Synthetische versuche in der gruppe hypotensiv wirksamer alkaloide XIX. Reduktion des (±)-5,8-dioxo-cis-1,4,5,8,9,10-hexahydro-1β-naphthoesäureisopropylesters nach meerwein (original) (raw)
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Helv Chim Acta, 1990
Glycolaldehyde phosphate aldomerizes in aqueous NaOH solution to a product mixture containing the racemates of the two diastereoisomeric tetrose 2,4-diphosphates and eight hexose 2,4,6-triphosphates. At room temperature in the absence of air and after 7 days, a solution 0 . 0 8~ in glycolaldehyde phosphate (= formylmethyl dihydrogenphosphate) and 2M in NaOH gives products, in up to 80% yield, with a tetrose/hexose derivative ratio of ca. 1 : 10 and with rue-allose 2,4,6-triphosphate comprising up to 50% of the mixture of sugar phosphates. When the reaction is run under the same conditions but in the presence of 0.5 mol-equiv. of formaldehyde, sugar phosphates are formed in up to 45% yield, with pentose 2,4-diphosphates now predominating over hexose triphosphates by a ratio of 3:1. rue-Ribose 2,4-diphosphate is found to be the major component, the ratios among ribose, arabinose, lyxose, and xylose 2,4-diphosphates being 52:14: 23: 11 in a representative experiment. The pentose diphosphates are constitutionally stable under the reaction conditions (observed for 23 weeks), but the diastereoisomeric ratios slowly change with time (to 22:34:30:14 after 23 weeks), showing that ribose 2,4-diphosphate is not the thermodynamically favored diastereoisomer. The observed product distributions in both the pentose and the hexose series (after 1 week) reveal an aldolization mode that is preferentially erythro in the product-determining step (the reaction of glycolaldehyde phosphate as its enolate with glycerinaldehyde 2-phosphate and tetrose 2,4-diphosphdte, respectively). An attempt is made to rationalize both this fact and the kinetic predominance of ribose 2,4-diphosphate in the pentose series and allose 2,4,6-triphosphate in the hexose series. Their configuration along the C-chain can be interpreted as corresponding to a minimum number of 1-5 repulsions in the packing of phosphate and OH substituents and minimal steric interaction between substituents at the reaction centers in the transition state of the product-determining step. The aldomerization of glycolaldehyde phosphate in the presence of formaldehyde is a variant of the formose reaction. It avoids the formation of complex formose product mixtures, largely as a consequence of the fact that aldoses which are phosphorylated at the C(2) 4. Mitteilung uber die Chemie von a -Aminonitrilen. 3. Mitteilung: [I].
1,4-DIOXASPIRO[4.5]DECA-6,9-DIEN-2,8-DIONE Durch Anodische Oxidation Von 4-METHOXYPHENOXYESSIGSÄUREN
Tetrahedron Letters, 1984
On preparative anodic oxidation in acetonitrile at graphite electrodes 4-methoxyphenoxyacetic acids 1 cyclize to 1,4-dioxaspirot4.5ldeca-6,9-dien-2,8-diones q.ElectroanaTytical results are given. Wir elektrolysierten 4-Methoxyphenoxyessigsauren synthesec7) und bei der Synthese von Morphinandienonen (8) durchgeftihrt, unseres Wissens aber sind Dioxaspirodecadiendione 2 durch anodische Oxidation von Hydro-xyphenoxyessigsauren oder deren Alkylethern bisher noch nicht hergestellt worden. Cyclische Voltammetrie der Carbonsauren 1 sowie der Methylester und Casiumsalze zeigt, da8 in einer Aromatenoxidation Elektronenubertragung vom aromatischen Kern und nicht von der Carboxylatfunktion stattfindet, da deren Derivatisierung auf das Oxidationspotential ohne EinfluB bleibt.
