Cyclopenta[c]pyridine aus Baldrinal und Homobaldrinal durch Reaktion mit primären Aminen

Cyclopenta[c]pyridines from Baldrinal and Homobaldrinal by Reaction with Primary Amines Baldrinal and Homobaldrinal ( 1a–b ) are readily converted into cyclopenta[c]pyridines 7 by treatment with primary amines. In addition, oxidation of the side chain at C-4 is observed yielding the carbaldehyde. Reactions with biogenic amines such as tyramine and histamine lead to the corresponding pseudoazulenes 8 and 9 .     

Unabhängige Synthese von 2H-Thiopyran-2-yliden-thioketonen

Independent Synthesis of 2H-Thiopyrane-2-ylidene-thioketones Diels-Alder reaction of 1-phenylisoprene (3) with thiophosgene (4) or methyl cyanodithioformate (7) leads to the 3,5-disubstituted thiopyranes 5 and 8 , rather than to the 4,6-disubstituted compounds. The α-pyrones 9 react with Lawesson reagent to give the pyrane-2-thiones 10. Rearrangement of 10 with NaSH yields the thiopyrane-2-ones 11 , which are once again sulfurised with Lawesson reagent to form 12. After alkylation of 12 with phenacyl bromide the pyrylium bromides 13 can be isolated. These lose sulfur on heating in pyridine and can be transformed to the 2H-thiopyrane-2-ylidene thioketones 2 with Lawesson reagent. Compound 2a is identical with the main isomer obtained by heating 3-methyl-5-phenyl-1,2-dithiolium perchlorate in pyridine/glacial acetic acid according to the literature.     

Unabhängige Darstellung und Hydrolyse des Nifedipin-Nebenmetaboliten

Independent Synthesis and Hydrolysis of the Side Metabolite from Nifedipine The hydrolysis of the title compound, obtained by Boekelheide rearrangement of the N-oxide 1b , is investigated.     

Olefine der Cholanreihe aus Desoxycholsäure und Cholsäure

Olefins of the Cholane Series from Deoxycholic and Cholic Acids On partial dehydration deoxycholic acid yielded two new olefins. By the same procedure five new olefins were obtained from cholic acid.     

Über Mannichbasen, 19. Mitt. Mannich-Reaktionen mit 1-Naphthol und primären Aminen

Mannich Bases, XIX: Mannich Reactions with 1-Naphthol and Primary Amines Under conventional Mannich conditions primary amines rarely react with 1-naphthol to yield uniform products. The hydrochlorides partly give methylene linked derivatives. However, mono- and disubstituted Mannich bases are formed from azomethines of tert.-alkylamines. Hexahydrotriazines of simple primary amines yield mono-Mannich bases in good yields.     

Das chemische Verhalten o-rhodanierter Phenylisothiocyanate bei der Umsetzung mit Ammoniak und primären Aminen 37. Mitt.: Über organische Rhodanverbindungen

The Reaction of o-rhodanated Phenylisothiocyanates with Ammonia and Primary Amines o-Rhodanated phenylisothiocyanates give with ammonia 2-aminobenzoic thiazole and ammonium thiocyanate; with primary amines 2-aminobenzoic thiazole as well as the corresponding isothiocyanates and their thioureas.     

β-Substituierte Enamine, 11. Mitt. Kondensationsprodukte aus γ-Chloracetessigester und primären aromatischen oder heteroaromatischen Aminen

β-Substituted Enamines, XI. Condensation Products from Reactions of γ-Chloroacetoacetic Ester with Primary Aromatic and Heteroaromatic Amines γ-Chloroacetoacetic ester ( 1a ) reacts with aniline via an α-(chloromethyl)enamine 2a to yield 4-anilino-5H-furan-2-one ( 4 ). It undergoes condensation reactions with heterocycles having primary aminogroups in position 2, e. g. 2-aminopyridine ( 6 ). 2-aminothiazole ( 9 ), 2-aminobenzimidazole ( 10 ), 2-aminobenzothiazole ( 11 ). Products are the fused chloromethylpyrimidones 8, 12, 13 and 14 .     

Zur Thermolyse von Mannich-Basen aus β-Ketosulfoxiden,Benzaldehyd und sekundären Aminen

Thermolysis of Mannich Bases from β-Ketosulfoxides, Benzaldehyde and Secondary Amines By condensation of ω-(methylsulfinyl)acetophenone (1) with benzaldehyde and secondary amines stable Mannich bases 2 are obtained as mixtures of four diastereomeric forms according to the presence of three chiral centers. Amine elimination above 180°C leads to a single E-diastereomer of 2-methylsulfinyl-1,3-diphenylpropenone (3) as indicated by the ¹H and ¹³C-NMR spectra.     

Benzhydroxamsäuren aus Nifedipin und der korrespondierenden 1,2-Dihydropyridin-Verbindung

Benzohydroxamic Acids from Nifedipine and the Corresponding 1,2-Di-hydropyridine Compound The nitro compounds 1 and 2 have been reduced to the phenylhydroxylamines 3 and 4 and transformed into the benzhydroxamic acids 5 and 6 . From the reduction of the 1,2-dihydropyridine 2 the 2,6-methano-1,5-benzodiazocine 10 could be isolated as a by-product. All dihydropyridines are characterized by their half-wave potentials, their retention times obtained by hplc and spectrometric methods.     

