Photochemische Reaktionen von Pyrazolidon-(3)-betainen. VII. Photochemische Dimerisierung von Pyrazolidon-(3)-azomethiniminen

Photochemical Reactions of 3-Pyrazolidone Betains. VII. Photochemical Dimerization of 3-Pyrazolidone Azomethinimines UV irradiation of 3-pyrazolidone azomethinimines 1 in methanol results in low yields in photochemical head-tail-dimerization of 1 to the hexahydrotetrazines 3 . The structure of 3 is elucidated by chemical and spectroscopic methods (IR, ¹H-, ¹³NMR).     

Photochemische Reaktionen von Pyrazolidon-(3)-betainen. IV. Photooxydation von Pyrazolidon-(3)-azomethiniminen

Photochemical Reactions of 3-Pyrazolidone Betains. IV. Photooxidation of 3-Pyrazolidone Azomethinimines Azomethinimines 1 , easily obtainable from 3-pyrazolidone and aldehydes, on dyesensitized photooxidation in methanol as a solvent undergo decomposition to nitrogen, methyl β-methoxypropionate 3 , methyl acrylate 4 and the corresponding aldehyde 2 . The formation of these products is interpreted by formation and decomposition of a cyclic peroxide 5 , produced by a 1,3-dipolar cycloaddition reaction between 1 and singlet oxygen. The photooxidation of 1 in acetonitrile produces: nitrogen, carbon dioxide, ethylene, β-propiolactone 9 , and the corresponding aldehyde 2 . The dye-sensitized photooxidation in methanol of the azomethinimines 16 , prepared from 3-pyrazolidone and ketones, gives the following products: nitrogen, methyl β-methoxypropionate 3 , methyl acrylate 4 , and the corresponding ketone, besides hydrazine and the corresponding α-methoxy-alkylhydroperoxides 17 and 21 . Key intermediate of the peroxide formation is the Criegee ozonization zwitterion which was trapped with acetaldehyde as an ozonide.     

Photochemische Reaktionen von Pyrazolidon-(3)-betainen. V. Photooxydation heteroaromatischer N-Ylide

Photochemical Reactions of 3-Pyrazolidone Betains. V. Photooxidation of Heteroaromatic N-Ylids The dye-sensitized photooxidation of the heteroaromatic N-ylids 3a and 3b yields 1-isoquinolone 8 together with ethyl mesoxalate 13 and bis(benzoyl-isoquinol-1-on-2-yl-methyl)ether 10 , respectively. These are decomposition products of fivemembered ring peroxides, formed by reaction of singlet oxygen with the N-ylids. One mole of the ylids 3c, 4 and 5 gives complete conversion with 0.5 moles of singlet oxygen, yielding the corresponding heteroaromatic and mesoxalic acid derivatives, respectively. The products and the oxygen consumption are discussed to be due to reaction of one molecule of the ylid with one molecule of alkylhydroperoxide 18 , formed as a primary product. N-Ylids 3c, 4 and 5 react in the same manner with hydrogen hydroperoxide or perbenzoic acid to the corresponding heteroaromatic and mesoxalic acid derivatives. For the reaction between 3c and substituted perbenzoic acids the HAMMETT correlation gives ϱ = +0.94.     

Azomethinimine. VII. Photochemisches und thermisches Verhalten azarylsubstituierter Pyrazolidon-(3)-azomethinimine

Azomethineimines. VII. Photochemical and Thermic Behaviour of Azarylsubstituted Pyrazolidone-(3)-Azomethineimines In principle the photochemical behaviour of azarylsubstituted pyrazolidone-(3)-azomethineimines 1 does not differ from other pyrazolidone-(3)-azomethineimines. Except for the acridyl-(9)-substituted compound in aprotic solvents they react to bicyclic diaziridines 2 . The quantum yield of this reaction has a value of nearly 0.3. For two of the diaziridines 2 the photochemical backreaction was realized. Results of the investigation of the thermic backreaction show the expected stability of the bicyclic diaziridines 2a – d . All the investigated compounds have a pronounced tendency towards several irreversible side reactions.     

