A facile synthesis of 4-aryl-2H-1-benzopyran-2-ones

Reaction of 2-hydroxybenzophenones (1,3,7,8) with ethoxycarbonyl-methylenetriphenylphosphorane affords 4-aryl-2H-1-benzopyran-2-ones (2,4–6) in excellent yields.

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Eine einfache Synthese für 4-Aryl-2H-1-benzopyran-2-one

Zusammenfassung Die Reaktion der 2-Hydroxybenzophenone1,3,7 und8 mit Ethoxycarbonyl-methylentriphenylphosphoran ergab die 4-Aryl-2H-1-benzopyran-2-one2 und4–6 in ausgezeichneten Ausbeuten.

     

Aminoalkohole, 4. Mitt.: Ein Trennverfahren zur Herstellung von enantiomerenreinem Midodrin

Zusammenfassung Das früher präsentierte Verfahren zur Bestimmung der Enantiomerenreinheit von Aminoalkoholen über die N-BOC-O-MBE-Derivate kann auch zur präparativen Trennung von Midodrin eingesetzt werden. Bei Verwendung der N-((Phenylmethoxy)carbonyl)-Schutzgruppe kann die Entfernung der N-Schutzgruppe selektiv vor der Abspaltung der O-MBE-Gruppe erfolgen, so daß die Kontrolle der stereochemischen Einheitlichkeit der Produkte5 und6 sehr leicht möglich ist. Diese können ohne Racemisierung in die enantiomerenreinen MidodrinhydrochlorideR-1 undS-1 übergeführt werden.

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A separation procedure for the preparation of enantiomerically pure midodrine

Summary Racemic midodrine chlorohydrate (rac-1) was N-protected to yield the racemic productsrac-2a-c. These were converted into the diastereomeric O-acetals3a-c/4a-c, which can easily be separated by chromatography. After removal of the N- and O-protective groups from3a-b/4a-b, respectively, enantiomerically pure midodrine chlorohydrateR-1 andS-1 could be isolated.

Unserem verehrten Lehrer Herrn Prof.O. Hromatka gewidmet     

Insect growth regulators. XVI Syntheses of juvenoids with the 3,3-dimethylcyclohexane system

New cyclic juvenoids containing the 3,3-dimethylcyclohexane (esters16,18,22,26, and ethers28 a, b) or the 5,5-dimethyl-2-cyclohexene system (esters15,17,21,25, and ethers27 a,b) have been obtained by a several-step synthesis starting from dimedone (1). The compounds obtained exhibited morphogenetic activity against larvae ofDysdercus cingulatus and they were inactive on pupae ofTenebrio molitor.

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Insekten-Wachstumsregulatoren. XVI. Synthesen von Juvenoiden mit dem 3,3-Dimethylcyclohexan-System

Zusammenfassung Ausgehend von Dimedon (1) wurden in mehrstufigen Synthesen neue, cyclische Juvenoide hergestellt, die das 3,3-Dimethylcyclohexan- (Ester16,18,22,26 und Ether28 a, b) oder 5,5-Dimethyl-2-cyclohexen-System (Ester15,17,21,25 und Ether27 a, b) enthalten. Die erhaltenen Verbindungen zeigen morphogenetische Aktivität gegenüber Larven vonDysdercus cingulatus und sind inaktiv gegenüber Puppen vonTenebrio molitor.

     

Naturstoffchemie, 174. Mitt. [1]: Oxidation von Acronycin mit Kaliumpermanganat

Zusammenfassung Die Oxidation des Acridonalkaloids Acronycin (1) mit Kaliumpermanganat führt zu (1S-cis)-1,2,3,12-Tetrahydro-1,2-dihydroxy-6-methoxy-3,3,12-trimethyl-7-H-pyrano[2,3-c]acridin-7-on (2), 1-Hydroxy-6-methoxy-3,3,12-trimethyl-1H-pyrano[2,3-c]acridin-2,7(3H,12H)-dion (3) und 1-Hydroxy-6-methoxy-3,3,12-trimethyl-1-(2-oxopropyl)-1H-pyrano[2,3-c]acridin-2,7(3H,12H)-dion (4).

