Dual type of reactivity op 1,2-disubstituted dihydro-N-heteroaromatic systems. 11. Aromatization of N-sulfonyl-1,2-dihydroquinolines and isoquinolines containing an α-indolyl or pyrrolyl substituent

When N-sulfonyl-1,2-dihydroquinolines and isoquinolines, containing an indolyl or pyrrolyl substituent at the -position, react with trityl perchlorate, this substituent is split off, and N-sulfonyl quinolinium and isoquinolinium cations and tritylindole or tritylpyrrole are formed. A similar reaction with 2,2,6,6-tetramethyl-1-oxopiperidinium perchlorate proceeds with splitting of hydrogen or retention of the -substituent, which leads to the corresponding -substituted N-sulfonylquinolinium and isoquinolinium cations.For Part 10, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1516–1518, November, 1986.     

The preparation and some chemistry of 2,2-dimethyl-1,2-dihydroquinolines

The cyclisation of N-(1,1-dimethylpropargyl) anilines, using cuprous chloride in refluxing toluene, yields 6-substituted-2,2-dimethyl-1,2-dihydroquinolines. The reactivity of the double bond in the heterocyclic ring of these products is exemplified by chlorination, to yield 6-substituted-3,4-cis-dichloro-2,2-dimethyl-1,2,3,4-tetrahydroquinolines which can be selectively dechlorinated to provide 6-substituted-3-chloro-2,2-dimethyl-1,2,3,4-tetrahydroquinolines; epoxidation to yield an epoxide, which can be hydrogenolysed to the corresponding 3-hydroxy product and in turn oxidised to the 3-keto derivative; and oxymercuration to provide a 4-hydroxy product and hence a 4-keto derivative. Dehydrochlorination of a 3,4-dichloro product provides a 3-chloro-1,2-dihydroquinoline which can be hydrolysed to a 3-keto system. The formation of cis 3,4-dichloro products from the chlorination, as well as the formation of a cis chlorohydrin from the chlorination of N-acetyl-2,2,6-trimethyl-1,2-dihydroquinoline in partially aqueous solution, suggests that N-acetyl, or N-trifluoroacetyl groups, participate in the addition process.     

Reactions of 1,2-dihydroquinolines

The addition of benzene to 2,2,4-trimethyl-1,2-dihydroquinoline (I) in the presence of AlCl₃ requires prior protonation or acylation of the amino group. Electron-donor substituents in the benzene ring of I hinder the reaction. The addition of halobenzenes proceeds under more severe conditions to give only para-substituted 4-aryl-2,2,4-trimethyl-1,2,3,4-tetrahydroquinolines.See [1,2] for communications I and II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 795–797, June, 1971.     

Preparations and reactions of 1,2,3-trialkyl-1,2-dihydroquinolines and its related compounds

Several 1,2,3-trialkyl-1,2-dihydroquinolines (4 and 5) were prepared from the reactions of N-alkylanilinomagnesium bromide (1 and 2) with aliphatic aldehydes (3). Solutions of these dihydroquinolines in carbon tetrachloride or chloroform gave the corresponding 1,2,3- trialkylquinolinium chlorides (10 and 11) in high yields. Alkali treatment of 1,3-dimethyl-2- ethylquinolinium chloride (10b) led to 1,3 - dimethyl - 2 - acetyl - 1,2 - dihydroquinoline (13), which was unstable and readily converted to 1,3-dimethyl-2-quinolone (6) in the air.     

Reactions of 1,2-dihydroquinolines

2,2,4-Trimethyl-1,2-dihydroquinolines readily add alkylbenzenes under the influence of aluminum chloride to form 2,2,4-trimethyl-4-(p-alkylphenyl)-1,2,3,4-tetrahydroquinolines.See [1] for Communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1512–1514, November, 1970.     

Reactions of 1,2-dihydroquinolines

Under the Influence of anhydrous aluminum chloride, cyclohexane converts 2,2,4-trimethyl-1,2-dihydroquinoline to the tetrahydro derivative and alkylates it at the 7-position with simultaneous reduction of the ³-bond.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 977–980, July, 1971.     

