Cer(IV)-Oxidationen von β-Aminoketonen. 3. Mitt.: Ein Syntheseweg zu 4-spirosubstituierten 1,2,3,4-Tetrahydroisochinolinen

Cerium(IV) Oxidations of β-Aminoketones. Part III: A Pathway to 4-Spiro-Substituted 1,2,3,4-Tetrahydroisoquinolines Substituted 2′-methyl-2′,3′-dihydro-1′H-spiro[cycloalkan-1,4′-isoquinolin]-2-ones and -[chroman-3,4′-isoquinolin]-4-ones are synthesized by cerium(IV) oxidation of (N-benzyl-N-methylamino)methylcycloalkan-1-ones or corresponding substituted chromanones.     

Cer(IV)oxidationen von β-Aminoketonen, 8. Mitt.: Synthese von im Piperidinteil verschieden substituierten 1,2,3,4-Tetrahydroisochinolinen

Cerium(IV) Oxidations of β-Aminoketones, VIII¹⁾: Synthesis of 1,2,3,4-Tetrahydroisoquinolines with Differently Substituted Piperidine Parts 1- and 3-Alkyl- and/or aryl substituted tetrahydroisoquinolines are obtained by oxidative cyclisation of N-benzyl-β-aminoketones with cerium(IV) sulphate. In nearly all cases formation of mixtures of diastereomeres is observed. If the ketone function is replaced with COOR-, CN-, CHO and NO₂-groups no cyclisation occurs under standard reaction conditions. The products of hydrolysis, N-benzyl-N-methylaminopropionic acid, and of oxidation in benzylic position, benzaldehyde and benzoic acid, are mainly formed during the reaction. The oxidation of the N-benzylaminopropionaldehydacetal 1k yields the isoquinolinedione 4k .     

Synthese von 2-Carbazoylthio-essigsäuren und deren Cyclisierung zu 3-Amino-thiazolidin-2,4-dionen

Synthesis of 2-(Hydrazinocarbonylthio)-acetic Acids and Cyclization to 3-Aminothiazolidine-2,4-diones N-mono- or N,N-disubstituted hydrazines are reacted with carbonyl sulfide, triethylamine and halogenoacetic acids to yield the 2-(hydrazinocarbonylthio) acetic acids 1 , which are cyclizised to yield the 3-aminothiazolidine-2,4-diones 2 by dicyclohexylcarbodiimide.     

Cer(IV)oxidationen von β-Aminoketonen, 6. Mitt.: Untersuchungen zum Reaktionsverlauf

Cerium(IV) Oxidations of β-Aminoketones., VI: Investigations on the Reaction Mechanism Cerium(IV)sulfate oxidations of N-benzyl-4-piperidones are characterized by a radical mechanism: the cyclisation product, the methanobenzazocine 2 , is formed via a C-3 intermediate, the dehydrogenation products 3 and 4 are obtained from peroxyradicals.     

Cer(IV)oxidationen von β–Aminoketonen. 7. Mitt.: Synthese von 4-Benzoylisochinolin und des davon abgeleiteten Lactams

Cerium(IV) Oxidations of β-Aminoketones. Part 7: Synthesis of 4-Benzoylisoquinoline and of the Corresponding Lactame     

Cyclisierung von α-Iminiumketon-Oximen

Cyclization of α-Iminium Ketone Oximes Reactions of α-aminoketones to the E/Z oximes and subsequent dehydrogenation to iminiumketoximes yield, depending on pH, the open chain derivatives, the cyclic nitrones or dihydrooxadiazines. Heating these with acetic acid/sodium acetate yields fused imidazoles.     

Zur Umsetzung von N-benzylsubstituierten Piperidoncarbonsäureestern mit Cer(IV)-sulfat

The Reaction of N-Benzyl-3-(methoxycarbonyl)-4-piperidones with Cerium(IV) Sulfate After oxidation reactions of N-benzyl-3-(methoxycarbonyl)-4-piperidones 1 with cerium(IV) sulfate the following heterocycles can be isolated: substituted hydrogenated 2,6-methano-2-benzazocin-5-ones 2 , 1,4,5,6-tetrahydro-3-(methoxycarbonyl)pyridin-4-ones 3 and 3-(methoxycarbonyl)pyridin-4-ones 4 . The structures of these compounds were determined by spectroscopic methods.     

Cer(IV)oxidationen von β-Aminoketonen. 5. Mitt. Synthese verschieden substituierter 5-Oxo-2,6-methano-2-benzazocine

Cerium(IV)sulfate Oxidations of β-Aminoketones. Part V: Synthesis of Various Substituted 5-Oxo-2,6-methano-2-benzazocines 5-Oxo-2,6-methano-2-benzazocines are obtained by oxidation of various substituted methyl N-benzyl-4-oxo-3-piperidine carboxylates 1a, c–g with cerium(IV)sulfate. The corresponding diester 1h leads to a dehydrogenated methanobenzazocine 5h , additionally. By-products of nearly all oxidations are the corresponding 1,4,5,6-tetrahydro-3-(methoxycarbonyl)-pyridin-4-ones 3 and 1,4-dihydro-3-(methoxycarbonyl)pyridin-4-ones 4 .     

