Dihydropyrimidines and related structures. I. N2-substituted 2-pyrimidinamines and dihydro-2-pyrimidinamines by reaction of phenylbutenones and monosubstituted guanidines

The reactions of monosubstituted guanidines 2 with phenylbutenones 7 and 10 exclusively yield N²-substituted 2-pyrimidinamines 8 and 9 . The structure of the reaction products is proved and their differing stability is discussed. Action of methyl- and benzylguanidine respectively ( 2b, c ) on 4-phenyl-3-buten-2-one ( 7 ) and of 2c on l-phenyl-2-buten-1-one ( 10 ) under atmospheric oxygen affords aromatic N²-substituted 2-pyrimidinamines 9b and c . The dihydropyrimidines 8b and c, probable intermediates of the reactions, could not be isolated. In contrast, heating of arylguanidines 2d , e with 7 leads to stable dihydropyrimidinarnines 8d and e, which can be isolated as bases. Addition of methanol to 8d yields 6-methoxy-2-pyrimidinamine 11d , boiling of 8d in DMF affords 9d . Under nitrogen, guanidine adds to 7 to yield aminopyrimidinol 13a , which is transformed by heating in benzene into pyrimidine 9a . The low stability of 8a-c is attributed to their strong basicity, the greater stability of 8d and e to their lower basicity. The structural formulae of 8d , e and 9b-d and their salts respectively were established partly ( 8e ) by nmr and partly ( 9b-d ) by comparison of the corresponding picrates with authentic samples [17].     

Flame synthesis of calcium-, strontium-, barium fluoride nanoparticles and sodium chloride

Non-oxidic salts such as NaCl, CaF2, SrF2 and BaF2 were synthesised using a flame spray method; optional doping of such fluorides with rare earth elements suggests possible applications in optics.     

Spezielle Reaktionen von α,β-ungesättigten Ketonen, 1. Mitt.: Über die Dimerisierung von 2-Benzyliden-1-indanon in Gegenwart starker Basen

Heating of 2-benzylidene-1-indanone (1) either in dimethylformamide in the presence of guanidine carbonate or inn-propanol in the presence of thiourea and sodium propylate yields a dimerP with the structure of 1,3-diphenyl-3a,8a-dihydrospiro{cyclopenta[a]indene-2,2(1H,3H)-indene}-1,8(3H)-dione (7); this was deduced from the 400 MHz-¹H- and 100MHz-¹³C-nmr-spectra and the corresponding two-dimensional HH- and CH-correlations. A possible mechanism for the formation of the spirocompound 7 is proposed; the stereo formula of the dimer7 K was established on the basis of a 400 MHz-HH-NOESY experiment.

     

The conformally invariant measure on self-avoiding loops

We show that there exists a unique (up to multiplication by constants) and natural measure on simple loops in the plane and on each Riemann surface, such that the measure is conformally invariant and also invariant under restriction (i.e. the measure on a Riemann surface that is contained in another Riemann surface is just the measure on restricted to those loops that stay in ). We study some of its properties and consequences concerning outer boundaries of critical percolation clusters and Brownian loops.

     

Stuck walks

We investigate the asymptotic behaviour of a class of self-interacting nearest neighbour random walks on the one-dimensional integer lattice which are pushed by a particular linear combination of their own local time on edges in the neighbourhood of their current position. We prove that in a range of the relevant parameter of the model such random walkers can be eventually confined to a finite interval of length depending on the parameter value. The phenomenon arises as a result of competing self-attracting and self-repelling effects where in the named parameter range the former wins.     

Reaktion der Tautomeren 4-Hydroxy-2H-thiopyran-2-thion und 2-Mercapto-4H-thiopyran-4-on mit aliphatischen Aldehyden

5,6-Dihydro-4-hydroxy-6,6-dimethyl-2H-thiopyrane-2-thione (1 I) and its tautomer 2-mercapto-4H-thiopyrane-4-one (1 II) react with aliphatic aldehydes under different reaction conditions to yield mainly 5R-7,8-dihydro-2H,5H,6H-thiopyrano[2,3—b:6,5—b′]-bisthiopyran-4,6(3H)-diones2 and 2′R,4′R-5,6,6′,7′-tetrahydro-2-thioxo-spiro(4H-thiopyran-3(2H), 3′(4′H)-2′H,5′H-thiopyrano-[2,3—b]-thiopyran)-4,5′-diones3. The mechanisms of formation of the condensates2 and3 and their stereochemistry are discussed. The reaction yielding2 is analogous to the condensation of dimedone with subsequent anhydride formation.3 might be generated byDiels-Adler reaction of intermediately formed 2-thioxo-3-alkylidenethiopyranones4. An X-ray crystal structure analysis was carried out on3 b to establish its configuration and conformation.     

Über Laplace-Ketten mit Kongruenzen von Goursat

Ohne Zusammenfassung     

Über die Reaktionen von monosubstituierten Guanidinen mit α,β-ungesättigten Ketonen

Action of methyl-, benzyl- and phenylguanidine on mesityloxide yields the 2-R ³-imino-4,4,6-trimethyl-1,2,3,4-tetrahydropyrimidines resp. 2-R³-aminopyrimidines8 b, c ande, cyclohexylidenacetone reacts with benzylguanidine to give the 2-benzylimino-4-methyl-1,3-diazaspiro[5.5]undeca-4-en resp. the benzylaminodiazaspiroundecadien (8 d). The isomeric 1- and 3-R³-pyrimidinimines (resp.-amines)9 b-e and10 b-e are not formed in the reaction. The structures were proved by spectroscopical and chemical methods.

Herrn Prof. Dr.G. Zigeuner zum 60. Geburtstag gewidmet.     

Über das 7-Methyl-4,5-diphenyl-4,4a,5,6,7,8,10,10a-octahydro-7,10a-methano-pyrimido[4,5—d][1,3]-diazocin-2,9(1H,3H)-dion

The condensation product (C₁₁H₁₂N₂O) _x synthesized byZigeuner andBrunetti ³ from urea and 4-phenyl-3-buten-2-one is a methanopyrimidodiazocinedione (7, title compound), which has the conformation formula7 K. The formulae7 and7K are constituted taking as a basis the 100 MHz-NMR-spectrum (with double resonance experiments) and the mass spectrum of7; two possible ways for the formation of7—genetic an ureylenchinazolinone—from urea and 4-phenyl-3-buten-2-one are suggested.