Preparation and stereochemical characterization of some N-acyl-[1]benzopyrano[3,4-c]pyrazole derivatives from rotenoids

Summary Several new N-acyl derivatives of 1-(4-hydroxy-2,3-dihydrobenzofuran-5-yl)-7,8-di methoxy-1,9 b,2,3,3 a,4-hexahydro-[1]benzopyrano[3,4-c]pyrazole-1-ene have been prepared by appropriate chemical transformation of isohydrazones of rotenone and amorphigenin. A study of their¹H- and¹³C-NMR spectra confirmed the presence of the twocis 3a, 9b, 2 and 3a, 9b, 2 diastereomers in the parent isohydrazones and revealed the strong predominance of the conformers withendo orientation of the 3-NAc group. The conformations due to rotation about the 1,5-bond between rings C and D in the 4-OH and 4-O-substituted compounds were also determined by taking into account the anisotropic effect of aromatic rings A and D, and the hydrogen bond between 4-OH and the 2-N atom, as well as by inspecting the Dreiding models.

---

Darstellung und stereochemische Charakterisierung einiger N-Acyl-[1]benzopyrano[3,4-c]pyrazol-Derivate von Rotenoiden

Zusammenfassung Mittels geeigneter chemischer Transformationen von Isohydrazonen von Rotenon und Amorphigenin wurden einige neue N-Acyl-Derivate von 1-(4-Hydroxy-2,3-dihydrobenzofuran-5-yl)-7,8-dimethoxy-1,9 b,2,3,3 a,4-hexahydro-[1]benzopyrano[3,4-c]pyrazol-1-en hergestellt. Eine Untersuchung ihrer¹H und¹³C-NMR-Spektren zeigt die Gegenwart von zweicis 3a, 9b, 2- und 3a, 9b, 2-Diastereomeren in den Ausgangs-Isohydrazonen und eine starke Bevorzugung der Konformeren mitendo-Orientierung der 3-NAc-Gruppe. Die Konformationen bezüglich der Rotation um die 1,5-Bindung zwischen Ring C und D werden für die 4-OH und 4-O-substituierten Verbindungen unter Berücksichtigung von Anisotropie-Effekten der aromatischen A- und D-Ringe, der Wasserstoffbrücken zwischen 4-OH und dem 2-N Atom und auch der Betrachtung der entspechenden Dreiding-Modelle diskutiert.

     

Synthesis of heterocycles from 1,5-diketones. 3. Alicyclic 1,5-diketones in reaction with phenylhydrazine

8-R-7aH-5,6,7,8,9,10,11,12-Octahydroindolo[3.2.1-d,e]acridines, 1,2,3,4-tetra-hydrocarbazole, 9-R-sym-octahydroacridines, and 9-R,10-phenyl-sym-octahydroacridinium salts are formed by the action of phenyl-hydrazine on alkylidene-2,2-dicyclohexanone or the corresponding 8-R-tricyclo(7.3.1.0^2,7)tridecan-2-ol-13-ones in an acid medium. Postulations were made for the paths of formation of these compounds.2,2-Dimethyl-3-oxa-4a-(2,2-dimethyltetrahydropyran-4-on-5yl-methyl)-4aH-1, 2,3,4-tetrahydrocarbazole, 3,3,14,14-tetramethyl-2-oxa-5a,10b-(methanoxyisobutane)-1,2,3,4,5a,10b,11,11a-octahydroquinindoline, 2,2-dimethyl-3-oxa-1,2,3,4-tetrahydrocarbazole and 3,3,6,6-tetramethyl-2,7-dioxa-sym-octahydroacridine were obtained by the reaction of methylene-3,3-di(6,6-dimethyltetrahydropyran-4-one) with phenylhydrazine in acetic acid. The quinindoline structure was confirmed by the synthesis of this compound from 2,2-dimethyl-3-oxa-4a-(2,2-dimethyl-tetrahydropyran-4-on-5-ylmethyl)-4aH-1,2,3,4-tetrahydrocarbazole by the action of ammonia.For article 2, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 46–52, January, 1986.     

