First synthesis of a selenazepane

The first synthesis of perhydroselenazepane derivatives by the reaction of aryl isoselenocyanates with 5-chlorobutylamine in the presence of triethylamine in DMF as a one-pot procedure is described.     

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.     

First regioselective iodocyclization of O-allylselenocarbamates

4-Alkyl-2-imino-1,3-oxaselenolanes were prepared in good yields with high regioselectivity under mild conditions by the reaction of selenocarbamates with I₂ or NIS. The resulting 4-alkyl-2-imino-1,3-oxaselenolanes on dehydrohalogenation gave 4-alkylidene-2-imino-1,3-oxaselenolanes. The formation of the (Z)- or (E)-isomer of 4-alkylidene-2-imino-1,3-oxaselenolanes, strongly depends on the configuration of the double bond of O-allylselenocarbamates.     

Synthesis of 5-amino-2-selenoxo-1,3-imidazole-4-carboselenoamides by the reaction of isoselenocyanates with aminoacetonitriles

Reaction of isoselenocyanates with aminoacetonitriles afforded 4-amino-2-selenoxo-1,3-imidazole-2-selenones, whereas reaction with aminopropionitriles led to selenoureas. We confirmed that it is easy to distinguish between selenoamides and selenoureas by comparison of their chemical shift differences in the ⁷⁷Se NMR spectra.     

One-pot synthesis of new 2,4,5-trisubstituted 1,3-thiazoles and 1,3-selenazoles

In this work, we describe the synthesis of new 2,4,5-trisubstituted-1,3-thiazoles and 1,3-selenazole achieved by an easy one-pot four-step procedure. Expected compounds were obtained in good yield from dimethyl cyanodithioimidocarbonate, which was the common starting material for the preparation of all 1,3-thiazoles and 1,3-selenazoles. Chemical diversity was introduced on thiazole and selenazole rings by varying the amines and the activated halides used.     

Regioselective synthesis of novel spiroindane-1,3-diones through 1,3-dipolar cycloaddition reactions

A facile synthesis of novel spiroindane-1,3-diones has been achieved via 1,3-dipolar cycloaddition of an azomethine ylide, generated in situ from ninhydrin and 1,2,3,4-tetrahydroisoquinoline, with the conjugated double bond of chalcone derivatives. The regiochemistry and structures of the cycloadducts were determined with spectroscopic data and by X-ray crystal structure analysis.     

One-pot synthesis of 1-substituted-5-alkylselanyl-1H-tetrazoles from isoselenocyanates: unexpected formation of N-alkyl-N-arylcyanamides and (Z)-Se-alkyl-N-cyano-N,N′-diarylisoselenoureas

1-Substituted-5-alkylsulfanyl-1H-tetrazoles are well known class of organic substances with various applications in medicinal chemistry or photographic industry. Their selenium analogues, 1-substituted-5-alkylselanyl-1H-tetrazoles are, however, much less explored because of the lack of suitable methods for their preparation. In this work we investigated the synthesis of 1-alkyl/aryl-5-alkylselanyl-1H-tetrazoles from synthetically available alkyl/arylisoselenocyanates. One-pot reactions of arylisoselenocyanates with sodium azide and alkylating agent led to the target 5-alkylselanyl-1-aryl-1H-tetrazoles but also to interesting side products, namely N-alkyl-N-arylcyanamides and (Z)-Se-alkyl-N-cyano-N,N′-diarylisoselenoureas. Nevertheless, when alkylisoselenocyanates were utilized as the substrates, the reactions led exclusively to the formation of 1-alkyl-5-alkylselanyl-1H-tetrazoles in good yields. This simple one-pot procedure brings new possibilities for the preparation of variously substituted selenium compounds. It also opens the way to further investigations of selenium isosteres of the widely utilized 5-thiotetrazole moiety in biomedical applications.     

A four-step tandem synthesis of 3,5-diaroyl-4-arylpyrazoles from 1,3-diaryl-propane-1,3-diketones

A novel four-step tandem procedure was developed for efficient synthesis of 3,5-diaroyl-4-arylpyrazoles by simply stirring the mixture of 1,3-diarylpropane-1,3-diketones, TsN₃, aqueous MeNH₂ and Na₂CO₃ in DMF at 85 °C for 3 h.     

A new synthesis of 2-substituted-1,3-dithianes from trichloromethyl compounds

Trichloromethyl compounds are efficiently converted into 1,3-dithianes upon reaction with a disodium 1,3-propanedithiolate-1,3-propanedithiol mixture in DMF solution at 0 °C. This synthesis is limited to those substrates where the substituent attached to the trichloromethyl group is an electron-withdrawing group.     

Reactions of 1,3-dioxacyclanes with acid halides a new synthesis for ω-halohydrine esters

Reaction of 1,3-dioxolanes and 1,3-dioxanes with aliphatic acid chlorides and bromides yields 2- or 3-halohydrine esters.