Azomethinimine. VI. Zum thermischen Verhalten des Photochromiesystems Azomethinimin/Diaziridin,untersucht an Pyrazolidon-(3)-azomethiniminen und deren Photoprodukten

Azomethineimine. VI. On the Thermic Behaviour of the Photochromic System Azomethineimine/Diaziridine, Investigated by Means of the Photoproducts of Pyrazolidone-(3)-Azomethineimines The photochemically obtained cycloproducts 2 of pyrazolidone-(3)-azomethineimines 1 react thermically to 1 in aprotic solvents. This backreaction was investigated by following up the growth of the intensive long wave absorptionband of 1 . The kinetic analysis was carried out according to SWINBOURNE [5, 6]. The thermic backreaction is accelerated by factors favouring a polarization of the C N(2)-bond (C^δ+  N^δ−) of diaziridine 2 . Such factors are polar solvents, donors in the substituent R and extensive, easily polarizable π-electronic systems in R. The influence of substituents on the backreaction can be correlated by means of the σ⁺-Hammett-constants. For most compounds the values of E_A ≈ ΔH^≠, Δ^≠ and ΔG^≠ were determined. The possible reaction mechanism is discussed. The influence of steric factors on the thermic backreaction is regarded as a first indication of an exo-form of the bicyclic diaziridines 2 .     

Photochemische Reaktionen von Arylglycidethern

Photochemical Reactions of Arylglycidyl Ethers The absorption, fluorescence and phosphorescence spectra, respectively, of arylglycidyl ether 1 correspond to those of other alkyl aryl ethers. Also the photolysis product distribution (λ = 254 nm) is in agreement with a normal ether photolysis. Furthermore, photoinduced epoxy ring opening takes place giving homopolyaddition oligomers and in methanolic solution also CH₃OH addition products. These reactions can be explained using the model of bichromophoric molecules with the ArO-chromophore as donor and the epoxy ring as acceptor. The calculations based on this model are in agreement with the experimental data. In the aromatic nucleus halogene substituted 1 were dehalogenated with high quantum yield (0.25 in the case of bromo substituted compound 1g ). The quantum yields of the ArO-C-bond scission are about 0.08 independently of the aromatic ring substituents. As indicated by sensitization and quenching experiments, respectively, with aromatic hydrocarbons the photo reactions proceed via S₁ state. It was found that phenol quenches the photodegradation of 1 very efficiently. Excited methyl phenyl glycerol ether 5a reacts with phenyl glycidylether 1a in its ground state producing oligomers.     

Synthesis and some reactions of 1-(4.6-dimethoxybenzo-furanyl)- and 1-(4.6.7-trimethoxybenzofuranyl)butane-1.2.3-trione-2-arylhydrazones

Both 4.6-dimethoxy-( 1c ) and 4.6.7-trimethoxy-5-acetoacetylbenzofuran 1d are obtained from visnaginone ( 1a ) and khellinone methyl ethers 1b , respectively, by a CLAISEN condensation. The β-diketones 1c and 1d couple with aromatic diazonium compounds to form the hydrazones 2a – i . 1-(4.6-Dimethoxybenzofuranyl)- and 1-(4.6.7-trimethoxybenzofuranyl)butane-1.2.3-trione-2-arylhydrazones 2 a–i react with hydrazine hydrate in acetic acid to yield the corresponding pyrazole derivatives 3a–i or 4a–i . The monohydrazones 5a–b are isolated when 2e or 2i are treated with hydrazine hydrate in ethanol. The hydrazones are converted to the respective pyrazoles by the action of glacial acetic acid. Hydroxylamine hydrochloride reacts with 1.2.3-trione-2-arylhydrazones 2a, c, e, f and i to yield the corresponding isoxazole derivatives 6a–e or 7a–e . The 2-arylhydrazones 2a, c, d, e, h and i form the corresponding pyrazole derivatives 8a–f when treated with semicarbazide hydrochloride.     

Reactions with 2-thiazolin 5-ones. IV. Action of amines on 4-substituted 2-alkoxy- and 2-benzylmercapto-2-thiazolin-5-ones

Whereas treatment of 2-butyloxy-, 2-pentyloxy- and 2-β-phenylethyloxy-4-arylazo-2-thiazolin-5-ones 1d–h with strong basic amines results in their rearrangement into 1-aryl- Δ²-1,2,4-triazolin-5-one-3-carboxylic acid derivatives 2 , the 2-isobutyloxy, 2-(2-octyloxy)- and the 2-cyclohexyloxy-4-arylazo-2-thiazoline-5-ones 1i–n rearrange upon treatment with the same reagents into Δ²- 1,2,4-triazoline-5-thione-3-carboxylic acid derivatives 3 . On the other hand, 1d–h,1 react with aromatic amines to give 1-aryl-2-alkoxy-1,2,4-triazole-3-carboxylic acid anilides 4a–i , via the loss of hydrogen sulphide. The phenylhydrazides 4j–l are obtained upon treatment of 1g, h,l with phenylhadrazine. Treatment of 4-arylidene-2-benzylmercapto-2-thiazolin-5-ones 6a–c with ammonia results in the formation of the thiohydantoin derivatives 7e, g . However, 6b, c react with phenylhydrazine to yield the phenylhydrazides 8b, c . The reaction of 6a–e with piperidine or morpholine involves to molecules of the reagent to yield 10a–d which are thermally cyclised to the thiazolone derivatives 11a–d .     