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Natural product chemistry, part. 174 [1]: Oxidation of acronycine by potassium permanganate

Summary Oxidation of the acridone alkaloid acronycine (1) by potassium permanganate results in oxidation of the cromenering to give (1S-cis)-1,2,3,12-tetrahydro-1,2-dihydroxy-6-methoxy-3,3,12-trimethyl-7H-pyrano[2,3-c]acridine-7-one (2), 1-hydroxy-6-methoxy-3,3,12-trimethyl-1H-pyrano-[2,3-c]acridine-2,7(3H,12H)-dione (3) and 1-hydroxy-6-methoxy-3,3,12-trimethyl-1-(2-oxopropyl)-1H-pyrano[2,3-c]acridine-2,7(3H,12H)-dione (4).

     

Synthesen und chemisches Reaktionsverhalten von neuen Azapseudophenalenonen,Azapseudophenaleniumsalzen und ihren Fulvenen sowie Fulvalenen

Alkylation of the aza-pseudophenalenone1 with trialkyloxoniumtetrafluoroborates yield the azapseudophenaleniumsalts2 a,2 b, reactions with C-nucleophiles the compounds3 a 3 e, the dihydro-azapseudophenalenone4 reacts with malodinitrile-sodium to5,1 b and1 d with tetrachlorocyclopentadiene to the fulvalenes6 a,6 b,1 b was olefinated withtert. butyl-cyano-ketene to theZ-isomer7.

Meinem lieben Kollegen und Freund, Herrn Prof. Dr.Werner Heimann, Karlsruhe, mit herzlichen Wünschen zum 70. Geburtstag gewidmet.     

Synthesen in der Isocamphanreihe, 38. Mitt.: Ozonolyse von 2-Acetyl-3,3-dimethylnorborn-5-en und Synthese eines neuen,tricyclischen Ketals mit patchouliartigem Geruch

Summary The ozonolysis ofendo-2-acetyl-3,3-dimethylbicyclo[2.2.1]hept-5-ene (endo-1) and itsexo-epimer (exo-1) is described. The reaction products, after reductive work up as well as after oxidative work up, are characterized. The first procedure furnished the corresponding cyclopentane derivatives in good yield, namely 1,1-dimethyl-2-(1-hydroxyethyl)-3,5-bis-hydroxymethyl cyclopentane (2) as a cristalline compound fromendo-1, the epimeric10 as an oil fromexo-1. The oxidative work up furnished in both cases via keto-enol-tautomerism the same acid, 4-acetyl-5,5-dimethyl-1,3-cyclopentane dicarboxylic acid, characterized as its methyl ester. Selective oxidation of the secondary hydroxyl group in2 lead to the novel, tricyclic, even acid stable ketal17, with very interesting olfactory properties.

Herrn Prof. Dr. Ulrich Schmidt mit den besten Wünschen zum 70. Geburtstag gewidmet     

Cyclisierungsreaktionen von Diazoalkenyl-phosphonsäureestern Synthese von Pyrazolyl- und 2,3-Benzodiazepinylphosphonsäureestern

Tosylhydrazones3 and4 of dialkyl 3-oxo-1-alkenylphosphonates1 and 1-oxo-2-alkenylphosphonates2, respectively, react with aqueous sodium carbonate to give the pyrazoles7 in excellent yields. Under analogous conditions the tosylhydrazone9 of diethylo-vinylbenzoyl phosphonate (8) affords diethyl 2-hydroxy-1-indanyl phosphonate (10). Upon thermolysis of the sodium salt12 generated from9 in anhydrousD M E, one obtains, depending on the reaction conditions, either the 1-H-benzodiazepinyl derivative14 or its 5H-isomer15. At room temperature the diazo compound13 cyclizes slowly to give14, which can be isomerized to15 by action of base.

