Studies on Glycosides VI. Facile Synthesis of Alkyl α-and β-D-Glucopyranosides

A facile Method for the synthesis of alkyl α- and β-D-glucopyranosides using 1-0-trimethylsilyt-2,3,4,6-tetra-O-benzyl-α-D-glucopyranose by the promotion of BF₃ET₂O was reported. The mixture of α -and β-anomers, in which β-anomers predominated, was obtained in good yields.     

Structure and Reactivity of Glycosides: IV. Koenigs-Knorr Synthesis of Aryl β-D-Glucopyranosides Using Phase-Transfer Catalysts

A series of acetylated aryl -D-glucopyranosides were prepared in 12-63% yields from tetra-O- acetyl--D-glycopyranosyl bromide and phenols containing acyl, formyl, and hydroxy substituents, and also from sterically hindered phenols in the two-phase system chloroform-aqueous alkali in the presence of triethylbenzylammonium chloride. Hydroxyethylated sucrose and dibenzo-18-crown-6 do not behave as phasetransfer catalysts in glycosylation of phenols.     

Chemical Synthesis of Several 2'-O-, 3'-O-Glycosylated Diosgenyl β-D-Glucopyranosides

ABSTRACT

Six 2'-O-, 3'-O-glycosylated diosgenyl β-D-glucopyranosides (4-9), which have a typical structural pattern of diosgenyl saponins, were synthesized; their synthetic routes are discussed.     

Efficient Synthesis of 3‐Substituted Coumarins

Abstract

The Mukaiyama's esterification protocol, using 2‐chloro‐1‐methylpyridinium iodide‐triethylamine reagent, has been successfully exploited to provide rapid access to a variety of 3‐substituted coumarins in satisfactory yields.     

The Synthesis of a Series of Phosphoryl Coumarins

Different hydroxy substituted coumarins were successfully phosphorylated with diisopropylphophite （DIPPH） by the Atherton-Todd reaction in 76-89% yields. Moreover, the reaction activities of different hydroxys of the coumarins in the Atherton-Todd reaction were studied.     

Synthesis of Modified Methylaluminoxane

Methylaluminoxane (MAO) is one of the most important cocatalysts of metallocene catalysts. The yield and activity of MAO is low when using Al2(SO4)3 nH2O and other inorganic hydrates to synthesize methylaluminoxane. The repeatability of this reaction is not good. The product cost is very high because one of the raw materials (Trimethylaluminium, TMA) to prepare MAO is very expensive. In addition, on standing, MAO toluene solution tends to gel. Gelled MAO can not be used to prepare su…     

Synthesis based on β-phenylethylamines. IX. Synthesis of sulfides of β-phenylethylamines and of N-benzyltetrahydroisoquinolines

New bimolecular sulfur-containing -phenylethylamines and N-benzyltetrahydroisoquinolines have been synthesized from formyl derivatives of diaryl sulfides. The possibility of using metals as catalysts for obtaining diaryl sulfides in the reaction of ortho-substituted benzaldehydes with SCl₂ has been shown for the first time.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 731–735, September–October, 1995. Original article submitted November 11, 1994.     

Combinatorial Synthesis of O-Pyrimidinyl Substituted Methyl-α-D-Glucopyranosides

Within last decade, many pyrimidinyl oxy substituted alcohols, aldehydes and carboxylic derivatives had been found with prominent bio-activities such as high herbicidal activities with wide spectrum. After extensively study of the relationship between structures and bioactivities, A brand-new scaffold combining both pyrimidinyl and glucoside moieties was designed and other building blocks were further introduced with the help of polymer-supported regioselective protecting groups. As shown below, a combinatorial synthesis was carried out by applying "mix-split" method to produce the following series of small compounds libraries both in solid-phase and liquid phase.     

Addition of Organocuprates to Ketoketenimines. Synthesis of β-enaminoketones

Base-induced ring cleavage of 3-unsubstituted isoxazolium salts followed by reaction of the resulting ketoketenimine with organocuprates affords asymmetric β-enaminoketones in high yields.     

Unsaturated ketones and macrocyclic lactones Communication 12. Synthesis of macrocyclic β-hydroxy lactones

Summary A sixteen-membered diacetylenic -hydroxy lactone was synthesized by the oxidative intramolecular condensation of acetylenes, and by its reduction the corresponding dienic and saturated -hydroxy lactones were prepared.Translated from Izvestiya Akademii Nauk SSR, Seriya Khimicheskaya, No. 5, pp. 860–863, May, 1964     

The β-Methoxyethoxymethyl Protecting Group in Alkaloid Synthesis. Synthesis of Abresoline

The isolation of abresoline (1), the only seco-Lythraceae alkaloid, is one of the few pieces of evidence for the proposed oxidative coupling pathway for the biosynthesis of the Type I Lythraceae alkaloids.¹ We required compound 2 for our study of oxidative ary1 coupling as a synthetic route to these alkaloids. The similarity between 1 and 2 prompted the investigation of the synthesis of abresoline as a model for the preparation of 2 and related compounds.     

Synthesis of affinity column of phosphatidylinositol-3,4-diphosphate

Phosphatidylinositol polyphosphates (PIPx) are related with tyrosine kinase activation, cell proliferation and carcinogenesis. In order to investigate the action mechanism of PIPx, it is desirable to synthesize affinity column of PI-3,4-P2, which is expected to be able to isolate the binding proteins of PI-3,4-P2. Thyramine reacted with CH-Sepharose 4B giving column 13. The p-amino group of 3'-(1',2'-distearoyl-glyceryl)-1-(2-p-aminobenzyl)-3,4-di-O-phosphoryl-myo-inosityl phosphate (12) was diazotized, then diazo-coupled with column 13 to give PI-3,4-P2 affinity column 14. This PI-3,4-P2 affinity column is an effective tool to pick up binding proteins of PI-3,4-P2.     

Synthesis of a New Polysiloxane Modified Polyurethane

It is well known that the polysiloxane polymers possess important physical and chemical properties, such as very good resistance to temperature and oxidant agents, very low glass-transition temperature, high permeability to gases and biocompatibility. But…     

Synthesis of 2-Methylenesuccinimides Modified by Germatranes

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Mono Halogenation of β-Keto Sulfides. Synthesis of β-Keto-α-phenylthio p-Tolyl Sulfones

β-Keto-α-Phenylthio p-Tolyl sulfones are obtained from β-keto-alkyl phenyl sulfides by halogenation with NCS followed by treatment with sodium p-toluene sulphinate.     

Synthesis of Unsymmetrical β-Arylaminoketones

Azomethines derived from aniline were condensed with acetophenone derivatives to obtain new unsymmetrical -arylaminoketones.     

New Synthesis of β-Iodostyrenes

A general procedure for the synthesis of -iodostyrenes is proposed. Aromatic aldehyde and ketone hydrazones are converted into the corresponding -iodostyrenes by treatment with CHI₃ in the presence of a catalytic amount of CuCl.     

Synthesis of β-Sulfoximinopropionic Acids

2-Benzyl-3-(methylsulfoximino)propionic acid has been prepared from 2-benzyl-3-(methylthio)propionamide by cyclization to a isothiazolinone hydrochloride with N-chlorosuccinimide, followed by peracid oxidation and acidic hydrolysis.