Azines and azoles: CXXVI. First example of a novel heterocyclic system: Pyrimido[1,6-<Emphasis Type="Italic">a</Emphasis>][1,5]benzodiazepines

4-Hydroxy-5-(2-R-2,3-dihydro-1H-1,5-benzodiazepin-4-yl)-2H-1,3-thiazine-2,6-diones readily undergo acylation at the N¹ atom of the benzodiazepine system by the action of acetic anhydride. Heating of the acetylated products in boiling dimethylformamide leads to the formation of 75–93% of the corresponding 7-acetyl-6-R-6,7-dihydropyrimido[1,6-a][1,5]benzodiazepine-1,3-diones that are derivatives of hitherto unknown fused heterocyclic system, pyrimido[1,6-a][1,5]benzodiazepine. 4-Hydroxy-5-(2-R-2,3-dihydro-1H-1,5-benzodiazepin-4-yl)-2H-1,3-thiazine-2,6-diones are converted into 1-(2-aminophenyl)-6-(2-R-vinyl)uracils on heating in boiling DMF.     

Cyclocondensation of N-aryl-3-oxobutanethioamides with 5-amino-3-R-4-R1-pyrazoles

The cyclocondensation products of N-aryl-3-oxobutanethioamides with 5-amino-3-R-4-R¹-pyrazoles are 4-(arylamino)-2-methyl-7-R-8-R¹-pyrazolo[1,5-a]pyrimidine and pyrazolo[1,5-a]pyrimidine-4-thione derivatives, the ratio of which depends on the nucleophilicity of the starting 5-amino-3-R-4-R¹-pyrazoles and the presence of a proton donor solvent. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1550-1555, October, 2008.     

Static and dynamic stereochemistry of 1,1′-bi(9,10-dihydro-9,10-ethano-anthryl)

Summary The title compound2 was prepared either by highpressure reaction of 1,1-bianthryl with ethylene or by coupling of 1-bromo-9,10-dihydro-9,10-ethanoanthracene (4). Both syntheses afforded a mixture of diastereoisomers (meso2a and racemate2b) in a ratio of 1.5:1 and 2.3:1, respectively. Configurational assignment was possible both from the¹H- and¹³C-NMR spectra and by coupling of laevorotatory4 (accessibly by enantioselective chromatography on triacetyl cellulose in ethanol) to laevorotatory2b. (+)-4 was tranformed into the dextrorotatory carboxylic acid (+)-5 of known configuration (9R) thus establishing the configuration of (+)-4 as (9R) too and hence the centrochirality in (–)-2b as (9S)(9S). The racemic form2b is a conformational (appr. 1.8:1) mixture of two rotamers.The rotational barrier was established as G ^#=92–95 kJ mol^–1 (depending on the temperature) both by¹H-NMR and CD kinetics (based on equilibration of the separated optically active rotamers ofracem.2). For the latter preferred conformations were assumed allowing the assignment of the axial chirality: e.g. (–)-(9S)(R)_a(9S) for the main rotamer of (–)-2 b [and (–)(9S)(S)_a(9S) for the underpopulated one].All assumptions were confirmed by X-ray crystal structure analyses of2 a and the main rotamer of2b with torsional angles around the 1,1-bonds of –111.1 and –121.2°, respectively.Dedicated to Prof. K. L. Komarek (Vienna) with cordial wishes on the occasion of the 65th anniversary of his birthday     

Investigation of naphthyridines

2-Acetyl-10-aryl-1,2,3,4-tetrahydrobenzo[b]-1,6-naphthyridines were obtained by reaction of 4-(2)-R-2-aminobenzophenones with 1-acetyl-4-piperidone, and their pK_a values were determined. It was found that they are oxidized by hydrogen peroxide to give the corresponding N-oxides in good yields. The N-oxides are converted to the 4-acetoxy derivatives by the action of acetic anhydride.See [1] for communication VII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1383–1385, October, 1976.     

