Synthesis of 1-Bromo-3-butyn-2-one and 1,3-Dibromo-3-buten-2-one

Synthetic procedures for the preparation of 1-bromo-3-butyn-2-one and 1,3-dibromo-3-buten-2-one are given. These compounds are prepared from 2-bromomethyl-2-vinyl-1,3-dioxolane, which can readily be prepared from 2-ethyl- 2-methyl-1,3-dioxolane. The synthetic routes are as follows: 2-bromomethyl-2-vinyl-1,3-dioxolane is converted to 2-(1,2-dibromoethyl)-2-bromomethyl-1,3-dioxolane. Double dehydrobromination with ^tBuOK affords 2-ethynyl-2-bromomethyl-1,3-dioxolane. Formolysis with formic acid gives 1-bromo-3-butyn-2-one. Deacetalized 2-bromoethyl-2-vinyl-1,3-dioxolane was treated with Br₂ and Li₂CO₃/12-crown-4 in tetrahydrofuran to give 1,3-dibrom-3-buten-2-one in moderate yield.     

Captodative Formyl- and Acyl(amino)alkenes Containing a Terminal Double Bond or a Weakly Basic Tertiary Amino Group

Piperidine reacts with 3-bromo-3-buten-2-one to give a mixture of 3,4-dipiperidinobutan-2-one and 3-piperidino-3-buten-2-one. The latter is also formed by the action of a strong base (Et₃N in THF or MeONa in MeOH) on the dipiperidino derivative. Analogous reaction of 2-bromo-3-phenylpropenal with N-methylaniline affords 2-[methyl(phenyl)amino]-3-phenylpropenal which is the first captodative formyl(amino)alkene having a weakly basic tertiary amino group.     

Preparation of 4-bromo-1-hydroxypyrazole 2-oxides by nitrosation of α-bromo-α,β-unsaturated ketoximes

Nitrosation of the oximes of 3-bromo-3-penten-2-one, 3-bromo-4-phenyl-3-buten-2-one, and 2-bromo-1,3-diphenyl-2-propen-1-one using sodium nitrite in acetic acid gave low yields of 4-pyrazolone 1,2-dioxides. Nitrosation using butyl nitrite in the presence of copper(II) sulfate and pyridine in aqueous ethanol produced insoluble copper complexes from which 3,5-dimethyl-, 3-methyl-5-phenyl-, and 3,5-diphenyl-4-bromo-1-hydroxypyrazole 2-oxides could be liberated by treatment with dilute potassium hydroxide, filtration, and acidification of the filtrate. High yields were obtained with the first two oximes, but, presumably due to unfavorable stereochemistry of the oxime, the diphenyl derivative gave a lower yield of the complex, accompanied by 4-bromo- and 4-nitro-3,5-diphenylisoxazole and 4-oximino-3,5-diphenyl-4,5-dihydroisoxazole.     

Condensation of γ-bromodypnone with thiocarbamides: Synthesis of 4,4-disubstituted 4,5-dihydro-1,3-thiazol-2-amines and thiazolidin-2-ones

The reaction of 4-bromo-1,3-diphenyl-2-buten-1-one with thiourea or N,N′-diphenylthiourea gives 2-(2-amino-4-phenyl-4,5-dihydro-1,3-thiazol-4-yl)-and 2-[3,4-diphenyl-2-(phenylimino)-1,3-thiazolidin-4-yl]-1-phenyl-1-ethanone — the products of nucleophilic substitution of the halogen atom and Michael addition at position 3 of the 2-buten-1-one system. A similar reaction with thiosemicarbazide and 1-phenylthiosemicarbazide gives the 4-(2-oxo-2-phenylethyl)-4-phenyl-and 4-(2-oxo-2-phenylethyl)-3,4-diphenyl-1,3-thiazolidin-2-one hydrobromides respectively. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 103–110, January, 2008.     