Syntheses of 3-Acyl-4-hydroxy-2(1H)quinolones

3-Acyl-4-hydroxy-2(1H)-quinolones 5 are obtained by hydrolytic ring opening and subsequent decarboxylation from the corresponding pyrano[3,2-c]quinolin-2,5(6H)-diones 4 , which in turn are easily obtained from 1:2 condensation of anilines 1 with diethyl malonate 2a or 1:1 condensation of diethyl alkyl- or arylmalonates 2b–e with 4-hydroxy-2(1H)-quinolones 3 . Nitropyranoquinolinediones 6 furnish after ringopening 3-nitroacetyl-4-hydroxy-2(1H)quinolones 8 . Pyranoquinolines 7 and 9 with acetyl- or aminosubstituents are hydrolyzed during basic ringopening to yield 5 .     

Zur Ring-Ketten-Tautomerie und Reaktionen eines bicyclischen 1-Hydroxy-3-imidazolin-3-oxids

Ring-Chain Tautomerism and Reactions of a Bicyclic 1-Hydroxy-3-imidazoline-3-oxide The reaction of 8-hydroxy-1, 4, 5, 7-tetramethyl-6,8-diaza-bicyclo[3.2.1]-oct-6-en-6-oxide ( 1 ), a 2,5-bridged bicyclic 1-hydroxy-3-imidazoline-3-oxide, with NaBH₄, dimethyl acetylene dicarboxylate and methylmagnesiumiodide, respectively, yields derivatives of the ring opened isomer 2 . Whilst on reaction with phenylisocyanate the bicyclic structure 1 is preserved and the urethane 3 is formed. The ring-chain tautomerism of 1 is important for the application of 1 as a spin trap or radical scavenger.     

Untersuchung der Struktur photochemisch aus Pyrazolidon-(3)-azomethiniminen erzeugter 1,5-Diaza-bicyclo-[3,1,0]-hexan-2-one mit Hilfe der LIS und der RKSA

LIS and X-Ray Investigations of the Structure of 1,5-Diaza-Bicyclo-[3,1,0]-hexanones-(2) Obtained by Irradiation of Pyrazolidone-(3)-azomethineimines 1,5-Diaza-bicyclo-[3,1,0]-hexanones-(2) 2 are the photoproducts of pyrazolidone-(3)-azomethineimines 1 . Generally they can exist in the exo-form or in the endo-form. ¹H-n.m.r.-measurements of 2a–d show that neither at normal temperature (298 K) nor at low temperatures (213 K) an exo/endo mixture is formed photochemically. Therefore the conclusion is drawn that the photoreaction is stereospecific. Chemical shift calculations of the methyleneprotons and the methyl-protons in 2c and 2d using the ring current model and lanthanoide induced shifts (LIS) on 2d with Eu(fod)₃ show that in solution the photoproducts have the exo-form. These results are in agreement with results of a single-crystal X-ray structure analysis on 2a .     

Zur Synthese von 3-Amino-naphth[c]isothiazolen

Synthesis of 3-Amino-naphth[c]isothiazoles 3-Amino-naphthonitrile-2 7 can be readily prepared by ring cleavage of 4-carboxy-methylthio-benzo[g]quinazoline 6 in aqueous medium at pH 9. 1-Amino-naphthonitrile- 2 11 is formed in good yield by thermolysis of 1H-benzo[g]-indoline-2,3-dione-3-oxime 13 (BEDFORD -PARTRIDGE reaction). The scope of both reaction types is studied. Appropriate syntheses of each precursor are reported. By base-catalyzed addition of hydrogen sulfide under pressure 7 and 11 were transformed into amino-thionaphthoic-2-acid amides 17 and 23 . Oxidation of 1-amino-thionaphthoic-2-acid amide 23 with hydrogen peroxide in methanol produced 3-aminonaphth[1,2-c]isothiazole 1b in almost quantitative yield. A similar oxidative cyclization of 3-amino-thionaphthoic-2-acid amide 17 to 3-amino-naphth[2,3-c]isothiazole 3b failed even if the reaction conditions were widely varied. The unsuccessful efforts to synthesize „linear”︁ naphthisothiazoles ( 3a and its 3-amino derivative 3b ) are discussed in terms of the superdelocalizability of these heterocycles. Azo dyes can be obtained from 1b and 7 .     

