Strukturelle Abwandlungen anN-Acetylneuraminsäure, 4. Mitt. Transformationen am Diethyl-dithioketal desN-Acetylneuraminsäure-γ-lactons

Partial protection of diethyldithioketal ofN-acetylneuraminic acid--lactone using one or two equivalents oft-butyldimethylchlorosilane leads to the 9-O-silyletherderivative7 and the 8,9-bis-O-silylderivative5, resp. The reaction of1 as well as7 with 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane (TIPSiCl₂) yields selectively the protected products4 and9. The 9,8,7,6-tetra-O-acetyl-N-acetylneuraminic acid--lactone derivative3 is formed by the oxidative desulfurazation of the peracteylated form of1 (i. e.2) by means ofNBS. By reaction of5 withTPPDEAD the 6,7-carbonato compound6 arises instead of the expected 6,7-epoxyderivative. The analogous carbonate8 is formed by treating7 with bisimidazolylcarbonate.

     

Synthesis of functionalized 3,4-dihydro-2H-pyrans by hetero —Diels-Alder reaction of an enaminoketone with enol ethers

Summary The hetero —Diels-Alder reaction of 3-(N-acetylbenzylamino)-2-cyano-1-phenyl-2-propen-1-one (3) with enol ethers (4) leads to diastereoisomeric cycloadducts5 and6 in good yields. The structure of the products is discussed in terms of configuration and preferred conformation. Reaction of5 with sulfuric acid yields 3-benzoyl-1,2-dihydropyridin-2-one (7).

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Synthese funktionalisierter 3,4-Dihydro-2H-pyrane durch Hetero —Diels-Alder — Reaktion eines Enaminoketons mit Enolethern

Zusammenfassung Die Hetero —Diels-Alder — Reaktion von 3-(N-Acetylbenzylamino)-2-cyano-1-phenyl-2-propen-1-on (3) mit Enolethern (4) führt in guten Ausbeuten zu den diastereomeren Cycloaddukten5 und6. Die Strukturen der Produkte werden im Zusammenhang mit ihrer Konfiguration und Vorzugskonformation diskutiert. Die Reaktion von5 mit Schwefelsäure liefert 3-Benzoyl-1,2-dihydropyridin-2-on (7).

     

The phosphonate-phosphate and phosphate-phosphonate rearrangement and their applications V. On the reaction ofs-butyllithium/TMEDA with symmetrical trialkyl phosphates

Summary 1-(Tributylstannyl)hexanol ((±)-8 is phosphorylated to give phosphate (±)-9 which is then transmetallated. The organolithium intermediate (±)-10 isomerizes to -hydroxyphosphonate (±)-12. Similar intermediates are also formed upon direct deprotonation of triethyl, tri-n-propyl, and tri-n-butyl phosphate, which subsequently rearrange to -hydroxyphosphonates (±)-14a–c.

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Die Phosphat-Phosphonat- und Phosphonat-Phosphat-Umlagerung und ihre Anwendungen, 5. Mitt. Über die Reaktion vons-Butyllithium/TMEDA mit symmetrischen Trialkylphosphaten

Zusammenfassung 1-(Tributylstanny)hexanol ((±)-8) wird phosphoryliert und liefert Phosphat (±)-9, das transmetalliert wird. Das lithiumorganische Zwischenprodukt (±)-10 isomerisiert zum -Hydroxyphosphonat (±)-12. Ähnliche Intermediate werden auch bei der direkten Deprotonierung von Triethyl-, Tri-n-propyl- und Tri-n-butylphosphat gebildet, die anschließend zu den -Hydroxy-phosphonaten (±)-14a–c umlagern.

