Synthesen auf der Basis von 2-Oxoglutarsäure. III [1] Synthese und Reaktionen von (E)-2-Oxoglutaconsäuredimethylester

Organic Syntheses Based on 2-Oxoglutaric Acid. III. Synthesis and Reactions of Dimethyl (E)-2-oxoglutaconate Dimethyl (E)-2-oxoglutaconate 1 obtained by dehydrobromination of dimethyl 3-bromo-2-oxoglutarate reacts with o-phenylendiamine to form the quinoxalin-2(1H)-one 2 , and with phenylhydrazine to yield the 4,5-dihydropyrazole 3 . Furthermore, a Doebner-von Miller-type reaction affords the 8-carboxy quinoline derivative 4 . Finally, addition of bromine leads diastereoselectively to the racemate of dimethyl 3S,4R- and 3R,4S-dibromo-2-oxoglutarate 5 .     

Cyclisierungsreaktionen β, γ-ungesättigter Kohlensäurederivate. II. Reaktionen β, γ-ungesättigter Carbamidsäurederivate mit elektrophilen Reagenzien - Synthese von N-substituierten Oxazolidin-2-onen

Cyclization Reactions of β,γ-Unsaturated Derivatives of Carbonic Acid. II. Reactions of β,γ-Unsaturated Carbamic Acid Esters with Electrophilic Reagents — Synthesis of N-Substituted Oxazolidine-2-ones N,N-Disubstituted β,γ-unsaturated urethans have been cyclized to N-substituted oxazolidine-2-ones by dry hydrogen chloride in methylene chloride. The N-substituted urethan 1a reacts with hydrogen chloride to form the urethan 2a and the 2-oxazoline 3 Reaction of 1 with bromine yields the corresponding N-substituted 5-bromomethyl oxazolidine-2-ones 6     

Über die Reaktionen von Benzimidazol-2-carbonsäurehydrazid mit Elektrophilen

About the Reactions of Benzimidazole-2-carbohydrazide with Electrophilic Compounds Benzimidazole-2-carbohydrazide ( 1 ) reacts with aldehydes and ketones to form N-alkylidene-benzimidazole-2-carbohydrazides( 2a–j ). With carbon disulfide, diphenyl carbonate and cyanates, ring closure takes place to afford 1,2,4-triazines and 1,3,4-oxadiazoles. Attempts to synthezise 2-isocyanato-benzimidazole failed. ¹H-n.m.r. and ¹³C-n.m.r. spectroscopic data of the compounds are given.     

Reaktionen von 2-Cyan-3-methoxy-maleinimid mit methylenaktiven Verbindungen und Enaminen

Reactions of 2-Cyano-3-methoxy-maleinimide with Methylene Active Compounds and Enamines The vinylogous ester 1 gives with methylenactive compounds 2 carbamoylmaleinimides 3 , which cyclize to pyridonimides 4 . Reactions of 1 with enamines form cyanomaleinimides 6-8 and aminopyridines 11 .     

Cyclisierungsreaktionen β,γ-ungesättigter Kohlensäurederivate. V . Reaktionen β,γ-ungesättigter Carbamidsäureester mit Sulfenylchloriden - Synthese von 3,5,5-trisubstituierten Oxazolidin-2-onen

Cyclization Reactions of β,γ-Unsaturated Derivatives of Carbonic Acid. V. Reactions of β,γ-Unsaturated Carbamic Acid Esters with Sulfenyl Chlorides — Synthesis of 3,5,5-Trisubstituted Oxazolidine-2-ones N,N-Disubstituted β,γ-Unsaturated urethanes 1 have been cyclized to 3,5,5-trisubstituted oxazolidine-2-ones 3 by aromatic sulfenyl chlorides in methylene chloride. The same oxazolidine-2-ones 3 were obtained by reaction of 5-bromomethyloxazolidine-2-ones 8 with thiophenols.     