Helvetica Chimica Acta, 1990
Glycolaldehyde phosphate aldomerizes in aqueous NaOH solution to a product mixture containing the racemates of the two diastereoisomeric tetrose 2,4-diphosphates and eight hexose 2,4,6-triphosphates. At room temperature in the absence of air and after 7 days, a solution 0 . 0 8~ in glycolaldehyde phosphate (= formylmethyl dihydrogenphosphate) and 2M in NaOH gives products, in up to 80% yield, with a tetrose/hexose derivative ratio of ca. 1 : 10 and with rue-allose 2,4,6-triphosphate comprising up to 50% of the mixture of sugar phosphates. When the reaction is run under the same conditions but in the presence of 0.5 mol-equiv. of formaldehyde, sugar phosphates are formed in up to 45% yield, with pentose 2,4-diphosphates now predominating over hexose triphosphates by a ratio of 3:1. rue-Ribose 2,4-diphosphate is found to be the major component, the ratios among ribose, arabinose, lyxose, and xylose 2,4-diphosphates being 52:14: 23: 11 in a representative experiment. The pentose diphosphates are constitutionally stable under the reaction conditions (observed for 23 weeks), but the diastereoisomeric ratios slowly change with time (to 22:34:30:14 after 23 weeks), showing that ribose 2,4-diphosphate is not the thermodynamically favored diastereoisomer. The observed product distributions in both the pentose and the hexose series (after 1 week) reveal an aldolization mode that is preferentially erythro in the product-determining step (the reaction of glycolaldehyde phosphate as its enolate with glycerinaldehyde 2-phosphate and tetrose 2,4-diphosphdte, respectively). An attempt is made to rationalize both this fact and the kinetic predominance of ribose 2,4-diphosphate in the pentose series and allose 2,4,6-triphosphate in the hexose series. Their configuration along the C-chain can be interpreted as corresponding to a minimum number of 1-5 repulsions in the packing of phosphate and OH substituents and minimal steric interaction between substituents at the reaction centers in the transition state of the product-determining step. The aldomerization of glycolaldehyde phosphate in the presence of formaldehyde is a variant of the formose reaction. It avoids the formation of complex formose product mixtures, largely as a consequence of the fact that aldoses which are phosphorylated at the C(2) 4. Mitteilung uber die Chemie von a -Aminonitrilen. 3. Mitteilung: [I].
Chemische Berichte, 1980
Die Monohydroxypyridine 1-3 werden mit Ameisensaure in Gegenwart von Dicyclohexylcarbodiimid in Methylenchlorid zu N-Formyl-4-(4) und N-Formyl-2-pyridon (5) sowie zu 3-(Formyl-0xy)pyridin (6) formyliert. Diese Acylpyridone liefern mit prim., sek. und tert. Alkoholen in selektiv fallender Reaktivitat die Formylester 7. Preparation of N-Formylpyridones-Selective Esterification of Primary, Secondary, and Tertiary Alcohols with N-Acylpyridones Polenskis) hatten bei einem Vergleich der Reaktivitaten von Azoliden schon festgestellt, da8 N-Formylazolide ca. hundertmal reaktiver sind als die entsprechenden Acetylazolide. Bei Verwendung formylierter Pyridone waren deshalb hohere Reaktivitaten zu erwarten, die eine Alkoholatkatalyse bei der Veresterung tertiarer Alkohole mbglicherweise uberfliissig machen konnten. Dariiber hinaus erschienen uns Formylpyridone auch fur die Einfuhrung des Formylrestes als haufig venvendeter Schutzgruppe in der Peptidchemies) gut geeignet. Darstellung formylierter Hydroxypyridine Von den drei Monohydroxypyridinen 1, 2 und 3 sind bisher noch keine Noder 0-Formylderivate beschrieben. Infolge der Instabilitat von Formylchlorid und Ameisensaureanhydrid ist von den in Lit. 3, aufgefiihrten Methoden zur Darstellung acylierter 4-Pyridone nur die Umsetzung der Hydroxypyridine mit Ameisensaure/Carbodiimid zur
Synthesen gezielt alkylierter Enolether derL-ribo-Reihe
Liebigs Annalen der Chemie, 1987
Wlhrend durch Reduktion der Enulose l a L-Digitoxal(3r) nur schwierig als Hauptprodukt und in miU3iger Ausbeute zu erhalten ist, llDt es sich aus L-Digitoxose (4.) vorteilhd in einem Drei-Stufen-Eintopf-Verfahren herstellen. Nach der Phasentransfer-katalytischen Methode oder iiber Stannyliden-Intermediate gelingt bevonugt die regioselektive 3-oder 4-0-Alkylierung zu vcrhiip funHahigen Monosccharid-VorlPufetstufen der trfbo-Reihe.
