1,3-Dioxolan-4-ones and 1,3-oxathiolan-5-ones. Configuration of cis and trans isomers

The attempted acid-catalyzed azeotropic removal of water from a mixture containing lactamide and chloral in refluxing toluene lead to the elimination of ammonia; both cis- and trans-5-methyi-2-(trichloromethyl)-1,3-dioxolan-4-one were isolated. A number of 1,3-dioxolan-4-ones and 1,3-oxathiolan-5-ones were obtained by cyclodehydration of aldehydes with α-hydroxy- and α-mercapto-carboxylic acids in the presence of boron trifluoride etherate. Geometric isomers were separated, and their configurations were determined by nuclear magnetic resonance.     

Synthetic studies toward 4H-1,3-benzodioxin-2-ones

The investigation into the synthesis of 4H-1,3-benzodioxin-2-ones, utilizing the corresponding 2-(hydroxy-methyl)phenol as the starting diol, is described. The results illustrate that the synthesis of 4H-1,3-benzodi-oxin-2-ones can be achieved utilizing carefully controlled reaction conditions, in a 3–15% yield.     

One-pot synthesis of 2-isopropyl-3-benzyl-1,3-thiazolidin-4-ones and 2-phenyl-3-isobutyl-1,3-thiazolidin-4-ones from valine, arenealdehydes and mercaptoacetic acid

A three-component one-pot synthesis of 2-isopropyl-3-benzyl-1,3-thiazolidin-4-ones and 2-phenyl-3-isobutyl-1,3-thiazolidin-4-ones from valine, arenealdehydes and mercaptoacetic acid with good yields is reported. Characterization of products was generally achieved by NMR techniques and specifically for 2-isopropyl-3-(4-nitrobenzyl)-1,3-thiazolidin-4-one by X-ray crystallography.     

Synthesis of 4H-1,3-benzoxazin-4-onium salts and 4-H-1,3-benzoxazin-4-ones

Salicylamide and its substituted derivatives react with aliphatic carboxylic acid anhydrides and perchloric acid to give 4H-1,3-benzoxazin-4-onium salts. These same compounds were obtained by acidic cyclization of O- and N-acylsalicylamides. The synthesized salts are converted to 2-substituted 4H-1,3-benzoxazin-4-ones by the action of triethylamine and are hydrolyzed by water to N-acylsalicylamides. The probable reaction scheme is examined.     

Synthesis and properties of 5-methylene-1,3-dioxolan-4-ones

A general method, which consists in the dehydroxypropanoic of 5-chloromethyl-1,3-dioxolan-4-ones, is proposed for the synthesis of 5-methylene-1,3-dioxolan-4-ones. With respect to their structure, the synthesized compounds are simultaneously derivatives of acrylic acid and vinyl ethers.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1316–1318, October, 1985.     

Synthesis of 1,2-benzisothiazolin-3-ones by ring transformation of 1,3-benzoxathiin-4-one 1-oxides

1,2-Benzisothiazolin-3-ones were synthesized from 1,3-benzoxathiin-4-one 1-oxides by means of a nonhazardous and inexpensive method. The 1,3-benzoxathiin-4-one 1-oxides were prepared by oxidation of 1,3-benzoxathiin-4-ones with hydrogen peroxide in the presence of a catalyst. Attack of amines on the carbonyl groups of the 1,3-benzoxathiin-4-one 1-oxides and subsequent elimination of carbonyl compounds likely produced sulfenic acids, which then underwent ring closure to afford the 1,2-benzisothiazolin-3-ones.     

Heterocyclization of functionalized heterocumulenes with C,N-and C,O-binucleophiles: VI. Synthesis of carbofused 2,3-dihydro-1,3-oxazin-4-ones and 3,4-dihydro-1,3-oxazin-2-ones

Condensations of 1-phenyl-2,2,2-trifluoro-1-chloroethyl isocyanate and 1-chlorobenzyl isocyanate with cyclic 1,3-diketones yield respectively carbofused 2,3-dihydro-1,3-oxazin-4-ones and 3,4-dihydro-1,3-oxazin-2-ones.     

Synthesis of 2-aryl-4-hydroxy-5-thio substituted 1,3-thiazin-6-ones via sulfenylation of 2-aryl-4-hydroxy-[1,3]thiazin-6-ones with sulfenyl chlorides

A series of 2-aryl-4-hydroxy-5-thio substituted 1,3-thiazin-6-ones were synthesized for human immunodeficiency virus-1 protease inhibition. These compounds were synthesized by the treatment of 4-hydroxy-5-thio substituted-1,3-thiazin-6-ones with the corresponding sulfenyl chlorides. The products were obtained in good isolated yields, inspite of the presence of bulkyl substitutents at the ortho position of phenyl sulfenyl chloride portion.     

Reaction of 4-Methylene-1,3-dioxolan-2-ones with Hydrazines

The structure of the products of the reaction of 4-methylene-1,3-dioxolan-2-ones with hydrazines is a function of the structure of the starting hydrazine. 1,3,4-Oxadiazin-2-one derivatives are obtained from hydrazine hydrate. 3-Arylaminooxazolidin-2-ones are obtained from monoarylhydrazines, while mixtures of these derivatives are obtained from aliphatic monoalkylhydrazines.     

Synthesis and structure of 1,3-dialkyl-4-(sulfonylimino)imidazolidin-2-ones

The reactions of 1,3-dialkyl-4,5-dihydroxyimidazolidin-2-ones with alkyl sulfamides have been studied and previously undescribed 1,3-dialkyl-4-(alkylaminosulfonylimino)imidazolidin-2-ones have been obtained. The structure of 1,3-dimethyl-4-(benzenesulfonylimino)imidazolidin-2-one was investigated by X-ray structural analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1159–1166, August, 2007.     