Darstellung und Reaktionen von 2-Arylazo-2-nitro-keten-aminalen

Synthesis and Reactions of 2-Arylazo-2-nitro-keten Aminals N,N′-Disubstituted 1-nitro-2,2-diamino ethylenes 1 undergo azo-coupling to form the title compounds 2 . Their treatment with oxalyl chloride yields the imidazolidin-4,5-dione-derivatives 4. 2 react with phosgene and thiophosgene to form 6-nitro-2,4-diaryl-5-arylimino−2,3,4,5-tetrahydro-1,2,4-triazin-3-ones 5 and -thiones 6 respectively. From 2 and N-(dichloromethylene)-arylsulfoamides the 6-nitro-2,4-diaryl-5-arylimino-3-aryl-sulfonylimino-2,3,4,5-tetrahydro-1,2,4-triazines 7 arise. The reduction of 2 yields the substituted oxalic amidines 9     

Reaktionen von β-Chlorvinylaldehyden. V [1]. Zur Bildung von 2,2′-Thiopyrylotrimethinfarbsalzen aus 2-(α-Formylalkyliden)-2H-thiopyranen

Reactions of β-Chlorovinylaldehydes. V. The Formation of 2,2′-Thiopyrylocyanine Dyes from 2-(α-Formylalkylidene)-2H-thipyranes Substituted β-chlorocrotonaldehydes react with Na₂S · 9H₂O to form 2-(α-formyl-alkylidene)-2H-thiopyranes 1 . The corresponding thiopyrylium salts 2 which are easily available from 1 and strong acids exist in the enolic form (2-β-hydroxyvinyl-thiopyrylium salts). They are converted at room temperature in methanol solution to dark green compounds, which are identified as 2,2′-thiopyrylotrimethincyanine dyes 3 . The mechanism of formation of compounds 3 is discussed.     

Reaktionen von β-Chlorvinylaldehyden. IV [1]. Synthesen von 2-Formylmethylen-2H-1-benzopyranen und Benzopyrylocyaninfarbstoffen aus β-Chlorvinylaldehyden

Reactions of β-Chlorovinylaldehydes. IV. Syntheses of 2-Formylmethylene-2H-1-benzopyranes and Benzopyrylocyaninedyes from β-Chlorovinylaldehydes α-Alkyl-β-chlorocrotonaldehydes react with salicylaldehyde in methanolic solution of potassium hydroxide forming 2-formyl-methylene-2H-1-benzopyranes 1 . The corresponding benzopyryliumsalts 2 which are easily available from 1 and strong acids, exist in the enolic form. They react at room temperature in alcoholic solution with elimination of ethyl formiate, yielding dark blue compounds which were identified as 2,2′-benzopyrylotrimethincyanindyes 3 . The structure of 3 has been elucidated by means of ¹H-n.m.r.-spectra.     

Furylvinylhalogenide. X [1]. Reaktionen von β-Fur-2-yl-β-chlor-α-cyanacrylsäurederivaten mit Hydrazinen

Furylvinylhalides. X. Reactions of β-Fur-2-yl-β-chloro-α-cyanoacrylic Acid Derivatives with Hydrazines β-Fur-2-yl-β-chloro-α-cyanoacrylic acid derivatives 3 react with hydrazines yielding 3-fur-2-yl-5-aminopyrazoles 5 or 3-fur-2-yl-4-cyanpyrazolin-5-ones 6 . In some cases the β-hydrazino-α-cyanoacrylic acid derivatives 4 , could be isolated.     

Reaktionen von Aroyl(Hetaroyl)iminodithiokohlesäureestern mit Carbanionen CH-acider Verbindungen

Reactions of Dimethyl N-Aroyl(Hetaroyl)carbimidodithioates with Carbanions CH-acidic Compounds Reactions of dimethyl N-aroyl(hetaroyl)carbimidodithioates 1 with carbanions 2 present new possibilities to synthesize 3-acyl-amino-3-methylthio-2-subst.-acrylnitriles 3 by monosubstitution of methylthiogroup. The reaction of 1 with 2-alkyl-benzothiazolium salts 4 yield deeply coloured N-acyl-(2,3-dihydrobenzothiazole-2-yliden) thioacetimido acid-methylates 5 of the 2-subst.-benzothiazoliumperchlorates 6 . The structures of the final products are determined by i.r.-, ¹H.-n.m.r.- and u.v.-spectra.     

3-Acetyl-2H-thiopyran-2-one durch [4+2]-Cycloadditionsreaktionen von Enaminothioketonen mit Acetylketen

3-Acetyl-2H-thiopyran-2-ones by [4+2]-Cycloaddition Reactions of Enaminothioketones with Acetylketene 3-Acetyl-2H-thiopyran-2-ones 3 are available in a one step procedure by [4+2]-cycloaddition reactions of enaminothioketones with acetylketene.     