Über Inhaltstoffe der Iris germanica (Schwertlilie)

Acetovanillon and the known flavonoids irisolidone, irigenin, irisolone, tectorigenin and dihydroquercetin-7.3-dimethylether were detected in the rhizomes of Iris germanica. Also a few unknown compounds could be isolated and their structure elucidated; 9-methoxy-7-(3.4.5-trimethoxyphenyl)-8H-1.3-dioxolo[4.5-g] [1]-benzopyran-8-on (=5.3.4.5-tetramethoxy-6.7-methylenedioxyisoflavone (III A); 9-methoxy-7-(3.4-dimethoxyphenyl)-8H-1.3-dioxolo[4.5-g] [1]-benzopyran-8-on (=5.3.4-trimethoxy-6.7-methylenedioxyisoflavone(III B); 9-hydroxy-7-(p-hydroxyphenyl)-8H-1.3-dioxolo[4.5-g] [1]-benzopyran-8-on (=5.4-dihydroxy-6.7-methylenedioxyiosoflavone (IX); 5.7-dihydroxy-3-(3-hydroxy-4-methoxyphenyl)-6-methoxy-4H-1-benzopyran-4-on (=5.7.3-trihydroxy-6.4-dimethoxyisoflavone (XI B); 5.7-dihydroxy-3-(4-hydroxy-3-methoxyphenyl)-6-methoxy-4H-1-benzopyran-4-on (=5.7.4-trihydroxy-6.3-dimethoxyisoflavone (XI C).The structure determination was effected by combined spectroscopical and chemical methods.

---

---

Herrn Prof. Dr.F. Hecht mit den besten Wünschen zum 70. Geburtstag gewidmet.     

Restricted helix inversion in chiral 2,18-bridged biliverdins

Summary The energy barrier to helix inversion in biliverdin is doubled if the pyrrolinone rings are bonded by a four-link chain as present in the chiral diastereoisomers of 2,18-(1,4-dimethoxybutane-1,4-diyl)-8,12-bis(2-methoxycarbonylethyl)-3,7,13,17-tetramethyl-1,19-(21H,24H)-bilindion1 and its hydroxy derivative2. The torsional restrictions thus imposed on the bilatriene moiety provide the basis for resolution by first-order asymmetric transformation with optically active mandelic acid. Interconversion barriers at 293 K range from 85 to 90 kJ mol^–1 and were determined monitoring the rate of isomerization processes (M-RR)-1 b(P-RR)-1 a, (P-SS)-1 b(M-SS)-1 a, and the racemization process (P-RS)-1 c(M-RS)-1 c by c.d. spectroscopy. Similar results were obtained with the bridged biliverdins2.

---

Behinderung der Helix-Interkonversion in 2,18-überbrückten Biliverdinen

Zusammenfassung Die Energiebarriere für die Helixinversion von Biliverdinen läßt sich durch Überbrücken der Pyrrolinonringe mit einer C-4 Einheit auf das Doppelte erhöhen. Derartige Verhältnisse liegen in den chiralen Diastereomeren des 2,18-(1,4-Dimethoxybutan-1,4-diyl)-8,12-bis(2-methoxycarbonylethyl)-3,7,13,17-tetramethyl-1,19-(21H,24H)-bilindions1 und seines Hydroxyabkömmlings2 vor. Die dadurch bedingten Torsionsrestriktionen im Bilatrienteil stellen die Grundlage für eine Spaltung durch asymmetrische Umwandlung erster Art mit optisch aktiver Mandelsäure dar. Die Barrieren liegen zwischen 85 und 90 kJ mol^–1 (293 K) und wurden aus der Geschwindigkeit der Isomerisierungsprozesse (M-RR)-1 b(P-RR)-1 a, (P-SS)-1 b(M-SS)-1 a, sowie des Razemisierungsprozesses (P-RS)-1 c(M-RS)-1 c mittels Circulardichroismus bestimmt. Ähnliche Ergebnisse wurden für die Isomeren von2 erhalten.

     

Zum Reaktionsmechanismus von Glutaraldehyd mit Proteinen

The interaction of glutaraldehyde with model aliphatic amines was studied in order to understand the crosslinking reaction of glutaraldehyde with proteins. The reaction in organic solvents gave N-alkyl-1,4-dihydropyridines and N,N-dialkyl-1,5-diiminopentanes. The isolated products are new or were previously described by us for the first time¹. Hydration of the reaction products led to stable N-alkylpiperidines and N,N-dialkyl-1,5-diaminopentanes. In aqueous solution the reaction depends on thepH: at apH above 7, N-alkyl-1,4-dihydropyridines and at apH below 7, polymers were obtained. For the crosslinking reaction of proteins with glutaraldehyde the following mechanism is proposed: Monomeric glutaraldehyde reacts with the protein to give intermediate N-alkyl-2,6-dihydroxypiperidines. Intramolecular dehydration leads to the corresponding N-alkyl-1,4-dihydropyridines. Condensation of the cyclic monohydrate of glutaraldehyde and N-alkyl-2,6-dihydroxypiperidines gives linear polymeric crosslinks containing -oxo-N-alkylpiperidine units.