Gold(III) chloride-catalyzed three-component reaction: a facile synthesis of alkynyl derivatives of 1,2-dihydroquinolines and isoquinolines

Gold(III) chloride is found to be an effective catalyst for the addition of alkynes on activated quinoline/isoquinolines to produce a series of alkynyl-substituted 1,2-dihydroquinolines and isoquinolines in a single-step operation. The easy availability of starting materials, convenient synthetic procedure, operational simplicity, and high regioselectivity makes this strategy very useful for the preparation of enyne derivatives of aza-aromatic compounds.     

The dual photochemical reactivity of 1,2-dihydroquinolines

Conclusions The lack of electrocyclic ring opening in 1,2-dihydroquinolines not containing a substituent at the nitrogen atom is related to the possibility of efficient homolytic dissociation in the excited state.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 768–772, April, 1985.     

均相体系中铱催化2-取代-1,2-二氢喹啉类化合物的脱氢芳构化

 采用原位制备的铱双膦(或膦氮)配合物在碘存在下催化2-取代-1,2-二氢喹啉、2-甲基-2,3-二氢吲哚、1,4-二氢吡啶及3,4-二氢异喹啉等化合物的脱氢芳构化反应, 并考察了不同金属前体、配体、催化剂用量、溶剂和碘等因素对反应速率和选择性的影响. 结果表明,原位制备的［Ir(COD)Cl］2/(±)-MeO-Biphep在碘的存在下催化2-取代-1,2-二氢喹啉的脱氢芳构化反应速率快, 选择性好,催化剂的用量少; 对1,4-二氢吡啶和2,3-二氢吲哚的催化脱氢芳构化反应则须在高温下进行; 而对 3,4-二氢异喹啉, 即使在加热回流条件下也只有不到5%的转化率. 催化体系中碘的存在可以明显提高反应速率.     

Dual reactivity in 1,2-disubstituted dihydro-N-heteroaromatic systems. 12. Aromatization of 1-substituted-2-(indol-3-yl)-1,2-dihydroquinolines with 1,3,5-trinitrobenzene

As the electron-acceptor properties of the N-substituents in 1-R-2-(indol-3-yl)-1,2-dihydroquinolines decrease, their ability to undergo heterolysis of the internuclear C-C bond to give ion pairs of 1-R-quinolinium cations and indole anions decreases. Reaction of these ion pairs with 1,3,5-trinitrobenzene gives salts of 1-R-quinolinium cations and the 1-(indol-3-yl)-2,4,6-trinitrocyclohexadiene anion. With undissociated dihydroquinolines, aromatization under similar conditions gives salts of 1-R-2(indol-3-yl)quinolinium cations and the 1,1-dihydro-2,4,6-trinitrocyclohexadiene anion.For Communication 11, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 80–84, January, 1988.     

A facile route to functionalized 1-arylsulfonyl-1,2-dihydroquinolines

Summary A one-pot synthesis of dialkyl 1-arylsulfonyl-1,2-dihydroquinoline-2,3-dicarboxylates by reaction of arylsulfonamide derivatives of 2-aminobenzaldehyde, dialkyl acetylenedicarboxylates, and triphenylphosphine in excellent yields is reported.

---

Ein einfacher Weg zu funktionalisierten 1-Arylsulfonyl-1,2-dihydrochinolinen

Zusammenfassung Es wird über eine Eintopfsynthese zur Herstellung von Dialkyl-1-arylsulfonyl-1,2-dihydrochinolin-2,3-dicarboxylaten durch Umsetzung von Arylsulfonamid berichtet. Die Reaktion liefert ausgezeichnete Ausbeuten.

     

Annulation reactions of 3-aminoisoquinolin-l(2H)-one. Synthesis of pyrimido[1,2-b]isoquinolines,pyrido-[2,3-c]isoquinolines and pyrrolo[2,3-c]isoquinolines

Reactions of the title compound with the malonic acid derivatives diethyl ethoxymethylenemalonate (EMME), ethyl ethoxymethylenecyanoacetate (EMCA) and ethoxymethylenemalononitrile (EMMN) are reported. Condensations occur at the amino group or C-4, depending on conditions and the former intermediate was successfully cyclized to the pyrimido[1,2-b]isoquinoline system. Reactions with 2,4-pentanedione and p-bromophenacyl bromide gave only the angular systems, pyrido[2,3-c]isoquinoline and pyrrolo[2,3-c]isoquin-oline, respectively.     