     

Stereochemie von Metallocenen, 44. Mitt.: Darstellung und Konfiguration von Tricarbonylchrom-Komplexen der Diphensäure und ihrer Derivate 3. Mitt. über Biphenyl-tricarbonylchrom-Komplexe

Mono and bis tricarbonylchromium complexes of diphenic acid and its monomethylester (3, 4, 15, 16) were prepared by treating the corresponding methyl and trimethylsilylesters (e.g.12) with Cr(CO)₆ and subsequent hydrolysis of the complexes1, 2, 13, and14. Diborane reduction of the carboxylic acids gave hydroxymethyl derivatives, amongst which the diol8 a is a key substance for configurational analyses by¹H-nmr and ir spectroscopy. In this context monosubstituted biphenyl complexes (9–11) were prepared as reference substances. Complexation of the lactone23 of 2-hydroxymethyl biphenyl-2-carboxylic acid afforded (besides two isomeric monocomplexes) mainly thetrans-biscomplex26 b, a key intermediate for ring opening and cyclization reactions.The stereochemical possibilities of the biscomplexes are discussed. The racemate configuration is preliminarily assigned to diphenic acid bistricarbonylchromium and its derivatives.

2. Mitt.; 1. Mitt.:K. Schlögl undR. Schölm, Mh. Chem.109, 1227 (1978).     

Triterpenester ausSanvitalia procumbens Lam

The flowering part ofSanvitalia procumbens Lam. contains—apart from a hydrocarbon-fraction—a mixture of triterpene esters. From this eight fatty acids as well as - and -amyrin were identified. The definite identification and differentiation of the amyrines was achieved by GC-MS.

Oesterreicher, U., Diplomarbeit, Universität Wien, 1980.     

Heterobimetallische Vanadium- und Thallium-2-(dimethylaminomethyl)ferrocenyl-Verbindungen

Zusammenfassung Synthesen und Eigenschaften von 2-(Dimethylaminomethyl)ferrocenyl-Derivaten der Formel (FcN) _n VCl_3–n (FcN=2-(Dimethylaminomethyl)ferrocenyl;n=1 (1), 2 (2), 3 (3)), die aus VCl₃·3THF und (FcN) Li (I) entstehen, werden mitgeteilt. WährendCp ₂VCl₂ (Cp=C₅H₅) mitI unter Bildung vonCp ₂ V(FcN) (4) reagiert, läßt sich VO (acac)₂ (acac=Anion des Acetylacetonates, C₅H₇O₂) in die 2-(Dimethylaminomethyl)ferrocenyl-Verbindung des vierwertigen Vanadiums (FcN)VO(acac),5) überführen. Dagegen entsteht bei Umsetzungen von VOCl₂·2THF mitI das Organovanadium (III)-Derivat Li [(FcN)₂V(O)Cl] (6).Reaktionen von VCl₄·2THF,Cp ₂VCl₂, VOCl₃ undCpVOCl₂ mit (FcN)₃Tl (II) führen unter Bildung von (FcN)₂TlCl (7) zu thermisch instabilen vanadiumorganischen Verbindungen. Eine eingehende Charakterisierung von1–7 erfolgte durch Elementaranalysen, Ermittlung der effektiven magnetischen Momente, IR-, Massen- und NMR-Spektroskopie sowie, insbesondere hinsichtlich der Ausbildung möglicher Chelatstrukturen, durch UV/Vis und Mößbauer-Spektroskopie.

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Heterobimetallic 2-(dimethylaminomethyl)ferrocenyl compounds of vanadium and thallium

Summary Syntheses and properties of 2-(dimethylaminomethyl)ferrocenylderivatives of the composition (FcN) _n VCl_3–n (FcN=2-(dimethylaminomethyl)ferrocenyl;n=1 (1), 2 (2), 3 (3)), which are formed from VCl₃·3THF and (FcN) Li (I), are reported. WhereasCp ₂VCl₂ (Cp=C₅H₅) reacts withI under formation ofCp ₂V(FcN) (4), VO(acac)₂ (acac=anion of acetylacetonate, C₅H₇O₂) can be transformed into the 2-(dimethylaminomethyl)-ferrocenyl compound of tetravalent vanadium (FcN)VO(acac),5). However, when VOCl₂·2THF reacts withI, the organovanadium(III)-derivative Li[(FcN)₂V(O)Cl] (6) is formed.Reactions of VCl₄·2THF,Cp ₂VCl₂, VOCl₃, andCpVOCl₂ with (FcN)₃Tl (II) lead to thermally instable vanadiumorganic compounds under formation of (FcN)₂TlCl (7). A detailed characterization of1–7 was carried out by elementary analysis, determination of effective magnetic moments, IR, mass and¹H NMR spectroscopy as well as — especially referring to the formation of possible chelate structures — by UV/Vis andMöbauer spectroscopy.

