A Facile One‐Step Method to Prepare Three‐Dimensional Ordered Latex Particles

Three‐dimensional ordered latex particles were prepared in presence of polymerizable anionic emulsifier—sodium undec‐10‐enoate (UDNa) in emulsion polymerization. Only under a certain monomer/emulsifier ratio can we get such a result. Three‐dimensional ordered latex particles cannot be acquired with the use of conventional emulsifiers such as sodium dodecyl sulfate (SDS), etc. The double bond of polymerizable emulsifier can copolymerize with the main monomer and become covalently bound to integrate with the main polymer chains which result in stable latexes. TEM and SEM images show that whether it is diluted or not the latexes can always keep in the three‐dimensional regularly order.     

A Facile Route for the One‐Step Synthesis of New Fully Aromatic Poly(urea‐imide)s

The direct preparation of various aromatic poly(urea‐imide)s (5a₁ –5b₄ ) from N‐[3,5‐bis(trimellitimido)phenyl]phthalimide (1) using diphenylphosphoryl azide (DPPA) was investigated. The polymers were obtained by the conversion of imide ring‐containing diacid 1 to corresponding di(carbonyl azide) 2 with DPPA and then to diisocyanate 3 through the Curtius rearrangement of compound 2. This was followed by polyaddition of 3 with two aromatic diamines (4a and 4b). In order to compensate the diisocyanate shortage against the diamines, some excess amounts of the initial triimide‐dicarboxylic acid 1 were used. The molecular weights of the resulting poly(urea‐imide)s were evaluated viscometrically. The poly(urea‐imide)s exhibited an excellent solubility in a variety of polar solvents. The crystallinity nature of the polymers was estimated by means of WXRD. The glass transition temperatures and the 10% wt loss temperatures of the polymers 5a₃ and 5b₃ were determined by DSC and TGA/DTG methods in nitrogen atmosphere, respectively. The transparent films of the resulting polymers were also prepared by casting the solution.     

Facile One‐Step Conversion of Ketones into α‐Azidoketones using [Hydroxy(tosyloxy)iodo]benzene and Sodium Azide in the Presence of a Phase‐Transfer Catalyst under Solvent‐Free Conditions

We have described a one‐step, solvent‐free synthesis of α‐azidoketones from the corresponding ketones that requires relatively benign [hydroxy(tosyloxy) iodo]‐benzene reagent, sodium azide, and phase‐transfer catalyst at room temperature. Generality of the protocol has been demonstrated by synthesizing various α‐azidoketones high in yield and purity within a short time.     

Lanthanum Trifluoromethane-sulfonate‐Catalyzed Facile Synthesis of Per‐O‐acetylated Sugars and Their One‐Pot Conversion to S‐Aryl and O‐Alkyl/Aryl Glycosides†

Lanthanum trifluoromethanesulfonate‐catalyzed solvent‐free per‐O‐acetylation with stoichiometric acetic anhydride proceeds in high yield (95%–99%) to afford exclusively pyranose products as anomeric mixtures. Subsequent anomeric substitution employing borontrifluoride etherate and thiols or alcohols furnished the corresponding 1,2‐trans‐linked thioglycosides and O‐glycosides, respectively, in good to excellent overall yield (75%–85%). Alternatively, reaction of free sugars in neat alcohol employing the same catalyst at elevated temperature gives the corresponding 1,2‐cis‐linked O‐glycosides (along with 1,2‐trans‐linked glycosides as minor product) in good yield (73%–80%). Anomeric mixtures of compounds thus produced were characterized as their per‐O‐acetylated derivatives.      

One‐Step Synthesis of Aromatic Terminal Alkynes from Their Corresponding Ketones under Microwave Irradiation

One‐step microwave‐assisted synthesis of phenylacetylenes 2a–j from the corresponding ketones 1a–j in the presence of a new reagent, PCl₅–pyridine, is described. The reaction is carried out under a simple operational and experimental procedure, avoiding the use of the complicated and harsh multistep reaction.     

One-pot Approach to the Conversion of Alcohols into α-Halo-α,β-unsaturated Esters

α-Halo-α, β-unsaturated esters are important intermediates in organic synthesis. For example, they are used for α-amino acid preparation1 and vinylogous Darzen reactions2, as a versatile fluorinated building block, they are also used for the preparati…     

One-Pot Approach to the Conversion of Alcohols into α-Iodo-α,β-unsaturated Esters

(Carboethoxymethylene)triphenylphosphorane 1 can undergo the tandem reaction of iodination–oxidation–Wittig reaction with alcohol in the presence of N-iodosuccinimide (NIS) and manganese dioxide. The reaction constitutes a stereoselective one-pot procedure for the preparation of Z-configured α-iodo-α,β-unsaturated esters in good to excellent yield.     

One Step of Palladium Catalyzed Benzodioxane Ring C–O Bond Formation,Synthesis of Isoamericanol A and Isoamericanin A

Abstract

A number of benzodioxane compounds were synthesized using the palladium‐catalyzed etherification of aryl halides by employing triphenylphosphane ligands. This method was used as key step in the synthesis of two natural products isoamericanol A and isoamericanin A.     

