[e,h]azulenes [1] ( 6a‐c and 7a‐c ), derived from dibenzo[b,f]oxepin, its 8‐chloro analogue and dibenzo[b,f]thiepin, respectively, is described. Aldol condensation of the starting ketones 4a‐c with (dimethyl‐hydrazono)‐acetaldehyde affords hydrazonoethylidene derivatives 5a‐c , which on reduction with sodium dithionite and subsequent cyclization provide the target tetracyclic 1‐aza‐dibenzo[e,h]azulenes 6a‐c . Regiospecific formylation of 6a‐c with Vilsmeier reagent leads to 2‐formyl derivatives 7a‐c . A series of derivatives 6a‐c and 7a‐c was tested for antiinflammatory activity as potential inhibitors of tumor necrosis factor alpha (TNF‐α) production in vitro.     

The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 22 Dibenzo[f,h]benzothieno[2,3‐c]quinoline,dibenzo[f,h]benzothieno[2,3‐c][1,2,4]triazolo[4,3‐a]quinoline and dibenzo[f,h]naphtho[2′,1′:4,5]thieno[2,3‐c]quinoline

Photocyclization of 3‐chloro‐N‐(9‐phenanthryl)benzo[b]‐thiophene‐2‐carboxamide ( 3 ) and 3‐chloro‐N‐(9‐phenanthryl)‐naphtho[1,2‐b]thiophene‐2‐carboxamide ( 10 ) yielded dibenzo[f,h]benzothieno[2,3‐c]‐quinolin‐10(9H)‐one ( 4 ) and dibenzo[f,h]naphtho[2′,1′:4,5]thieno[2,3‐c]quinolin‐10(9H)‐one ( 11 ), respectively. Further elaboration of the lactams provided three novel unsubstituted new ring systems.     

Phenanthrene-fused azo-ene-ynes: synthesis of dibenzo[f,h]cinnoline and dibenzo[e,g]isoindazole derivatives

The cyclization reactions of a phenanthreno-fused azo-ene-yne compound have been studied both experimentally and computationally. Experimental results show that this system is prone to dimerization, more so than previously studied naphthalene- and benzene-based analogues. Calculations reveal that pyrazoles and arene-fused pyrazoles strongly stabilize carbenes in the 5-position through "coarctate conjugation", suggesting a stationary concentration of the carbenes/carbenoids during cyclization that is high enough for dimerization.     

Synthesis Of 1,8‐dioxa‐dibenzo[e,h]azulenese

A novel synthetic route to 2‐methyl‐1,8‐dioxa‐dibenzo[e,h]azulenes [1] via cyclisation of the corresponding 1,4‐dicarbonyl compound is described. 1,4‐Dicarbonyl compounds were synthesized by the alkylation reaction of the 11H‐dibenzo[b,f]oxepine‐10‐one while analogous alkylation of 11H‐dibenzo[b,f]thiepine‐10‐one resulted in formation of O‐alkylated products. Selective oxidation of 2‐methyl group afforded 1,8‐dioxa‐dibenzo[e,h]azulenes with formyl and hydroxymethyl functionality at C(2) position.     

Synthesis of dibenzo[b,f][1,4]oxazepin-11(10H)-ones from 2-nitrobenzoic acids

Base-catalyzed intramolecular nucleophilic substitution for the 2-nitro group in 2-hydroxyanilides of 2-nitrobenzoic acids gave dibenzo[b,f][1,4]oxazepin-11(10H)-ones. In particular, 3-nitrodibenzo[b, f][1,4]oxazepin-11(10H)-one was obtained from N-(2-hydroxyphenyl)-2,4-dinitrobenzamide. The nitro group in the product could also be replaced under the action of O- and S-nucleophiles. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 529–533, March, 2006.     

Synthesis and anti‐inflammatory activity of 8H‐1‐thia‐8‐aza‐dibenzo[e,h]azulenes

Synthesis of a novel class of fused heterotetracyclic compounds, 8H‐1‐thia‐8‐aza‐dibenzo[e,h]azulenes ( VII ), is described. Starting N‐benzoyl‐protected 5H‐dibenzo[b,f]azepine ( XI , PG = Bz) was oxidized to 5‐benzoyl‐10,11‐epoxy‐10,11‐dihydro‐5H‐dibenzo[b,f]azepine ( 2 ), which subsequently rearranged in Lewis acid‐induced epoxide ring opening to give 5‐benzoyl‐5,11‐dihydro‐10H‐dibenzo[b,f]azepin‐10‐one ( 3 ). Vilsmeier reaction of 3 provided β‐chlorovinyl aldehyde 4 that readily cyclized with ethyl 2‐mercaptoacetate to form dibenzazepino[4,5]‐fused thiophene structure 5 . Further transformation of substituent at C‐2 position of 5 and N‐deprotection led to final aminoalkoxy derivatives 9 . All compounds with tetracyclic skeleton were tested in vitro for their anti‐inflammatory activity. J. Heterocyclic Chem., (2011).     