Synthesis of 2,4-diphenyl-1H-pyrrol-1-amine derivatives

The direction of the reaction of 4-bromo-1,3-diphenyl-2-buten-1-one (γ-bromodypnone) with hydrazines depends on the nature of the substituent they contain. Reaction with 1-methylhydrazinium hydrosulfate gives 1-methyl-3,5-diphenylpyridazin-1-ium bromide but carboxylic acid hydrazides give N-(2,4-diphenyl-1H-pyrrol-1-yl)carboxylic acid amides. γ-Bromodypnone and phenylhydrazine give both 1,3,5-triphenyl-1,4-dihydropyridazine and N,2,4-triphenyl-1H-pyrrol-1-amine (15%). 1-(2,4-Dinitrophenyl)hydrazine gives the 2,4-dinitrophenylhydrazone of (Z)-4-bromo-1,3-diphenyl-2-buten-1-one. Condensation of 2,4-diphenyl-1H-pyrrol-1-amine with aromatic aldehydes readily leads to N-(arylmethylidene)-2,4-diphenyl-1H-pyrrol-1-amines and alkylation with methyl iodide gives N,N-dimethyl-2,4-diphenyl-1H-pyrrol-1-amine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 404–414, March, 2009.     

Interaction of (z)-4-bromo-1,3-di(2-thienyl)- 2-buten-1-one with amines,synthesis of di(2-thienyl)azolo[<Emphasis Type="Italic">a</Emphasis>]pyridines

(Z)-4-Bromo-1,3-di(2-thienyl)-2-buten-1-one was obtained by the bromination of 1,3-di(2-thienyl)-2-buten-1-one by NBS in anhydrous CCl₄. The starting butanone was obtained by the condensation of 1-(2-thienyl)-1-ethanone by the action of SOCl₂. The reaction of (Z)-4-bromo-1,3-di(2-thienyl)-2-buten-1-one with tertiary amines such as Et₃N, pyridine, 1-alkyl-1,3-diazole, 1-alkylbenzimidazole, and 1-alkyl-1,2,4-triazole leads to quaternary salts. The azolium salts cyclize by the action of base to give di(2-thienyl)azolo[a]pyridinium derivatives. 3-Methyl-6,8-di(2-thienyl)[1,3]thiazolo[3,2-a]pyridin-4-ium and 2,4-di(2-thienyl)pyrido[2,1-b]benzothiazol-10-ium bromides were obtained by the same procedure but without separating the intermediate quaternary salts.     

Synthesis of N-aryl-substituted pyrroles via γ-bromodypnone

A series of 1-aryl-2,4-diphenylpyrroles were obtained by the reaction of 4-bromo-1,3-diphenyl-2-buten-1-one (γ-bromodypnone) with substituted anilines in the presence of sodium acetate. In the reaction with di-and trimethylenediamines the corresponding 1,2-and 1,3-di(N-pyrryl)alkanes were obtained. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 848–853, June, 2006.     

Reaction of 3,4,4-Trichloro-1-(4-methylphenyl)-3-buten-1-one with Amines

Reaction of 3,4,4-trichloro-1-(4-methylphenyl)-3-buten-1-one with amines results in replacement of the internal chlorine atom and is accompanied by prototropic allyl rearrangement leading to formation of the corresponding 3-amino-4,4-dichloro-1-(4-methylphenyl)-2-buten-1-ones. The reaction of the title compound with 2,4-dinitrophenylhydrazine yields 3,4,4-trichloro-1-(4-methylphenyl)-3-buten-1-one 2,4-dinitrophenylhydrazone and is not accompanied by allyl rearrangement.     

1,1-bis(3,5-dimethyl-1-pyrazolyl)- and 1-Amino-1-(3,5-dimethyl-1-pyrazolyl)-4,4-dichloro-1-buten-3-ones

Reaction of 1,1,4,4-tetrachloro-3-buten-2-one with 3,5-dimethylpyrazole gave 1,1-dichloro- 4,4-bis-(3,5-dimethyl-1-pyrazolyl)-3-buten-2-one. Treatment of the latter with amines resulted in replacement of one pyrazole ring by the amine residue with formation of the corresponding 4-amino-1,1-dichloro-4-(3,5- dimethyl-1-pyrazolyl)-3-buten-2-ones.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004, pp. 1557–1560.Original Russian Text Copyright © 2004 by Potkin, Petkevich, Kaberdin, Kurman.     

