Zur Bestimmung von 2,3-Dihydropyran

Ohne Zusammenfassung     

Kristallstruktur von Morpholinium-2,3-dicyano-hydrochinolat

Summary On deprotonation of 2,3-dicyano-p-hydroquinone by morpholine, a network of hydrogen bonds is formed in which the chains of hydroquinone monoanions are connected by strongerN-H...O and by weakN-H...N bondsvia the morpholinium nitrogens.

     

Stereochemie der Polymerisation von 2,3-Dideuteromethyloxiran

Ohne Zusammenfassung     

Die gaschromatographische Bestimmung von 2,3-Diketonen

Ohne Zusammenfassung     

Die Bestimmung von 2,3-O-Isopropyliden-l-sorbose und 2,3;4,6-Di-O-Isopropyliden-l-sorbose bei der Herstellung von l-Ascorbins?ure

Ohne Zusammenfassung     

Exo- und endo-Tricarbonyleisenkomplexe von bicyclischen 2,3-Dimethylidenverbindungen

Exo- and endo-Tricarbonyliron Complexes of Bicyclic 2,3-Dimethylidene Compounds. The preparation of exo- and endo-tricarbonyliron complexes (exo- and endo- 5 , -6 , -8 , and 9 ) of 2,3-dimethylidene-5-bicyclo[2.2.1]heptene( 1 ), -bicyclo[2.2.1]-heptane ( 2 ), -5-bicyclo[2.2.2]octene ( 3 ) and -bicyclo[2.2.2]octane ( 4 ) is described. The complexes are obtained by thermal reaction of the bicyclic butadienes with di-ironenneacarbonyl in hexane solution. exo- and endo- 5 are also formed photochemically from ironpentacarbonyl and 1 in pentane solution at ?35°. The structural assignment of exo- and endo -5 and -6 is based on their mass-spectra and on coordination shifts in ¹H- and ¹³C-NMR.-spectra exo- and endo -6 are correlated with exo- and endo -5 , respectively, by hydrogenation. Hydrogenation of the uncomplexed double bond in exo- and endo -5 occurs in both complexes from the exo side as shown by deuteration experiments. The free ligand 1 reacts in the same stereospecific manner.     

Coulometrische Mikrobestimmung von 2,3-Dimercaptopropanol (BAL)

Ohne Zusammenfassung     

Synthese von Furo [2,3-b]chinolinen

A new route to furo[2,3-b]quinolines has been developed based on the use of N-arylaconamides as starting materials. These anilides when heated with polyphosphoric acid, readily underwent intramolecular cyclization to furnish the respective 1,2-dihydro-2-oxo-quinoline-3-acetic acids which were then transformed into the corresponding dihydrofuro[2,3-b]quinolines by literature procedures. Sequential treatment of the dihydro compound withNBS andDBU afforded the corresponding furo[2,3-b]quinoline. The NMR spectra of the furoquinolines are discussed.

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Mitt.: siehe Lit.     

Cyclisierungsreaktionen von Diazoalkenyl-phosphonsäureestern Synthese von Pyrazolyl- und 2,3-Benzodiazepinylphosphonsäureestern

Tosylhydrazones3 and4 of dialkyl 3-oxo-1-alkenylphosphonates1 and 1-oxo-2-alkenylphosphonates2, respectively, react with aqueous sodium carbonate to give the pyrazoles7 in excellent yields. Under analogous conditions the tosylhydrazone9 of diethylo-vinylbenzoyl phosphonate (8) affords diethyl 2-hydroxy-1-indanyl phosphonate (10). Upon thermolysis of the sodium salt12 generated from9 in anhydrousD M E, one obtains, depending on the reaction conditions, either the 1-H-benzodiazepinyl derivative14 or its 5H-isomer15. At room temperature the diazo compound13 cyclizes slowly to give14, which can be isomerized to15 by action of base.

     

Synthese von 4H-Pyrano[2,3-d]pyrimidinen

Summary Good yields of substituted 5-(5R-2-furyl)-4H-pyrano[2,3-d]pyrimidines4 were obtained in the reaction of 2-ethoxymethyleneamino-3-cyano-4H-pyranes2 with ammonia. Compounds2 were prepared by the condensation of the starting 2-amino-5-acetyl-3-cyano-6-methyl-4H-pyranes1 with ethyl orthoformate. Spectral properties of the bicyclic system4 in relation to compounds3 are discussed.

     

Synthese von Thieno[2,3—f]chinolin-Derivaten

Catalytic hydrogenation of 2.3-dihydro-thieno[2.3?f]-quinoline-1.1-dioxide yielded 2.3.6.7.8.9-hexahydrothieno-[2.3?f]quinoline-1.1-dioxide, which was substituted via the corresponding chloroacyl compounds to several 6-aminoacyl-derivatives.Skraup's synthesis using 6-amino-2.3-dihydro-3-morpholino-benzo[b]thiophen-1.1-dioxide gave 2.3-dihydro-3-morpholino-thieno[2.3?f]quinoline.     

Zur Bestimmung von 2-p-Chlorphenyl-3-methyl-2,3-butandiol

Ohne Zusammenfassung     

Synthese von 2,4-Diamino-thieno[2,3-d]pyrimidin-Derivaten

Synthesis of 2,4-Diamino-thieno[2,3-d]pyrimidines Condensation of 2-aminothiophene-3-carbonitrile ( 4 ) with guanidine or sequential addition of CS₂ and NH₃ to 4 provides 2,4-diaminothieno[2,3-d]pyrimidine ( 7 ). This compound yields, after sequential addition of sec-BuLi and either [3-(trifluoromethyl)benzene]sulfenyl chloride ( 8 ) or the corresponding disulfide 9 , followed by acidic work up, 2,4-diamino-6-{[3-(trifluoromethyl)phenyl]thio}thieno[2,3-d]pyrimidine ( 10 ). In another approach, 2-amino-5-{[3-(trifluoromethyl)phenyl]thio}thiophene-3-carbonitrile ( 11 ) obtained from 4 and 8 is transformed to 10 by condensation with guanidine. Corresponding to the second route, 2,4-diamino-6-[(naphth-2-yl)thio]thieno-[2,3-d]pyrimidine ( 16 ) is synthesized. Oxidation of 10 with m-chloroperbenzoic acid gives 2,4-diamino-6-{[3-(tri-fluoromethyl)phenyl]sulfinyl}thieno[2,3-d]pyrimidine ( 13 ).     

Zur Konformation von 3-Chlormethylsubstituierten 2,3-Dihydro-1,4-benzoxathiinen

The preferential conformation of some 3-substituted 1,4-benzoxathianes has been determined by means of ¹H n.m.r. spectroscopy.