Lubig R., Dissertation, RWTH Aachen, 1974.     

Azide-tetrazole tautomerism of diazidodiazines and their benzo analogs

It has been discovered with the aid of IR and NMR spectroscopy that 5-azidotetrazolo [1,5-a]quinazoline exists in solutions in a tautomeric equilibrium with ditetrazolo [1,5-a:1,5-c]quinazoline, and the thermodynamic and kinetic characteristics of the equilibrium have been determined. Azide-tetrazole tautomerism is not observed under these conditions for ditetrazolo[1,5-a:5,1-c]pyrazine, 6-azidotetrazolo [1,5-b]pyridazine, and their benzo analogs.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2002–2007, September, 1989.     

Reaction of Adenine and Guanine with [Ru(RaaiR′)2(EtOH)2](ClO4)2 · Spectral and Electrochemical Characterization of the Products [RaaiR′ = 1-Alkyl-2-(arylazo)-Imidazole]

[Ru(RaaiR)₂(EtOH)₂](ClO₄)₂[RaaiR= 1-alkyl-2-(arylazo)imidazole, p-R-C₆H₄-N = N-C₃H₂N-N(1)-R, R = H (a), Me (b), Cl (c), R= Me (1, 3), Et (2, 4)] reacts with nucleobases [NB – adenine (A), guanine (G)] in aqueous EtOH to give red–violet mixed ligand complexes of the type [Ru(RaaiR)₂(NB)(H₂O)](ClO₄)₂. The solution electronic spectra exhibit a strong MLCT band at 540–560 nm in MeCN. The cyclic voltammogram shows a Ru^III/Ru^II couple at 1.3–1.4 V versus Ag/AgCl along with three successive ligand reductions.     

The structures of 1-(2′-hydroxybenzoyl)piperidine and 4-(2′-hydroxybenzoyl)morpholine

1-(2-hydroxybenzoyl)piperidine, C₁₂H₁₅NO₂, orthorhombic, Pbc2₁-C _2v ⁵ ;a=9.529 (1),b=10.001 (1),c=11.652 (1) Å;Z=4. The structure was determined from 1 510 single crystal X-ray data by direct methods and the refinement of the structure parameters yieldedR=0.040. There is one molecule in the asymmetric unit.4-(2-hydroxybenzoyl)morpholine, C₁₁H₁₃NO₃, orthorhombic, P2₁2₁2₁-D ₂ ⁴ ;a=13.006 (1),b=17.258 (2),c=9.125 (1) Å;Z=8. The structure parameters of the isotypic compound 4-(2-hydroxythiobenzoyl)morpholine were used in a starting set of refinement; finallyR=0.054 was obtained for 1 900 single crystal X-ray data. There are two molecules in the asymmetric unit.In both compounds the hydrogen atoms could be located by means of differenceFourier summations. The intermolecular hydrogen bonds with O ... O distances of 2.649 (2) Å for the piperidine derivate and 2.688 (3) resp. 2.754 (3) Å for the morpholine derivate are typical for intermediate bond strengths.

---

Die Strukturen von 1-(2-hydroxybenzoyl)piperidin und 4-(2-hydroxybenzoyl)morpholin

Zusammenfassung 1-(2-hydroxybenzoyl)piperidin, C₁₂H₁₅NO₂, orthorhombisch, Pbc2₁-C _2v ⁵ ;a=9.529 (1),b=10.001 (1),c=11.652 (1) Å;Z=4. Die Struktur wurde aus 1 510 Einkristallröntgendaten mittels direkter Methoden bestimmt; die Strukturverfeinerung ergabR=0.040. Es ist ein Molekül in der asymmetrischen Einheit.4-(2-hydroxybenzoyl)morpholin, C₁₁H₁₃NO₃, orthorhombisch, P2₁2₁2₁-D ₂ ⁴ ;a=13.006 (1),b=17.258 (2),c=9.125 (1) Å;Z=8. Die Strukturparameter der isotypen Verbindung 4-(2-hydroxythiobenzoyl)morpholin wurden als Startsatz für die Strukturverfeinerung benutzt. Es wurdeR=0.054 aus 1 900 Einkristallröntgendaten erreicht. Es befinden sich zwei Moleküle in der asymmetrischen Einheit.In beiden Verbindungen konnten mittels Differenz-Fourier-Summierungen die Wasserstoffatome lokalisiert werden. Die intermolekularen Wasserstoffbrükken mit O ... O-Distanzen von 2.649 (2) Å für das Piperidinderivat und 2.688 (3) bzw. 2.754 (3) Å für das Morpholinderivat sind typisch für mittlere Bindungsstärken.