     

Cycloaddition reactions of 1-tert-butyl-4-vinylpyrazole

Summary 1-tert-Butyl-4-vinylpyrazole1 a reacts with dimethyl acetylenedicarboxylate (DMAD), methyl propiolate (MP) and N-phenylmaleimide (NPMI) affording the indazole derivatives2,3, and5 as a result of a Diels-Alder ([4 + 2]) cycloaddition. With diethylazodicarboxylate (DEAZD), tetracyanoethylene (TCNE) and 4-phenyl-1,2,4-triazole-3,5-dione (PTAD) the reaction takes place exclusively through the olefinic substituent and the adducts6,7, and9 were isolated. The alkenylpyrazoles1 b–d reacted withDMAD and N-phenylmaleimide to give polymers.

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Cycloadditionen von 1-tert-Butyl-4-vinylpyrazol

Zusammenfassung 1-tert-Butyl-4-vinylpyrazol1 a reagiert mit Acetylendicarbonsäure-dimethylester (DMAD), Propiolsäuremethylester (MP) und N-Phenylmaleimid (NPMI) zu den entsprechenden Indazolderivaten2,3 bzw.5, als Ergebnis einer Diels-Alder-([4+2])-Cycloaddition. Bei der Reaktion mit Azodicarbonsäure-diethylester (DEAZD), Tetracyanethylen (TCNE) und 4-Phenyl-1,2,4-triazol-3,5-dion (PTAD) wird exklusiv die Olefingruppe von1 a angegriffen, wobei die Addukte6,7 bzw.8 isoliert werden. Die Alkenylpyrazole1 b–d reagieren mitDMAD und N-Phenylmaleimid unter Bildung von Polymeren.

     

Untersuchungen über Chinone, 10. Mitt. Zur Reaktion vonp-Benzochinon mit sekundären aliphatischen Aminen

Summary p-Benzoquinone (1) reacts with dialkylamines2a-d to 2-dialkylamino-p-benzoquinones3, 2,5-bis-dialkylamino-p-benzoquinones4, 2-dialkylamino-8-hydroxydibenzofuran-1,4-quinones5, and in pyridine also to 2-dialkylamino-5-p-hydroxy-phenoxy-p-benzoquinones6. A method affording almost exclusively3 has been developed which is also applicable to compounds2e-h.

     

4-Phosphoranylidene-5(4H)-oxazolones — A novel synthesis and properties

Summary 4-Phosphoranylidene-5(4H)-oxazolones (2), a hardly known class of phosphorus ylides, were readily prepared from 4-unsubstituted-5-(4H)-oxazolones (1) by treatment with Ph₃P-Br₂, Bu₃P-Br₂, Ph₃P-CCl₄, or Ph₃P-CBr₄ adducts in the presence of triethylamine in CH₂Cl₂ at room temperature in a novel, efficient one-pot procedure. The spectroscopic properties of the ylides are reported and discussed.

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4-Phosphoranyliden-5(4H)-oxazolone — Eine neue Synthese und Eigenschaften

Zusammenfassung 4-Phosphoranyliden-5(4H)-oxazolone, eine sehr wenig bekannte Gruppe der Phosphor-ylide, wurden auf einfache Weise nach einem neuen Eintopfverfahren mit guten Ausbeuten hergestellt. Als Ausgangsverbindungen wurden 4-unsubtituierte-5-(4H)-Oxazolone (1) eingesetzt, die unter der Einwirkung von Addukten wie Ph₃P-Br₂, Bu₃P-Br₂, Ph₃P-CCl₄ oder Ph₃P-CBr₄ in Anwesenheit von Triethylamin in CH₂Cl₂ bei Zimmertemperatur die Titelverbindungen liefern. Die spektroskopischen Eigenschaften der Ylide werden berichtet und diskutiert.

