A Short and Highly Stereoselective Synthesis of Cerebrosterol

Ｃｅｒｅｂｒｏｓｔｅｒｏｌ (2 4Ｓ ｈｙｄｒｏｘｙｃｈｏｌｅｓｔｅｒｏｌ,1)ｆｏｒｍｅｄｉｎｓｍａｌｌａｍｏｕｎｔｓｉｎｈｕｍａｎａｎｄａｎｉｍａｌｂｒａｉｎ1ｆｒｏｍｃｈｏｌｅｓ ｔｅｒｏｌｉｓｉｍｐｏｒｔａｎｔｆｏｒｃｈｏｌｅｓｔｅｒｏｌｈｏｍｅｏｓｔａｓｉｓｉｎｔｈｉｓｏｒｇａｎ .Ｔｈｅｅｘｃｅｓｓｃｈｏｌｅｓｔｅｒｏｌｉｓｃｏｎｖｅｒｔｅｄｉｎｔｏ 2 4Ｓ ｈｙｄｒｏｘｙ ｃｈｏｌｅｓｔｅｒｏｌｂｙａｕｎｉｑｕｅｂｒａｉｎ ｓｐｅｃｉｆｉｃ 2 4Ｓ ｈｙｄｒｏｘｙｌａｓｅ ,ｗｈｉｃｈｃｏｕｌｄｂｅｒ…     

A Convenient Method for the Synthesis of Distamycin Analogue

A novel distamycin analogue was synthesized by chloroform reaction and DCC/HOBT coupling reaction without using amino protection and deprotection.     

A Convenient Method for the Asymmetric Synthesis of KAD-1229

A new method for preparation of the potent hypoglycemic KAD-1229 was developed.The key step of this method is diasteroselective alkylation in high optical purity and good yield by using easily available Oppolzer‘s camphor sultam as chiral auxiliary.     

A Convenient Method for the Synthesis of α-Functionalized Chlorophosphonic Esters

α-Functionalized chlorophosphonic monoesters were easily prepared by a selective chlorination of the corresponding phosphonic diesters with phosphorus oxychloride.     

A Convenient Method for the Generation of Dihalocarbenes

Yamawaki reported that alumina coated with potassium fluoride(KF-Al_2O_3),could b(?)used as a strong base to promote the generation of dichlorocarben(?) from chloroform,usingcyclohexene as the trapping agent.However,the yield of 7,7-dichlorobicyclo-[4.1.0]hep-     

A Convenient Method of Synthesis of Ferrocenylethynyl Ketones

It is well known that molecules possessing extensive conjugated π-electron systems exhibit large non-linear optical properties,[1,2] but the compounds of ferrocenylethynyl ketones have not been reported so far. We now reported preparation of some ferrocenylethyl ketones. These new ethynylketones containing ferrocenyl were prepared conveniently via coupling reaction catalyzed by PdCl2(PPh3)2/PdBzCl(PPh3)2-CuI from ferrocenylethyne and acyl chlorides. This coupling reaction proceeded smoothly in argon and free-water atmosphere at room temperature and gave coupling products in satisfactory yields. All products were characterized by 1H NMR, MS, IR and UV spectra.     

An Efficient and Convenient Cyclization Method for the Synthesis of Flavans

Flavansrefertoalargegroupofnaturallyoccurringcompoundspossessinga2-phenyl-chromannucleus.Naturallyoccurringflavansexhibitanumberofimportantbiologicalactivitieswhichifexploitedproperly,mayleadtovaluablenewdrugsoragrochemicals'.Inflavansynthesis,thekeystepistoconstructthe3,4-dihydrobenzopyranring-Variousmethodshavebeendevelopedfortheringformation,butmostoftheminvolvemultiplestepsandgivelowoverallyields2.Inthispaper,BF3wasusedforthefirsttimeasanefficientcatalysttoformthepyranringfroml,3-diaryIp…     

A Convenient Method for the Synthesis Of Tröger's Base Analogues

Para substituted anilines have been converted to Tröger's base analogues by refluxing with a mixture of methylal and methanesulfonic acid.     

Convenient Electrochemical Method for the Synthesis of α-Bromo Alkyl Aryl Ketones

An electrochemical procedure for the effective α-bromination of alkyl aryl ketones in excellent yield has been reported. The simple experimental procedure, catalyst-free conversion, and excellent yield of monobrominated products are the advantages of this method.     

