Phosphate-Phosphonate Rearrangement of Aliphatic Phosphates

Abstract

Phosphorylation of various aliphatic alcohols gives phosphates 1 which are deprotonated by sBuLi/TMEDA in diethyl ether, THF or hexane at ?78 °C. The organo-lithiurns 2 and 4 formed isornerize to α-hydroxy- phosphonates 3 and 5 (phosphate-phosphonate rearrangement^[1.2]     

PHOSPHORORGANISCHE VERBINDUNGEN 851 SYNTHESE UND ANWENDUNG OPTISCH AKTIVER TERTIÄRER PHOSPHINE ALS CO-KATALYSATOREN DER HOMOGENHYDRIERUNG MIT RHODIUM-PHOSPHIN-KOMPLEXEN

Abstract

Die Darstellung der optisch aktiven Methyl-n-propyl(bzw.-isopropyl)arylphosphine 1 bis 8 wird beschrieben. Hierbei ist Aryl: p-Methoxyphenyl (1 und 2), p-Dimethylaminophenyl (3 und 4), o-Methoxyphenyl (5 und 6), o-Dimethyl-aminophenyl (7) und o-Aminophenyl (8).

Die Phosphine 1 bis 8 werden als optisch aktive Co-Katalysatoren bei der Homogenhydrierung von α- und ß-Methylzimtsäureethylester, der α-Acetaminoacrylsäure und der α-Acetaminozimtsäure mit Rhodium-Phosphinkomplexen eingesetzt und jeweils die optische Induktion bestimmt. Folgende Ergebnisse (Vgl. die Tabellen 1 bis 4) wurden erhalten:

1) Die CH₃O-Gruppe und N(CH₃)₂-Gruppe verändern unabhängig von ihrer Stellung die optische Induktion bei der Homogenhydrierung von α- und ß-Methylzimtsäureethylester nur unwesentlich im Vergleich zu den entsprechenden Methyl-n-propyl (bzw.-isopropyl)-phenylphosphinen.

2) Bei der Homogenhy drierung von α-Acetaminoacrylsäure und α-Acetaminozimtsäure üben para-ständige OCH₃- und (CH₃)₂N-Gruppen in den optisch aktiven Co-Katalysatoren (Verbindungen 1 bis 4) keinen Einfluß auf die Höhe der optischen Induktion aus.

3) In ortho-Stellung verknüpfte OCH₃- und (CH₃)₂N-Gruppen (Verbindungen 5 bis 7) führen jedoch bei der Homogenhydrierung von α-Acetaminoacrylsäure und α-Acetaminozimtsäure zu einer beachtlichen Erhöhung der optischen Induktion. Bei α-Acetaminozimtsäure und 7 als Co-Katalysator beträgt die optische Induktion 80%! Hierbei übertrifft die (CH₃)₂N-Gruppe die CH₃O-Gruppe an Wirksamkeit.

4) Methyl-n-propyl-o-aminophenylphosphin 8 ist als Co-Katalysator unbrauchbar, da es offenbar durch Wechsel-wirkung der NH₂-Gruppe mit Rhodium die Koordinierung des prochiralen Olefins mit dem Komplex unterdrückt.

5) Eine experimentell begründete Deutung für das Zusammenwirken der am Aufbau der Homogenkatalysatoren beteiligten Komponenten konnte nicht gegeben werden.

Tabelle 5 zeigt die Abhängigkeit der Hydriergeschwindigkeit von Art und Stellung der Substituenten im Phenylrest. Die Hydriergeschwindigkeit ist bei den induktionsstarken Co-Katalysatoren 5 bis 7 deutlich vermindert.

The preparation of the optically active methyl-n-propyl(isopropy) aryl phosphines 1 ± 8 is described, whereby the aryl group is p-methoxyphenyl (1, 2), p-dimethylaminophenyl (3, 4), o-methoxyphenyl (5, 6), o-dimethylaminophenyl (7) and o-aminophenyl (8).

The phosphines 1–8 were used as chiral co-catalysts at the rhodium complex in the homogeneous hydrogenation of α- and ß-methyl cinnamic acids, α-acetaminoacrylic acid and α-acetaminocinnamic acid. The optical induction in the products was measured. The following results (see Tables 1–4) were obtained:

1) The methoxy and dimethylamino groups, independent of their site, have only negligible influence on the optical yield in the reduction of α- and ß-methylcinnamic acids compared with the parent methyl-propylphenylphosphine.

2) In the hydrogenation of acetaminoacrylic acid and α-acetaminocinnamic acid, para methoxy- or dimethylamino groups (compounds 1–4) show likewise no special influence on the optical yield.

3) Ortho methoxy or dimethylamino groups (compounds 5–7), however, result in a measurable increase in optical yield in the reduction of α-acetaminoacrylic- and α-acetaminocinnamic acids. In the case of compound 7 with α-acetaminocinnamic acid, an optical purity of 80% was obtained! The dimethylamino group is in this case more effective than the methoxy group.     