     

Reaction of 4-aminouracil with 2-(arylmethylene)indan-1, 3-diones

The reaction of the arylmethyleneindanones (I) with 4-aminouracil or its N-methyl derivative (IV) gives new multinuclear nitrogencontaining systems—5-aryl-2,4,6-trioxo-1-R-3-R-1,2,3,4,5,11-hexahydro-11-azafluoreno[3,2-d]pyrimidines (V), which are oxidized by chromic anhydride to 5-aryl-2,4,6-trioxo-1-R-3-R-1,2,3,4-tetrahydro-11-azafluoreno[3,2-d]pyrimidines (VI). The UV and IR spectra of the compounds synthesized are given.     

Triazolopyridines. Part 24: New polynitrogenated potential helicating ligands

The synthesis of novel 7-{[1,2,3]triazolo[1,5-a]pyridin-3-yl}-[1,2,3]triazolo[1,5-a]pyridines 7, 2-pyridyl-[1,2,3]triazolo[1,5-a]pyrid-7-ylmethanols 11, 3-(6-substituted-2-pyridyl)-[1,2,3]triazolo[1,5-a]pyridines 12, and 7,7′-disubstituted-3,3′-[1,2,3]triazolo[1,5-a]pyridine 20, interesting polynitrogenated ligands as potential helicating compounds or luminescent sensors, from [1,2,3]triazolo[1,5-a]pyridines is described.     

An NMR-Based Approach to the Measurement of High Log K HL Values at Low Ionic Strength. 31P NMR Study of 1,2-Diaminoethane-N,N,N′,N′-tetra(methylenephosphonic Acid) Protonation Equilibrium at pH > 12

A sequential NMR based approach is proposed for measurements of high log K values at low ionic strength. [³¹P] NMR technique is used to determine the protonation constants of 1,2-diaminoethane-N,N,N,N-tetra(methylenephosphonic acid) (EDTPH, H₈L) at 25°C in 0.1 mol-dm^–3 KNO₃ and at 37°C in 0.15 mol-dm^–3 NaCl at pH 11–14. For equilibrium L + H HL log K are found to be 13.3 (0.1) and 12.9 (0.1), respectively.     

Über Tetrahydrospiro [cyclohexan-1,4′(1′H)-chinazolin]-2′(3′H)-one

Zusammenfassung Cyclohexanon bzw. Cyclopentanon sowie ihre durch Aldolreaktion entstehenden Dimeren reagieren mit Harnstoff im sauren Medium zu 5,6,7,8-Tetrahydrospiro[cyclohexan-1,4(1H)-chinazolin]-3(2H)-onen (2) bzw. zum Dihydrospiro-(cyclopentan-1,4(1H)-5H-cyclopenta[d]pyrimidin)-2(3H)-on (10). Substituierte Harnsotoffe geben Gemische der isomeren 5,6,7,8-Tetrahydro- und 4a,5,6,7-Tetrahydroverbindungen (2, 3) bzw. 6,7-Dihydro-tH- und 5,6-Dihydro-4aH-verbindungen (10, 11). Charakteristisch für2 (3),10 (11) ist die Reaktivität der Kernstellen 8 bzw. 7 gegenüber elektrophilen Agentien (2f-v, 3f-j, 9 a-i, 10 d-f). Äthylmalonsäurebis-trichlorphenylester bzw. Formaldehyd und prim. Amine führen2 in ein partiell hydriertes 1H-Pyrido[3,2,1-ij]chinazolintrion (6) bzw. 1H-Pyrimido[5,6,1-ij]chinazolinon (7) über. Die 1-Alkylverbindungen (2) geben mit Formaldehyd und primären Aminen Hexahydro-8a-hydroxy-4a,8-propanospiro-(cyclohexan-1,4(1H)-pyrido[4,3-d]pyrimidin)-2(3H)-one (8).

