Polymeric organosilicon systems. XVII. Synthesis and photochemical and conducting properties of poly[o-and m-(disilanylene)phenylene]s

Poly[o-(tetramethyldisilanylene)phenylene] ( 2a ), poly[o-(1,2-dimethyldiphenyldisilanylene)-phenylene] ( 2b ), poly[m-(tetramethyldisilanylene)phenylene] ( 2c ), and poly[m-(1,2-dimethyldiphenyldisilanylene)phenylene] ( 2d ) were prepared by the sodium condensation reaction of the corresponding 1,2-and 1,3-bis (chlorosilyl)benzenes in toluene. Irradiation of thin films of 2a-2d in air resulted in a rapid decrease of absorption maxima in the ultraviolet region. The photolysis of 2b and 2d in benzene afforded photodegradation products with low molecular weights. When thin films of 2b and 2d were doped with antimony pentafluoride vapor, films which have conductivities of semi-conductor level were obtained. © 1993 John Wiley & Sons, Inc.     

Quinazolines and 1,4-benzodiazepines. XLVI. Photochemistry of nitrones and oxaziridines

The cyclic nitrones 7-chloro-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepin-2-one 4-oxide ( 5a ) and 1,3-dihydro-7-methylthio-5-phenyl-2H-1,4-benzodiazepin-2-one 4-oxide ( 5b ) are photoisomerized to readily isolable oxaziridines, 7-chloro-4,5-epoxy-5-phenyl-1,3,4–5-tetrahydro-2H-1,4-benzodiazepin-2-one ( 6a ) and 4,5-epoxy-5-phenyl-1,3,4,5-tetrahydro-7-methylthio-2H-1,4-benzo-diazepin-2-one ( 6b ). Oxaziridine 6b upon further irradiation gave ring expansion and ring contraction products, 4,6-dihydro-2-phenyl-9-methylthio-5H-1,3,6-benzoxadiazocin-5-one ( 7b ) and 4-benzoyl-3,4-dihydro-6-methylthioquinoxalin-2(1H)-one ( 8b ) respectively. The ring contraction product, 4-benzoyl-6-chloro-3,4-dihydroquinoxalin-2(1H)-one ( 8a ), was obtained from irradiation of oxaziridine 6a .     

Reactions of ethyl 4-chloro-5-pyrimidinecarboxylates with 2-aminopyridine. Synthesis of 5H-pyrido[1,2-A]pyrimido[5,4-e]pyrimidin-5-ones and 5H-pyrido[1,2-a]pyrimido[4,5-d]pyrimidin-5-ones and rearrangement of the former to the latter

5H-Pyrido[1,2-a]pyrimido[5,4-e]pyrimidin-5-ones IVa,b and 5H-pyrido[1,2-a]pyrimido[4,5-d]pyrimidin-5-ones Va,b were synthesized from ethyl 4-chloro-5-pyrimidinecarboxylate and 2-aminopyridine. The former compounds were obtained directly upon heating the reactants in ethanol, and the latter were prepared by the fusion of ethyl 4-(2-pyridylamino)-5-pyrimidinecarboxylates obtained as minor products from the above reaction. The angular fused cyclic compounds, IVa,b were rearranged to the linear tricycles, Vb-f upon heating with amines.     

Oxidative Coupling Of 2-Alkyl-6,6-dimethylpentafulvenyl Anions

Cucl₂-Induced oxidative coupling of 2-(tert-butyl)-6,6-dimethylpentafulvenyl anion 9 predominantly takes place at C(7) and C(5) to give [7–7] and [7–5] coupling products 15 and 16 in 35 and 47% yields, respectively (Scheme 3) whose structures are elucidated from 1D- and 2D-NMR analysis. Compared with the product distribution observed for 6,6-dimethylpentafulvenyl anion 2 (Scheme 1), no coupling at C(2)/C(3) of 9 is observed. This means that, besides electronic effects, steric effect are also important in oxidative couplings of fulvenyl anions. The same couplings occur in the case of 2,3-bis(6,6-dimethylfulven-2-yl)-2,3-dimethylbutane dianion 10 as well but, due to electronic as well as conformational effects (Scheme 5), intermolecular coupling (to give polymers 17 , Scheme 4) is strongly favored over intermolecular coupling. Mechanisms explaining base-catalyzed isomerization 15a ? 15b ? 15c (Scheme 6) as well as isomerization 16a ? 16b (Scheme 7) are proposed.     