2,7,12,18-四甲基-13,17-二(3-羟基丙基)卟啉的改进合成

以次氯化血红素为原料,经脱铁、酯化、还原3步反应合成了光敏剂2,7,12,18-四甲基-13,17-二(3-羟基丙基)卟啉。在次卟啉的合成过程中,用硫酸亚铁-浓盐酸-醋酸酐作脱铁试剂,于95℃反应2h,收率92.2%;在浓硫酸的作用下,次卟啉与甲醇反应30min,合成次卟啉二甲酯,收率90.3%;再利用硼氢化钠-氯化锂-四氢呋喃体系还原次卟啉二甲酯,得到2,7,12,18-四甲基-13,17-二(3-羟基丙基)卟啉,收率75.2%。产物通过ESI-MSFTIR及1HNMR等方法表征。     

Radikalreaktionen an N-Heterocyclen. V. EPR-Untersuchungen von Nitroxid-Radikalen substituierter 3-Anilino-1,5-diphenyl-pyrazole

Radical Reactions of N-Heterocyclic Compounds. V. ESR-Investigation of Nitroxide Radicals of Substituted 3-Anilino-1,5-diphenyl-pyrazoles The correlation of the e.s.r. splitting constants with the Hammett values for nitroxides from substituted 3-anilino-1,5-diphenylpyrazoles 1a – e and substituted 1,5-diphenyl-3-p-toluidino-pyrazoles 1f – i provides evidence for extensive interannular conjugation between the N¹-benzene ring and the pyrazole ring of these nitroxides. The conjugation between the arylamino group and the pyrazole ring is extensive only in the nitroxides derived from 1f – i . The captodative substituted p-toluidino-nitroxides 2g, h have a better spin distribution than the nitroxide 2i with two electron-donating substituents.     

熔融法合成(S)-1-苄基-3羟基吡咯烷-2,5-二酮

以L-苹果酸为原料,与苄胺反应,再经熔融法得到标题化合物。考察了反应温度和时间对反应收率的影响,优化条件为:反应温度140℃,反应时间8 h,标题化合物的收率为68%。目标化合物结构经核磁共振氢谱、红外、比旋度确证。     

Zur Reaktion von N-(N′,N′-Dialkyl(aryl)amino-thiocarbonyl)benzimidoylchloriden mit Kaliumthiocyanat

Reactions of N-(N′,N′-Dialkyl(aryl)amino-thiocarbonyl)benzimidoylchlorides with Potassium Thiocyanate The treatment of the title compound N-(amino-thiocarbonyl)-benzimidoylchloride 1 with potassium thiocyanate leads in dependence on the solvents (methanol, acetic acid, acetone) either to the 1,3,5-thiadiazine-2-thione 2a–d or to the ring opened isothiocyanate 4a , b . In the case of methanol the N-(amino-thiocarbonyl)benzimidates were formed as by-products. The structure of the products is confirmed by analytical data and by chemical transformations. 2a reacts with methyl iodide to form the 2-methylthio-6-morpholino-4-phenyl-1,3,5-thiadiaziniumiodide 3a . From 4a and water the N-(morpholino-thiocarbonyl)benzamide 5a arises. The reaction of morpholine with 4a yields the benzamidine 6a .     

Synthese und Polymerisation von 2-Aryl-5-methylen-1,3-dioxolan-4-onen und Arylbis(5-methylen-1,3-dioxolan-2-yl-4-on)en

Synthesis and Polymerization Behaviour of 2-Aryl-5-methylene-1,3-dioxolan-4-ones and Arylbis(5-methylene-1,3-dioxolan-2-yl-4-on)es Starting from 2,6-di(hydroxymethyl)-4-methylphen-ol-Na-salt-1-hydrate ( 1 ) a synthesis of 2-alkoxy-5-methyliso-phthaldialdehydes ( 3a,b ) is described via alkylation and oxidation. Condensation of aromatic aldehydes with 3-bromo-2-hydroxypropanoic acid (β-bromolactic acid) affords diastereoisomeric mixtures of new 2-aryl-5-bromomethyl-1,3-dioxolan-4-ones ( 6a–h ) as well as the corresponding bisdioxolanones ( 6i–l ). Dehydrobromination of 2-aryl-5-bromomethyl-1,3-dioxolan-4-ones ( 6a–d,i ) with DBU leads to 2-aryl-5-methylene-1,3-dioxolan-4-ones ( 8a–e ). Polymerization of compounds 8a , b , d and e proceed via opening of the dioxolanone ring.     