---

Heterocycles, XXV: tetrahydrospiro [cyclohexane-1,4(1H)-quinazoline]-2(3H)-ones

Cyclohexanone and cyclopentanone, resp., as well as their dimers (formed by aldol reaction) react with urea in the presence of acids to 5,6,7,8-tetrahydrospiro[cyclohexane-1,4-(1H)-quinazoline]-3(2H)-ones (2) and to the dihydrospiro-(cyclopentane-1,4(2H)-5H-cyclopenta[d]pyrimidine)-2(3H)-one (10), resp. Substituted ureas give the isomeric 5,6,7,8-tetrahydro- and 4a,5,6,7-tetrahydro compounds (2, 3), and 6,7-dihydro-5H- and 5,6-dihydro-4aH-compounds (10, 11), resp. Characteristic for2 (3),10 (11) is the reactivity of the nuclear places 8 and 7 with electrophilic agents (2f-v, 3f-j, 9a-i, 10d-f). Ethylmalonic acid bistrichlorophenylester resp. formaldehyde and primary amines react with2 to the partially-hydrogenated 1H-pyrido[3,2,1-ij]-quinazolinetrione (6) and 1H-pyrimido[5,6,1-ij]-quinazolinone (7), resp. The 1-alkyl compounds (2) give with formaldehyde and primary amines hexahydro-8a-hydroxy-4a, 8-propanospiro(cyclohexane-1,4-(1H)-pyrido[4,3-d]pyrimidine)-2(3H)-ones (8).

     

Acetylenchemie 2. Mitt.: Sigmatrope Umlagerungen bei der phasentransferkatalysierten Umsetzung von 9(10H)-Acridinon mit 3-Chlor-3-methylbut-1-in

1-Isopropyl-pyrrolo[3,2,1-d,e]acridine-6-one and 10-(3,3-dimethylallenyl)-9(10H)-acridinone were obtained by the reaction of 9(10H)-acridinone with 3-chloro-3-methylbut-1-yne under ptc-conditions.

     

Study of the conformational equilibria of some 2-(2′-hydroxyphenyl)-4-aryl-3H-1,5-benzodiazepines using1H,13C, and15N NMR spectroscopy

Summary Variable temperature¹H NMR experiments of 2-(2-hydroxyphenyl)-4-phenyl-3H-1,5-benzodiazepine (5a) and its derivatives5d and5e were carried out in order to investigate the conformational behaviour of these compounds. The G* values for the ring inversion barriers of5a and5d areca. 52 kJ/mol,i.e. they do not differ significantly as compared to analogous compounds without phenolic OH group(s). This indicates that the hydrogen bond has not to be opened during the inversion process. In5e the barrier is about 2–3 kJ/mol higher which can be explained by steric interference between the additional methoxy group and the H-3 atoms during ring inversion.¹⁵N NMR data which can be discussed in terms of hydrogen bond strength support this interpretation.

---

Untersuchung des Konformationsgleichgewichtes einiger 2-(2-Hydroxyphenyl)-4-aryl-3H-1,5-benzodiazepine mit Hilfe der¹H- und¹⁵N-NMR-Spektroskopie

Zusammenfassung Es wurden¹H-NMR-Experimente mit 2-(2-Hydroxyphenyl)-4-aryl-3H-1,5-benzodiazepin (5a) und seinen Derivaten5d und5e bei unterschiedlichen Temperaturen durchgeführt. Die G*-Werte für die Ring-Inversion von5a und5d betragenca. 52 kJ/mol, d.h. sie sind gegenüber Verbindungen ohne eine phenolische OH-Gruppe kaum verändert. Das zeigt an, daß die Wasserstoffbrückenbindung während der Inversion nicht geöffnet werden muß. In5e ist die Barriere um ungefähr 2–3 kJ/mol höher, was durch eine sterische Wechselwirkung zwischen der zusätzlichen Methoxygruppe und den H-3-Atomen während der Inversion erklärt werden kann.¹⁵N-NMR-Daten können als Hinweise auf die Stärke der Wasserstoffbrückenbindung interpretiert werden.