Reactions of O-methyl o-quinone monoximes with methyl-, methylene- and methine- substituted aromatic compounds. Synthesis of benzo[d]oxazole and 1,4-benzoxazine derivatives

O-Methyl o-quinone monoxime 1 reacts thermally with compounds 2a-d or 6a,b or 7a,b to give mainly the corresponding 2-substituted phenanthroxazoles 3a-c and 8 . The reaction of 1 with aromatic methylene compounds lOa-c affords the ketones 13a-c in moderate to high yields. Similar products are also obtained from the reaction of monoximes 15a,b with some of the above reactants. The unexpected products 5 and 20 are obtained from the reaction of 1 with 2-methylimidazole ( 2d ) and with phenyloxirane ( 19 ) respectively, while the 4H-1,4-oxazine derivative 23 is obtained from the reaction of 1 with indene ( 21 ).     

The reaction of lithium phenylacetylide and phenyllithium with N-(ω-Bromoalkyl)phthalimides

Lithium phenylacetylide reacted with short-chain N-(ω-bromoalkyl)phthalimides 1b and 1c to give tricyclic products 2b and 2c in moderate yields. Likewise, tricyclic products 3a-c were obtained when short-chain imides 1a-c were treated with phenyllithium. When longer-chain imides 1d-f in this series were treated with lithium phenylacetylide only tertiary alcohols 4d-f could be isolated. Partial hydrogenation of 2b and 2c yielded the corresponding alkenes 5b and 5c , products which corroborated the structural assignment of 2b and 2c .     

Die Hydrolyse von 6exo-substituierten 2exo- und 2endo-Norbornylestern der p-Toluolsulfonsäure. Norbornanreihe. 3. Mitteilung

The Hydrolysis of 6 exo -Substituted 2 exo - and 2 endo -Norbornyl p -Toluenesulfonates. Norbornane Series. Part 3 Hydrolysis of the 6exo-substituted 2exo- and 2endo-norbornyl p-toluenesulfonates 1b - 1 and 2b - 1 , respectively, in 70% dioxane led to different amounts of the following products: Unrearranged 2exo-norbornanols 3 and norbornenes 5 , accompanied in somes cases by small amounts of the rearranged Rendo-epimers 4 and 6 and by norticyclenes 7 . When the 6exo-substituent was a nucleophilic group as in 1e - 1 and 2e - 1 , various amounts of tricyclic products were also formed by endo-cyclization. These results show that the 2exo- and 2endo-esters 1 and 2 , respectively, react by way of different intermediates. In cases where the 6exo-substituent was an n-electron donor, as in 1m - r and 2m - r , quantitative fragmentation to (3-cyclopentenyl)acetaldehyde (13) occurred.     

Furopyridines. XX. Wittig-horner reaction of a phosphonate of reissert analogues of furo[3,2-c]-, -[2,3-c]- and -[3,2-b]pyridines

Furo[3,2-c]-( 1a ), -[2,3-c]- ( 1b ) and -[3,2-b]pyridine ( 1c ) were reacted with isopropyl chloroformate and trimethyl phosphite to give dimethyl 5-isopropoxycarbonyl-4,5-dihydrofuro[3,2-c]pyridine-4-phosphonate ( 2a ), dimethyl 6-isopropoxycarbonyl-6,7-dihydrofuro[2,3-c]pyridine-7-phosphonate ( 2b ) and dimethyl 4-isopropoxycarbonyl-4,7-dihydrofuro[3,2-b]pyridine-7-phosphonate ( 2c ) as unstable syrups. Reaction of 2b and 2c with n-butyllithium and then with benzaldehyde, p-methoxybenzaldehyde, p-cyanobenzalde-hyde or propionaldehyde afforded the normal Wittig reaction products 5b-H, 5b-OMe, 5b-CN, 5b-Et, 5c-H, 5c-H, 5c-OMe and 5c-CN , except for 2b with propionaldehyde. While, the same reactions of compound 2a and the reaction of 2b with propionaldehyde afforded the unexpected products, 5-isopropoxycar-bonylfuro[3,2-c]pyridinio-4-aryl-(or ethyl)methoxides 3a-H, 3a-OMe, 3a-CN and 3a-Et , 4-(1′-aryl(or ethyl)-1′-hydroxymethyl)furo[3,2-c]pyridines 4a-H, 4a-OMe, 4a-CN and 4a-Et accompanying formation of the normal products. Treatment of the normal Wittig reaction products with lithium diisopropylamide and then with acetone gave the derivatives alkylated at the 2-or the benzylic positions.     