Intramolekulare Aromatenalkylierungen, 12. Mitt.1) Synthese von 1-(3-Methylpyridin-2-ylmethyl)-1,2,3,4-tetrahydronaphthalinen

Intramolecular Alkylations of Aromatic Compounds, XII¹⁾: Synthesis of 1-(3-Methylpyridin-2-ylmethyl)-1,2,3,4-tetrahydronaphthalenes Treatment of tetrahydronaphthalenones 10 with 3-methyl-2-picolyllithium (9) yields the tetrahydronaphthalenols 11 , which can be converted into the title compounds 13 by dehydration and subsequent catalytic hydrogenation in a one-pot method. The hydrogenolysis of 11 fails to give 13 immediately. The structures of 11 and 13 were elucidated by ¹H-NMR spectroscopy.     

Cer(IV) Oxidationen, 10. Mitt.: Oxidation von ω-Phenylalkyldicarbonyl- und dicarbonyl-analogen Verbindungen

Cerium(IV) Oxidations, X: Oxidation of ω-Phenylalkyldicarbonyl- and Dicarbonyl-analogous Derivatives Oxidations of the ω-phenylalkylmalonate derivatives 1a-f afford cyclization products 2 as well as nitro-, alcohol and acetoxy compounds 3–7 . The distribution of products depends sensitively on the temp, and on the water content of the reaction medium and as well on the chemical nature of the carbonyl functions. Ce³⁺-ion formed during the reaction is responsible for the observed ring-opened side products.     

Intramolekulare Umsetzung von Iminiumverbindungen mit Carbonsäuren

Intramolecular Reactions of Iminium Compounds with Carboxylic Acids 5-Nitrobenzoic acids which are substituted at C-2 with cyclic amines are dehydrogenated with mercury EDTA. The piperidine and perhydroazepine derivatives yield tricyclic oxazinones with a small amount of decarboxylated product. The pyrrolidine compound reacts in unusual solvents only, mainly with loss of the carboxy group and to a small degree with dehydrogenation. Comparative experiments were made in order to explain these results.     

Einige N-funktionelle Derivate von N-(α-Tosylaminoacyl)-β-alaninen

Syntheses of dipeptidenitriles 1a-e starting from α-tosylaminoacidchlorides and β-aminopropionitrile and their conversion to the esters of dipeptide-imide acids 2a-d , esters of dipeptide acids 5a-d , to amides of dipeptide acids 6a-d and amidines of dipeptide acids 4a-e are described. Condensations of amidines of tosyldipeptide acids 3a, c with ethyl acetoacetate yield pyrimidines 7a, c .     

Zur Cyclisierung von α-(2-Mercapto- bzw. -2-Amino-benzoyl)-lactamen; Synthese von Benzothiopyrano [4,3-b]pyrrolinonen sowie von Pyrrolino- bzw. Tetrahydropyridino [3,2-c] chinolinonen1)

Cyclisation of α-(2-Mercaptobenzoyl)- and α-(2-Aminobenzoyl)lactames; Synthesis of Benzothiopyranopyrrolinones and Pyrrolinoquinolinones Compounds 8a, 8b, 8d, 8e and 8f are obtained by heating the mercaptobenzoyl- or methylaminobenzoyl-lactames 6a, 6b, 6d, 6e and 6f. With pyridine/HCI removal of the pyrroline N-methyl group takes place under formation of 8c and 8g. Cyclisation of the acyllactame 6i under the same conditions leads to the tetrahydropyridinoquinolinone 18. After hydrolysis of the acyllactames 6e, 6i or 6d the aminoalkyl(hydroxy)quinolinones or aminobenzoyl-γ-aminobutyric acid derivatives 11, 19 and 13 are isolated, which can be cyclized to 8e, 20 and 8d. The pyrroles 15a and 15b are formed by dehydrogenation of the pyrroline derivates 8b and 8e with DDQ.     

Über das Polymorphie-Verhalten von 7-(β-Hydroxypropyl)- und 7-(β,γ-Dihydroxypropyl)-theophyllin

On the Polymorphism of 7-(β-Hydroxypropyl)-and 7-(β,γ-Dihydroxypropyl)-theophylline The polymorphism of 7-(β-hydroxypropyl)- and 7-(β,γ-dihydroxypropyl)-theophylline was studied with differential scanning calorimetry and thermomicroscopy. Crystallization in vitreous supercooled melts yields polymorphic modifications. Their formation and transformation with time was studied.