A New Route to the Synthesis of Ninhydrin

邻苯二甲酸二丁酯同乙酰乙酸乙酯的钠盐反应得到１，３－二酮氢化茚，再经二氧化硒氧化合成出较高收率的茚三酮。     

A New Synthetic Route for Preparation of 2-Chloro-6-fluoro-benzonitrile and 2-Chloro-6-fluorobenzoic Acid

An effective synthetic route for preparation of 2-chloro-6-fluorobenzonitrile, 2-chloro-6-fluorobenzamide and 2-chloro-6-fluorobenzoic acid has been described. It includes diazotization,fluorination, ammoxidation and hydrolysis reactions.     

Hypochlorous Acid. A Synthesis of α-Chloro-β-Lactones

Herein we report that the reaction of hypochlorous acid with certain α,β-unsaturated acids in a two phase system^1,2 affords α-chloro-β-lactones^3,4 in poor to fair yield. Thus, β-lactones 4, 5, and 6 are obtained from acids 1, 2 and 3, respectively, where the β-carbon of the acid is disubstituted.     

Azo-coupling Decarboxylation Reaction of α-Carboxy Ketene Dithioacetals in Water-a New Route to 1,2-Diaza-1,3-butadienes

Under basic conditions,a series of 4,4-dialkylthio-1,2-diaza-1,3-butadienes were synthesized in good to excel-lent yields via a novel azo-coupling decarboxylation reaction by reacting α-carboxyl ketene dithioacetals witharyldiazonium salts in aqueous medium.     

A New Synthetic Route to 5-Isoxazolamines

5-Isoxaz0lamineshavebeenusedasintermediatesforthesynthesis0fderivatives0fantihistaminic,analgetic,antibacterial,insecticidal,herbicidalandfungicidalactivity'.Usuallytheyaresynthesizedbytheintramolecularcondensation0fhydr0xylamineand0-nitrilegr0up'.Otherapproaches,suchasreductivecyclizati0nofZ-a-cyano-6-nitroethylenesandIithiumaIuminumhydridereduction0f3-cyanooxazoleshaveals0beenrepoFted'-'.HerewerepoFtanewsyntheticrouteofthesecompounds.Ohn0andNaruse7havereportedthatthereactionof2-chlorocycl…     

The Reaction of α-Amino-Substituted Diphenylphosphine Oxides with Elemental Sulfur and Selenium. A New Route to Thio- and Selenoamides

Abstract

Lithiated α-amino-substituted diphenylphosphine oxides 1 showed an interesting reactivity towards sulfur and selenium, leading to the formation of thioamides 2 and selenoamides 3, which could be isolated in good yields. Two equivalents of the chalcogene were found to be needed for complete conversion of the phosphine oxide anions. In the case of sulfur, diphenylphosphinothioic acid 4 was isolated as a side product, thus explaining the stoichiometry of the reaction (Scheme 1).     

A New Route for Synthesis of Entecavir

2-Amino-1,9-dihydro-9-[(1S,3R,4S)-4-hydroxy-3-(hydroxymethyl)-2-methylenecyclopen tyl]-6H-purin-6-one (entecavir, Scheme 1) is a novel carbocyclic 2-deoxyguanosine analog drug which has potent and selective anti hepatitis B virus (HBV) activity1-3. Entecavir is also effective against lamivudine-resistant YMDD mutants4. The US Food and Drug Administration (FDA) approved entecavir as a new preferred drug for the treatment of HBV after lamivudine in March, 2005. Scheme 1 The structure o…     

1,3-Dipolar Addition of Methyl α-Diazoacetoacetate to Enamines： A New Synthetic Route to 5-Amino-4,5-dihydrofurans

The reaction of methyl α-diazoacetoacetate with enamines catalyzed by dirhodium and copper complexes underwent formal 1,3-dipolar addition to give 5-amino-4,5-dihydrofurans in moderate yields. The reaction was suggested to proceed via a nucleophilic addition of enamines to rnetal-carbenes and a subsequent intramolecular cyclization of the resulting zwitterionic intermediates.     