Cyclization of ylidenemalononitriles. X. Synthesis of benzazapropellane derivatives from α-Cyano-β-chloroalkylcinnamonitriles

The reaction of nucleophilic and non-nucleophilic bases wtih 2-carbamoyl-3-(γ-chloropropyl)-1-indenone ( 5 ) have been investigated. Condensation of γ-chlorobutyrophenone with malono-nitrile afforded α-cyano-β-(3-ehloropropyl)cinnamonitrile which was cyclized in concentrated sulfurie acid to produce 5 . Two other products obtained from the cyclization reaction were 2-carbamoyl-3-(γ-ehloropropylidene)-1-indanone ( 4 ) and α-carbamoyl-β-(3-chloropropyl)cinnam-amide. Treatment of a solution of 4 in ethyl acetate with piperidine resulted in cyclization of the γ-chloropropyl side chain to give 2-carbamoyl-3-cycIopropyl-1-indanone. The same compound was obtained in improved yield by the treatment of 4 or 5 with sodium hydroxide solution. The reaction of dirnethylamine with 5 in benzene gave initial Michael addition of the amine followed by internal alkylation of the carbanion so formed to yield 3a-dimethylamino-2,3,3a,8-tetrahydro-8-oxoeyclopent[a]indene-8a(lH)earboxamide ( 7a ). Similarly addition of ammonia, pyrrolidine, piperidine, benzenethiol, p-toluenethiol, 2-naphthalenethiol and nitromethane to the indenone I gave respective analogs of type 7 . Treatment of 5 with sodium cyanide in aqueous t-butyl alcohol resulted in a similar Michael addition followed by internal alkylation. In addition, cyclization between the nitrile and the carbamoyl functions occurred in the same step to give 2-oxo-4-imino-7,8-benzo-3-aza[3.3.3]-propellan-6-one ( 13a ). Hydrolysis of the iminopyrrolido ring in 13a to the corresponding suecin-irnide gave 2,4-dioxo-7,8-benzo-3-aza[3.3.3]propellan-6-one ( 13b ). Reactión of 13b with methyl iodide, allyl bromide, benzyl bromide, and diethyluminoethyl chloride afforded the corresponding N-alkylated products. A similar sequence starling with δ-ehlorovalerophenone led to 5,6-fused ring systems, including a [4.3.3]propellane. 2,9-Dioxo-4-methyl-7,8-benzo-3-aza[4.3.3]propell-4-ene was obtained by the reaction of 5 with acetone in dilute alkali.     

Bildung von 4-, 5- und 6gliedrigen Heterocyclen durch ambidoselektive Ringschlüsse von Enolat-Ionen

Formation of 4-, 5- and 6-membered heterocycles by ambidoselective cyclization of enolate anions N-Acylmethyl-N-chloracetyl-2,6-dimethylanilines 4 were cyclized with base to 4-, 5- or 6-membered ring compounds, depending on the substituent R² (Scheme 2). All products can be rationalized as derived from the intermediate enolate anions a and b . The enolate anion a reacts by intramolecular alkylation to yield either 1, 4-oxazines 5 or azetidines 6 (Schemes 1, 3 and 7). The regioselectivity observed is expected on the basis of the allopolarization principle. The enolate anion b reacts only with formation of a new C? C bond (Scheme 5). Comparison with the behaviour of the 2, 6-unsubstituted anilines 9, 1a and 12 , shows a strong dependence not only on electronic but also on steric factors (Scheme 4 and 6).     

Studies on the synthesis of heterocyclic compounds. Part VI. The action of methyl salicylate on some 5-aminopyrazoles

Some 1-phenyl-3-R-5-aminopyrazoles reacted with methyl salicylate to give N-(1-phenyl-3-R-pyrazol-5-yl)-2-methoxybenzamides ( 3a,b,c ), 1-phenyl-2-methyl-3-R-salicyloilimino-3-pyrazolines ( 4a,b,c ) together with 1-phenyl-3-R-5-methylamino pyrazoles ( 5a,b,c ). The structures of the new compounds 3 and 4 were determined on the basis of analytical and spectroscopic data as well as on the acid hydrolysis products.     