     

DMF acetals as alkylating and cyclizing agents: A facile route to substituted pyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-diones

Summary Several 7-methyl-5-alkyl-2-vinylpyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-diones were prepared. The successful cyclization and alkylation of 6-(-methylbenzylidenehydrazino)-1-methyluracils2a–d using dimethylformamide acetals at high temperature provided6a–d,7a–d, and8a–d. Treatment of6a–d and7a–d with acid afforded 7-methyl-5-alkylpyrazolo[3,4-d]pyrimidine-4,6(5H,7H)-diones9a,b; under the same conditions,3a–d reacted to 7-methylpyrazolo[3,4-d]-pyrimidine-4,6(5H)-dione (4) in good yield.

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DMF-Acetale als Alkylierungs- und Ringschlußreagentien: ein einfacher Weg zu substituierten Pyrazolo[3,4-d]pyrimidin-4,6(5H,7H)-dionen

Zusammenfassung Es wurden verschiedene 7-Methyl-5-alkyl-2-vinylpyrazolo[3,4-d]pyrimidin-4,6(5H,7H)-dione hergestellt. Cyclisierung und Alkylierung der 6-(-Methylbenzylidenhydrazino)-1-methyl-uracile2a–d mit Hilfe von Dimethylformamidacetalen bei hohen Temperaturen ergab6a–d,7a–d und8a–d. Behandlung von6a–d und7a–d mit Säure lieferte die 7-Methyl-5-alkylpyrazolo[3,4-d]pyrimidin-4,6(5H,7H)-dione9a,b; unter den gleichen Bedingungen reagierten3a–d in guter Ausbeute zu 7-Methylpyrazolo[3,4-d]pyrimidin-4,6(5H)-dion (4).

     

Synthesis and functionalization oftrans-2-(2′-aminocyclohexyloxy)-andtrans-2-(2′-azidocyclohexyloxy)acetic acid

Summary Synthesis of the hydrochloride oftrans-2-(2-aminocyclohexyloxy)acetic acid (4) fromtrans-2-(2-azidocyclohexyloxy)acetic acid (1) is described.4 was acylated at the amino group to give compounds5–8.1 was converted into acid chloride (9) and amides10–13.

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Synthese und Funktionalisierung dertrans-2-(2-Aminocyclohexyloxy)- undtrans-2-(2-Azidocyclohexyloxy)essigsäure

Zusammenfassung Die Synthese destrans-2-(2-Aminocyclohexyloxy)essigsäurehydrochlorids (4), ausgehend vontrans-2-(2-Azidocyclohexyloxy)essigsäure (1), wird beschrieben.4 wurde durch Acylierung der Aminogruppe in die Verbindungen5–8 übergeführt.1 wurde in das Säurechlorid9 und die Carbonsäureamide10–13 umgewandelt.

     

Synthesis of 5′-amino- and 5′-azido-2′,5′-dideoxy nucleosides from thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione

