A Facile Route to Cyclic and Acyclic Alkyl-Arginines

Treatment of commercially available alkyl and cycloalkyl thioureas with methyl iodide provides the corresponding S-alkylisothiouronium iodide which reacts directly with ornithine to yield the title compounds.     

Efficient Synthesis of Epoxides from Vicinal Diols Via Cyclic Sulfates

Reaction of cyclic sulfates of vic-diols with sodium hydroxide in THF-MeOH produced the corresponding epoxides in excellent isolated yields at room temperature. Cyclic sulfates of trans-diols gave cis-epoxides, and cyclic sulfates of cis-diols afforded trans-epoxides exclusively. Various cyclic sulfates of vic-diols can be converted into the epoxides under the conditions.     

A Facile Route to Indolo

Treatment of 1-(2'-bromobenzyl)-3,4-dihydroisoquinolines 2 in the presence of K(2)CO(3) in boiling DMF efficiently provided a variety of alkoxy-substituted indolo[2,1-a]isoquinolines 3. Application of this cyclization to 7-benzyloxyisoquinoline derivatives, followed by further elaboration of the resultant 2-benzyloxy-5,6-dihydroindolo[2,1-a]isoquinolines 16a,b, led to the formal synthesis of dibenzopyrrocoline alkaloids, (+/-)-cryptaustoline (1a) and (+/-)-cryptowoline (1b).     

A Facile Conversion of Tertiary Alcohols to Olefins

An efficient method for the dehydration of tertiary alcohols to obtain olefins in high yield, employing methanesulfonyl chloride-triethylamine and catalytic amount of 4-dimethylaminopyridine in dichloromethane, is described.     

Transformation of Terminal Diols of Cyclic and Acyclic Saccharides to Epoxides and Alkenes by Reaction with Triphenylphosphine,Imidazole and Iodine

ABSTRACT

Reaction of various terminal diols 1,4,6,8-12, derived from cyclic and acyclic monosaccharides, with 2 mol equivalents each of TPP-imidazole-I₂ between -8 °C and 15 °C in THF afforded the corresponding epoxides 2,5,7,13-17, respectively, with 4 mol equivalents each of TPP-imidazole-I₂ in toluene at reflux temperature the starting diols afforded the corresponding alkenes 3,18-24, respectively.     

A Facile Route to Unsymmetrical Sulfide

Unsymmetrical sulfides can be generated by the reaction of chlorine substituted aromatic compounds in sulfoxide in the presence of fluorine anion in fair yield.A likely mechanism was proposed.     

A Facile Synthetic Route to L-Phosphinothricin

Phosphinothricin, the active ingredient of the well known broad-spectrum herbicideglufosinate-ammonium, is a naturally occurring amino acid possessing the uniquemethylphosphinate moiety, and its strong herbicidal activity has been attributed to anability to inhibit glutamine synthetase in plants and bacteria1. Further research showedthat L-enantiomer of phosphinothricin was the carrier of the activity, whereas the D formonly had a small action2, therefore the stereoselective synthesis of L-pho…     

A Short Facile Route to cis-Caronaldehyde

The title compound has been preapared by reduction of ciscaronic anhydride using disodium tetracarbonylferrate in good yield.     

一种直接混合生成Al13硫酸盐晶体的简易方法

将一定量的Na₂SO₄溶液直接加入在60～80 ℃温度下预处理过的Al₁₃溶液中，然后室温陈化12 h，可简便快速地制备具有四面体形貌和纤维状形貌的Al₁₃基硫酸盐晶体。所得晶体的SEM和OS图显示：用本文报道的方法合成的四面体形貌的硫酸盐晶体尺寸大小在150～200 μm，而通过滴定方法的却只有15～25 μm；纤维状的硫酸盐晶体的长径尺度分别是>1 000 μm和0.5～1 μm。对四面体形貌的Al_13<     