Zur Reaktion von Cyanodithioformiaten mit primären Aminen

Reactions of Cyanodithioformates with Primary Amines N-Alkyldithiooxamides 3 and N,N -dialkyldithiooxamides 4 were synthesized in good yields by reaction of cyanodithioformates 1 with primary aliphatic amines. N-Alkylcyanothioformamides 2 , intermediates in these reactions were obtained in very low yields only. The reaction of 1 and diaminoethane or 1.3-diaminopropane afforded imidazolidine-2-thione 5a respectively perhydropyrimidine-2-thione 5b . The reaction of 1 with 1-chloro-2-aminoethane did gave 2-thiocarbamoylthiazoline 7 .     

Ringspaltung von 4-(4-Nitrophenylazo)-substituierten Pyrazolidin-3,5-dion – Derivaten zu α-(4-Nitrophenylhydrazono)semicarbaziden und Folgeprodukten

Ring Cleavage of 4-(4-Nitrophenylazo)-substituted Pyrazolidine-3,5-diones to α-(4-Nitrophenylhydrazono)semicarbazides with Consecutive Reactions The reaction of 1 and 2 with ammonia, methylamine and dimethylamine in aprotic solvents, e. g. diethyl ether, yields the compounds 3 – 8 which can exist in two isomeric forms (form a/b ). On conditions which are usually chosen for spectroscopic investigations only form a could be detected. Nevertheless, under the influence of bases like KOH or ammonia in water or alcohol these compounds are mainly converted to semicarbazides ( 11–15 ) which means that this reaction must run via form b . Those semicarbazides which are unsubstituted at the N-4 of their semicarbazide-moiety show great tendency to cyclize, thus forming the triazolederivatives 16–18 . In contrast to these products, in the case of the N-4-monomethylated semicarbazide 14 the six-membered heterocyclus 19 was obtained. In comparison with 1 and 2 , stable intermediates such as 3–8 in the reaction with 21 could not be isolated.     

Reaktionen von Malonsäureethylesteraniliden mit Heterokumulenen

Reactions of Malonanilic Acid Ethyl Esters with Heterocumulenes Malonanilic acid ethyl esters 1 react with carbon disulfide in the presence of sodium hydride to give disodium salts 2 . Treatment of 2 with an alkylation reagent yields the openchain or cyclic ketene S,S-acetals 3 and 4 , respectively. Adding only one equivalent of methyl iodide to 2 and acidifying the reaction mixture lead to the dithioesters 5 . Reaction of 3 with amines or o-amino-thiophenol yields S,N- and N,N-acetals only in some cases. S,N-acetals 6 are further available by addition of phenyl isothiocyanate to 1 whereas N,N-acetals are synthesized, too, by chlorination of 3 and reaction with amines. Acidifying of 11 gives the thioacetoanilides 12 . Some more reactions (oxidation of 3a , d and saponification/decarboxylation of 4a ) are discussed.     

Darstellung und Reaktionen von 2-Mercapto-6-thioxo-thiopyran-3-carbonsäure-Derivaten

Synthesis and Reactions of 2-Mercapto-6-thioxo-thiopyran-3-carboxylate derivatives 6-Amino-thiopyran-2-thiones ( 1 ) react with dihydrogen sulfide in the presence of pyridine and triethyl amine to yield 6-thioxo-thiopyran-2-thiolates ( 2 ). Methylation of 2 gives the methylthio compounds 3 and 4 . Further methylation of 3a and 4a yields the thiapyrylium salt ( 7 ). The reaction of 2-imino-thiopyran ( 6 ) with carbon disulfide represents another route to the 6-methylthio-thiopyran-2-thione ( 4a ). The 2-methylthio-thiopyran-6-thione ( 3a ) undergoes substitution of the methylthio group with amines to 8 or reacts with phenylhydrazine to phenylhydrazono-thiopyrane ( 9c ). 6-Thioxo-thiophen-2-thiolates ( 2a , b ) react with hydrazine hydrate to give hydrazono-thiopyranes ( 10a , b ) which can be S-methylated. On the contrary 2c gives with hydrazine hydrate under ring transformation the pyridine-2-thiolate ( 11 ). N,S-Acetals ( 12 ) and 1,3,4-thiadiazoles ( 15 ), which give rise to new pyridine derivatives ( 14 ) and ( 17 ), can be obtained from 1-Amino-pyridin-2-thiolate ( 11 ).     

