Synthese von 15,16-Dimethoxy-8-oxo-cis-erythrinan-6-carbonsäureäthylester

The cyclisation of either 1a or 3a with acid yielded the cis-fused erythrinanone 2; no trans-isomer could be detected. The structure of this unexpected product was determined by NMR. and confirmed by an X-ray analysis. Various tetrahydro- and hexahydro-2-indolinones were prepared to facilitate the interpretation of the NMR.-spectrum of 2.     

Zur Imidazolbildung aus 2H-Azirinen bzw. Vinylaziden und Nitrilen unter Säurekatalyse

Acid-Catalysed Formation of Imidazoles from 2H-Azirines or Vinylazides and Nitriles The reaction of 2H-azirines with nitriles in the presence of boron trifluoride etherate to yield the corresponding imidazoles is described. 2,3-Diphenyl-2H-azirine ( 10 ) gives 2-substituted 4,5-diphenyl imidazoles in moderate bis good yields (see Table 1). The reaction of 10 with acrylonitrile only leads to the formation of 4,5-diphenyl-2-vinylimidazole ( 17 ). No products resulting from an addition to the C,C double bond are observed. 2H-Azirine 10 and ethyl cyanoacetate yield the expected imidazole 18 (30%) but also 2-cyanomethyl-4,5-diphenyloxazole ( 20 ; 7%) (see Scheme 4). The yield of imidazole formation mainly depends on the substituents in position 2 of the 2H-azirines (see Scheme 6), a change of the substitutents in position 3 having only little influence. The best yields are observed with a phenyl group at C(2) of the 2H-azirines. These observations are in agreement with the occurrence of 1-azaallyl cations formed by ring opening of the 2H-azirines linked to the Lewis acid (boron trifluoride). Similar results are obtained with the corresponding vinyl azides with the exception of 1-azido-1-phenylethylene ( 28 ). Whereas the corresponding 3-phenyl-2H-azirine ( 24 ) gives 2,4-diphenylimidazole ( 33 ; Scheme 6) in the presence of benzonitrile and boron trifluoride etherate, the azide 28 yields only acetanilide (86%). In the presence of triethyloxonium tetrafluoroborate 2H-azirines and benzonitrile react to yield the corresponding 1-ethylimidazoles (see Scheme 9). This again demonstrates that 1-azaallyl cations must be intermediates which react with the nitrile presumably in a Ritter type reaction. ¹³C-NMR. spectra of 2H-azirines are also reported (Table 2).     

Ein Indicatorsystem aus Diphenylcarbazid bzw. -carbazon und o-Phenanthrolin

Ohne Zusammenfassung     

Poly-N-carbonyl- und -N-sulfonyl-guanidine aus N-Dichlormethylencarbonsäureamiden bzw. N-Dichlormethylen-sulfonamiden und Diaminen

Zusammenfassung Poly-N-carbonyl- und Poly-N-sulfonyl-guanidine wurden durch Zwischenphasenpolykondensation aus N-Dichlormethylen-carbons?ureamiden bzw. N-Di-chlormethylen-sulfonamiden und Diaminen hergestellt. Die Viskosit?ten und Erweichungsbereiche der Polymeren wurden bestimmt und ihre IR-Spektren mit entsprechenden niedermolekularen Modellverbindungen verglichen.

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Summary Poly-N-carbonyl- and Poly-N-sulfonyl-guanidines were prepared by interfacial polycondensation of N-Dichloromethylenecarbonicacid-amides and N-Dichlor-methylene-sulfonicacid-amides respectively with diamines. The viscosities and softening points of the polymers were determined. Their IR-spectra were compared with those of low molecular weight modell compounds.

     

Über die Darstellung von Phosphoniumsalzen aus Yliden und den freien Säuren bzw. ihren Ammoniumsalzen

The Synthesis of Phosphonium Salts from Ylids and Free Acids or Their Ammonium Salts Tetramethylphosphonium-acetate, -hydrogendiacetate, -azide, -thiocyanate, -nitrate, -sulfate, and -thiosulfate have been prepared from trimethylmethylene phosphorane and the corresponding acids or their ammonium salts, with liberation of ammonia. The reactions were conducted in inert solvents or in alcohol/water mixture and yield pure products in high yields.     

