Synthesen von kernsubstituierten N,N-Diphenyl-β-alaninen

Zusammenfassung N,N-Diphenyl--alanine mit Substituenten in einem oder in beiden Phenylresten wurden durch Umsetzung von entsprechenden Diphenylaminderivaten mit -Propiolacton erhalten. In ähnlicher Weise reagierte Diphenylamin mit -Butyrolacton zu -(N,N-Diphenylamino)-buttersäure. 4,4-Diäthyldiphenylamin und 2-Chlor-6-methyl-diphenylamin wurden als Ausgangsmaterialien für die entsprechenden -Alanine hergestellt.

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N.N-Diphenyl--alanines with substituents in one or in both of the phenyl groups were synthesized by reactions of the corresponding diphenylamine derivatives with -propiolactone. Similarly diphenylamine reacted with -butyrolactone to give -(N.N-diphenylamino)-butyric acid. 4.4-Diethyldiphenylamine and 2-chloro-6-methyldiphenylamine were prepared as starting materials for the corresponding -alanines.

     

Synthese von basisch substituierten 2-Methyl-2,3-dihydro-benzo[b]thiophenen

N-substituted {2-methyl-benzo[b]thienyl-(3)}-acetamides were oxidized to the corresponding 1,1-dioxides, catalytic hydrogenation of which gave N-substituted {2-methyl-2,3-dihydro-benzo[b]thienyl-(3)}-acetamide-S,S-dioxides. The latter were reduced by LiAlH₄ to give N-substituted 2-methyl-3-(β-amino-ethyl)-2,3-dihydro-benzo[b]thiophenes.     

Über den Einfluss der pK-Werte von Anilinen auf die Bildung und Folgereaktionen von substituierten Butadienen aus Cumalinsäure-methylester

The Influence of Aniline pK Values on the Formation and Reactivity of Substituted Butadienes from Methyl Coumalate The product of the reaction between 2 equiv. of methyl coumalate ( 1 ) and 1 equiv. of a substituted aromatic amine depends on the pK value of the latter. Aromatic amines with pK values between 1.05 and 2.8 produce bicyclic lactones 4 , whereas those with higher pK values also give 2-azabicyclo[3.3.1]nona-3,7-diene-9-carboxylic acids 9 . The latter, products of the intramolecular Diels-Alder reaction 8 → 9 , may in certain cases even prevail.     

Synthesen von 5-Alkyl-2-aryl-pyrimidin-4(3H)-onen

The title substances with R²=H (type1) were synthesized by reductive desulfurization of corresponding 2-aryl-thieno-[2,3-d]pyrimidin-3(3H)-ones and 2-aryl-[1]benzothieno[2,3-d]-pyrimidin-4(3H)-ones (both:A), those with R²=CH₃ (type2) by cyclization of -alkyl-acetoacetates with benzamidines. Some derivatives of1 and2 were also prepared (type3). In some cases Raney-Ni desulfurization ofA gave 2-cyclohexylproducts (type4).

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Teilweise unter Mitarbeit vonMorteza Baradar.     

Cyclisierungsreaktionen zu Thiazolo[3,2—a]thieno[2,3-d]pyrimidinen

Cyclisation of 2-(-oxo-alkylthio)-thieno[2.3-d]pyrimidin-4(3H)-ones gave separable mixtures of the title substances and their [2.3-b]-isomers. The structure of the two isomers were be proved by comparison with a linear product synthesized by an unambiguous method. Similar cyclisations were achieved by reactions of 2-mercapto-thieno[2.3-d]pyrimidin-4(3H)-ones with chloroacetone, 1.2-dibromoethane or 1.3-dibromopropane.     

Synthesis and X-ray structure of new spiro-imidazo[2,1-b]thiazole

Spiro[5,5]undecane-3-one 1 was converted to 4 ,7-dihydrospiro[benzo[d]thiazole-6(5H),1′-cyclohexane]-2-amine 3 , which is condensed with bromomethyl (halo)phenyl ketones and cyclized to compounds 5a-5c . The X-ray crystallography of the 5b reveals that formation route for 5 is via 3-position-substituted-spiro-iminothiazole 4 .     

Embedding the three-dimensional pseudo-sphere

We construct the embedding of the manifold x ² + y ² − u ² − v ² = 1 carrying the most general homogeneous metric into the eight-dimensional pseudo sphere.     

Femtosecond vibrational dynamics of self-trapping in a quasi-one-dimensional system

We have directly time resolved the lattice motions associated with the formation of the self-trapped exciton in the quasi-one-dimensional system [Pt(en)(2)] [Pt(en)2Br2];(PF6)(4) ( en = ethylene-diamine, C2H8N2), using femtosecond impulsive excitation techniques. A strongly damped, low-frequency wave packet modulation at approximately 110 cm(-1) accompanies the formation of the self-trapped exciton on a approximately 200 fs time scale following excitation of the intervalence charge-transfer transition. Coherent oscillations at the ground state vibrational frequency and its harmonics are also detected.