     

Synthese von 3,3a-Dihydro-2H,5H-azeto[2,1-b]benzo[d]-1,3-oxazin-2,5-dionen,I

The thioformimidates4, which may be obtained by S-alkylation of the thioformamides3, react with chloroacetylchloride/triethylamine to yield the (3R, 4S/3S, 4R)-3-chloro-4-methylthio-2-azetidinones5. Dehalogenation of5 leads to6, which undergoes ring closure by the action of mercuric oxide. Treatment of8, which may be synthesized by chlorolysis of7, with triethylamine gives also the title compounds9.

     

[a]-Anellated carbazoles with antitumor activity: Synthesis and cytotoxicity

Summary The cycloadducts3,5, and7, readily available from methoxy-substituted 3-vinylindoles1 and2, were dehydrogenated withDDQ to the coplanar [a]-anellated carbazoles4,6, and8. Compound4a, also characterized by X-ray structural analysis, shows significant cytotoxicity against K562 und RXF393 human tumor cell lines.

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[a]-Anellierte Carbazole mit Antitumoraktivität: Synthese und Cytotoxizität

Zusammenfassung Die aus den methoxysubstituierten 3-Vinylindolen1 und2 zugänglichen Cycloaddukte3,5 und7 lassen sich mitDDQ zu den coplanar-anellierten Carbazolen4,6 und8 dehydrieren. Verbindung4a, die auch durch eine Röntenstrukturanalyse charakterisiert wurde, zeigt signifikante Cytotoxizität gegen Humantumor-Zellinien (K562 und RXF93).

     

Synthesen von Heterocyclen, 147. Mitt.: Chinolizine und Indolizine VII: Zur Synthese eines Benzindolizino-indigofarbstoffes

Zusammenfassung Durch saure Hydrolyse des Tetrahydrochinolin-8-glyoxalacetals7, welches in dreistufiger Reaktion aus dem Benzchinolizinon1 zugänglich ist, erhält man neben dem Benzindolizino-indigo8 den Indirubinfarbstoff9 sowie das Isatin-10 und das Dioxindolderivat11.

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Syntheses of heterocycles, CXLVII: Quinolizines and indolizines VII: The synthesis of a benzindolizino-indigo

Acid catalized hydrolysis of tetrahydroquinoline-8=glyoxalacetal7, obtained by a three step synthesis starting with the benzoquinolizinone1, yields not only the benzindolizino-indigo8, but also the indirubin dye9, the isatin derivative10, and the dioxindole derivative11.

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Mit 1 Abbildung

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Herrn Prof. Dr.R. Tschesche, Bonn, zum 65. Geburtstag gewidmet.     

Synthesen von Heterocyclen, 146. Mitt.: Zur Synthese polymerer Indigofarbstoffe mit potentiellen Halbleitereigenschaften

Zusammenfassung Die Darstellung von polymeren Indigofarbstoffen (PI) nach dem Verfahren vonZiegler undKappe ^{2, 3} wird beschrieben. Ausgehend von Benzidin (1 a) und Tolidin (1 b) erhält man so diePI 6 a bzw.6 b. In analoger Weise wird aus Tetrahydrochinoxalin (7), der N,N-überbrücktePI 12 gewonnen.

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Syntheses of heterocycles, CXLVI: The synthesis of polymeric indigos with potential semiconductor properties

The synthesis of polymeric indigos (PI) according to the procedure ofZiegler andKappe ^{2, 3} is described. Starting with benzidine (1 a) or tolidine (1 b) thePI 6 a and6 b, resp., are obtained. In a similar way the N,N-bridgedPI 12 is synthesized from tetrahydroquinoxaline (7).

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Aus den Dissertationen vonH. G. Foraita undL. F. Werner, Universität Graz, Januar bzw. Juni 1963.     

Synthesis in the isocamphane series,XVI. The regioselectivity of some lewis acids in the catalyzed Diels-Alder-reaction of cyclopentadiene and mesityloxide

Zusammenfassung The regioselectivity of 9Lewis acids in the catalyzedDiels-Alder-reaction of cyclopentadiene and mesityloxide is described and theendo: exo-ratio of1 a and1 b determined by quantitative HPLC- and¹H-NMR-measurements. The reaction mixture of1 a+1 b normally contains more of theendo epimer1 a, e.g. 31 for1 a1 b, and is therefore in agreement with theendo rule, only TiCl₄ favors theexo epimer1 b.