Selektive Herstellung von l- oder u-Aldolen aus Äthyl-trityl-keton und aromatischen Aldehyden über Lithium- bzw. Aluminium-Enolate

Selective Preparation of l- or u-Aldols from Ethyl Trityl Ketone and Aromatic Aldehydes through Lithium and Aluminium Enolates, Respectively The ethyl trityl ketone ( 1 ) is deprotonated to the (Z)-enolate 2 which adds to aromatic aldehydes with relative topicity ul to give the aldols 3 (?78°, THF, kinetic control). If, on the other hand, 1 is heated with trimethylaluminium in toluene, the aluminium enolate formed combines with aromatic aldehydes and with cinnamic aldehyde with opposite relative topicity (lk) to the aldols 5 (+20°, toluene, 2 d, precipitation of the aluminium aldolate 4 , thermodynamic control). The mechanism is discussed (cf. Fig. 1). The adducts to benzaldehyde ( 3a , 5a ), furfural ( 3f , 5f ), and cinnamaldehyde ( 3i , 5i ) are O-(2-methoxyethoxy)methyl (MEM) protected and cleaved by lithium triethylborohydride to the 1,3-diol derivatives 9–11 with a free primary and a protected secondary OH-group. Analogous conversions of 1 and other ketones may also be diastereoselective, but turned out to be of less preparative value (see 6–8 , 12 ).     

Aminomethylierung von Thiophosphorsäuredialkylester-, Phosphon- bzw. Thiophosphonsäurealkylesteramiden,Phosphon- bzw. Thiophosphonsäurediamiden und Diphenylthiophosphinsäureamid

Aminomethylation of Phosphoro-, Phosphono-, Phosphinoamidoates and -amidothioates Dialkylphosphoroamidates, alkyl-phosphonoamidates and phosphonoamidothioates react with C₂H₅O? CH₂? NR₂ and HCOH/HNR₂, respectively, as like as a N-aminomethylation forming the corresponding derivatives of the general formula R₂P(X)? NR′? CH₂? NR″₂? R = alkoxy, alkyl, aryl; R′ = H, alkyl; X = O, S; R″ = alkyl, cycloalkyl —. Under the same conditions phosphonodiamidoates and phosphonodiamidothioates yield RP(X)-[NR′? CH₂? NR″₂]₂ or RP(X)? NHR′? (NR′? CH₂? NR″₂) only. These compounds are not formed by interactions of RP(X)(NR′? CH₂OH)₂ with sec. amines. The aminomethylation of (C₆H₅)₂P(S)NH₂ gives unexceptional [(C₆H₅)₂P(S)]₂N? CH₂? NR′₂. The i.r. and ¹H-n.m.r. data of the prepared compounds, which can't be distilled mostly, are discussed.     

Über kondensierte Heterocyclen aus β-Isothiocyanatoketonen und Aminoalkoholen bzw. Diaminen

2- and 3-aminoalcohols, o-aminobenzylalcohol, o-hydroxybenzylamine and o-amino(thio)-phenol react with 4-isothiocyanato-4-methyl-2-pentanone (1) to yield derivatives of condensed heterocycles (oxazolopyrimidines7, pyrimidooxazine8, pyrimidobenzoxazines9, 10, pyrimidobenzoxazole11 a and pyrimidobenzothiazole11 c respectively). Ethylenediamine or 1,3-diaminopropane react with1 to yield either imidazo-pyrimidine13 and pyrimidopyrimidine14 respectively or the 1,2-ethylene- and trimethylenebisdihydro-2(1H)-pyrimidinethione15 a, b respectively, according to the molar ratio of the reactants. o-Phenylenediamine gives pyrimidobenzimidazole11 d. 11a undergoes ring cleavage in boiling dimethylformamide followed by methylpyrimidine-pyridine rearrangement to dihydrohydroxyphenylamino-2(1H)-pyridinethione12, while15 a is converted into the bis-4-(ethanediimino)-pyridinthione16.     

