Kathodische Reduktion von Säureaziden Elektrolytische Untersuchungen an Vinylaziden, 8. Mitt.

The cathodic reduction of the O=C-N₃-system in aprotic solvent in the presence of anhydrides proves to be a convenient way to triacylammonia derivatives. Using the complexation of Li⁺ ions with the acid azide this synthetic methods can start from non-dangerous acid halides.The complex formation constant has been estimated and the chemical stability of N,N-diacylamides produced has been investigated. Mechanistic details about the role of Li⁺-ions in these electrolyses are given. Further reduction of the triacylammonia derivatives at more negative potentials results in protected aldehydic functions, i.e. 1-acyloxy-1-diacylaminomethanes, in good yields.

     

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.

     

Heterocyclensynthesen mit 5-Phenyl-isoxazoliumsalzen, 3. Mitt.: Synthese von Pyrrolo[1,2-a]chinazolin-5-onen

Refluxing of ethanol-acetic acid solutions of N-aroyl-N-methyl-benzoylacetamides3 causes elimination of acetophenone and generation of N(1)-substituted N(3)-methyl-1H,3H-quinazoline-2,4-diones5. In contrast, at room temperature in acetanhydride3 eliminate water yielding 2-benzoylmethylene-quinazolinones4, which at 60 °C cyclize to pyrrolo[1,2-a] quinazolin-5-ones6. The transformation4 6 may be explained in terms of a normalKnorr reaction. A anomalousKnorr reaction was observed in the case of the more rigid4 d leading to a mixture of diasteromere7 d cis and7 d trans in kinetically controlled reaction. Favoured by intramolecular hydrogen bonding7 d cis converts to the thermodynamically more stable6 d by warming of the ethanolic solution for 3 hours.

     

Zur Reaktion von 4-Alkylaminodihydro-2(1H)-pyridinthionen bzw. -onen mit Ethylmalonsäure-bis-trichlorphenylester

4-Alkylamino-2(1H)-pyridinethiones (1) react with bis-trichlorphenylethylmalonate (3) to give four isomeric products: 5-thioxo-1,6-naphthyridine-2(1H)-ones (4), 7,7-dimethyl-4H-thiopyrano[2,3-b]pyridine-4-ones (6), 2,2-dimethyl-2H-thiopyrano[2,3-b]pyridine-5,7-dioles (7) and 2,2-dimethyl-2H-thiopyrano[2,3-b]pyridine-5(3H)-ones (8). On treatment with alkali the thioxogroup of4 is hydrolyzed and 1,6-naphthyridinediones (5) are formed. Compound5 can also be synthesized by heating the alkylaminopyridones (2) together with3.6 can be hydrolyzed to 2-thioxo-3-pyridylpropylketones (12). On treatment with diluted alkali or conc. acid the aminogroup of7 and8 is hydrolyzed and10 is formed. By heating in 20% NaOH10 is transformed to the dihydroxymercapto-3-pyridylmethylketone (11).

Herrn Prof. Dr.Erich Ziegler mit den besten Wünschen zum 70. Geburtstag gewidmet.     

Formation of bicyclic adducts in the reactions of fluorinated 2,4-cyclohexadien-1-ones with 2-carboxyhenzenediazonium

Benzyne generated during the decomposition of 2-carboxybenzenediazonium interacts with 6-chloro-2,3,4,5,6-pentafluoro-2,4-cyclohexadien-1-one, 6-chloro-2,4,5,6-tetrafluoro-3-methoxy-2,4-cyclohexadien-1-one, 6-chloro-2,4,5,6-tetrafluoro-3-(pentafluorophenoxy)-2,4-cyclohexadien-1-one, and perfluoro-6-phenoxy-2,4-cyclohexadien-1-one to form [4+2]-cycloaddition products. The latter are easily converted to 1-naphthylacetic acid derivatives by the action of O- and N-nucleophiles.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1634–1637, September, 1994.This work was carried out with the financial support of the International Science Foundation (Project No. Ch₂-6713-0925).     