Summary Thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione (4) was silylated and condensed with methyl 5-azido-2,5-dideoxy-3-O-(4-methylbenzoyl)-D-erythro-pentofuranoside (2) in the presence ofTMS triflate to afford the corresponding protected nucleoside6 and acyclic nucleoside7. Deprotection of6 with MeONa/MeOH at room temperature gave 1-(5-azido-2,5-dideoxy--D-erythro-pentofuranosyl)-thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione (8) and the corresponding anomer9, whereas compound7 yielded 5-azido-2,5-dideoxy-1-(2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-1-yl)-1-O-methyl-D-erythro-pentitol (10) under the same reaction conditions. 1-(5-Amino-2,5-dideoxy--D-erythro-pentofuranosyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione (11) was obtained on treating9 with Ph₃P in pyridine followed by hyrolysis with NH₄OH. The anomeric nucleosides14 and15 and the corresponding acyclic nucleoside16 were obtained when4 was trimethylsilylated and condensed with methyl 2-deoxy-3,5-di-O-(4-methylbenzoyl)-D-erythro-pentofuranoside (3) followed by deprotection with MeONa in MeOH. Compounds8 and9 were also obtained when the anomeric mixture14/15 was treated with a mixture of NaN₃, Ph₃P, and CBr₄ in dryDMF at room temperature.On leave from Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt     

Synthesis of the grapevine moth sex pheromone by Grignard—Schlosser cross-coupling: The effect of the electrophile structure on the stereoisomeric ratio in the reaction products

1-Acetoxy-2E,4Z-heptadiene (4) and 1-bromo-3E,5Z-octadiene (5) were obtained with 90 and 88–92 % configurational purity, respectively, starting from 2,4-heptadiyn-1-ol or 3,5-octadiyn-1-ol. The Li₂CuCl₄-catalyzed cross-coupling of the allylic acetate4 with 5tert-butoxypentylmagnesium chloride affords 1-tert-butoxy-7E,9Z-dodecadiene (11) contaminated with 25 % of minor stereoisomers in 54–60 % overall yield. Under similar conditions, the homoallylic bromide5 reacts with 4-tert-butoxybutylmagnesium chloride to give in 50–52 % yield another sample of diene11 containing 17 % of minor stereoisomers. If the latter coupling is carried out with enyne8 instead of5 followed bycis-hydrogenation of the triple bond in the resulting product, the configurational purity of diene11 is as high as 84.7 % (45 % overall yield). The reaction of11 with Ac₂O in the presence of FeCl₃ leads directly to the target 7E,9Z-dodecadienyl acetate (1) with somewhat lower configurational purity than that of the starting ether11.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1133–1137, June, 1993.     

Über die Synthese von Dihydro-1,2,3,5-thiatriazol-1,1-dioxiden, 2. Mitt.

By reaction of several N-phenyl-benzamidrazones with SO₂F₂ 2-phenyl-2,5-dihydro-1,2,3,5-thiatriazole-1,1-dioxides2 a–c are formed. By reaction of N,N-diethyl-N-chlorosulfonyl-chloroformamidine8 with hydrazines the corresponding 4-diethylamino-substituted derivatives9 a–d are obtained. Methylation of2 b yields two isomeric products5 and6, whereas by methylation of9 d only one product9 b is obtained.

     

Darzens reaction as a convenient method for the synthesis of α-chloroketones, α-chloroepoxides,and symmetrically substituted dioxines

Summary TheDarzens reaction of dichloroacetophenone (DCAP) with substituted benzaldehydes has been studied. The structure of the products was shown to depend on the phenyl group substituents. Reaction of benzaldehyde, 4-bromo-, and 2,4-dichlorobenzaldehydes results in 1-phenyl-3-aryl-3-chloropropane-1,2-diones (2a–c), reaction ofpara- ormeta-nitrobenzaldehydes yields 1-phenyl-2-chloro-3-aryl-2,3-epoxypropane-1-ones (3a, b). Upon the introduction of an alkoxy group into the phenyl ring of benzaldexyde and/or dichloroacetophenone, symmetrically substituted dioxines were obtained (6a–c). The structure of the reaction products has been established by single crystal X-ray investigations.