α-SUBSTITUIERTE PHOSPHONATE 50.1 Elektrochemisch generierte Basen als Reagenz für die Horner-Reaktion

Abstract

The radical anion 2 (electrochemically generated base), formed by electrochemical reduction of azobenzene (probase), is suitable for deprotonation of differently substituted phosphonates 4. α-Phosphonyl aniones 5, obtained by such approach, reacted in situ with carbonyl compounds to give α-substituted olefines 6. Similar reaction took place with stilbene as probase. —Side reactions with the solvent were observed with less acidic phosphonates, e.g. 4h.

Das bei kathodischer Reduktion von Azobenzen (Probase) entstehende Radikalanion 2 (elektrochemisch generierte Base) eignet sich zur Deprotonierung unterschiedlich substituierter Phosphonsäureester 4. Die so erhaltenen α-Phosphonylanionen 5 wurden in situ mit Carbonylverbindungen zu α-substituierten Olefinen 6 umgesetzt. Gleiche Reaktion trat mit Stilben als Probase ein.—Bei wenig aciden Phosphonaten wie 4h wurden Nebenreaktionen mit dem Lösungsmittel beobachtet.     

Synthesis of α- and β-Methyl NEU5Ac α-(2→8) NEU5Ac Disaccharides

ABSTRACT

Acid hydrolysis of colominic acid, an α-(2→8)-linked oligomer of sialic acid, yielded Neu5Ac α-(2→8) Neu5Ac (di-Neu5Ac) 2 as one of the products. Starting from this disaccharide, it was possible to prepare two potential di-Neu5Ac donors, 5 and 8, as their corresponding 2-chloro derivatives. Subsequent reaction of the donor 8 with methanol as a simple acceptor led to the α- and β-methyl Neu5Ac α-(2→8) Neu5Ac glycosides.     

Stereochemie von Metallocenen, 15. Mitt.: 38. Mitt. über Ferrocenderivate Lösungsmitteleinflüsse auf die optische Aktivität und das Konformationsgleichgewicht von α-Acetyl-methylferrocen

Zusammenfassung Aus den molaren Amplituden desCottoneffektes (um 440 nm) von Ferroceno[1.2]cyclohexenon (1) und -Acetyl-methylferrocen (2) in verschiedenen Lösungsmitteln und Lösungsmittelgemischen kann unter Verwendung eines früher beschriebenen Modells der Einfluß des Lösungsmittels sowohl auf die optische Aktivität dieser Verbindungen als auch auf das Konformationsgleichgewicht von 2 abgeleitet werden.

---

The molecular amplitudes of theCotton effects (at about 440 nm) of ferroceno[1.2]cyclohexenone (1) and -acetylmethylferrocene (2) were measured in various solvents and solvent mixtures. Using a model, described earlier, the influence of the solvent both upon the optical activity of these compounds and the conformational equilibrium of 2 can be deduced from these amplitudes.

---

---

Mit 3 Abbildungen

---

14. Mitt.:Heike Gowal undK. Schlögl, Mh. Chem.99, 267 (1968).

---

37. Mitt.:H. Falk undG. Haller, Mh. Chem.98, 2290 (1967).     

SYNTHESIS OF α-AMINOORTHOESTERS FROM O-TOSYLHYDROXIMATES

ABSTRACT

The abstraction of the acid hydrogen of O-tosylhydroximates 1 by sodium ethylate, then nucleophilic attack of the excess of sodium ethylate at the more hindred carbond atom of azirine 2 and aziridine 3 intermediates to give the α-aminoorthoesters (35–45% yields). The α-aminoorthoester 4a is transformed into α-iminoorthoesters 5a (63% yield) and α-amidoorthoester 6a (65% yield).     

A Proline-Based Aminophosphinic Acid Ligand and It’s Vanadyl Complex: Synthesis,Characterization and In Vitro Inhibitory Effects on α-Amylase And α-Glucosidase

Abstract

A proline-based aminophosphinic acid ligand and it's vanadium complex have been synthesized and characterized by spectroscopic techniques. The inhibitory activity on pancreatic α-amylase and Baker's yeast α-glucosidase has been examined in vitro. The novel complex showed more inhibitory potency against pancreatic α-amylase and Baker's yeast α-glucosidase compared to acarbose as an antidiabetic drug.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis of Novel Bisphosphonate Inhibitors of Phosphoglycerate Kinase (3-PGK) (E.C.2.7.2.3)

Abstract

Novel, aromatic bisphosphonates have been synthesised as non-systematic analogues of 1,3-bisphosphoglyceric acid (1,3-BPG). These incorporate non-scissile α-halo and α-methylene phosphonates and have submicromolar K _i values for 3 -PGK.     

Efficient α-Thiocyanation of Ketones Using Pyridinium Hydrobromide Perbromide

Abstract

The direct α-thiocyanation of ketones with ammonium thiocyanate has been achieved using pyridinium hydrobromide perbromide under mild and neutral conditions to produce α-ketothiocyanates in excellent yields and with high selectivity.     