Chinazolincarbonsäuren, 10. Mitt. Synthese von 1-Methyl-2,4-dioxo-chinazolin-3-yl-essigsäure, 2,4-Dioxo-chinazolin-1-yl-essigsäuren, 2,4-Dioxo-1,3-chinazolindiessigsäuren und deren Estern

2,4-Dioxo-quinazolin-1-yl-acetic acid esters (2) were prepared by the reaction of either 3,1-benzoxazine-2,4-diones (1) with urea in the melt or in solution or of the substituted anthranilic acid ester4 with potassium cyanate in acid solution. The anthranilamides5 with trichloromethyl chloroformate (diphosgene) gave also2. Alkaline hydrolysis of2 affords the 2,4-dioxo-quinazolin-1-yl-acetic acids (3), which were independently obtained by the sequence5 6 7. 2,4-Dioxo-1,3-quinazolinediacetic acids (11) were synthesized from1 and glycine ester. Reaction of8 with ethyl chloroformate gave9 and treatment of the latter with KOH furnished the potassium salt10, which was converted to11 by acids.Quinazoline-2,4-dione (12) with ethyl bromoacetate yielded13 and with chloroacetonitrile14. 13 was hydrolyzed to11. 14 could not be converted into11.1-Methyl-3,1-benzoxazine-2,4-dione (15) was transformed under similar conditions into 1-methyl-2,4-dioxo-quinazolin-3-yl-acetic acid (16).

     

Zur Umsetzung von 8a-Methoxy-3,4-dihydro-2H-1,4-benzoxazin-6(8aH)-onen mit Diazoalkanen, 2. Mitt.

Summary 8a-Methoxy-3,4-dihydro-2H-1,4-benzoxazin-6(8aH)-ones2 undergo regio- and stereospecific 1,3-dipolar cycloaddition reactions with diazomethane or diazoethane to yield 3,4,6a,9,9a,9b-hexahydro-pyrazolo[3,4-h][1,4]benzoxazin-6(2H)-ones3, which slowly isomerize in solution to give the 3,4,8,9,9a,9b-hexahydro-pyrazolo[3,4-h][1,4]benzoxazin-6(2H)-ones5. The carbon of the diazoalkane dipole is attached to carbon C-8 of the benzoxazinone. The structures of the obtained products were determined by¹H- and¹³C-NMR spectroscopy. An X-ray crystal structure analysis of3 a was carried out at room temperature:C₁₁H₁₅N₃O₃,M _r =237.26, orthorhombic, Pc2₁n,a=9.173 (5),b=9.133 (4),c=13.281 (6),V=1112.6 (9) ų,Z=4,d _x =1.416 g/cm^–3, =0.93 cm^–1,R=4.33%,R _w =3.95% (919 observations, 168 parameters).

Herrn Prof. Dr. W. Fleischhacker zum 60. Geburtstag gewidmet     

Aromatische Spirane, 20. Mitt.: Darstellung von dimethylsubstituierten 2-Carboxymethyl-indan-1-onen und Benzylchloriden als Synthone für Synthesen von di- bis tetramethylierten 2,2′-Spirobiindandionen

Summary The isomeric dimethyl methylbenzoates5, obtained from the bromidesvia Grignard reactions with dimethylcarbonate, were reduced with LiAlH₄ to the hydroxymethyl derivatives6. The latter were then transformed both to the benzylchlorides7 (with SOCl₂) and to the aldehydes8 (with pyridinium chlorochromate).Knoevenagel-Doebner reaction of8 afforded the acrylic acids9 which (after hydrogenation to11) were cyclized to the desired indanones12 with polyphosphoric acid. On the other hand,12c and12e were prepared from dimethyl 3-chloropropiophenone (14) by warming with sulfuric acid. After NaH-catalyzed reaction with dimethylcarbonate, the indanones12 gave the ketoesters15 which then could be hydrogenated to the indanes16. All reactions proceeded with satisfactory to excellent yields (60–90%).

     

Reaktivität der Pyrrolpigmente, 2. Mitt.: Deprotonierung von 3-Pyrrolin-2-onen

Deprotonation of 3,4-dimethyl-3-pyrrolin-2-on (1) int-butyl alcohol/potassiumt-butoxide solutions takes place on the N atom, as shown by¹H/²H exchange andpK _a determinations of1 (pK=17.1), 1,3,4-trimethyl-3-pyrrolin-2-one (pK _a =17.6), and 3,4-dimethyl-5-methoxy-2_H-pyrrole (pK _a =16.7). The SCF-MO approximation MINDO/3 indicates, however, that in the gas phase deprotonation of1 should occur at the C atom.

1.Mitt.:Ribó, J. M., Trull, F., Mh. Chem.110, 201 (1979).     

