Synthese und Reaktionen von 2-[Bis-(alkylthio)-methyliden]-indan-1,3-dionen

Synthesis and Reactions of 2-[Bis-(alkylthio)-methyliden]-indan-1,3-diones The 2-[bis-(alkylthio)-methyliden]-indan-1,3-diones 3 and especially the methyl-compound 3a react with nucleophiles by substitution of the CH₃ S group. The reaction with amines are yields the S,N or N,N-acetales 7 and 8 , respectively. Diamines, amino hydroxy- or amino-mercapto compounds as dinucleophiles give the cyclic compounds 9 or the condensed heterocycles 12 and 16 , where the carbonyl group has been integrated in the cyclisation. Also carbanions react with 3a under substitution. The structures of the final products are determined with ir-, ¹H-n.m.r.- and ms-spectra.     

Synthese von Benzo[b]thioxanthenen

Synthesis of Benzo[b]thioxanthenes Benzo[b]thioxanthenes, heterocyclic compounds related to tetracenes and tetracyclines can be obtained by the reaction of 2H-benzo[b]thiete ( 1 ) and 1,4-naphthoquinones ( 3a–g ). The primary cycloadducts 4a–g undergo an autoxidation process leading to the quinones 6a–g . The dihydroxy compound 4e shows an additional isomerization by a tetrafold H transfer ( 4e → 5e ′). Another preparative route to benzo[b]thioxanthenes makes use of the cycloadditon reaction of 1 and 1,4-epoxynaphthalenes ( 7a–d ). The primary adducts can be transformed to the title compounds by catalytic dehydration processes ( 8a–d → 9a-d ). An alternate regioselective opening of the oxygen bridge can be performed by the action of trimethyliodosilane ( 8a → 10a ). Methylation of 9a furnishes the sulfonium salt 14a which rearranges in a strongly alkaline medium to 16a ; in the presence of oxygen ketone 17a is generated.     

Oxokohlenstoffe und verwandte Verbindungen. 27. Synthese von Dihydrocyclobuta[a]naphthalen-1,2-dionen und Cyclobuta[a]naphthalen-1,2-dionen durch Anellierung von Alkoxy-(1-alkenyl)benzolen mit 3-Chlor-3-cyclobuten-1,2-dion. Anwendungsbereich und Grenzen

Oxocarbons and Related Compounds. 27. Synthesis of Dihydrocyclobuta[a]naphthalene-1,2-diones and Cyclobuta[a]naphthalene-1,2-diones via Annulation of Alkoxy-(1-alkenyl)benzenes with 3-Chloro-3-cyclobutene-1,2-dione. Scope and Limitations The reaction of alkoxy-(1-alkenyl)benzenes with semisquaric chloride ( 3 ) has been investigated systematically. 1,2-Dialkoxy- and 1-alkoxy'-2-alkoxy″-4-(1-alkenyl)benzenes ( 6a–j ) and ( 11a–i ) react with 3 to give the 3,4-dihydrocyclobuta[a]naphthalene-1,2-diones ( 8a–j ) and ( 12a–i ). Treatment of the dihydrocyclobuta[a]naphthalene-1,2-diones with 1.2 equiv. bromine effects dehydrogenation and affords cyclobuta[a]naphthalene-1,2-diones ( 9a–e ) and ( 13b–f ). Any efforts to extend this annulation reaction to dimethoxy-(1-alkenyl)benzenes with the methoxy groups in other than the 1,2-positions, e. g. 14a, b, 16a, b have been unsuccessful. The reaction of 1,2,3-trimethoxy-4-(1-propenyl) [and 4-(1-butenyl)]-benzenes ( 18a ) and ( 18b ) with semisquaric chloride ( 3 ) leads to the elimination of HCl and CH₃OH and gives 5,6-dimethoxy-3-methyl [and 3-ethyl]-cyclobuta[a]naphthalene-1,2-diones ( 20a ) and ( 20b ). The reaction pathway of this novel annulation reaction is discussed.     

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 .     

Synthese und Struktur von Imino-bis[1]benzothiopyrano[4,3-b: 4,3-f] [1,5]dithiocinen

Synthesis and Structure of Imino-bis[1]benzothiopyrano[4,3-b:4,3-f][1,5]dithiocines Several substituted 3-Alkyl- respectively 3-Aryl-aminomethylene-2H-[1]benzothiopyran-4-thiones undergo a thermal reaction yielding the light yellow title compounds 2 . For the mechanism of this reaction we propose a condensation reaction of the starting compounds 1 loosing one molecule of amine in the first step followed by electrocyclisation reactions of the intermediates to products 2 . The structure of compounds 2 is elucidated by ¹H nmr spectroscopy and also x-ray analysis in case of compound 2b .     

Synthese und Transportuntersuchungen von Dioxapolyazacalix[4]arenen und Triazino-Kronenethern

Synthesis and Transport Investigations of Dioxapolyazacalix[4]arenes and Triazino Crown Ethers Synthesis and characterisation of new dioxapolyazacalix[4]arenes 5a–c and triazino crown ethers 9a–i are described. The structures and conformations of these novel macrocyclic ring systems have been investigated by various NMR methods. Transports of metal ions across a liquid membrane are also reported.     

Synthese von 8H-1,2,4-Triazolo[4,3-a]perimidinen

Synthesis of 8H-1,2,4-Triazolo[4,3-a]perimidines Reaction of 2-hydrazinoperimidine ( 3 ) with carboxylic acids or its orthoesters leads to 8H-1,2,4-triazolo[4,3-a]perimidines ( 5a – h ). 3 and aldehydes yield the aldehydehydrazones ( 6b , c , d ) which are converted in 5 by air oxidation. The structures of the new compounds were determined by means of i.r., u.v., ¹H-n.m.r. and mass spectroscopy.     

Synthese und Reaktionen von 3-Bromisothiazolo[5,4-b]pyridinen

Synthesis and Reactions of 3-Bromoisothiazolo[5,4-b]pyridines The reaction of 3-cyano-pyridine-2-thiones with bromine yields 3-bromisothiazolo[5,4-b]pyridines 2 which by treatment with bases undergo ring opening. From 2a and piperidine the pyridine-2-sulfenamide 3 arises, with diethylmalonate the substituted 3-amino-thienopyridine 5 , and with cuprous cyanide the 2-thiocyanato-pyridine 4 are obtained. The quaternary pyridinium salts derived from 2a—d contain active methyl groups.     

HF-unterstützte Synthese von Orthoestern und Oxazolinen. [1]

A convenient method is reported to generate the ortho-pivalic acid esters 5 and 7 from meso-erythrit 3 ) and D -mannitol ( 6 ), respectively, using a HF-supported procedure. Furthermore, the α-D -glucopyrano[1,2-d]-2-oxazolines 9 and 10 were prepared from starch and nitriles (pivalonitrile and benzonitrile) by a Ritter-type reaction in anhydrous hydrogen fluoride. The separation of the products 5 , 7 , 9 , and 10 was possible by quenching of their HF-solutions with triethylamine. The structure of the orthoester 7 and the oxazoline 10 was confirmed by X-ray analyses.