Synthesis and Reactivity of Fluoro(Organyl)Phosphanes

Abstract

A new method for producing fluoro(organyl) phosphanes is presented. They are prepared by Cl/F-exchange from the corresponding chloro compounds using Et₃N.nHF as a fluorinating agent. Phosphanyl fluorophospharanes, R₂P-PR₂F₂, are found to be intermediates of the disproportionation of Fluoro (diorganyl) phosphanes. R₂PF react with aldehydes to form phosphinito phosphoranes, R₂PF₂-CHR'-OPR₂. Oxaphospholenes are formed in their reaction with α, β- unsaturated aldehydes. Furthermore, the reactions with 1.2-diketones, carboxylic acid derivatives, and covalent azides are described.     

First,Highly Stereoselective Synthesis of Neotrehalosamines

ABSTRACT

Among the known non-symmetrical naturally occurring aminotrehaloses possessing antimicrobial activity, the stereoselective synthesis of α, α-linked D-glucosaminyl-D-glucoside as well as of D-glucosaminyl-D-mannoside has been reported.¹ In contrast, the synthesis of the α, β-isomer composed of two 2-amino sugar units occurring in tunicamycin antibiotics 1 has not been studied to the same extent and is not readily obtainable in pure form.     

New Bisphosphonates,Synthesis and Reactions

Abstract

The synthesis and reactions of new bisphosphonates with different substituents in α-position as well as a new type of trisphosphonate are described.     

Reactions of α-Formyl-α-Chlorcyclonones and γ-Butyrolactone with S-Trirnethylsilyl Ester of Dialkyldithiophosphoric Acid

Abstract

α-Formyl-α-chlorsubstituted cyclonones or α-formyl-α-chlor-γ-butyrolactone react with O,O-diizopropyltrimethylsilyldithiophosphate to give adducts which rearrange thermaly to α- dithiophos phoryl contained β-dicarbonic compounds.     

β-Ketonitrosamines as Synthetic Equivalents of α-Methinyl Methylamino (R-Chnhch3) and α-Methinyl Alkylamino (R−Chnhr′) Anions

Abstract

β-Ketonitrosamines have been established as anionic synthons of the type (RCO^{+ ?}CHNHR′). The enhanced acidity of protons at the α-carbon, as well as the ease of fragmentation of the title compounds, established them as synthetic equivalents of α-methylenealkylamino anions (^?CH2NHR). We now report the equivalency of β-ketonitrosamines to α-methinyl methylamino (R^?CHNHCH₃) and α-methinyl alkylamino (R ^?CHNHR′) anions.     

IODODECARBOXYLATION OF α-CARBOXYLATE, α-CINNAMOYL KETENE CYCLIC DITHIOACETALS

ABSTRACT

The iododecarboxylation reaction of α-carboxylate, α-cinnamoyl ketene cyclic dithioacetals 2 was successfully performed with iodine as halogenation reagent and in water insensitive media. This reaction provides a mild and efficient method for the preparation of α-iodo, α-cinnamoyl ketene cyclic dithioacetals 3 which are important kinds of potential new intermediates to be valued.     

Novel Rearrangements and Heterocyclisation of P-Imides

Abstract

The preliminary introduction of electron accepting dichlorophosphine group at nitrogen atom of N-monosub-stituted α-aminoketones or α-aminocarbon acid esters increases the mobility of the α-carbon hydrogen atom so, that the intermolecular O-phosphorylation is enabled.¹     

Syntheses of D-Myo-Inositol-1,2,6-Trisphosphate and -2,6-bisphosphate

Abstract

A D-myo-inositol derivative (3), obtained from methyl α-D-glucopyranoside by Ferrier rearrangement, was efficiently transformed to D-myo-inositol 1,2,6-trisphosphate (1, α-trinositol) and D-myo-inositol 2,6-bisphosphate (2).     

Chiral α-Aminophosphonates: Synthesis and Transport Properties

Abstract

Synthesis of chiral α-aminophosphonates and their transport properties (rates, enantioselectivity) as membrane carriers for oxy and amino acids are discussed.     

A Simple and Catalyst-Free One-Pot Synthesis of α-Aminophosphonates in Polyethylene Glycol

Abstract

A simple and efficient method has been developed for the one-pot synthesis of α-aminophosphonates using polyethylene glycol (PEG) as a green reaction media.     

Assay of Brain Tocopherols Using High Performance Liquid Chromatography

Abstract

The four natural tocopherols were separated using a μ-Bondapak-NH₂ column. For the analysis of brain tocopherols 5,7-dimethyltocol was used as an internal standard. α-Tocopherylquinone and other tocopherols than α-tocopherol were not detected. Rat cerebral cortex and cerebellum contained 19.3 μmol/g and 11.2 μmol/g of α-tocopherol, respectively. A chromatographic system with a reversed-phase column proved less suitable.