Eur J Inorg Chem, 1992
Silanol, acetyl-, crystal structure of 1 Microbial reduction Synthesis of the Si-Functional Acetylsilanes tBu(Me,SiCH,)[MeC(O)]SiF and tBu(Me,SiCH,)[MeC(O)]SiH as well as Synthesis and Crystal Structure of the Acetylsilanol tBu(Me,SiCH,)[MeC(O)]SiOH: Substrates for Microbial Reductions The racemic Si-functional acetylsilanes tBu(Me3SiCHz)-1-3 were found to be reduced by cells of Trigonopsis vari-[MeC(O)]SiF (1) and tBu(Me,SiCH,)[MeC(O)]SiH (2) and the abilis (DSM 70714) [ =SiC(O)Me + =SiCH(OH)Me]. The racemic acetylsilanol tBu(Me,SiCH,)[MeC(O)]SiOH (3) were crystal and molecular structure of 3 was studied by singlesynthesized from Si(OMe)4 (4) as substrates for microbial re-crystal X-ray diffraction. In the crystal, racemic 3 forms infinite ductions [4 + tBuSi(OMe)3 (5) + tBu(Me,SiCH,)Si(OMe), (6) chains built up by intermolecular 0-H-.O bonds between-+ tBu(Me3SiCHz)SiFz (?)-+ tBu(Me3SiCHz)(CHz= C(OMe)]SiF the hydroxyl and acetyl groups of molecules of the same ab-(8) + 1; 8 + tBu(Me3SiCH,)[CH2=C(OMe)]SiH (9)-+ 2; 6 + solute configuration. tBu(Me3SiCHz)[CHz = C(OMe)]SiOMe (10)-+ 31. Compounds 3 Si(1)-0(1) 1.638(1) Si(1)-C(5) 1.925(2) Si(1)-C(1) 1.846(2) C(1)-Si(1)-0(1) 11441) C(1)-Si(1)-C(5) 107.1(1) C(1)-Si(1)-C(7) 112.3(1) C(5)-Si(l)-0(1) 104.3(1) C(5)-Si(1)-C(7) 106.9(1) Si(1)-C(7) 1.9OO(2) C(5)-0(2) 1.227(2) C(5)-C(6) 1.493(3) C(7)-Si(1)-O(1) 111.4(1) Si(1)-C(1)-Si(2) 1 18.9(1) Si(1)-C(5)-C(6) 12 1.7(1) Si(1)-C(5)-O(2) 117.4(1) C(6)-C(5)-O(2) 1 20.8(2) Die erstmalig dargestellten Si-funktionellen Acetylsilane 1 und 2 sowie die ebenfalls noch nicht beschriebenen Zwischenstufen 6-10 sind im Vakuum unzersetzt destillierbare, nur wenig hydrolyseempfindliche Fliissigkeiten. Das Acetylsilanol 3 fie1 dagegen als kristalliner Feststoff an. 1-3 Das Acetylsilanol 3 kristallisiert als Racemat in der zentrosymmetrischen Raumgruppe P'i rnit zwei Molekiilen in der Elementarzelle. Bestimmend fur den Aufbau des Kristalls ist die Gliederung in polare und unpolare Bereiche
Neue Synthesewege zu aminosubstituierten 1,6-Methano[10]-annulenderivaten
Monatshefte f�r Chemie Chemical Monthly, 1991
Summary. Syntheses of 1,6-methano[10]annulene-phthalimido-derivatives 4, 5 a, 5b, 5c, and 6 are described, starting from 2,7-disubstituted 1,6-methano [ 10] annulenes; derivative 8 was prepared from 2-bromo-11,11-difluoro-l,6-methano[10]annulene (9). 4 and 8 can be changed to the 2-amino-l,6methano[10]annulenes 10 and 11.
Säurederivate der Tetrachlorterephthalsäure
Archiv Der Pharmazie, 1966
Diester der Tetrachlorterephthalsäure wurden als potentielle Weichmacher durch Umsetzung von Tetrachlorterephthaloylchlorid mit einem Überschuß von Alkoholen oder Phenolen dargestellt. Weiterhin wurden von der Tetrachlorterephthalsäure synthetisiert: der Bis(β-rhodanoäthylester), der Diacetessigester, der Dithiolester, das Diamid und Dinitril.