Mehrfunktionelle N-Tenside. I. Nucleophile Substitutionen an Bischlornitrosoverbindungen 2. Reaktionen mit Thioharnstoff,substituierten Thioharnstoffen,Salzen und Estern von Dithiocarbaminsäuren und Mercaptoheterocyclen [1]

Polyfunctionalized N-Tensides. I. Nucleophilic Substitutions with Bischloronitroso Compounds. 2. Reactions with Thiourea, Substituted Thioureas, Salts and Esters of Dithiocarbamic Acid and Mercaptoheterocyclic Compounds Reaction of bischloronitroso compounds 1 with thiourea and substituted thioureas gives 2-aminothiazoles and 3-alkyl-2-iminothiazolines-(4). Ammoniumdithiocarbamate formes 4-thiazolinethiones-(2), and esters of the dithiocarbamic acids give 2-alkylmercaptothiazoles. N-substituted salts of dithiocarbamic acid and mercaptoheterocyclics react in boiling ethanol to form S-(β-oximinoalkyl)-dithiocarbamates 8 and in some cases 4-thiazolinthiones-(2) 9 .     

水溶液中4-(2-羟基-苯甲酸酯基)-2-环戊烯砜的合成

以3,4-二溴环戊砜(1)为原料,在无水吡啶作用下发生消除反应,得到反应中间体4-溴-2-环戊烯砜(2),再与水杨酸钠(3)在水溶液和DMF中发生酯化反应,合成水杨酸酯环戊烯砜衍生物(4),用IR,1H NMR,MS,元素分析表征了它们的结构,并讨论了酯化反应在在水溶液和DMF中的最佳反应条件。结果表明:水溶液中的酯化反应后处理更加简单,产率最高。     

Furylvinylhalogenide. IX. Reaktionen von β-Fur-2-yl-β-chlor-α-cyanacrylsäureestern mit Aminen

Furylvinylhalides. IX. Reactions of β-fur-2-yl-β-chloro-α-cyanoacrylates with amines β-Fur-2-yl-β-chloro-α-cyanoacrylates 4 react with amines to yield β-Fur-2-yl-β-amino-α-cyanoacrylates 5 . The ¹H-n.m.r. spectra of 5 are discussed.     

Cyclisierungsreaktionen β,γ-ungesättigter Kohlensäurederivate. IX. Regiochemie der elektrophilen Cyclofunktionalisierung β,γ-ungesättigter Carbamidsäureester mit Brom – Synthese von Oxazolidin-2-onen und Tetrahydro-2H-1,3-oxazin-2-onen

Cyclization Reactions of β,γ-Unsaturated Derivatives of Carbonic Acid. IX. Regiochemistry of Electrophilic Cyclofunctionalization of β,γ-Unsaturated Carbamic Acid Esters with Bromine – Synthesis of Oxazolidine-2-ones and Tetrahydro-2H-1,3-oxazine-2-ones N,N-Disubstituted β,γ-unsaturated urethanes ( 1 ) and bromine react in methylene chloride at room temperature. The crotyl urethanes ( 1a – 1c and 1e ) and bromine give mixtures of corresponding saturated urethanes (dibromine adducts) ( 2a – 2c and 2e ), the oxazolidine-2-ones ( 3a – 3c and 3e ), and the tetrahydro-2H-1,3-oxazine-2-ones ( 4a – 4c and 4e ). The reaction of γ,γ-dimethylallyl urethanes ( 1f – 1h ) with bromine gives similar results. A useful synthetic route to N-substituted tetrahydro-2H-1,3-oxazine-2-ones ( 4l – 4q ) is demonstrated by the reaction of cinnamyl urethanes ( 1l – 1q ) with bromine.     

Ringöffnungs- und SubstitutionsReaktionen von 4,4-Dihalogen-pyrazolin-5-onen durch Nucleophile

Ring Opening and Substitution Reactions of 4,4-Dihalo-pyrazolin-5-ones with Nucleophiles 1-Aryl-4,4-dihalo-3-methyl-pyrazolin-5-ones ( 1a – c ) undergo ring opening with alkoxides and form alkyl 3-arylazo-2-halo-2-butenoats ( 2a – d ). Analogous reactions take place with ammonia and amines. 4-Nitro-phenoxide reacts with substitution of both halogens to the 4,4-bis(4-nitro-phenyl)-compound ( 5 ). Phenols are selectively orthobrominated by the title compounds 1a and b .