An Efficient One Pot Synthesis of α-Iodo-α,β-unsaturated Esters,Ketones and Nitriles via Arsonium Salts

A number of α-iodo-α,β-unsaturated compounds 3 were synthesized under mild conditions via corresponding readily available arsonium salts 1 in one pot reaction.     

A Convenient Synthesis of Vinyl Epoxides from Glycidic Esters via α-Hydroxy-β,γ-unsaturated Esters

Glycidic esters, upon isomerisation with BF₃.Et₂O yield α-hydroxy-β,γ-unsaturated esters. These are then reduced with LiAlH₄ to vicinal diols which are converted to vinyl epoxides in two steps.     

A Convenient Synthesis of β-Ketosulfoxides

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

A Convenient Synthesis of β-Chloro, β-Methylthio α,β-Unsaturated Ketones from β-Oxodithioesters

The reaction of β-oxodithioesters with the Vilsmeier-Haack reagent prepared from POCl₃ and DMF provide β-chloro, β-methylthio α,β-unsaturated ketones in good yields.     

A Convenient Synthesis of Protected α-Hydroxyacetaldehydes

Starting from 2, 3-O-isopropylideneglycerol (1), a general procedure for the preparation of protected α-hydroxyacetaldehydes has been developed.     

Synthesis of β-carbolines from aldehydes and ketones via the α-siloxy α,β-unsaturated esters

We report an efficient method for the synthesis of β-carbolines from α-siloxy α,β-unsaturated esters, which are accessible from a variety of aldehydes and ketones.     

A Convenient Synthesis of β-Amino Acid

We have reported the reductive cleavage of azlactones¹ and phenylhydrazones² of carbonyl compounds in the presence of a suitable catalyst. In this paper a general method involving a one step synthesis of β-amino acid^3,4, in good yield, through catalytic reduction of oximes of α-β-unsaturated acid is reported. This method involves the reaction of α, β-unsaturated acid with hydroxylamine hydrochloride in the presence of sodium acetate. Markovnikov's rule is followed in the synthesis of oximes of α, β-unsaturated acids.     

A Convenient Synthesis of α-Hydrosyiminoacetonitriles from Aldoximes

Aromatic α-hydroxyiminoacetonitriles can be conveniently prepared by a facile one-pot procedure in high yields involving chlorination of the corresponding aldoximes with tert-butyl hypochlorite followed by reaction with alkali cyanide.     

An Improved Synthesis of α-Phenylseleno Arsonium Ylides

The first a-seleno arsonium ylides have been synthesized by Typical procedure for the synthesis of compound sa. To a stirred suspension ofmethoxycarbonylmethylene triphenylarsorane (4a) (0.378 g, I mmol) and triethylamine(0. I I g, 1. 1 mmol) in MeOH-Et,O (0.6 mml, v/v=l f I ) was added dropwise the solutionof phenylselenenyl iodide 2 (0.85 mmol) in MeOH-Et,O (2.8 mml, v/v=l f l) at 0 "C for14 hrs. The mixture was stirred again for 6 hrs. After the solvent in the mixture wasevaporated un…     

Reactions of α-halo-α, β-unsaturated aldehydes with secondary amines

Reactions of 2-halo-2-alkenals R(R)C=CX-CHO with secondary amines R₂NH occur asipso-substitution of the halogen atom, along with fragmentation and condensation, yielding 1,2-diaminoethenes R₂NCH=CHNR₂, carbonyl compounds RC(O)R, 1,3-bis(amino)-2-haloolefins R(R)C(NR₂)CX=CHNR₂, and formamides R₂NCHO. The ratio between the competing reactions depends on the structure of the starting compounds and the experimental conditions.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp, 135–138, January, I996.     

A New Convenient Synthesis of α-Arylpropionic Acid Esters and α-Arylpropionitriles

Various types of α-arylpropionic acid esters were effectively obtained by the coupling reaction of aryl Grignard reagents and α-bromopropionic acid esters in the presence of nickel catalysts. α-Arylpropionitriles, precursors of α-arylpropionic acids, were also synthesized by the reaction of α-methanesulfonyloxypropionitrile and arylcopper reagents prepared from equimolar amount of arylmagnesium halides and copper(I) bromide.     