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Synthesis in the isocamphane series, XVI. The regioselectivity of some lewis acids in the catalyzed Diels-Alder-reaction of cyclopentadiene and mesityloxideShort communication

Teil der Diplomarbeit vonHuber, U., Universität Wien, 1980.     

Eine Synthese für Cyclopropandiyl-bis-(isopropylidenmalonate)

Reaction of HexahydroazepinobicycloalkylMeldrum's acid7 Ba-7 Bd or PiperidinocyclopropylMeldrum's acid7 Ce withMeldrum's acid (1) generates cyclopropanes possessing two isopropylidene malonate moieties. In the solid state the bicyclic derivatives were found to be dienolic compounds11 a-11 d, whereas the monocyclic system has the tetracarbonyl structure10e. 7a-7d, the starting materials for the synthesis of11 a-11 d, were obtained from1 and O,N-acetal4B or aminal6B.

     

Zum Mechanismus der Reduktion von 1,3-Benzodithiol-2-thionen

Carbophilic reaction of 1,3-benzodithiole-2-thione (1) with trideuteroborane · dimethylsulfide, synthesized from NaBD₄ and BF₃ ·Me ₂S inTHF, gave 2,2-dideutero-1,3-benzodithiole (5 b) as well as the minor side-products7 b,8 and9 b.

     

Zum Schwingungsverhalten pentakoordinierter Zinn(IV)-organischer Verbindungen. IR- und Raman-Untersuchungen an 2,8,9-Tricarbastannatranen

Summary Results are reported of IR and Raman investigations on four 1-substituted 2,8,9-tricarbastannatranes (1,X=Cl;2,X=Br;3,X=I;4,X=Me). Group-theoretic investigations confirm the trigonal-bipyramidal configuration of the tin atoms. The vibrational frequencies of the coordination (SnN) are correlated to the distancesd (Sn-N). Besides the results on the vibrations of the coordination polyhedrons other results are reported concerning the enantiomerization of the chiral atran skeleton.

     

Methoden zur Darstellung von 4-Azido-2(1H)-chinolonen

4-Hydroxy-2-quinolones1 are generally found to be converted to the 4-azidocompounds3 via the 4-chloroquinolones2, the 4-tosyloxyquinolones6, or the 4-aminoquinolones4, respectively. Choice of the reaction conditions and yields depend on the substituent in position 3 of the quinoline nucleus. For comparison the O-analogous coumarin derivatives9 have been studied to give the 4-azidoderivatives11 via the 4-chlorocoumarins10.

     

Über die Struktur der Acrylnitril-Guanidin-Kondensate Über Heterocyclen, 78. Mitt.

Repetition of the work ofSugino andTamaka ¹ showed that acrylonitrile and guanidine react inDMF to yield not only 3,4,6,7-tetrahydro-2H-pyrimido[1,2—a]pyrimidine-2,8(1H)-diimine (1), but a mixture (F) of1 (as a main product) and 2-amino-4-imino-1,4,5,6-tetrahydropyrimidine-1-propionitrile (7) besides one or two bases not identified so far.1 and7 were isolated as picrates. For the prove of their structures,1- and7-picrate were also prepared by an unequivocal synthesis starting from iminodipropionitrile hydrochloride8 · HCl: The latter on reaction with cyanamide gave9 which cyclized to afford a mixture of1,7 and 2-amino-4-oxo-1,4,5,6-tetrahydropyrimidine-1-propionitrile (10). The picrates of1 and7 were identical with those prepared from the acrylonitrileguanidine-condensateF. This result supports the prior proposed¹ structures of pyrimidopyrimidine1 and of4,5 and6, obtained by hydrolysis of1. Nmr-, ir-and some of the mass spectra of1,4,7–10 (and their salts) are reported.