A Convenient Method for the Synthesis of Chiral N-Protected 1, 2-Amino Alcohols via the Reduction of the Aminoketones

A series of optically active N-protected 1,2-amino alcohols were synthesized via the reduction of the corresponding α-aminoketones starting from the readily available L-amino acids.     

A New Method for the Synthesis of Ketone Diperoxide

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A Convenient Procedure for the Synthesis of 6-O-Mono-Phosphate β-Cyclodextrins

Abstract

The synthesis of β-cyclodextrin derivatives bearing one phosphate group on the primary rim is reported. These compounds were prepared in good to excellent yields, by reacting β-cyclodextrin with dialkyl chlorophosphates in the presence of 4-dimethyl amino pyridine (DMAP) catalyst and dimethylformamide (DMF) as solvent. The methodology described is highly selective and the purification of the title compounds is simple, because difficulties due to phosphate regioisomers mixture are avoided.     

A Convenient Method for the Conversion of α-Tetralones to Aryl Acetates

A facile synthesis of aryl acetates from α-tetralone has been performed with isopropenyl acetate and p-toluenesulfonic acid, followed by dehydrogenation with air or DDQ, in a one-pot procedure.     

New Stereoselective Synthesis of 4-Butyl-α-agarofuran

A potent anxiolytic 4-butyl-α-agarofuran (AF-5) was synthesized from ( )dihydrocarvone. Acid catalyzed hydration of ( )dihydrocarvone and interconversion with β-O-ketone 8 and the key intermediate α,β-unsaturated ketone 5 made this synthesis more practical.     

Convenient and One-pot Method for Synthesis of the Amino-methylene Bisphosphonic Acid Derivatives from Aldehydes

Bisphosphonic acids and their ester derivatives, carbon analogues of inorganic pyrophos- phate, are the most important organophosphorus compounds and exhibit unique physical and chemical properties in interaction with the alkaline earth cations or heavy m…     

Convenient Method for the 3‐Functionalization of Isoindazoles

The C‐3 position of isoindazoles is readily functionalized by metalation with lithium diisopropylamide followed by reaction with a variety of electrophiles.     

Novel Stereoselective Synthesis of （E）-β-Silylvinylstannanes via Hydromagnesiation of Silylarylacetylenes

Hydromagnesiation of silylarylacetylenes 1 in diethyl ether gave(E)-β-silylvinyl Grignard reagents 2,whichreacted with trialkylstannyl chlorides 3 to afford stereoselectively(E)-β-silylvinylstannanes 4 in good yields.     

Bismuth Mediated Organic Reaction: A Convenient Method for the Synthesis of Allylic (Benzylic) Selenides and α-Organylselenocarbonyl Compounds in Aqueous Media

Organic reactions promoted by active metals have aroused much interest in recent years. Active bismuth has been used in Barbier-type reaction of allylic halides with aldehydes1 and aldimines2 as well as Reformatzky type reaction3. Other publications referred to the cross coupling between aldehydes and α-diketones4, the substitution to benzotriazole drivatives5 and the reductive coupling reaction of nitro compounds6. These reactions generally promoted by elemental bismuth generated in situ fr…     

（Z）—α—Selanyl Alkenyl grignard Reagents as Convenient Precursors for Stereose

（Z）-α-Selanyl alkenyl Grignard reagents 2 were prepared conveniently by treatment of α-bromovinylselenides 1 with magnesium filings in THE Intermediates 2 were reacted with alkyl iodides in the presence of Cul or Pd(PPh3)4 to afford(Z)-1,2-disubstituted vinylselenides 3,which were cross-coupled with Grignard reagents in the presence of (PPh3)2NiCl2 to give trisubstituted alkenes 4 stereoselectively in good yields.     

A Convenient Synthesis of β-Ketosulfoxides

β-Ketosulfoxideshaveattractedmanyorganicchemistsbecauseoftheirwideuseinsynthesisofketones,a-ketols,glyoxals,a-ketoacids,glycols,a-hydroxyacidsandsoculGenerally,6-ketosulfoxidescanbepreparedbythereactionofesterwithsulfoxidel',acylchloridewithsulfoxi...