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Darzens-Reaktion als bequemes Verfahren zur Synthese von -Chloroketonen, -Chloroepoxiden und symmetrisch substituierten Dioxinen

Zusammenfassung DieDarzens-Reaction von Dichloracetophenon (DCAP) mit substituierten Benzaldehyden wurde untersucht. Die Struktur der Produkte ist von den Substituenten an der Phenylgruppe abhängig. Die Umsetzung mit Benzaldehyd, 4-Brom- und 2,4-Dichlorbenzaldehyd liefert 1-Phenyl-3-aryl-3-chloropropan-1,2-dione (2a–c), die Reaktion vonpara- odermeta-Nitrobenzaldehyd 1-Phenyl-2-chloro-3-aryl-2,3-epoxipropan-1-one (3a,b). Durch Einführung einer Alkoxygruppe in den Phenylring des Benzaldehyds und/oder des Dichloracetophenons erhält man symmetrisch substituierte Dioxine (6a–c). Die Struktur der Reaktionsprodukte wurde mittels Röntgenstrukturanalyse bestätigt.

     

Stereochemie von Metallocenen, 43. Mitt.: Torsionsisomere Biphenyl-tricarbonylchrom-Komplexe: Darstellung,Konformationsanalyse und Kinetik der Interkonversion

Complexation of methyl 3-nitro-2-(o-tolyl)-benzoate (2, ano-trisubstituted biphenyl) with hexacarbonyl chromium gave the isomeric Cr(CO)₃ complexes3 and4 both existing as two torsional isomersa andb, as seen by nmr. For the main product3 the preferred conformations of the two torsional isomersa andb were deduced by the lanthanide induced shift (LIS) technique. The activation energy for the interconversion process could be determined from kinetic measurements and especially from¹H-nmr coalescence temperature of the methylsignals. The barrier of 91±1.5 kJ/mol (21.7±0.3 kcal/mol) in3 reflects the interaction of theo-H-atom of the benzene ring passing the Cr(CO)₃ moiety of the benchrotrene ring during the interconversion.A partial optical resolution of3 was achieved by asymmetric reduction with a chiral lithium-aluminium hydride yielding (+)-3 with [] _D ²⁰ +30° (benzene) and the levorotatory alcohol (–)-7.

42. Mitt.:K. Schlögl undR. Schölm, Mh. Chem.109, 1227 (1978).     

Synthesis and reactions of dicarbonyl (η2-indene)-η5-indenyl complexes of manganese and rhenium

Photochemical reactions of M(CO)₃(⁵-C₉H₇), where M=Mn (1) or Re (2), with indene have produced ²-indene complexes M(CO)₂(²-C₉H₈)(⁵-C₉H₇), where M=Mn (3) or Re (4). Deprotonation of complex3 witht-BuOK in THF at –60 °C gives the anion [Mn(CO)₂(¹-C₉H₇)(⁵-C₉H₇)^– (5), in which there occurs a rapid interchange of the Mn(CO)₂(⁵-C₉H₇) group between positions 1 and 3 in the ¹-indenyl ligand. The reaction of complex4 with Ph₃CPF₆ in CH₂Cl₂ at 0 °C leads to the complex [Re(CO)₂(³-C₉H₇)(⁵-C₉H₇)PF₆, whereas the similar reaction of complex3 gives only decomposition products even at –20 °C.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1280–1285, July, 1993.     

Vibrational spectra and structure of “staircase” carbonyl π-complexes of transition metals

FTIR spectra have been studied for staircase cyclopentadienyl complexes containing two or three metal carbonyl fragments bound by the metal-carbon bond Cp(CO)₂Fe-CpmMn(CO)₃ (1), Cp(CO)₂Fe-CpmFe(CO)₂CH₂Ph (2), Cp(CO)₂Fe-Cpm(CO)₂Fe-CpmMn(CO)₃ (3), Cp(CO)₂Mo-Cpm(CO)₂Fe-CpmMn(CO)₃ (4), Cp(CO)₃W-Cpm(CO)₂Fe-CpmMn(CO)₃ (5), Cp(CO)₂Fe-Cpm(CO)₂Fe-BmCr(CO)₃ (6), Cr(CO)₃Bm-CpmFe(CO)₂CH₂Ph (7), where Cp = ₅-C₅H₅, Cpm = ¹⁵-C₅H₄, Bm = ¹⁶-C₆H₅. Temperature-dependent FTIR spectra were measured inn-pentane solutions over a wide temperature range and in the low-temperature solid matrices of argon and nitrogen. Rotamers, formed due to rotation about the metal-carbon -bond, were found in solutions and matrices. A molecular mechanics calculation of1 proved the possibility of such rotation.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1952–1956, November, 1994.The authors are grateful to the Russian Foundation for Basic Research (project code No 93-03-18592) and to the International Science Foundation (project code No MEQ000).     