     

Substitutions of organopalladium(II) species with benzimidazole derivatives

The [Pd(cod)(cotl)]ClO₄ complex (cod = cycloocta-1,5-diene; cotl = cyclooctenyl, C₁₈H₁₃ ^–) undergoes substitutions with new Schiff base ligands containing benzimidazole L [L = 2-(2-N-n-propylidenephenyl)benzimidazole (L¹); 2-(2-N-i-propylidenephenyl)benzimidazole (L²); 2-(2-N-n-butylidenephenyl)benzimidazole (L³); 2-(2-N-i-butylidenephenyl)benzimidazole (L⁴)]. Facile displacement of cod by L occurs to produce complexes of the type [Pd(cotl)L]ClO₄· nMe₂CO (n= 0; L = L¹, L² or L³; n= 2, L = L⁴). Dihalobridge complexes of the type [Pd(cotl)X]₂(X = Cl or Br) undergo halogen-bridge cleavage with L¹–L⁴ to give mononuclear complexes of the type Pd(cotl)LX · nH₂O (n= 2, X = Cl, L = L¹; n= 0, X = Br, L = L¹; n= 0, X = Cl, L = L²; n= 0, X = Cl or Br, L = L³; n= 0, X = Cl, L = L⁴; n= 2, X = Br, L = L⁴) and a binuclear complex [Pd(cotl)Br]₂L². The complexes were characterised by physical properties, i.r., ¹H- and ¹³C-n.m.r. spectral techniques and by mass spectra. Probable structures have been proposed.     

Zur Mannich-Reaktion von Dihydro-6-methyl-2(1H)-pyrimidinonen

Zusammenfassung Dihydro-4,4,6-trimethyl-2(1H)-pyrimidinone reagieren mit Formaldehyd und sekundären bzw. primären Aminen zu 6-Dialkylaminoäthylidentetrahydro-2(1H)-pyrimidinonen bzw. Hexahydro-2(1H)-pyrido[4,3-d]Pyrimidinonen. Mit Succindialdehyd bzw. Glutardialdehyd und primären Aminen entstehen 5,7-Äthanohexahydro-2(1H)-pyrido[4,3-d]pyrimidinone bzw. Tetrahydro-6,8-propano-6H-pyrimido[1,6-c]pyrimidin-1(2H)-one. Die 6-Dialkylaminoäthylidentetrahydro-2(1H)-pyrimidinone geben mit Phenolen Tetrahydrospiro([1]benzopyran-2,4(1H)-pyrimidin)-2(3H)-one, mit cycl. -Dicarbonylverbindungen Hexahydrospiro([1]benzopyran-2,4(1H)-pyrimidin)-2,5(3H, 6H)-dione bzw. Tetrahydrospiro(2H,5H-pyrano[3,2-c][1]benzopyran-2,4(1H)-pyrimidin)-2(3H),5-dione bzw. mit Malonestern -(Tetrahydro-4,4-dimethyl-2-oxo-6-pyrimidyl)-äthylmalonester.Zusammenfassung Dihydro-4.4.6-trimethyl-2(1H)-pyrimidinones react with formaldehyde and sec. and prim. amines resp. to 6-dialkylaminoethylidentetrahydro-2(1H)-pyrimidinones and hexahydro-2(1H)-pyrido[4.3-d]pyrimidinones, resp. succindialdehyde and glutaraldehyde with primary amines give 5.7-ethanohexahydro-2(1H)-pyrido[4.3-d]pyrimidinones and tetrahydro6.8-propano-6H-pyrimido[1.6-c]pyrimidin-1(2H)-ones, resp. 6-Dialkylaminoethylidentetrahydro-2(1H)-pyrimidinones react with phenols to tetrahydrospiro([1]benzopyran-2.4(1H)-pyrimidin)-2(3H)-ones, with cyclic -dicarbonyl compounds to hexahydrospiro([1]benzopyran-2.4 (1H)-pyrimidin)-2,5 (3H), 6H)-diones and tetrahydrospiro(2H,5H-pyrano[3.2-c][1]benzopyran-2.4(1H)-pyrimidin)-2(3H),5-diones, resp., with malonates -(tetrahydro-4.4-dimethyl-2-oxopyrimidyl-6)-ethylmalonates.

---

Mannich reaction with dihydro-6-methyl-2(1H)-pyrimidinones

---

Herrn Prof. Dr.F. Kuffner zum 65. Geburtstag gewidmet.