Cathodic synthesis of 2-amino-2-propene-1-ones electrolytical studies on vinylazides,VII

The cathodic preparation of enamino ketones from enazidoketones has been generalised to include heteroaromatic and aliphatic derivatives. Mechanistically the role of different sites of protonation, either on N¹ of the N₃-group or on carbonyl depending on electrolysis potential and acid strength, apparent by product distribution, is clarified. Aldehydic groups are preferentially reduced compared to the vinylazide part. Purely aliphatic azidoketones yield conjugated dienes under reductive acetylation, which might be useful for cycloaddition reactions.Die kathodische Synthese von Enaminoketonen aus ungesättigten Azidoketonen wurde auf heteroaromatisch substituierte und auf rein aliphatische Derivate übertragen. Zum Reduktionsmechanismus wurde der Einfluß verschiedener Stellen der Protonierung (am N¹ der N₃-Gruppe bzw. an der Carbonylgruppe), abhängig von Potential und Säurestärke, untersucht. Aldehydische Gruppen als weitere funktionelle Gruppen im Enazid werden leichter als die Vinylazide reduziert. Die rein aliphatischen Enazidoketone ergeben bei reduktiver Acylierung konjugierte Diene.

---

Elektrolytische Untersuchungen an Vinylaziden, 7. Mitt.: Kathodische Synthese von 2-Amino-2-propen-1-onen

     

Zur Chemie der 4-Amino-thiazolin-2-thione, 2. Mitt.

Summary 6-Amino-thiazolo[4,5-c]isothiazole derivatives4 are obtained by addition of hydrogen sulfide to the 4-Amino-thiazoline-5-carbonitrile2 followed by cyclooxidation of the intermediate thioamides3. In the presence of sodium sulfite the hydrolysis of the4-amino-2-methylthio-thiazolium salts5 derived from the title compounds1 yields the4-amino-thiazolin-2-ones6. By their further hydrolysis the 2,4-dioxo-thiazolidin-5-carboxamides8 are formed. The 2-oxo-and 2-thioxo-thiazolo [4,5-d]pyrimidin-7-ones and -thiones available from1 undergo ring opening by hydrolysis to give the substituted 4-amino-6-oxo- and 4-amino-6-thioxo-pyrimidine-5-thiols15a–h and13i–e. They have been isolated as their disulfides14 or 5-alkyl derivativesi.e. the substituted 4-amino-5-alkylthiopyrimidin-6-ones and -thiones16. In analogy, the intermediate 6-amino-7-oxo-thiazolo[4,5-d] pyrimidin-2-thione18 and the 7-amino-thiazolo[4,5-d]-pyrimidin-2-thione24 derived from1 react by ring cleveage to yield the 1,4-and 4,6-diamino-pyrimidin-5-thiole derivatives22 and27, respectively, isolated as their disulfides or alkylthio-derivatives. From the pyrimidine16b the pyrimido[5,4-b]1,4-thiazine derivative18 can be obtained.

     

Synthese von benzanellierten Carbacephamen, 1. Mitt.

Summary The direct intramolecular acylation and alkylation of the phenylsulfonylmethyl-group in the -lactames5a and7 are not successful. The postulated intermediate8 of the acylating reaction could be quenched with trimethylchlorosilane as the stable silylketale10. Desulfonation and desilylation of10 leads to the title compound12. The reaction of7 with base does not result in a carbacephame. Instead, the benzo[b]-azepinones15c,d have been obtained.

     

Aromatische Spirane, 17. Mitt.: Darstellung von anellierten und substituierten 2,2′-Spirobiindan-1-onen und 4,5′-disubstituierten 2,2′-Spirobiindanen

Summary The spiroketones9, 16, and28 were prepared by cyclisation of the carboxylic acids7c, 13b, and25c and their acid chlorides, resp. (7d, 13c, and25d) with polyphosphoric acid (PPA) or SnCl₄. The precursors of the latter compounds were synthesized by alkylation of the appropriate -ketoester1 or2 with the benzylchlorides3 or4 with NaH inDMF. Subsequent hydrogenation with Pd/C led to the desired alkylated indane-esters. The chiral compounds11, 17, and31 were obtained by Friedel-Crafts acetylation. The chiral disubstituted 2,2-Spirobiindanes22 and36 were prepared from the ketones20 and32/33 by catalytic reduction followed by Friedel-Crafts acetylation.

     

Synthesis of two new families of fluorinated compounds: 1H,1H,2H,2H-perfluoro-3,5-alkyldiynols and 1H,1H-perfluoro-2,4-alkyldiynols and their acrylates and methacrylates

The synthesis of two new families of compounds, 1H,1H,2H,2H-perfluoro-3,5-alkyldiynols and 1H,1H-perfluoro-2,4-alkyldiynols, and their acrylates and methacrylates, precursors of polymeric systems with important physical properties, is described.     

Über Reaktionen mit Betain, 24. Mitt.: Über Umsetzungen von Trimethylammoniumessigsäurebetain mit reaktiven Halogenverbindungen

Summary Diethyl bromomalonate and bromoacetonitrile, respectively, react with trimethylammonium acetic acid betaine in ethanol to give diethyl tartronate and glycolic acid nitrile, respectively. By analogy, ethyl -chloroacetonate and ethyl bromopyruvate yield the respective hydroxy derivatives which were identified by their osazones2 and3. Under the same experimental conditions, mesoxalic acid and its dimethyl ester, respectively, are formed from dibromo malonic acid and its dimethyl ester and were characterized by their known hydrazones8 and9.