Synthese,Reaktionen und NMR-Spektren von 2-Brom-3-oxo-1-alkenyl- und 3-Oxo-1-alkinyl-phosphonsäure-dialkylestern

Dialkyl (E)-3-oxo-1-alkenylphosphonates (1), on reaction with bromine and subsequent HBr-elimination, yield the isomeric -bromovinyl derivatives (Z)-3 and (E)-3 and the alkinylphosphonates4. -Bromovinyl compounds3 can also be obtained by reaction of1 withNBS in aqueous solution. The configuration of the -disubstituted vinylcompounds is assigned from their¹³C-NMR spectra. Both bromovinyl compounds3 and alkinylderivatives4 are used for regioselective syntheses of acylsubstituted pyrazolylphosphonates5.

     

Zur Reaktion von Permethylcyclosilanen mit Halogenen

The series of ,-diiodopermethylpolysilanes, I(SiMe ₂) _n I, (n=4–6) andX(SiMe ₂)₄ X, (X=Cl, Br) has been prepared by the action of halogen on the corresponding cyclic compounds (SiMe ₂) _n . The mass spectra, NMR-, IR- andRaman-spectra of these compounds have been recorded.

Herrn Prof. Dr.Josef Schurz zum 60. Geburtstag gewidmet.     

Schiff base derivatives of lanthanons-synthesis of La(III), Pr(III) and Nd(III) derivatives of β-ketoimines derived from 2,4-pentanedione

Reactions of the isopropoxides of some of the lighter lanthanons with bidentate -ketoimines, such asAAH-n-C₄H₉ andAAH-C₆H₅ (donor system: N,OH) and tridentate -ketoimines such asAA(CH₂CH₂)H₂ andAA(CH₂CHCH₃)H₂ (donor system: HO,N.OH) have led to products of the typesLn(O-i-C₃H₇)_3n (AA-R) _n ,Ln(Oi-C₃H₇) (AAR') andLn ₂(AAR')₃ [Ln=La(III), Pr(III) or Nd(III);n=1 or 2;R=-n-C₄H₉ or-C₆H₅ andR'=-CH₂CH₂-or-CH₂CHCH₃-]. Some undergo exchange reactions with an excess oftert-butanol, leading to the corresponding complexesLn(O-tert-C₄H₉)_3n (AA-n-C₄H₉) _n andLn(O-tert-C₄H₉) (AA-CH₂CH₂). All these have been characterised by elemental analysis, molecular weight determinations and their ir spectra. A thermogravimetric analysis of the diisopropoxy derivatives has also been carried out.

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Schiff-Basen Derivate von Lanthaniden-Synthese von La(III), Pr(III) und Nd(III) chelaten mit -Ketoiminen

Zusammenfassung Reaktionen von Lanthanid-Isopropoxiden mit zweizähnigen -Ketoiminen [AAH-n-C₄H₉ undAAH-C₆H₅; Donorsystem: N,OH] und dreizähnigen -Ketoiminen [AA(CH₂CH₂)H₂ undAA(CH₂CHCH₃)H₂; Donorsystem: OH, N,OH] führten zu Produkten vom, TypLn(O-i-C₃H₇)_3-n (AA-R) _n ,Ln(O-i-C₃H₇) (AAR') undLn ₂(AAR')₃ [Ln=La(III), Pr(III) oder Nd(III);n=1 oder 2;R=n-C₄H₉ oder C₆H₅ undR'=CH₂CH₂ oder CH₂CHCH₃]. Einige Komplexe unterliegen bei Behandlung mit einem Überschuß vontert-Butanol einer Austauschreaktion, die zu den entsprechenden Butoxid-Komplexen führt [Ln(O-tert-C₄H₉)_3-n , (AA-n-C₄H₉) _n undLn(O-tert-C₄H₉) (AACH₂CH₂)]. Alle Derivate wurden mittels Elementaranalyse, Molgewichtsbestimmung und IR-Spektroskopie charakterisiert. Eine thermogravimetrische Analyse der Diisopropoxi-Derivate wurde ebenfalls ausgeführt.