Asymmetric radical additions using chiral 1,3-dioxolane-4-ones

Moderate facial selectivities are observed in additions of alkyl radicals to the chiral (c,d) olefin (2S)-2-tert-butyl-5-ethoxycarbonylmethylene-1,3-dioxolane-4-one 1. The following hydrogen abstraction from tributylstannane proceeds with excellent asymmetric stereocontrol, leading to two of four possible diastereoisomers with high diastereomeric excesses. Additions of chiral radicals obtained from (2R,5R)-5-alkyl-5-bromo-1,3-dioxolane-4-ones to ethyl acrylate show high asymmetric 1,3-induction.     

Ring contraction reactions of 2,3-dihydro-4H-1,3-oxazin-4-ones under electrospray ionization conditions

The mass spectral behavior of 2,3-dihydro-4H-1,3-oxazin-4-ones has been investigated using electrospray ionization multi-stage mass spectrometry (ESI-MS(n)). All compounds showed a predominant retro-Diels-Alder (RDA) fragmentation pathway, and a novel ring contraction reaction by loss of isocynates was also found. The fragmentation mechanisms proposed for 4H-1,3-oxazin-4-ones are supported by ESI-MS/MS/MS spectra.     

Synthesis of 5-alkynyl-2,2,6-trimethyl-1,3-dioxin-4-ones and 1,4-disubstituted-1,2,3-triazoles

Herein we report an approach to the formation of 5-alkynyl-1,3-dioxin-4-ones using Suzuki-Miyaura cross-coupling reaction of potassium alkynyltrifluoroborate salts with 2,2,6-trimethyl-5-iodo-1,3-dioxin-4-one. The resulting 5-ethynyltrimethylsilyl-1,3-dioxin-4-ones obtained through the Sonogashira reaction were further reacted in a Cu(I)-catalyzed Huisgen azide-alkyne 1,3-dipolar cycloaddition to form functionalized 1,4-disubstituted-1,2,3-triazoles in good yields, using mild conditions and ultrasonic radiation to expedite the reaction.     

Synthesis of 1,3-dialkyl-5-(hetaryl-1-yl)-1,3-dihydrobenzimidazol-2-ones

Reactions of 5-amino-1,3-dialkyl-1,3-dihydrobenzimidazol-2-ones with 2,5-dimethoxytetrahydrofuran and 2,6-dimethyl-γ-pyranone led to the formation of 1,3-dialkyl-1,3-dihydro-5-(pyrrol-1-andл)benzimidazol-2-ones and 1-(1,3-dialkyl-2-oxo-1,3-dihydrobenzimidazol-5-yl)-2,6-dimethylpyridin-4-ones.     

Synthesis of 2-aryl-2-trifluoromethyl-1,3-thiazolidin-4-ones and 2-aryl-2-trifluoromethyltetrahydro-4<Emphasis Type="Italic">H</Emphasis>-1,3-thiazin-4-ones and their oxidation with hydrogen peroxide

Reactions of aryl trifluoromethyl ketone imines with 2-sulfanylacetic and 3-sulfanylpropanoic acids afforded 2-aryl-2-trifluoromethyl-1,3-thiazolidin-4-ones and 2-aryl-2-trifluoromethyltetrahydro-4H-1,3-thiazin-4-ones, respectively. Their subsequent oxidation with hydrogen peroxide gave the corresponding 2-aryl-2-trifluoromethyl-1,3-thiazolidin-4-one 1-oxides and 2-aryl-2-trifluoromethyltetrahydro-4H-1,3-thiazin-4-one 1-oxides and 1,1-dioxides.     

Diastereoselective synthesis of alpha-methyl and alpha-hydroxy-beta-amino acids via 4-substituted-1,3-oxazinan-6-ones

1,3-oxazinan-6-ones have been utilized in a series of enolate reactions to produce 5-hydroxy and 5-alkyl-4-substituted-1,3-oxazinan-6-ones with excellent trans diastereoselectivity. Highlighting the versatility of the oxazinanone, a number of transformations were performed to produce a variety of protected N-H and N-methyl alpha-hydroxy- and alpha-methyl-beta-amino acids.     

Chlorination of 1,3-dioxolan-4-ones

It is shown that the direction of chlorination of 1,3-dioxolan-4-ones in the presence of benzoyl peroxide is determined by the nature of the substituent at the 5-position of the ring. In this case a chloromethyl group, having a —I effect, promotes a selective replacement of hydrogen at the 2-position, while a methyl group mainly causes replacement of hydrogen at the 5-position.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 187–189, February, 1986.     

Facile stereoselective synthesis of 1,3-disubstituted-4-trichloromethyl azetidin-2-ones

The highly stereoselective synthesis of 1,3-disubstituted-4-trichloromethyl azetidin-2-ones by the [2+2] cycloaddition of ketenes with imines derived from chloral is described.     

Selective synthesis of novel 2-imino-1,3-selenazolidin-4-ones and 2-amino-1,3,4-selenadiazin-5-ones from isoselenocyanates

An efficient and regioselective synthesis of 2-imino-1,3-selenazolidin-4-ones and 2-amino-1,3,4-selenadiazin-5-ones was achieved via one-pot reaction of isoselenocyanates, hydrazines, and ethyl chloroacetate or chloroacetyl chloride, respectively. Plausible mechanisms for these transformations were given.     

Synthesis of 2-selenoxoperhydro-1,3-selenazin-4-ones via diselenocarbamate intermediates

The reactions of the diselenocarbamates, generated from isoselenocyanates and sodium hydroselenide, with acryloyl chlorides afforded 2-selenoxoperhydro-1,3-selenazin-4-ones. The structure of the product was confirmed by X-ray diffraction analysis.