Herrn o. Prof. Mag. pharm. Dr. H. Junek, Karl-Franzens-Universität Graz, zur Vollendung des 60. Lebensjahres mit besten Wünschen gewidmet     

Straightforward Preparation of (2E,4Z)-2,4-Heptadien-1-ol and (2E,4Z)-2,4-Heptadienal

Abstract

A concise synthesis of (2E,4Z)-2,4-heptadien-1-ol and (2E,4Z)-2,4-heptadienal is presented. Commercially available (Z)-2-penten-1-ol was converted to ethyl-(2E,4Z)-2,4-heptadienoate by reaction with activated MnO₂ and (carboethoxymethylene)triphenylphosphorane in the presence of benzoic acid as a catalyst. Ethyl-(2E,4Z)-2,4-heptadienoate was converted to (2E,4Z)-2,4-heptadien-1-ol with LiAlH₄. The alcohol was partially oxidized to (2E,4Z)-2,4-heptadienal with MnO₂. The title compounds are male-specific, antennally active volatile compounds from the Saltcedar leaf beetle, Diorhabda elongata Brulle (Coleoptera: Chrysomelidae) and have potential use in the biological control of the invasive weed saltcedar (Tamarix spp).     

A comparative study of the synthetic paths from 1-butyne to 2E,4Z-heptadien-1-ol

2E,4Z-Heptadien-1-ol (1), the key intermediate in the synthesis of the grapevine moth sex pheromone, was obtained from 1-butyne by a number of alternative procedures, including various variants of the stereocontrolled building of the conjugatedE,Z-diene system (Cadiot—Chodkiewicz cross-coupling, alkyne—vinyl halide cross-coupling catalyzed by palladium complexes, anionotropic allylic rearrangement, partialcis- andtrans-reduction of the triple bond). None of them could provide for configurational uniformity of1. The most acceptable path to obtain1 in multigram amounts appears to be that which proceeds via the conjugated diynol and enynol intermediates with subsequent catalyticcis-hydrogenation.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 769–772, April, 1993.     

1-Oxa-3-azapentalen-2-ones as Precursors of cis-2-Amino Alcohols: Synthesis from Propargyl Alcohols, CO2, and Amines Using an Intramolecular Amidoalkylation Reaction of Oxazolidin-2-ones

The reaction of 5-methyl-5-(4-methyl-3-pentenyl)-4-methylene-1,3-dioxolan-2-one with primary amines gives the corresponding 4-hydroxy-4-methyloxazolidin-2-ones. These undergo an intramolecular amidoalkylation reaction to form 1-oxa-3-azapentalen-2-ones which are potential precursors of cyclopentanyl cis-2-amino alcohols.     

Studien zur Chemie von thienoanellierten O,N- und S,N-haltigen Heterocyclen, 10. Mitt.: Synthese von 2- substituierten Thieno-Diltiazemderivaten

Summary The syntheses of 2-acetyl-, 2-benzyl-, and 2-ethyl-thieno-diltiazem derivatives are described starting from the corresponding 5-substituted 3-nitro-2-thiophenthiolvia reaction with racemic methyltrans-3-(4-methoxyphenyl)-glycidate under different conditions (solvent, catalyst, temperature) to obtain purethreo orerythro products. The nitro groups of these products were reduced and the resulting amino esters cyclized. The thieno[2,3-b][1,4]thiazepin-5(4H)-ones were N-alkylated and acetylated in position 3. The desired 2-substituted 4-(2-dimethylaminoethyl)-4,5,6,7-tetrahydro-7-(4-methoxyphenyl)-5-oxothieno[2,3-b][1,4]thiazepin-6-yl acetates were isolated in good yields.

     

Zur Umsetzung von 3,4-Dihydro-8a-methoxy-2H-1,4-benzoxazin-6(8aH)-onen mit Diazoalkanen, 1. Mitt.

Summary 3,4-Dihydro-8a-methoxy-2H-1,4-benzoxazin-6(8aH)-ones — quinol derivatives of 2-hydroxyethylamino-1,4-benzoquinones — react with diazoalkanes to yield 2,3,9a,9b-Tetrahydro-9H-pyrazolo[3,4-h]-1,4-benzoxazin-6(6aH)-ones (3). Their structures were established on basis of NMR-techniques including two-dimensional experiments. The orientation phenomena of the reaction is discussed.