     

Synthesis of 5,7,11 b,12-tetrahydro-isoindolo[2,1-b]isoquinolinium methiodides and theirStevens rearrangement

The title compounds5 were synthetized in two steps from the corresponding isoindolo[2,1–b]isoquinoline-5(7H)-ones3, obtained in high yields from 3-ethoxy-1H-isoindoles2 and homopthalic anhydrides1. TheStevens rearrangement of5 gave 2-methyl-2,3-dihydro-1H-isoindole-1-spiro-2-indanes6.

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Synthese von 5,7,11 b,12-Tetrahydro-isoindolo[2,1-b]isochinolinium Methiodiden und ihre Stevens-Umlagerung

Zusammenfassung Die Titelverbindungen5 wurden in zwei Stufen aus den entsprechenden Isoindolo[2,1–b]isochinolin-5(7H)-onen (3) dargestellt, die ihrerseits in hohen Ausbeuten aus 3-Ethoxy-1H-isoindolen (2) und Homophthalsäureanhydriden erhältlich sind. DieStevens-Umlagerung von5 führte zu 2-Methyl-2,3-dihydro-1H-isoindol-1-spiro-2-indanen (6).

     

Synthesis of 2′,3′-dideoxynucleosides from 5-alkoxymethyluracils

Summary A modified synthesis of protected 2,3-dideoxyribose5 starting fromL-glutamic acid (1) is described. Reaction of5 with silylated 5-hydroxymethyluracil7 a and 5-alkoxymethyluracils7 b–e in the presence of trimethylsilyl triflate afforded an anomeric mixture of 2,3-dideoxyuridine derivatives8 a–e and9 a–e. Deprotection with methanolic ammonia and separation by chromatography gave the corresponding nucleosides10 a–e and11 a–e. Treatment of9 b–e with tri(1H-1,2,4-triazol-1-yl)phosphine oxide and subsequent reaction of12 b–e with ammonia in dioxane afforded the cytosine derivatives13 b–e which on treatment with methanolic ammonia gave the corresponding 2,3-dideoxycytidine derivatives14 b–e and15 b–e. In contrast with the parent compounds, these alkoxymethyl derivatives had no appreciable activity against human immunodeficiency virus (HIV-1).

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Synthese von 2,3-Dideoxynucleosiden aus 5-Alkoxymethyluracilen

Zusammenfassung Ausgehend vonL-Glutaminsäure (1) wird eine modifizierte Synthese von geschützter 2,3-Dideoxyribose (5) beschrieben. Reaktion von5 mit silyliertem 5-Alkoxymethyluracilen7 b–e in Gegenwart von Trimethylsilyltriflat ergab anomere Mischungen der 2,3-Dideoxyuridinderivate8 a–e und9 a–e. Abspaltung der Schutzgruppe mit methanolischen Ammoniak und chromatographische Trennung ergab die entsprechenden Nucleoside10 a–e und11 a–e. Behandlung von9 b–e mit Tri(1H-1,2,4-triazol-1-yl)phosphinoxid und nachfolgende Reaktion von12 b–e mit Ammoniak in Dioxan ergab die Cytosinderivate13 b–e, welche nach Behandlung mit methanolischem Ammoniak die entsprechenden 2,3-Dideoxycytidinderivate14 b–e und15 b–e ergaben. Im Gegensatz zur Stammverbindung hatten diese Alkoxymethylderivate keine nennenswerte Wirksamkeit gegen den menschlichen Immunschwächevirus (HIV-1).