6,7‐Dihydrodibenzo[e,g]azulen‐8(5H)‐one and 12,13‐dihydrobenzo[e]­napth­[2,1‐g]­azulen‐14(11H)‐one

In the structures of the title compounds, 6,7‐di­hydro­dibenzo[e,g]­azulen‐8(5H)‐one, C₁₈H₁₄O, (I), and 12,13‐di­hydro­benzo[e]­napth­[2,1‐g]­azulen‐14(11H)‐one, C₂₂H₁₆O, (II), the azulene group is in a boat‐envelope conformation. The structures are stabilized by weak C—H?O interactions.     

One‐Pot Three‐Component Synthesis of Benzo[f]thiopyrano[3,4‐b]quinolin‐11(8H)‐one Derivatives

A series of novel benzo[f]thiopyrano[3,4‐b]quinolin‐11(8H)‐one derivatives were synthesized via the reaction of aryl aldehyde, 2H‐thiopyran‐3,5(4H,6H)‐dione, and β‐naphthylamine in glacial acetic acid. This protocol features mild reaction conditions, high yields, and short reaction time.     

Diastereoisomeric forms of 11‐ethyl‐6,11‐dihydro‐5H‐dibenzo[b,e]azepine‐6‐carboxamide: syntheses and the molecular and supramolecular structure of the minor form (6RS,11RS)‐11‐ethyl‐6,11‐dihydro‐5H‐dibenzo[b,e]azepine‐6‐carboxamide

Compounds containing the tricyclic dibenzo[b,e]azepine system have potential activity in the treatment of a number of diseases. Continuing with our studies on the synthesis of new small and potentially bioactive molecules, a synthetic route, involving acid‐catalysed intramolecular Friedel–Crafts cyclization, to the readily separable diastereoisomers of 11‐ethyl‐6,11‐dihydro‐5H‐dibenzo[b,e]azepine‐6‐carboxamide, a potentially useful precursor in the synthesis of analogues of some anti‐allergenic, antidepressant and antihistaminic drugs currently in use, has been developed starting from 2‐allylphenylamine and methyl 2‐bromo‐2‐phenylacetate and proceeding via racemic methyl 2‐[(2‐allylphenyl)amino]‐2‐phenylacetate (A) and racemic 2‐[(2‐allylphenyl)amino]‐2‐phenylacetamide (B), to give the two diastereoisomers (I) and (II), C₁₇H₁₈N₂O. Isomers (I) and (II), and their precursors (A) and (B), have all been fully characterized spectroscopically. Structure analysis of the minor isomer (I) shows that it has the (6RS,11RS) configuration, and that the azepine ring adopts a conformation intermediate between the boat and twist‐boat forms, with the carboxamide and ethyl substituents both occupying quasi‐equatorial sites. The molecules of (I) are linked by a combination of N—H…O, N—H…π(arene) and C—H…π(arene) hydrogen bonds to form complex sheets. Comparisons are made with the structures of some related compounds.     

Microwave‐Assisted Synthesis of Substituted Dibenzo[b,f][1,4]thiazepines,Dibenzo[b,f][1,4]oxazepines,Benzothiazoles, and Benzimidazoles

A highly efficient synthesis for possessing 7‐membered rings with two heteroatoms is described, using efficient microwave‐assisted one‐pot method to synthesize (substituted) dibenzo[b,f][1,4]thiazepines [1] and dibenzo[b,f][1,4]oxazepines [2] in high yields (up to 99%) by cyclocondensations of o‐aminothiophenol or o‐aminophenol with o‐halobenzaldehydes, o‐fluoroacetophenone, and o‐fluorobenzophenone. In the absence of base, o‐aminothiophenol reacted with o‐halobenzaldehydes to afford benzothiazoles.     

Electron transfer from dibenzo[b,f]-1-azapentalene dianion: Attempted synthesis of dibenzo[b,f]-1-azapentalene

When dibenzo[b,f]-1-azapentalene dianion (3) was allowed to react with either iron (III) chloride or ethylene bromide, a one-electron transfer from3 took place readily to give the radical anion11. Further electron transfer from11 did not occur presumably due to the antiaromatic character of dibenzo[b,f]-1-azapentalene (1) that would have resulted. The radical anion11 underwent further transformation by hydrogen abstraction from the solvent to give 5,10-dihydroindeno[1,2-b]indole (2) and by dimerization to themeso and (R,S) isomers of 5,5,10,10-tetrahydro-10,10-biindeno[1,2-b]indole (4 a and4 b) respectively.

