Ein neuer zugang zu indeno[1,2-b]pyridinen

A new synthesis of 5H-indeno[1,2-6]pyridines [IV] starting from 4-cyanobutyrophenones [I] or their cyclization products, the 6-phenyl-3,4-dihydropyridin-2-ones [II], is reported. The condensation of I or II in polyphosphoric acid with aromatic or heteroaromatic aldehydes [III] yields 1,2,3,4-tetrahydro-5H-indeno[1,2-b]pyridin-2-ones [IV]. 2,3,4,4a,5,9b-Hexahydro-1H-indeno[1,2-b]pyridines [X, XI] which were previously difficult to obtain can now be easily synthesized from compounds IV.     

One-Pot Green Synthesis of Novel Polysubstituted 1,2-Dihydronaphtho[2,1-b]furans

A simple and highly efficient one-pot protocol for the synthesis of novel polysubstituted 1,2-dihydronaphtho[2,1-b] furans has been developed by three-component coupling reaction of 2-aminopyridines, naphthols, and glyoxal in the presence of guanidinium chloride as a polyfunctional organocatalyst under solvent-free conditions. The protocol avoids the use of expensive catalysts, toxic solvents, and chromatographic separation and provides a wide range of novel dihydronaphthofurans in good to excellent yields.     

Synthesis, crystal structures, and properties of 6,12-diaryl-substituted indeno[1,2-b]fluorenes

Fused polycyclic indeno[1,2-b]fluorene derivatives with aryl substituents at the 6,12-positions have been prepared as a potential antiaromatic 20π electronic system. They showed strong absorptions in the visible region and amphoteric redox properties. The quinoid-type molecular structures were revealed by X-ray crystal-structure analysis, which indicated that the bond lengths of the quinoid unit depend on the aryl substituents. Whereas nucleus-independent chemical shift NICS(1) calculations indicate the antiaromatic nature of the s-indacene core, they have higher stability than substituted acene derivatives. The derivatives with difluorophenyl or anthryl groups were stable in solution. Vapor-deposited thin films showed ambipolar carrier transportation in the field-effect transistor devices.     

Synthesis of cyclopropa[c]indeno[1,2-b]quinolines through a MCR/Staudinger/aza-Wittig sequence

Spirocyclopropanes were prepared from aromatic aldehydes, 1,3-indandione and acetophenones through a halogenation/S_N2-displacement/Michael-initiated ring-closing sequence by a pyridinium-ylide-assisted multicomponent reaction, and their further use was also researched in the construction of cyclopropa[c]indeno[1,2-b]quinolines through subsequent Staudinger/aza-Wittig reactions.     

Synthesis of enantiomerically pure perhydrofuro[3,4-b]pyrans and perhydrofuro[3,4-b]furans

Olefinic diols, prepared from (R)-(+)-2,2-dimethyl-1,3-dioxolane-4-carboxaldehyde via olefination and hydrolysis, were converted into enantiomerically pure hydroxy substituted tetrahydrofuran derivatives by cyclization using N-phenylselenophthalimide and BF₃. The PhSe group in the C-4 position of these tetrahydrofurans was then substituted by an allyl group using allyltributylstannane in the presence of AIBN. The selenium promoted cyclizations of the allyl tetrahydrofurans in which the OH and the allyl groups are trans to each other formed the enantiopure perhydrofuro[3,4-b]pyrans, while the cyclization of the allyl tetrahydrofurans in which the OH and the allyl groups are cis gave rise to the perhydrofuro[3,4-b]furans. These bicyclic products were finally deselenenylated with triphenyltin hydride and AIBN.     

Synthesis of pyrrolo[1,2-b]cinnolines

The synthesis of the pyrrolo[1,2-b]cinnoline analogs 2 and 4–13 is described. The key step of this synthesis involves an intramolecular aromatic halide displacement on [2-(2-halobenzoyl)pyrrol-1-yl]carbamic acid esters. Several reactions of these cinnoline analogs with electrophilic reagents have been investigated.     

Synthesis of 1H-thieno[3,4-c]pyrazoles,thieno[3,4-b]furans,selenolo[3,4-b]furans and pyrrolo[3,4-d]thiazoles

Starting from the readily available aryl 2-methyl-5-phenyl-3-furyl ketones, 5-methyl-1H-1-phenylpyrazole-4-yl ketones and 4-methyl-2-phenyl-5-thiazolylcarboxaldehyde, a series of 2-phenyl-4-arylthieno[3,4-b]-furan, 2-phenyl-4-(p-methoxyphenyl)selenolo[3,4-b]furan, 4-aryl-1H-1-phenylthieno[3,4-c]pyrazole and 5-benzyl-2-phenylpyrrolo[3,4-d]thiazole were prepared in high yield.     

A novel one-pot isocyanide-based four-component reaction: synthesis of highly functionalized 1H-pyrazolo[1,2-b]phthalazine-1,2-dicarboxylates and 1H-pyrazolo[1,2-a]pyridazine-1,2-dicarboxylates

A new protocol has been developed for the efficient synthesis of structurally diverse 1H-pyrazolo[1,2-b]phthalazine-1,2-dicarboxylates and 1H-pyrazolo[1,2-a]pyridazine-1,2-dicarboxylates via a four-component reaction of hydrazine hydrate, dialkyl acetylenedicarboxylates, isocyanides and various cyclic anhydrides such as succinic anhydride, maleic anhydride and phthalic anhydride in ethanol/acetone (1:1) at room temperature in good to moderate yields.     

