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.     

Platinum complexes of dibenzo[1,2]dithiin, dibenzo[1,2]dithiin oxides and related polyaromatic hydrocarbon ligands

The synthesis of platinum bisphosphine complexes of biphenyl- 2,2'-dichalcogenates and the oxides of dibenzo[1,2]dithiin and related ligand systems by oxidative addition to [Pt(PPh(3))(4)] is reported. We also describe the synthesis of a new compound, dibenzothiophen-4-yldiselenide and its simple platinum complex (obtained by oxidative addition). All complexes have been fully characterised, principally by using multinuclear NMR spectroscopy and in six cases by means of single-crystal X-ray diffraction studies. The majority are simple S/S or Se/Se complexes, however the addition of dibenzo[1,2]dithiin trioxide to [Pt(PPh(3))(4)] gives a bimetallic system, [Pt[2-[S(O)],2'-[S(O)(2)]-biphen}(PPh(3))](2), containing a central Pt(2)S(2)O(2) core in which the ligand behaves as a tridentate S,S,O donor.     

Synthesis of polyoxygenated dibenzo[a,e]cycloheptatrienes

A successive route for the synthesis of substituted dibenzo[a,e]cycloheptatriene 1 was established by the reduction of 2-allylbenzaldehyde 4, the BF₃·OEt₂-mediated intermolecular coupling of 2-allylphenylmethanol 5 with oxygenated benzenes 6, the olefinic oxidative cleavage of 7 and the intramolecular ring-closure of 8. Functionalized anthracene 13 were prepared from 2-vinylbenzaldehyde 9. The key structures were confirmed by X-ray single crystal diffraction analysis.     

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.

     

螺[二苯并[a,j]氧杂蒽-14,9'-芴]的合成及性质

芴酮与2-萘酚在硫酸和3-巯基丙酸的作用下反应得到化合物螺[二苯并[a,j]氧杂蒽-14,9'-芴]. 采用核磁共振、 质谱、 红外光谱和元素分析等对该化合物进行了表征, 并通过X射线衍射法测得了其晶体结构, 确定该化合物是通过二苯并[a,j]氧杂蒽中的含氧六元杂环和芴中的五元环共用一个碳原子形成一个螺环. 利用荧光光谱和热分析等手段对该化合物的性质进行了研究, 结果表明其最大荧光发射峰为366 nm, 熔点为297 ℃, 热分解温度为329 ℃, 具有较高的热稳定性.     

A cyclopenta-fused dibenzo[b,d]thiophene-co-phenanthrene macrocyclic tetraradicaloid

A cyclopenta-fused macrocyclic tetraradicaloid, MC4-S, containing alternating phenanthrene (Phen) and dibenzo[b,d]thiophene (DBTh) units was synthesized and isolated in single-crystal form. Compared with its all-carbon isoelectronic structure, CPTP-M, the incorporation of two sulfur atoms leads to a smaller radical character and a larger singlet–triplet energy gap. X-ray crystallographic analysis reveals that the spin–spin coupling through the DBTh unit is stronger than that through the Phen moiety. In addition, the electron-rich sulfur atoms also raise the energies of both the HOMO and LUMO in MC4-S, but the overall optical and electronic energy gaps are close to that of the CPTP-M. MC4-S displays global anti-aromaticity according to the NMR measurements and theoretical calculations (NICS, ACID and 2D ICSS), with a 36π ring current circuit along the all-carbon periphery excluding the two sulphur atoms. Its dication becomes globally aromatic due to the existence of a dominant 34π-conjugation pathway. This study sheds some light on the effect of heteroatoms on the electronic properties of open-shell polyradicaloids.

The first member of sulfur-heterocycloarene neutral tetraradicaloids, MC4-S, was synthesized in crystalline form, which displays strong global anti-aromaticity and unique properties.     

New reactions of a dibenzo[a,e]pentalene

Reduction of dibenzo[a,e]pentalene 3 (denoted as dibenzopentalene hereafter) with excess lithium gave dilithium dibenzopentalenide 1. Since oxidation of 1 with iodine gave 3, redox behavior between 1 and 3 is controllable and reversible. Reaction of 3 with methyllithium gave lithium 5-methyldibenzopentalenide 5, the formation of which was evidenced by some trapping experiments and X-ray crystallographic analysis. Reactions of 3 with halogens gave 5,10-dihalodibenzopentalenes, 8 and 9. Some optical properties of novel dibenzopentalene derivatives are also demonstrated.     

Dihydrodiols and diol epoxides of dibenzo[a,i]-and [a,h]pyrene

Syntheses of dihydrodiols and highly mutagenic diol epoxides of the carcinogenic polycyclic aromatic hydrocarbons dibenzo[a,i]-and [a,h]pyrene are described.     