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Reaktionen von 1,3-Dioxacyclanen mit Säurehalogeniden. Eine neue Synthese für -Halogenhydrinester (Kurze Mitteilung)

Zusammenfassung Die Reaktion von 1,3-Dioxolanen und 1,3-Dioxanen mit aliphatischen Säurechloriden ergab 2- bzw. 3-Halogenhydrinester

     

Diastereoselective synthesis of 6-functionalized 4-aryl-1,3-oxazinan-2-ones and their application in the synthesis of 3-aryl-1,3-aminoalcohols and 6-arylpiperidine-2,4-diones

Halocyclocarbamation of benzyl N-(1-phenyl-3-butenyl)carbamates afforded 6-functionalized 4-aryl-1,3-oxazinan-2-ones with moderate to excellent diastereoselectivity depending on the N-substituent. Importantly, in contrast to reported cyclocarbamations of homoallylic carbamates, which are generally trans-diastereoselective, cyclization of N-unsubstituted Cbz-protected homoallylamines led to cis-1,3-oxazinan-2-ones, predominantly. The use of N-benzylated and in situ prepared N-silylated derivatives resulted however in trans-selectivity. Transition states are proposed to explain the stereochemical influence of the N-substituent on the cyclocarbamations. The functionalized 1,3-oxazinan-2-ones could be further elaborated towards biologically or synthetically important 6-arylpiperidine-2,4-diones and 3-aryl-1,3-aminoalcohols.     

Synthesis of novel heterocyclic fused 1,3-diazabuta-1,3-dienes and accompanying rearrangements in their cycloaddition reactions with ketenes: synthesis of heterocyclic fused pyrimidinone derivatives

The reactions of 1,3-diazabuta-1,3-dienes 1 with 2-aminothiophenol have been shown to result in excellent yields of N-benzothiazol-2-yl-N′-aryl benzamidines 2. Their regioselective [4+2] cycloadditions with various ketenes are shown to yield novel benzothiazolo pyrimidinones 4. A similar and convenient protocol for the synthesis of bisthiosubstituted 1,3-diazabuta-1,3-dienes 8 and 9 and interesting rearrangements accompanying their [4+2] cycloadditions with a number of ketenes are described.     

A new route for the synthesis of 1,3-diketones

A simple route for the synthesis of 1,3-diketones by the reaction of acetylenic ketones with amines followed by hydrolysis of the resulting aminovinylketons is suggested.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 710–714, April, 1995.     

PEG-assisted one-pot three-component synthesis of 1,3-oxazino quinoline and chromeno 1,3-oxazin derivatives under catalyst free condition

Abstract

A straightforward and greener PEG-assisted protocol has been disclosed for the cascade synthesis of [1,3]Oxazino quinoline, and chromeno[1,3]oxazin derivatives via three component reaction of multifarious aromatic amines with formaldehyde and 4-hydroxyquinoline-2(1H)-one or 4-methylumbelliferone by using very convenient reaction conditions. This methodology represents a sustainable approach for rapid access to a library of diversity oriented highly pure [1,3]oxazino scaffolds with broad substrate scope.     

Green synthesis of 1,3-diynes from terminal acetylenes under solvent-free conditions

Herein, we report the microwave-assisted synthesis of 1,3-diynes from terminal acetylenes, catalyzed by CuI and tetramethylethylenediamine, in the presence of air as the oxidant, at 100 °C for only 10 min under solvent-free conditions. This efficient methodology allowed the homocoupling of several terminal alkynes in moderate to excellent yields. Moreover, the same protocol was also applicable for the synthesis of some unsymmetrical 1,3-diynes through the cross-coupling reaction.     

一锅法绿色合成烯酰胺和1,3-二炔(英文)

结合绿色化学概念,将酮肟还原酰化和末端炔氧化偶联在一锅进行反应,发展了一种Pd/Cu协同催化一锅绿色合成烯酰胺和1,3-二炔的新方法.该方法无需外加任何氧化剂和还原剂,可同时得到烯酰胺和1,3-二炔,产率高,反应条件温和.     

Efficient synthesis of isoxazolidine-substituted bisphosphonates by 1,3-dipolar cycloaddition reactions

Several bisphosphonates bearing a substituted isoxazolidine ring have been synthesized in good yield by direct 1,3-dipolar cyclization reaction, under microwaves catalysis, in the absence of solvent. The method allows the simultaneous incorporation, on the geminal position of the bisphosphonate framework, of a basic nitrogen and of an oxygen atom, as third hook. Hydrophobicity-hydrophilicity of BPs is discussed with the help of distribution coefficients.     

Selenium-containing heterocycles from isoselenocyanates: synthesis of 2-methylidene-1,3-selenazolidine derivatives

A convenient and unequivocal synthesis of the title compounds from isoselenocyanates, malononitrile or 2-cyanoacetate, and 1,2-dibromoethane or α-halogenated carboxylic acid derivatives is reported. The proposed reaction mechanism involves in situ cyclization of different halogenated compounds with an intermediate keten-N,Se-acetal, generated by the base promoted nucleophilic addition of the acidic cyanomethylenes to aliphatic and aromatic isoselenocyanates. Chemical and spectroscopic evidence for the structures of the new compounds is presented.     

First total synthesis of tuberonic acid

A vinyl group as an acetic acid side chain was attached to the optically active monoacetate of 4-cyclopentene-1,3-diol with CH₂CHMgBr, LiCl, and a CuCN catalyst to produce the S_N2-type product, from which the full carbon skeleton of tuberonic acid was constructed through Mitsunobu inversion, Claisen rearrangement, and Wittig reaction. At the last stage, the THP protective group was removed with MgBr₂ in Et₂O. The diastereomeric ratio of tuberonic acid and the trans isomer was 92:8 by ¹H NMR spectroscopy.     

Stereoselective synthesis of 1,3-dienylstannanes by palladium catalyzed cross-coupling reactions

(Z)-α-Bromovinylstannanes are new difunctional group reagents, which undergo palladium catalyzed cross-coupling reactions with (E)-alkenylzirconium complexes to give stereoselectively 1,3-dienylstannanes in good yields.