Synthesis of Alkyl and Aryl Substituted Benzo[h]Naphtho[1,2-b][1,6]naphthyridines

The reaction of 4-chloro-2-methylquinolines and 1-naphthylamine under neat conditions yielded 2-methyl-N-(1-naphthyl)quinolin-4-amines. These potential intermediates on reaction with aliphatic and aromatic carboxylic acids yielded the respective 7-alkyl and -aryl substituted benzo[h]naphtho[1,2-b][1,6]naphthyridines. The highly deshielded protons in the final compounds were assigned on the basis of 2D NMR studies.     

Regio and diastereoselective synthesis of functionalized 2,3-dihydrofuro[3,2-c]coumarins via a one-pot three-component reaction

An efficient and straightforward synthesis of furo[3,2-c]coumarins via the one-pot three-component condensation of aromatic aldehydes, 4-hydroxycoumarin and α-chloroketones in refluxing n-propanol is described. Pyridine or a mixture of AcOH and AcONH₄ was used as a basic catalyst.     

Synthesis of 3H[1,2]diazepino[5,6-b]indole and 3H[1,2]diazepino[4,5-b]indole derivatives

The synthesis of two new derivatives of 3H[1,2]diazepino[5,6-b]indole, 5 and 11 , and one new derivative of 3H[1,2]diazepino[4,5-b]indole, 16 , are described. Compound 5 was obtained by the reaction of methyl 2-(3-methoxycarbonyl-1-methylindole)acetate 2 , with hydrazine. Compound 11 was obtained in two ways from ethyl 2-(1-methylindole)acetate ( 8 ) by formylation and reaction with hydrazine. Compound 16 was obtained treating 3-(2-ethoxycarbonylindole)acetonitrile ( 14 ) with hydrazine.     

无过渡金属参与下茚并-[1,2-b]吲哚-10(5H)-酮的合成

发展了一种从3-(2-溴代苯甲酰基)-吲哚出发在无过渡金属参与下合成茚并吲哚酮类化合物的新方法。在甲苯/四氢呋喃(2∶1)混合溶剂中,3-(2-溴代苯甲酰基)-吲哚、正丁基锂和碘化锌原位生成的2-吲哚锌在碘化锂辅助下与芳基溴化物发生分子内加成-环化反应,合成了一系列取代的茚并-[1,2-b]吲哚-10(5H)-酮类化合物,且均获得了较好的收率。考察了溶剂、卤化锌、添加剂对产率的影响。     

Synthesis of new 4-aroyl-pyrano[c]chromenes via a one-pot,three-component reaction based on aryl glyoxals

A new library of pyrano[c]chromenes containing an aroyl group has been synthesized by a novel multicomponent process involving the reaction of various aryl glyoxals with 4-hydroxycoumarin and malononitrile. The reactions were catalyzed efficiently by ammonium dihydrogen phosphate to yield the desired products in good to excellent yields.     

3-炔基咪唑并[1,2-b]哒嗪的简便合成

以咪唑并[1,2-b]哒嗪为原料,与N-碘代丁二酰亚胺在三氟乙酸/二氯甲烷中于室温进行碘代反应制得3-碘咪唑并[1,2-b]哒嗪(3);3与三甲基硅基乙炔在Pd(OAc)_2催化下经Sonogashira偶联反应制得3-三甲基硅基乙炔基咪唑并[1,2-b]哒嗪(4);4在碳酸钾作用下脱除三甲基硅基合成了3-炔基咪唑并[1,2-b]哒嗪,总收率61.2%,其结构经~1H NMR和HR-MS确证。     

Synthesis of some 6-methoxyimidazo[1,2-b]pyridazines

The synthesis of 6-methoxyimidazo[1,2-b]pyridazine and its 2-methyl analog is reported. Carboxylic acids, esters and quaternary salts derived from this ring system are described and the heterocyclic system is shown to undergo the Mannich reaction. A condensation reaction of the 2-methyl group is reported and nuclear magnetic resonance (nmr) spectra and acidity constants of some imidazo[1,2-b]pyridazines are recorded.     

A ‘One Pot’ Synthesis of Acenaphtho[1,2-b]Benzo[f] and Acenaphtho[1,2-b]Benzo[h]Quinolines

A short, simple and high yielding ‘one pot’ synthesis of two acenaptho[1,2-b]benzo-quinolines have been described which involved highly regioselective thermal cyclization of enaminoimine hydrochlorides from 2-chloro-1-formylacenaphthylene and ½-naphthylamine.     

Synthesis of 5-oxoindeno[1,2-b]pyridinium salts

When N-methylated 4-aryl-5-oxo-4,5-dihydroindeno[1,2-b]pyridines are oxidized with hydrogen peroxide in the presence of perchloric acid, in addition to the formation of the indenopyridinium perchlorates, cleavage of the dihydropyridine ring occurs, giving the 2-arylideneindan-1,3-dione.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 88–90. January, 1986.