Transformations in the dibenzo[a,d]cycloheptene series

The synthesis of 5-aminomethyl-5-hydroxy-5H-dibenzo[a,d]cycloheptene derivatives 3 was accomplished by two separate routes. The first route involves the reaction of 4 with Corey's Reagent followed by reaction with either amines or hydrazines. The reaction products with hydrazines (e.g. 6 ) were hydrogenolyzed, either with hydrogen in the presence of platinum, or with hydrazine in the presence of Raney nickel to yield 3 . The second route to these compounds ( 3 ) proceeds by a Reformatsky reaction on 4 followed by acid-hydrazide formation and Curtius degradation of 8 to afford spirooxazolidones 9 . Compounds 9 can be alkylated on nitrogen ( 10 ), and either 9 or 10 hydrolyzed to give the target compounds 3 .     

Eight-membered organosulfur heterocycles. Synthesis of dibenzo[d,g][1,3,6,2]dioxathiaphosphocin and dibenzo[d,g][1,3,6,2]dioxathiasilocin ring systems

The reaction of 2,2′-thiobisphenols with either phenylphosphonous dichloride or phosphorus trichloride followed by an alcohol gave derivatives of the dibenzo[d,g][1,3,6,2]dioxathiaphosphocin ring system. The analogous reaction of 2,2′-thiobisphenols with alkyl and aryl dichlorosilanes gave the heretofore unreported dibenzo[d,g][1,3,6,2]dioxathiasilocin ring system. The analytical and spectral data are reported.     

First rational synthesis of dibenzo[fg,op]naphthacene discotics

A novel, versatile and regiospecific synthesis of variable degree substituted dibenzo[fg,op]naphthacene (also named dibenzopyrene) is described which involves the preparation of a tetraphenyl using a palladium-catalysed cross-coupling of arylboronic acids followed by photochemical cyclization.     

螺[二苯并[a,j]氧杂蒽-14,9’-芴]的合成及性质简

芴酮与2-萘酚在硫酸和3-巯基丙酸的作用下反应得到化合物螺[二苯并[a,j]氧杂蒽-14,9’-芴]. 采用核磁共振、质谱、红外光谱和元素分析等对该化合物进行了表征,并通过X射线衍射法测得了其晶体结构,确定该化合物是通过二苯并[a,j]氧杂蒽中的含氧六元杂环和芴中的五元环共用一个碳原子形成一个螺环. 利用荧光光谱和热分析等手段对该化合物的性质进行了研究,结果表明其最大荧光发射峰为366 nm,熔点为297 ℃,热分解温度为329 ℃,具有较高的热稳定性.     

Microwave assisted synthesis of indolo[2,3-b]dibenzo[b,g][1,8]naphthyridines

We have developed an effective microwave assisted p-TsOH catalyzed synthesis of indolo[2,3-b]dibenzo[b,g][1,8]naphthyridines via a one pot reaction of 3-amino-9-ethylcarbazole and 2-chloro-3-formylquinolines.     

First rational synthesis of dibenzo[fg,op]naphthacene discotics

A novel, versatile and regiospecific synthesis of variable degree substituted dibenzo[fg,op]naphthacene (also named dibenzopyrene) is described which involves the preparation of a tetraphenyl using a palladium-catalysed cross-coupling of arylboronic acids followed by photochemical cyclization.     

Synthesis of multi‐substituted dibenzo[b,d]furan

The synthesis of multi‐substituted dibenzo[b,d]furan derivatives 7a‐b and 11a‐b from readily available starting materials is described. These compounds are important intermediates for synthesis of molecules having wide therapeutic applications.     

Direct, two-step synthetic pathway to novel dibenzo[a,c]phenanthridines

Novel dibenzo[a,c]phenanthridines are prepared regioselectively by the application of a straightforward synthetic pathway, starting from new 3,4-diaryl- and 3,4-dihydro-3,4-diarylisoquinolines prepared via Ritter-type heterocyclization and the more classical two-step reductive amination/Bischler-Napieralski cyclization of triarylethanones, respectively. A comparative study of nonphenolic oxidative coupling methodologies provides a highly efficient procedure, based on the hypervalent iodine reagent phenyliodine(III) bis(trifluoroacetate) (PIFA), to accomplish the final coupling step.     

Functionalized derivatives of dibenzo [c,j] dipyrazolo-[3,4-f∶3′,4′-m] [1,2,5,8,9,12] hexaazacyclotetradecinate

A number of derivatives of dibenzo [c,j] dipyrazolo [3,4-f3,4-m] [1,2,5,8,9,12]-hexaazacyclotetradecinate with peripheral nitro, amino, and acetylamino groups have been synthesized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 106–114, January, 1984.