Photolysis of 1,2-dihydroquinolines in micellar solutions of anionic and cationic surfactants

The kinetics of the photolysis of substituted 1,2-dihydroquinolines (DHQ) in micellar solutions was studied by steady-state and flash photolysis. The photolysis mechanism depends dramatically on the location of DHQ molecules in micelles, which is governed by the surfactant nature. In micellar solutions of the anionic surfactant sodium dodecyl sulfate (SDS), where the DHQ molecules are located in the Stern layer, the intermediate species decay kinetics follows a first-order law. When DHQ is in neutral form (pH 4–12), the rate constant of the intermediate carbocation decay increases from 25 to 198 s^?1 with an increasing concentration of DHQ in micelles. The positive micellar catalysis is caused by the acceleration of the final product formation with the DHQ molecule via proton abstraction from the intermediate cation. The formation of several types of intermediate species—carbocations in the aqueous phase and aminyl radicals in micelles—is observed in micellar solutions of the cationic surfactant cetyltrimethylammonium bromide (CTAB) due to the preferential location of DHQ molecules in the micellar core. The carbocation decays via a pseudofirst-order reaction with a rate constant close to that in the aqueous solution. The lifetime of the DHQ aminyl radicals in the micellar solutions is longer by several orders of magnitude than the lifetime observed for homogeneous solutions of hydrocarbons and alcohols.     

Acid-base properties of N-methyl-substituted 1,2-dihydroquinolines in the ground and excited states

Changes in the absorption and fluorescence spectra of 1,2,2,3-tetramethyl-(1), 1,2,2,4-tetramethyl-(2), 6-ethoxy-1,2,2,4-tetramethyl-(3), and 1,2,6-trimethyl-1,2-dihydroquinolines (4) were studied in aqueous solution over a wide pH range from 1.0 to 12.0. The quantum yields of fluorescence and the values of pK _a of dihydroquinolines (DHQs) under study in the ground and excited states were determined, pK _a = 4.5, 3.8, 4.5, and 4.2 for the ground state of compounds 1–4, respectively, and pK _a ∼ 1.7 for the S ₁^* state for all DHQs.     

Specifics of the photolysis of alkylated hydroxy-1,2-dihydroquinolines in water and methanol

Comparative study of photoinduced reactions of 6-and 8-hydroxy-2,2,4-trimethyl-1,2-dihydroquinolines (6-OH-DHQ and 8-OH-DHQ) in water and methanol was carried out by continuous and pulse photolysis. The products of MeOH addition to the dihydroquinolines under study were isolated and identified. The spectral and kinetic parameters of active transient species generated in the photolysis were measured. The rate constants of the transient carbocations strongly depend on the position of the hydroxy group on the aromatic ring and are an order of magnitude lower for 6-OH-DHQ than 8-OH-DHQ (80 versus 870 s^?1, respectively). Two factors that play a significant part in the photolysis mechanism were revealed, namely, an increase in the acidity of the phenolic group in the excited state and the possibility of intramolecular hydrogen bonding between phenolic and amino groups in 8-OH-DHQ, which are in close proximity. The former factor causes the formation of by-products from the deprotonated excited state of OH-DHQ, which increases substantially in water. The latter affects the structure and the composition of transient species in the case of 8-OH-DHQ.     

Novel synthesis of isoquinolines using isobenzofuran-nitrile Diels-Alder reactions

[reaction: see text] The synthesis of isoquinolines through coupling of 2-alkynylbenzaldehyde derivatives with beta-cyanocarbene complexes has been examined. The reaction involves formation of an isobenzofuran followed by intramolecular Diels-Alder reaction with the nitrile, a process with limited precedent. The unique success of this process in this system has been attributed to deoxygenation of the initial adduct to form the isoquinoline ring system.     

Aromatization of some derivatives of 2-acetyldihydroresorcinol

Conclusions 2-Acetyl-2-cyclohexen-1-ones, containing either a chlorine atom or a methoxy group in the C-3 position, easily undergo aromatization.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2625–2627, November, 1970.