Tertiary amines as vinyl source for the formations of aryl or pyrrole ring on amido-substitued 1,4-quinone with the assistance of palladium salt

The one-pot synthesis of 3-isopropyl-6-methyl-1H-benzo[f]indole-4,9-dione ( 3e ), N-(4-[isopentylamino]-3,6-dioxocyclohexa-1,4-dien-1-yl)acetamide ( 4d ), 2-(isopentylamino)-6-methylnaphthalene-1,4-dione ( 5b ), and 2-(4-acetamido-3,6-dioxocyclohexa-1,4-dien-1-yl)-N,N-diisopentyl-3-methylbutanamide ( 6a ) has been achieved via either pyrrol/aryl ring formations or amination reactions from the Pd(II)-catalyzed reaction of N-(3,6-dioxocyclohexa-1,4-dien-1-yl)acetamide ( 2a_BQ ) and in the presence of triisopentylamine. More 3 -, 4 -, 5 -, and 6 -like derivatives were obtained while other trialkylamines were used. Crystal structures of 3d_O , 3e , 4b , 4c , 4d , 5b, and 6a were determined by single-crystal X-ray diffraction methods. The 3 - and 5 -like products reveal the formations of newly generated benzene rings with/without substitutions. The formation of 6a also implies an unusual reaction pathway of its generation. Based on the structural conformations of various 3 -like products, as well as 6a , mechanisms were proposed to account for the formations of these compounds. Various fascinating conformations of products observed in this work demonstrate the diversities of this type of reactions.     

4,4-Disubstituierte Imidazol-Derivate aus der Umsetzung von 3-Amino-2H-azirinen mit Salicylamid

4,4-Disubstituted Imidazole Derivatives from the Reaction of 3-Amino-2H-azirines with Salicylamide Reaction of 3-amino-2H-azirines 1a–c with salicylamide ( 7 ) in MeCN leads to imidazoles 10 and 11 in different rates, depending on the conditions. In the case of 1a and 1b, 11a and 11b , respectively, have been obtained as the main product at 50°; in reactions at 80°, 10a and 10b are the favored products (Tables 1 and 2). 2,2-Dimethyl-3-(N-methyl-N-phenylamino)-2H-azirine ( 1c ) reacts with 7 in MeCN mainly to 2-(2-hydroxyphenyl)-5,5-dimethyl-3,5-dihydroimidazol-4-one ( 10a ); in boiling toluene, 11c is formed with low preference (Table 3). The structure of the products has been established by spectroscopic means, and in the case of 10b and 11c , by X-ray crystallography. Two different reaction mechanisms for the formation of the products are discussed (Scheme 2).     

Tetrazole compounds. 9. A new approach to tetrazolyl-substituted quinoline derivatives

The acid-catalyzed reaction of 1-aryl-5-(2-dimethylaminovinyl)-1H-tetrazoles 2 with arylamines suitably functionalized in the ortho-position resulted in Z-configurated transamination products which were cyclized to novel 3-tetrazolylquinolines by the action of sodium ethoxide. Thus, on reacting 2 with 2-aminoacetophenone or 2-aminobenzophenone, respectively, the 2-[2-(1-aryl-1H-tetrazol-5-yl)vinyl-amino]aryl ketones 3a-g were obtained, the cyclization of which gave 4-substituted 3-(1-aryl-1H-tetrazol-5-yl)quinolines 4 . In the case of the transamination products 3h-1 , prepared from 2 and methyl anthranilate, the ring closure afforded 3-(1-aryl-1H-tetrazol-5-yl)-1H-quinolin-4-ones 5 . Starting from 2 and anthranilonitrile 4-amino-3-(1-aryl-1H-tetrazol-5-yl)quinolines 10 were obtained via the corresponding intermediates 9 .     

The synthesis of benzofuroquinolines. I. Some benzofuro[2,3-b]quinoline and benzofuro[3,2-c]quinoline derivatives

Benzofuro[2,3-b]quinoline ( Ia ) and its 11-methyl derivative ( Ib ) were synthesized by demethylcyclization of 3-(o-methoxyphenyl)-1,2-dihydroquinolin-2-ones (VIa,b). Benzofuro[2,3-b]quinoline-11-carboxylic acid (Id) was synthesized by chlorination followed by the action of potassium hydroxide of a lactone (IX) prepared by demethyl-cyclization of 3-(o-methoxyphenyl)-2-oxo-1,2-dihydroquinoline-4-carboxylic acid (VIII). Isomeric benzofuro[3,2-c]quinoline (Ha) and its 6-methyl derivative (IIb) were synthesized by demethyl-cyclization of 3-(o-methoxyphenyl)-1,4-dihydroquinolin-4-ones (XIa,b). Both the methyl derivatives (Ib and IIb) were converted to the carboxylic acids (Id and IId) through condensation with benzaldehyde followed by oxidation. The benzofuroquinolines (Ia,b,d and IIa,b) thus obtained were oxidized to the corresponding N-oxides (IIIa,b,d and IVa,b).     