Beiträge zur Chemie des Hydrazins und seiner Derivate. 56. Kristall- und Molekülstruktur von 1,2-Hydrazindicarbonsäure-diäthylester

Contributions to the Chemistry of Hydrazine and its Derivatives. 56. Crystal and Molecular Structure of Diethyl 1,2-Hydrazinedicarboxylate The structure of Diethyl 1,2-Hydrazinedicarboxylate 1 was determined by an X-ray analysis. 1 crystallizes in the monoclinic space group C2/c with a = 13.279 Å, b = 8.746 Å, c = 7.646 Å, β = 97.30°; Z = 4, d_calc. = 1.328 g/cm³. The molecules contain a 2-fold rotation axis perpendicular to the N? N bond and consist of two planar halfs which are arranged nearly perpendicular to each other. The molecular data and in the crystal existing CO …? HN hydrogen bonds are discussed.     

Über die Stereoselektivität der α-Alkylierung von (1R, 2S) (+)-cis-2-hydroxy-cyclohexancarbonsäureäthylester

The Stereoselectivity of the α-Alkylation of (+)-(1R, 2S)-cis-Ethyl-2-hydroxy-cyclohexanecarboxylate In continuation of our work on the stereoselectivity of the α-alkylation of β-hydroxyesters [1] [2], we studied this reaction with the title compound (+)- 2 . The latter was prepared through reduction of 1 with baker's yeast. Alkylation of the dianion of (+)- 2 furnished (?)- 4 in 72% chemical yield (Scheme 1) and with a stereoselectivity of 95%. Analogously, (?)- 7 was prepared with similar yields. Oxidation of (?)- 4 and (?)- 7 respectively furnished the ketones (?)- 6 (Scheme 3) and (?)- 8 (Scheme 4) respectively, each with about 76% enantiomeric excess (NMR.). It is noteworthy that yeast reduction of rac- 6 (Scheme 3) is completely enantioselective with respect to substrate and product and gives optically pure (?)- 4 in 10% yield, which was converted into optically pure (?)- 6 (Scheme 3). The alkylation of the dianionic intermediate shows a higher stereoselectivity (95%) from the pseudoequatorial side than that of 1-acetyl- or 1-cyano-4-t-butyl-cyclohexane (71% and 85%) [9] or that of ethyl 2-methyl-cyclohexanecarboxylate (82%). The stereochemical outcome of the above alkylation is comparable with that found in open chain examples [1] [2]. Finally (+)-(1R, 2S)- 2 was also alkylated with Wichterle's reagent to give (?)-(1S, 2S)- 9 in 64% yield. The latter was transformed into (?)-(S)- 10 and further into (?)-(S)- 11 (Scheme 5). (?)-(S)- 10 and (?)-(S)- 11 showed an e.e. of 76–78% (see also [11]). Comparison of these results with those in [11] confirmed our former stereochemical assignment concerning the alkylation step.     

Bildung von 2-(1-Methyl-1, 4, 5, 6-tetrahydropyridyl-3)-2-oxazolin-4-on aus 1-Methyl-1, 4, 5, 6-tetrahydronicotinsäureamid und Bromessigsäureäthylester und seine Überführung in O-(1-Methylnipecotinoyl)glykolsäureamid via das dazu tautomere Cyclol

The main product of the reaction between 1-methyl-1, 4, 5, 6-tetrahydronicotin-amide and ethyl bromoacetate is shown to be the 2-(1-methyl-1, 4, 5, 6-tetrahydropyridyl-3)-2-oxazoline-4-one which on partial hydrogenation followed by reaction with alkali affords O-(1-methylnipecotinoyl)glycolic amide, presumably via the tautomeric cyclol.