Eung K. Ryu

A Convenient Synthesis of Nitrile Oxides from Aldoximes by 1-Chlorobenzotriazole

Abstract Nitrite oxides can be conveniently prepared from aldoximes utilizing 1-chlorobenzotriazole in dichloromethane. The reaction and work-up procedures are simple and the isolated yields high.

The synthesis, characterization, and preliminary biological evaluation of 1-β-D-arabinofuranosylcytosine-5′-diphosphate-L-1,2-dipalmitin

Abstract Recently, 1-β- D -arabinofuranosylcytosine-5′-diphosphate- DL -1,2-dipalmitin (VIa) was reported to inhibit the growth of L51784 cells in mice and of human colon carcinoma HCT-15 cells, also in mice. This paper describes the synthesis of a single diastereomer by conversion of 1-β- D -arabinofuranosylcytosine 5′-monophosphate (II) to the nucleoside 5′-phosphomorpholidate (III), followed by reaction with L -α-dipalmitoylphosphatidic acid (IV) to give 1-β- D -arabinofuranosylcytosine-5′-diphosphate- L -1,2-dipalmitin (V) in good yield. The separation of the product is described and its characterization by chromatography, elemental analysis, and spectroscopic methods. The lipophilic nature of V renders it insoluble in aqueous media and a method of sample preparation utilizing sonication techniques is described which provides a clear solution suitable for biological evaluation. In addition, the ability of V to inhibit the in vitro growth of L1210 cells and of mouse myeloma MPC 11 cells is desscribed and compared with 1-β- D -arabinofuranosylcytosine (I) and other lipophilic prodrugs of I.

A convenient synthesis of isothiocyanates from nitrile oxides

Abstract Isothiocyanats were prepared in quantitative yields from the reaction of nitrile oxides with thiourea in tetrahydrofuran at room temperature in short time.

Unusual iodine catalyzed lactonization of γ-methyl-γ,δ-pentenoic acids: A facile synthesis of γ,γ-dimethyl-γ-butyrolactones

Abstract γ,γ-Dimethyl-γ-butyrolactones were exclusively obtained from γ-methyl-γ,δ-pentenoic acids with a catalytic amount of iodine in good yields in methylene chloride.

Lewis acid promoted electrophilic aromatic substitution reaction of nitrile oxide: Increase of the electrophilicity of carbon atom of nitrile oxide by Lewis acid complexation

Abstract Nitrile oxides complexed with Lewis acid have their increased electrophilic character at the carbon atom and could be used as hydroxynitrilium ion equivalents toward aromatic compounds.

OXIDATIVE CHLORINATION OF ACETANILIDES WITH HYDROGEN CHLORIDE/M-CHLOROPERBENZOIC ACID/N,N-DIMETHYLFORMAMIDE SYSTEM

Abstract The reaction of phenols with relevant amounts of HCl and m-chloroperbenzoic acid in DMF at room temperature gave regioselective chloro-substituted phenols in good yields.

Improved Dehydration Method of Aldoximes to Nitriles: Use of Acetonitrile to Triphenylphosphine/Carbon Tetrachloride System

Abstract Nitrites can be conveniently prepared from aldoximes in improved and excellent yields using Ph3P/CCl4 in acetonitrile.

Friedel-Crafts Type Reactions of Some Activated Cyclic Ketones with Phenol Derivatives

Abstract Friedel-Crafts type reactions of phenol derivatives with some cyclic ketones such as ninhydrin (1), alloxan (2), isatin (3), and parabanic acid (4) were examined. 2-Monoaryl- and 2,2-diaryl-1,3-indanedione derivatives were obtained depending on the acid catalyst in the cases of ninhydrin and alloxan. In the case of isatin, the corresponding diarylated derivative was obtained as the sole product in high yields. Parabanic acid was unreactive under the reaction conditions.

Friedel-Crafts alkylation reactions of benzene with amide bond containing compounds

Abstract The reactions of benzene and various amide derivatives in the presence of anhydrous aluminium chloride or concentrated sulfuric acid have been examined, and found that these amide derivatives could be used as the electrophile sources in the Friedel-Crafts alkylation reactions.

A Convenient Synthesis of Isothiocyanates from Primary Nitroalkanes

Abstract The reaction of primary nitroalkanes with thiourea in the presence of 4-chlorophenyl isocyanate and a catalytic amount of triethylamine in benzene afforded isothiocyanates in moderate yields.