Facile One‐Step Syntheses of Modified O‐Glycoprotein Galβ1‐3GalNAc Structures by Transglycosylation Employing Three β‐Galactosidases from Bovine Testes,Xanthomonas manihotis,and Bacillus circulans *

Natural O‐glycoproteins such as the Thomsen‐Friedenreich antigen or gangliosides contain the motif Galβ1‐3GalNAc as an important disaccharide with significant biologic activity. The arrangement of spatial functionalities in this structure are of particular interest with regard to the development of potential leads en route to pharmaceuticals. Therefore, it was desired to obtain access to a range of modified derivatives of the aforementioned motif paying particular attention to introducing specific deoxy functions instead of hydroxyl groups.     

1,6‐C‐H and 1,5‐O‐Si Insertion Reactions of Alkylidenecarbene Derivatives of Monosaccharides*

A new protocol has been developed for the generation of alkylidenecarbene derivatives of monosaccharides based on the reaction of trimethylsilylazide and Bu₂SnO with α‐cyanomesylates derived from uloses. When this method is applied to conveniently functionalized carbohydrate derivatives it provides novel heterocyclic ring systems by the rare 1,6‐C‐H or 1,5‐O‐Si insertion reactions.     

A Facile Synthesis of α-Phenylthio-α,β-Unsatuated Esters

α-phenylthio-α，β-unsaturated esters 6 were synthesized by Witting reaction of 3.which were prepared by a phenylsulfenyllation-trans-ylidation reaction.     

W/O/W Multiple Emulsions Obtained by One‐Step Emulsification Method and Evaluation of the Involved Variables

The effects of some composition variables on the development of multiple emulsions by one‐step method were evaluated and their morphology characterized. The formulations that remained stable during the period of the test were submitted to centrifugation and thermal stress tests. The stability and the morphology of multiple droplets were affected not only by the type and concentration of the surfactants employed, but also by the water/oil ratios used. The results suggest that the formation of multiple droplets could involve a combination of transitional and catastrophic phase inversions. The results provide improved knowledge about the one‐step emulsification method, a simplified process to prepare multiple emulsions when compared to the two‐steps method.     

Facile Deprotection of Aromatic tert‐Butyl and Allylic Esters Under Microwave Irradiation Conditions

Abstract

A simple and efficient method for the deprotection of tert‐butyl and allylic esters is described, which occurs under microwave irradiation with p‐toluenesulfonic acid in solvent‐free conditions.     

Acid‐Promoted Ring Opening of α‐Hydroxyl Cyclobutanones: A Novel and Facile One‐Pot Synthesis of Nitrile Derivatives

A facile one‐pot synthesis of nitriles via a ring‐opening reaction of cyclobutanone adducts with hydroxylamine hydrochloride was developed.     

High-Yielding One-Step Conversion of D-Glucose and D-Galactose to the Corresponding α and β Methyl-D-glucofuranosides and Galactofuranosides

D-Glucose and D-Galactose are transformed to the corresponding α and β -Methyl D-Glucofuranosides in good yields using methanol and Ferric chloride as catalyst.     

Synthesis,Crystal Structure,and Conversion of the Polycyclic Tris‐Anhydrotetramer of O‐Aminobenzaldehyde to Cu(TAAB)2+

Abstract

Polycyclic tris‐anhydrotetramer 6 of o‐aminobenzaldehyde was synthesized directly from reduction of o‐nitrobenzaldehyde and its structure was determined by X‐ray crystallography. This provides a practical synthesis of 6, as opposed to starting from the unstable o‐aminobenzaldehyde. The tris‐anhydrotetramer 6 is useful for the synthesis of a variety of TAAB‐metal complexes.     

A Facile Method for the Preparation of Pure cis‐2,4‐Pentanediol

Abstract

The isolation of diastereomerically pure cis‐2,4‐pentanediol from a crude mixture of both cis‐ and trans‐2,4‐pentanediols is described through a short procedure involving thermodynamic acetal formation with acetophenone, followed by hydrogenolysis of the acetal protecting group.     

A Single‐Step Assembly of Coumarin Ring Skeleton from Oxygenated Phenols and Acetylenic Esters by Catalytic Indium Chloride in the Absence of Solvent

Abstract

Ring oxygenated coumarins were obtained in a single‐step by condensation of appropriately substituted phenols with acetylenic esters by catalytic amounts of indium chloride in the absence of solvent.     

Efficient and Catalytic Conversion of Epoxides into 1,3‐Dioxolanes with LiBF4

Abstract

Lithium tetrafluoroborate catalysis the efficient conversion of epoxides with acetone to the corresponding 1,3‐dioxolanes in excellent isolated yields.     

A Novel,Convenient Synthesis of the 3‐O‐β‐D‐ and 4′‐O‐β‐D‐Glucopyranosides of trans‐Resveratrol

Abstract

trans‐Resveratrol‐3‐O‐β‐D‐glucupyranoside (trans‐piceid, 2) and trans‐resveratrol‐4′‐O‐β‐D‐glucupyranoside (trans‐resveratroloside 3) are the naturally occurring O‐glucoside conjugates of the polyphenolic stilbenoid trans‐resveratrol 1. Recently, attention has been drawn towards the interesting biological properties of the glucoside conjugates 2 and 3 as well as those of the aglycone 1. The fact that only limited quantities can be obtained by extraction from natural sources has prompted the development of novel syntheses of 2 and 3, based on a convergent Heck‐coupling strategy, which now conveniently allows for the preparation of multi‐milligram to gram quantities of each.