Furane und Thiophene aus Etacrynsäure

Furans and Thiophenes from Etacrynic Acid . The 1,4-dicarbonyl- and 1,4,7-tricarbonyl compounds 1 react with polyphosphoric acid (PPA) to yield the furans 3 ; with P₄S₁₀ the thiophenes 4 are obtained. The γ-keto carboxylic acid 2 cyclizes with PPA to form the α,β-unsaturated butyrolactone 6. 2 is reduced by NaBH₄ chemo- and diastereoselectively to give the γ-hydroxy carboxylic acid 5 . The lactone 7 is prepared by dehydration of 5 with PPA. The sulfones 8a,b are obtained from the thiophenes 4a,b by oxidation with magnesium monoperoxyphthalate (MMPP). Under the same conditions the furan 3b is cleaved to yield the enedione 9 , which tautomerizes slowly forming 10 .     

1,2,4-Benzodithiazine-Reaktionsprodukte aus o-rhodanierten Arylisothiocyanaten und sekundären Aminen 38. Mitt.: Über organische Rhodanverbindungen

1,2,4-Benzodithiazines - Reaction Products from o-rhodanated Arylisothiocyanates and secondary Amines The synthesis of substituted 1.2.4-benzodithiazines is reported. These new heterocyclic compounds can be transferred under elimination of sulphur into the corresponding benzthiazoles.     

Eine dreistufige Synthese der δ-Aminolaevulinsäure

A Three-Step Synthesis of δ-Aminolaevulinic Acid Piperidine-2,5-dione (4) is prepared by catalytic hydrogenation of 5-hydroxy-2-pyridone (3) . Ring opening of the lactam 4 with concentrated hydrochloric acid yields the hydrochloride of δ-aminolaevulinic acid (2) .     

Eichungsfreie (struktur-unabhängige) Photometrie von Aminen und Amin-Hydrochloriden durch Indikator-Deprotonierung und Ionenpaar-Metathese1)

Calibration-Free (Structure-Independent) Photometry of Amines and Amine Hydrochlorides by Deprotonation of an Indicator Acid Combined with Ion Pair Metathesis¹⁾ Quantitative protonation of amines by a large excess of (in methylene chloride) colourless bromthymol blue (BTB) combined with an in situ ion pair metathesis induced by a large excess of N-butylscopolamine bromide generates an equivalent amount of the butylscopolamine salt of BTB. This technique allows a simple and reliable determination by photometry of amines using the standard absorption parameters λ_max = 412 nm and ? = 18620. Arylamines are not determined quantitatively. Amine hydrochlorides can be analyzed in the same manner if their solutions in methylene chloride are shaken with yellow mercury(II) oxide prior to mixing with the combined BTB -butylscopolamine bromide reagent.     

Zur Synthese der 5-Hydroxy-2,4-dimethyl-1-hexen-1,5-dicarbonsäure (Nemorensinsäure)

The Synthesis of 5-Hydroxy-2,4-dimethyl-1-hexene-1,5-dicarboxylic Acid (Nemorensic Acid) The synthesis of nemorensic acid in the open-chain form, i.e. of 5-hydroxy-2,4-dimethyl–1-hexene-1,5-dicarboxylic acid is described.     

Natürliche und synthetische Derivate der Carnosolsäure

Natural and Synthetic Compounds of Carnosic Acid In the leaves of Rosemary and Save two new derivatives of Carnosic acid are found; the 7β-methylether of the γ-lacton and after methylation of the resin the 7α-methylether of the same lacton with methylated phenolic groups. To the 7-hydroxy-lacton of the same compund, isolated by Wenkert, Fuchs and McChesney, is attributed a 7β-equatorial conformation of the hydroxylgroup. The phenolic group of Carnosol and Thymol, neighboured to the isopropylgroup of these compounds, can only be methylated with dimethylsulfate, not, however, with diazomethane.     

Über ein Polymerisationsprodukt aus Cyclohexa-1,3-dien und Dichloressigsäure

A Polymer of Cyclohexa-1,3-diene and Dichloroacetic Acid Cyclohexa-1,3-diene and dichloroacetic acid react to a polymer. It is formed from 17 molecules of the diene and one molecule of dichloroacetic acid, which is bound as ester.     

1,2-Dihydro-4-chinazolinone aus Anthranilamiden und Oxoverbindungen – Untersuchungen zum Reaktionsverlauf der Ringschlußreaktion

1,2-Dihydro-4-quinazolinones from Anthranilic Amides and Oxocompounds – Studies of the Ring Closure Using MNDO Calculations Heating of anthranilic amides 1a-c with oxo-compounds without solvent represents a simple synthetic access to 1,2-dihydro-4-quinazolinones 8–25 . Under drastic conditions β-dicarbonyl compounds give the methylquinazolinones 26/27 by elimination. Thermodynamic control explicates the course of the reactions and the formation of the products. The enaminones 28/29 isolated from cyclic β-diketones are transformed to quinazolinyl pentanones 34/35 in the presence of acetic acid. The ring transformation is explained by perturbation theory.