A New Route to S-(-)Zearalenone

Zearalenone1isolatedfromthemyceliumofthefungusGibberellaZeaeisa14-memberedβresorcyliclactonemacrolide.1Itexhibitsantibiotic,estrogenicandantibacterialactivitiesinvitroandinvivo.2SincethestructureofzearalenonewaselucidatedbyUrryin19663quiteanumberofsynthesisofracemicandnaturallyoccurringzearalenonehavebeenreported4-5Thedifferencesofthosesynthesisweremainlyonthemethodsofformationofthel4-memberedringandthecreationofthechiralcenter.HerewereportanewroutetothisnatUrall}'occurringmacrolide.Retro-s…     

A New Approach to α—Bromochalcones

α-Bromo benzolymethylene triphenylphosphorane 3 has been synthesized by the reaction of benzoylmethylene triphenylphosphorane 1 with N-bromosuccinimide in the yield of 87% and can react with aromatic aldehydes 4 to give α-bromochalcones 5 in good yields.     

Chromium(II) Chloride Reduction of α-Aryl, α,β-Unsaturated Nitroalkenes. A Facile Route to Oximes

α, β-Unsaturated nitroalkenes are rapidly reduced by chromium(II) chloride to oximes.     

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-Pot Synthesis of Pyrazolyl-Containing α-Aminophosphonates

Abstract

A series of novel pyrazolyl-containing α-aminophosphonates were synthesized by one-pot reaction from 4-formylpyrazole, substituted aromatic amines, and dialkylphosphites. The synthesized compounds were characterized by elemental analysis, ¹H NMR, and IR spectroscopy. Single-crystal X-ray diffraction data of compounds 4a and 5b were obtained, and some of these compounds showed inhibitory effect on eggplant-infecting Botrytis cinerea.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: Tables S1-S4. Figures S1 and S2 .cif files.     

A New Synthetic Route to 12-Oxo-1, 15-pentadecanlactam

12-Oxo-1,15-pentadecanlactam 7 was synthesized from cyclododecanone with a totalyield of 36% in a seven-step reaction. The azide 5 to 12-nitro-1,15-pentadecanlactam 6 is the key step featured by direct ring expansion.     

One-Pot, Three-Component Coupling Approach to the Synthesis of α-Iminocarboxamides

A one-pot, three-component coupling was accomplished via the nucleophilic addition of an alkylsamarium(III) species to isocyanides and the subsequent addition of the resultant imidoyl samarium(III) species to isocyanates under mild conditions for the formation of α-iminocarboxamides. The developed sequential C-C bond-forming procedure enabled the rapid synthesis of the α-iminocarboxamides in good to excellent yields from readily available starting materials.     

A New Route for the Synthesis of N-Substituted Diketopiperazine Derivatives

Eight N-substituted diketopiperazines (DKPs) were synthesized by solid-phase protocols. The introduction of iminodiacetic acid (Ida) and followed another α-amino acid residue as the precursor of DKP framework made the present synthesis to be very facile and efficient.     

A New Synthesis of α-Methylene Carbinols

The synthetic utility of α-methylene carbinols has prompted considerable recent preparative interest. However, many of the reported methods¹ lack scope and require reagents or reaction conditions which are incompatible with sensitive functional groups. We report below two closely related methods for the synthesis of α-methylene carbinols which are based on the reductive elimination of β,γ-epoxysulfones. Both methods give the desired products in moderate overall yield in a four-step sequence which is mild and experimentally facile.     

New transformation of α-acetylenic ketones under the action of 1,2-diaminoethane

A reaction of 3-aryl-1-(3,4,5-trimethoxyphenyl)prop-2-yn-1-ones with 1,2-diaminoethane in boiling dioxane leads to 2-aryl-4,5-dihydro-1H-imidazoles and 1-(3,4,5-trimethoxy-phenyl)ethanone.     

A Convenient Route to α-Alkoxy Ester from Olefin Vla Organoborane-Catalyzed Hydroalumintaion

Organoborane-catatyzed hydroalumination of olefin with dichloroaluminum hydride and subsequent functionalization of the resulting organoaluminum with methyl α-chloro-α-methoxyacetate give rise to the corresponding α-methoxy ester in good yield.