A Facile Synthesis Route to 1,3-dichlorodisilazanes

Since the pioneering work of Verbeek', considerable attention has focussed on researchdevoted to the preparation of silicon nitride- and silicon carbide- based ceramic materials.Owing to their promising potential for the formation of high-purity non-oxide siliconbased ceramics, organosilicon compounds (precursors) have attracted considerableinterest in recent years 2. The structures and the chemical composition of the precursorsstrongly effect the properties of the final ceramic materials. Acc…     

A Facile Route for Cyclic Polyelectrolyte Synthesis without Any Protection or Deprotection Process

Conventionally, protection and deprotection are required in the preparation of alkyne-terminated polymers. Herein, by tuning the feed molar ratio of catalyst to initiator or using proper solvent, well-defined alkyne-terminated poly(acrylic ester)s have been directly synthesized via atom transfer radical polymerization (ATRP), and the protection and deprotection are even avoided in this controlled polymerization process. After that, the terminal bromine is translated into azide group completely, and the obtained linear poly(acrylic ester) as PtBA is converted into cyclic PtBA by click reaction. Finally, cyclic poly(acrylic acid) (PAA) is prepared after hydrolysis of the cyclic PtBA, and it can be found that the desired cyclic polyelectrolyte actually exhibits quite different properties on conductivity and DSC compared with the linear one.     

A Facile Route to Group 13 Difluorodiorganometalates:

A facile synthesis utilizing tetra-n-butylammonium hydrogen difluoride and Group 13 alkyl compounds leads to the soluble salts 1 - 4. Compound 1 is the smallest difluoro-diorganoaluminate so far characterized. The corresponding gallium and indium derivatives 3 and 4 are not sensitive to moisture.     

A Convenient Method for the Synthesis of Alkenes from Vic-diols via Cyclic Sulfates with Magnesium Iodide

Reaction of cyclic sulfates of vic-diols with magnesium iodide in acetonitrile produced the corresponding olefins in excellent isolated yields at room temperature. Cyclic sulfates of trans-diols gave trans-alkenes exclusively. Cyclic sulfates of cis-diols gave a mixture of cis- and trans- alkenes. However, the cyclic sulfate of cyclic cis-diol afforded the corresponding cis-alkene only.     

A Facile Approach to 2-Arylethylamines Via Polymeric Palladium Catalyst

2-Arylethylamines were synthesized in moderate yields via Heck reaction of acrylamide with iodobenzenes in the presence of polymeric catalyst P-ph—phen. Pd (0) followed by hydrogenation and subsequent Hofmann reaction.     

A Facile and Convenient Synthesis of Lipophilic Tetraalkylammonium or Phosphonium Hydrogen Sulfates

Lipophilic tetraalkylammonium or phosphonium hydrogen sulfates are easily synthesizeó in very high yields by action of KHS0₄ in 10% aqueous sulfuric acid on the corresponding quaternary azides, the latter being obtained by preparative ion-pair extraction from quaternary methanesulfonates or chlorides.     

A Facile Route to 9-Phosphorylated Neuraminic Acid Derivatives

The phosphitylation of 2-α-O-Benzyl-N-acetylneuraminic acid (2) and of the methyl 2-α-O-methyl-N-acetylneuraminate (3) with 2-chloro-4H-1,2,3-benzodioxaphosphorin-4-one (4) is described. The reaction affords a ready access to 9-phosphorylated derivatives of N-acetylneuraminic acid (1).     

Synthesis of Unsaturated Nitriles from Trisubstituted Olefins Via Ene-Type Chlorination

Unsaturated nitriles have been synthesized from trisubstituted olefins via ene-type chlorination and regioselective substitution with cyanide ion followed by double bond migration.     

Reaction of Polymer-supported Selenovinyl Bromide with Grignard Reagents： A Facile Route to the Synthesis of （E）-1, 2-Disubstituted Olefins

Polymer-supported selenovinyl bromide, easily prepared from polymer-supported selenenyl bromide with acetylene, reacts with different Grignard reagents using a step-by-step strategy to obtain （E）-1, 2-disubstituted ethenes in good yields.