Reactions with hydrazidoyl halides. IV. Synthesis of thiazolo[3,2-a]benzimidazoles,imidazo[2,1-6]thiazoles and pyrazolo[4,3-b]thiazines

Hydrazidoyl halides were condensed with 2-mercaptobenzimidazole yielding 4a-c and 7a,b which were cyclized to the corresponding 2-arylhydrazonothiazolo[3,2-a]benzimidazol-3-ones 5a,b and 3-substituted 2-arylazo thiazolo[3,2-a]benzimidazoles 8a,b respectively. Imidazo[2,1-b]thiazoles were obtained by the reaction of hydrazidoyl halides with 2-mercapto-4,5-dihydroimidazole. Also, hydrazidoyl halides 6a,b were reacted with 3-amino-4-mercapto-5-phenylpyrazole to give pyrazolo[4,3-b]thiazines 15a,b . The structures of the products were assigned on the basis of their elemental analysis and spectral data.     

Polycyclic nitrogen compounds. Part I. Synthesis of new heterotricyclic quinoxalinones with bridgehead nitrogen atoms

New tricyclic quinoxalinone skeletons with a fully-reduced ring ‘C’ -1,2,3,3a-tetrahydropyrrolo[1,2-α]quin-oxalin-4-one (I-II) and 7,8,9,10-tetrahydropyrido[1,2-α]quinoxalin-6-one (III-IV) derivatives were obtained by selective hydrogen transfer reductive cyclisation of N-(2-nitrophenyl)pyrrolidine-2-carboxylic acid esters and N-(2-nitrophenyl)piperidine-2-carboxylic acid esters (VIa,b and VIIIa,b), respectively.     

Furopyridines. XXIII. Synthesis and reactions of chloropyridine derivatives of furo[2,3-b]-, -[2,3-c]- and -[3,2-c]pyridine

Chlorination of the N-oxides of furo[2,3-b]- 1a , -[2,3-c]- 1b and -[3,2-c]pyridine 1c with phosphorus oxychloride afforded compounds substituted normally at the α- or λ-position to the ring nitrogen, 2a, 2′a, 2b, 2c, 2′c and 2′c , and in addition, in the case of 1b , compounds substituted on the furan ring, 2′b and 2″b . The structures of these compounds were confirmed from their ir, nmr and mass spectra. The major chlorinated products 2a, 2b and 2c were converted to methoxy- 5a, 5b and 5c , N-pyrrolidyl- 7a, 7b and 7c , and phenylthiofuropyridines 8a, 8b , and 8c .     

Synthesis of 4H-furo[3,2-b]indole derivatives. III. Preparation of 4H-furo[3,2-b]indole-2-carboxylic acid derivatives

Methyl or ethyl 4H-furo[3,2-b]indole-2-carboxylates (Va,b) were prepared from deoxygenation of methyl or ethyl 5-(2-nitrophenyl)-2-furoates (IIIa,b) and thermolysis of methyl or ethyl 5-(2-azidophenyl)-2-furoates (VIIIa,b). 4H-Furo[3,2-b]indole-2-carboxylic acid amides (XIa-h) were obtained by the reaction of 4H-furo[3,2-b]indole-2-carboxyl chloride (X) with the appropriate amines.     

Die Wohl-Ziegler-Bromierung von Tiglin- und Angelika-säureestern

The Wohl-Ziegler bromination (with N-bromo-succinimide = NBS) of methyl tiglate ( 1b ) gave a 2:1 mixture of methyl γ-bromotiglate ( 3b ) and methyl β′-bromotiglate ( 5b ). This ratio of γ- to β′-bromination was unaffected by changes of solvent, catalyst or size of the ester alkoxy group. The same products were obtained from the NBS treatment of methyl angelate ( 2b ). This NBS-bromination appears to be thermodynamically controlled, since both angelic and tiglic acid as well as their methyl esters were brought into equilibrium ( 1 ? 2 = > 9:1) with catalytic amounts of NBS.