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Elektronentransfer von Dibenzo[b,f]-1-azapentalen-Dianion: Ein Versuch zur Synthese von Dibenzo[b,f]-1-azapentalen

Zusammenfassung Die Reaktion von Dibenzo[b,f]-1-azapentalen-Dianion (3) mit Eisen (III) oder Ethylenbromid ergab einen Ein-Elektronentransfer zum Radikalanion11. Ein weiterer Elektronentransfer fand nicht statt, vermutlich wegen des antiaromatischen Charakters von Dibenzo[b,f]-1-azapentalen (1), das dabei entstehen müßte. Das Radikalanion11 ergab unter Wasserstoffentzug aus dem Lösungsmittel 5,10-Dihydroindeno[1,2-b]indol (2), das weiter zummeso- bzw. (R,S)-5,5,10,10-tetrahydro-10,10-biindeno[1,2-b]indol (4 a bzw.4 b) dimerisierte.

     

Synthesis of Dibenzo[c,e]oxepin‐5(7H)‐ones from Benzyl Thioethers and Carboxylic Acids: Rhodium‐Catalyzed Double CH Activation Controlled by Different Directing Groups

A rhodium(III)‐catalyzed cross‐coupling of benzyl thioethers and aryl carboxylic acids through the two directing groups is reported. Useful structures with diverse substituents were efficiently synthesized in one step with the cleavage of four bonds (C? H, C? S, O? H) and the formation of two bonds (C? C, C? O). The formed structure is the privileged core in natural products and bioactive molecules. This work highlights the power of using two different directing groups to enhance the selectivity of a double C? H activation, the first of such examples in cross‐oxidative coupling.     

New derivatives of dibenzo[b,e][1,4]diazepin‐1‐ones by an efficient synthesis and spectroscopy

An efficient synthesis of four steps to obtain twelve new derivatives of 3,3‐dimethyl‐2,3,4,5,10,11‐hexahydro‐8‐[(o‐; and p‐methoxy)phenoxy]‐11‐[(o‐; and p‐R)phenyl]‐1H‐dibenzo[b,e][1,4]diazepin‐1‐ones IV, 1‐12 with possible biological and pharmacological activity as anticonvulsant and schizophrenia treatment in the central nervous system (CNS). The final products were obtained by condensation and cyclization between 3‐{4‐[(o‐; and p‐methoxy)phenoxy]‐1,2‐phenylenediamine}‐5,5‐dimethyl‐2‐cyclohexenone with (o‐; and p‐R)benzaldehyde. The structure of all products was corroborated by spectroscopy of ir, ¹H‐nmr, ¹³C‐nmr, with bidimensional experiments and MS in Low and high resolution with Collision‐Induced Dissociation experiments (CID).     

Dibenz [b,f]-1, 4-oxazepin-11 (10 H)-one und Dibenz [b,e]-1, 4-oxazepin-11 (5 H)-one. 12. Mitteilung über siebengliedrige Heterocyclen

The syntheses of dibenzo [b, f]-1, 4-oxazepin-11 (10 H)-ones (I) with electron-attracting substituents in position 2 by ring closure of the sodium salts of 2-halogeno-2′-hydroxy-benzanilides (II) are described. The reaction of II (R = SO₂·N(CH₃)₂) in N-methylpyrrolidone also led, by SMILES rearrangement, to the isomeric minor product dibenzo [b, e]-1, 4-oxazepin-11 (5 H)-one (III; R = SO₂·N(CH₃)₂), whose constitution was proven by synthesis from VI. In the case of II (R = SO₂·CH₃), the 5-methylsulfonyl-2-(2-hydroxyanilino)-benzoic acid (VI; R = SO₂·CH₃) was obtained directly after hydrolysis. The lactam I (R = NO₂) was rearranged to the corresponding acid VI by heating with dilute caustic soda.     

Synthesis of new benzo[h]‐ and benzo[f]chromeno[2,3‐b]‐pyridine‐5‐ones

A number of new benzo[h]‐ and benzo[f]chromeno[2,3‐b] pyridine‐5‐ones derivatives were synthesized from benzo[h]‐ and benzo[f]‐chromone‐carbonitriles and amino‐benzo[h]‐ and benzo[f]chromone‐carbaldehydes. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:2–7, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20152