Pyryliumverbindungen. 42. Benzocycloalkenone und Dihydro-2H,7H-1-benzopyranone aus 2,4,6-Triaryl-pyryliumsalzen und Cycloalkan-1,2-dionen

Pyrylium Compounds. 42. Benzocycloalkenones and Dihydro-2H,7H-1-benzopyranones from 2,4,6-Triarylpyrylium Salts and Cycloalkane-1,2-diones 2,4,6-Triarylpyrylium salts 1 react with cycloalkane-1,2-diones 2 in the presence of an appropriate condensing agent to yield benzocycloalkenones 3 . Thus, sodium acetate and cyclo-hexane-1,2-dione ( 2a ) lead to the dihydro-2H-naphthalenones 3a – i , whereas with cycloheptane-1,2-dione ( 2b ) and piperidine acetate, triethylamine or sodium acetate the tetrahydro-5H-benzo-cyclohepten-5-ones 3j – r are formed. As shown for the example 3a, j → 4a, b , benzocycloalkenones of type 3 can be converted into phthalazines 4 on heating with hydrazine in ethanol. By reaction of the dione 2a and an equimolar mixture of triethylamine and acetic acid or morpholine acetate with the salts 1 5,6-dihydro-2H,7H-1-benzopyran-8-ones 5 are obtained as a result of a new type of ring transformation. The pyrans 5 can be cleaved with perchloric acid in ethanol to 5,6,7,8-tetrahydro-8-oxo-1-benzopyrylium perchlorates 6 . If the pyrans 5 are heated with sodium acetate in ethanol, a conversion to benzocycloalkenones 3 is achieved (cf. 5a → 3a ). The structure of the new compounds was established by spectroscopic methods.     

Zur Chemie der 3-Aroylimino-3H-1,2-dithiole

Reactions of 3-Aroylimino-3H-1,2-dithioles The thiolates 3 and 10 prepared from 3-aroylimino-4-aroylthio-5-cyano-3H-1,2-dithioles 1 with bases, react with alkylhalides and acylhalides to the corresponding 4-S-substituted compounds 6, 11 and 7 , respectively. Treatment of the thiolates with 1-chloropropanone gives the bicyclic compound 12 by intramolecular cyclization involving the 5-cyano-group. 3,6-Bis-(acylimino)-3H,6H-[4,3-c] [1,2]-dithioles 2 or 8 are prepared from the S-acylated dithioles 1 or 7 and sulphur in pyridine/benzene. 1,2,4-Triazines 13 are formed by the reaction of dithiol es 1 orthiolates 3 with phenylhydrazine. The thiolates give upon protonation the mesoionic dithioliumthiolates 4 . Coordination compounds are obtained from the reaction of the thiolates with cations of 3d-elements. On the basis of the chemical behaviour of the new 3-acylimino-1,2-dithioles and the results of spectroscopic measurements a strong bonding interaction between the N-acyl-carbonylgroup and the dithiole ring system in these compounds is supposed.     

Some reactions of 1,3-Dichloro-2-azoniaallene Salts with heteronucleophiles

1,3-Dichloro-2-azoniaallene hexachloroantimonates ( 1 ) reacted with H₂S to give 1,2,4-dithiazolium salts 2 . With hydrazines 1,2,4-triazolium salts ( 3, 4 ) were formed. 1,3-Dimethylurea, respectively 1,3-dimethylthiourea or ethyl allophanate, reacted with 1 to afford 2-oxo- or 2-thioxo-1,3,5-triazinium salts ( 5–7 ). With diphenylmethaneimines imino substituted 2-azoniaallene salts 8 were produced. From chloroacetonitrile dichloropyrimidines 9 , and from the tricyanomethyl anion a hexatriene 10 and a triazine 11 could be prepared. The 1,5-dichloro substituted 2-azoniaallene salts 12 reacted as bifunctional electrophiles with nucleophiles such as benzophenone hydrazone or anilines, to furnish 1,3,5-triazinium salts 14 . Against benzohydrazide the allene 12j behaved as trivalent electrophile giving the bicyclic 1,3,5-oxadiazinium salt 13j , the constitution of which has been secured by a crystal structural analysis. The vinyl-2-azoniaallene salt 1i cyclized on heating to the 1,3-thiazinium salts 16, 17 . From 17 the triazinium salts 18 were prepared with alcohols.