Cyclization Reaction of α-Triazolyl-α, β-unsaturated Ketones with Phenyl hydrazine

InourpreviousworkwehavereportedthestudiesonthereactionofvinyItriazolcderivativeswithhydroxylamine,andfOundthatcycloadditiontookp1aceandthenewheterocycliccompoundsl,2-oxazocyclopentaneshavingplant-growthregulatingactivitywereobtainedl,2.InordertosynthesizenewheterocycliccompoundsandtosearchfOrnewcompoundshavingbioactivity,thereactionofa-triazolyl-a,ll-unsaturatedketones(Z)-or(E)-4,4-dimethyl-1-aryl-2-(l,2,4-triazol-l-yl)-l-penten-3-onesI.-bwithphenylhydrazinewasstudied.Theresultshowedthatcycl…     

Regioselective synthesis of α-bromo-α,β-unsaturated carbonyl compounds via photocatalytic α-bromination reactions

A visible light-mediated approach for the preparation of α-bromo-α,β-unsaturated ketones and aldehydes was developed. In comparison to traditional methods that generally take two steps to afford the above compounds, this protocol was highlighted by its operational simplicity, avoiding using hazardous bromine and mild reaction conditions.     

A Facile Stereoselective Synthesis of Ether-Linked β-D-Maltosyl- and β-D-Lactosyl-glycerolipids via Peracetylated Disaccharide α-Phosphoramidates

The reaction of 1-O-hexadecyl-2-O-methyl-sn-glycerol with 2,3,6,2′,3′,4′,6′-hepta-O-acetyl-α-lactosylphosphoramidate or α-maltosylphos-phoramidate in the presence of trimethylsilyl triflate and molecular sieves afforded 1-O-hexadecyl-2-O-methyl-3-O-(2,3,6,2′,3′,4′,6′-hepta-O-acetyl-β-lactosyl)-sn-glycerolipid or β-maltosyl-sn-glycerolipid stereoselectively in moderate yields after column chromatography. Alkaline hydrolysis of the O-peracetyl glycerolipids gave the desired β-glycolipids 1 and 2.     

Stereoselective Synthesis of Sulfonyl-substituted trans-2,3-Dihydrofuran Derivatives via Reaction of Arsonium Ylides with α,β-Unsaturated Ketones

Trans-2,3-dihydrofuran derivatives 3 or 4 substituted with a sulfonyl group were prepared with high chemoselectivity and good yields by [1＋4]-addition reaction of α,β-unsaturated ketones 1 with arsonium bromide 2 in CH2Cl2 in the presence of potassium carbonate at room temperature.The structures of the products were characterized by IR,MS,^1H NMR,elemental analysis and single crystal X-ray diffraction analysis.A mechanism for the formation of products was also proposed.     

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 New Convenient Synthesis of Pyridine-N-oxides

ＡＮｅｗＣｏｎｖｅｎｉｅｎｔＳｙｎｔｈｅｓｉｓｏｆＰｙｒｉｄｉｎｅ－Ｎ－ｏｘｉｄｅｓＴａｏＬＵ；ＸｉｎＺｈｏｎｇＳＨＩ；ＹｉＭｉｎｇＷＵ（Ｄｅｐｔ．ｏｆＯｒｇａｎｉｃＣｈｅｍｉｓｔｒｙ，ＣｈｉｎａＰｈａｒｍａｃｅｕｔｉｃａｌＵｎｉｖｅｒｓｉｔｙ，Ｎａ...     

A Convenient Synthesis of Unsymmetrical N,N′-Disubstitutedα,ω-Diaminoalkanes

A general procedure is described for regiospecific construction of unsymmetrical N-alkyl (or aralkyl)-N′-aryl-α,ω-diaminoalkanes 3 (n=2,3,4) by reduction of N-(ω -arylaminoalkyl)amides 2 with borane. Compounds 2 are readily obtained by condensation of N-(ω-haloalkyl)amides 1 with aromatic amines.