The Heck synthesis of β-arylated ketones catalyzed by palladium immobilized on functional polysiloxane microspheres

Palladium catalysts, obtained by the impregnation of Pd(OAc)₂ on aminopropyl- or pyridine-functionalized polysiloxane microspheres, were used in the Heck reaction of iodobenzene with 3-buten-2-one and 3-buten-2-ol at 120°C using an oil bath or microwave heating. The synthesis of 4-phenyl-3-buten-2-one was one-step arylation of ketone while 4-phenyl-2-butanone was formed in two-step arylation–isomerization sequential transformation of alcohol. A very low palladium loading, 0.05 mol%, was sufficient to obtain a yield of ketones higher than 90%. In recycling experiments, an effect of the functional group present in polysiloxane was observed and much better results were obtained for the aminopropyl-modified polymer. The catalyst was easily retrieved and reused in eight consecutive runs in the reaction of 3-buten-2-one, while with 3-buten-2-ol 11 subsequent cycles were performed with practically the same yield.     

烯氨酮晶体结构研究

研究了氨基分别为1'-四氢吡咯,1'-六氢吡啶和4'-吗啉的1-苯基-3-氨基-2-丁烯-1-酮的晶体结构. 它们的构型.构象均为trans, S-cis.由于共轭体系的扩展,这些烯氨酮的氮原子都比相应的烯胺有程度更大的电子离域,其中又以扭式构象的四氢吡咯基的离域程度最高.四氢吡咯形成N-不饱和化合物的特殊活性与此有关.     

Stereoselectivity in the transfer of the 2-(1-dimethylaminoethyl)phenyl group,R*, from LiR*2Cu and Li(R*) (2-thienyl)Cu to enones

One diastereomer is formed in large excess (98 – 76 % diastereomeric excess) on addition of the 2-(1-dimethylaminoethyl) phenyl group, R^*, to 3-penten-2-one, 2-cyclohexenone, 4-phenyl-3-buten-2-one, and 5-phenyl-2,2-dimethyl-4-penten-3-one.     

Synthesis of 5-Bromomethylisoxazoles and Their Reactions with Secondary Amines

Treating R-3-chloro-4-bromo-2-buten-1-ones with hydroxylamine hydrochloride afforded 3-alkyl(aryl, furyl)-5-bromomethylisoxazoles. By reaction of the latter with secondary amines new previously unknown aminoisoxazoles were synthesized.     

Synthesis of 3-aminomethyl-2-aryl- 8-bromo-6-chlorochromones

[reaction: see text] An efficient synthetic route to Cbz-protected 3-aminomethyl-2-aryl-8-bromo-6-chlorochromones has been developed. 3-Aryl-1-(3-bromo-5-chloro-2-hydroxyphenyl)-2-propen-1-one or 2-aryl-8-bromo-6-chlorochroman-4-one could be reacted under Mannich conditions yielding 2-aryl-8-bromo-6-chloro-3-methylenechroman-4-one, which was further converted to the target compound via an aza-Michael reaction followed by an SeO(2) oxidation. This procedure represents a new method to introduce a primary aminomethyl group at the 3-position of a 2-arylchromone scaffold. The Cbz-protected 3-aminomethyl-2-aryl-8-bromo-6-chlorochromones can, e.g., be used in the synthesis of chromone-based beta-turn peptidomimetics.     

Synthesis of 1,3-dithianes and 1,3-dithiolanes. Baker's yeast reduction and lipase-catalyzed resolution for synthesis of enantiopure derivatives.

Three 1,3-dithiolanes and four 1,3-dithianes have been synthesised from 1-(1,3-dithiolan-2-yl)-2-propanone and 1-(1,3-dithian-2-yl)-2-propanone, respectively. Asymmetric reductions of these ketones using baker's yeast gave the corresponding enantiopure (S)-alcohols. Baker's yeast also reduced the double bond in 3-(1,3-dithian-2-yl)-3-buten-2-one enantioselectively to give (S)-3-(1,3-dithian-2-yl)-2-butanone. 3-(1,3-Dithian-2-yl)-3-buten-2-one was also reduced chemo-selectively and the resulting 3-(1,3-dithian-2-yl)-3-buten-2-ol was resolved by transesterification in organic solvent using lipase B from Candida antarctica to yield the (S)-alcohol and the (R)-acetate with very high enantiomeric ratio, E. Racemic 1-(1,3-dithiolan-2-yl)-2-propanol and 1-(1,3-dithian-2-yl)-2-propanol were also resolved under similar conditions to give the (S)-alcohols and the corresponding (R)-acetates.     

Addition von aldehyden an aktivierte doppelbindungen,XXVII. Mitteilung : Ein einfacher weg zu 2-hydroxy-cyclopentenonen

A new, easy synthetic route to 2-hydroxy-3-alkyl-cyclopentenones starting from the thiazolium salt catalyzed addition of aldehydes to 1-acetoxy-3-buten-2-one is described.     

Regioselective Synthesis of 4-Acetyl-and 5-Acetyl-3-methylisoxazole: Their Conversion into Silyl-and Methyl Enol Ethers

Acetonitrile oxide reacts regioselectively with 3-buten-2-one and (E)-4-methoxy-3-buten-2-one to give 5-acetyl-2 and 4-acetyl-3-methylisoxazole 3, respectively. Treatment of ketones 2 and 3 with trimethylsilyl trifluoromethanesulfonate gave the silyl enol ethers 4 and 5, whereas the methyl enol ethers 8 and 9 were obtained via elimination of methanol from the corresponding dimethyl ketals.     

Reactions of <Emphasis Type="Italic">N</Emphasis>-and <Emphasis Type="Italic">C</Emphasis>-Alkenylanilines: VII. Synthesis of Indole Heterocycles from Products of Reaction between <Emphasis Type="Italic">N</Emphasis>-Mesyl-2-(1-alken-1-yl)anilines and Halogens

N-Mesyl-2-(1-methyl-1-butenyl)-6-methylaniline reacted with Br₂ to afford N-mesyl-2-(3-bromo-1-penten-2-yl)aniline that under treatment with NH₃ or amines underwent cyclization into N-mesyl-7-methyl-3-methylene-2-ethylindoline. The reaction of N-mesyl-2-(1-methyl-1-buten-1-yl)-4-methyl- and 2-(1-methyl-1-buten-1-yl)aniline with Br₂ gave rise to the corresponding N-mesyl-2-(2-bromo-1-methyl-1-buten-1-yl)anilines. Under the similar conditions N-tosyl-2-(1-cyclohexen-1-yl)aniline was converted into N-tosyl-2-(6-bromo-1-cyclohexen-1-yl)aniline that under treatment with NH₃ furnished N-tosyl-1,2,3,9a-tetrahydrocarbazole. The reaction of N-mesyl-1,2,3,9a-tetrahydrocarbazole with CuBr₂ in MeOH afforded N-mesyl-4-methoxy-1,2,3,4-tetrahydrocarbazole. N-Mesyl-6-methyl-2-(1-cyclopenten-1-yl)aniline in reaction with Br₂ in the presence of NaHCO₃ was oxidized into the corresponding cyclopentenone, and with NBS it gave N-mesyl-2-(2-bromo-1-cyclopenten-1-yl)aniline.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 5, 2005, pp. 730–737.Original Russian Text Copyright © 2005 by Gataullin, Sotnikov, Spirikhin, Abdrakhmanov.     

Synthesis and properties of z-1,3-bis-(aryl)-4-bromo-2-buten-1-ones

Bromination of 1,3-bis(aryl)-2-buten-1-ones by N-bromosuccinimide in anhydrous carbon tetrachloride gives Z-1,3-bis(aryl)-4-bromo-2-buten-1-ones. The effect of the nature of substituent in the benzene ring on the course of a reaction with nucleophiles has been studied. Heating an alcohol solution of these ketones (Ar = 4-MeOC₆H₄, 4-ClC₆H₄) in the presence of acid or in the presence of base (Ar = Ph) gave 2,4-bis(aryl)furans. Treatment of 1,3-bis(aryl)-4-bromo-2-buten-1-ones with thioacetamide gave 2,4-bis(aryl)thiophenes. The oxidation of the halo-substituted dypnones with H₂O₂/NaOH gave (3-bromomethyl-3-aryl-2-oxiranyl)(aryl)methanones. The reaction of halo-substituted dypnones with aryl hydrazines gave 1,3,5-triaryl-1,6-dihydropyridazines or 1,3,5-triarylpyridazinium bromides depending on the structure of the reagents.     

超声波和无溶剂条件下1-芳基-5-二茂铁基-1,4-二烯-3-酮的合成

在室温下使用超声波或无溶剂条件下,4-二茂铁基-3-烯-2-酮和芳香醛的羟醛缩合能以83％～97％的收率得到1-芳基-5-二茂铁基-1,4-二烯3-酮。这种方法具有操作简单,反应条件温和,产率高和低能耗等优点。