Synthesis of 1′,3′-Dioxolan-2′-one by the Reaction of Steroidal Oxiranes with Carbon Dioxide: Synthesis of Five-Membered Cis Cyclic Carbonates

The reaction of 3β-acetoxy-5,6α-epoxy-5α-cholestane 1, its 3β-chloro analogue 2, and 5,6α-epoxy-5α-cholestane 3 with carbon dioxide gas in the presence of sodium bromide as catalyst with continuous stirring at 100 °C for 30 min affords selectively the corresponding 1′,3′,-dioxolan-2′-ones (steroidal cyclic cis-carbonates) 4–6 in excellent yields. The structures of these products have been established on the basis of their elemental analysis and spectral data (infrared, ¹H NMR, and mass).     

Synthesis of spiro[furan-3,3′-indolin]-2′-ones by PET-catalyzed [3+2] reactions of spiro[indoline-3,2′-oxiran]-2-ones with electron-rich olefins

An efficient procedure for the synthesis of spiro[furan-3,3′-indolin]-2-ones and dispiro[cycloalkane-1,2′-furan-3′,3″-indolin]-2″-ones has been achieved in high yields and stereoselectivity by photoinduced electron transfer-catalyzed [3+2] reactions of substituted spiro[indoline-3,2′-oxiran]-2-ones with olefins. The reactions proceed by ring opening of spiro[indoline-3,2′-oxiran]-2-ones via C_β–O bond cleavage and subsequent cycloaddition with olefins by using 2,4,6-triphenylpyrylium tetarfluoroborate (TPT) as a sensitizer.     

Synthesis and Investigation of Mass Spectra of 3-[5′-(2′-Substituent)thienyl]benzo[5,6]coumarins

3-[5'-(2'-Hydroxycarbonyl)thienyl]benzo[5,6]coumarin ( 3 ) was prepared via condensation of 2 with thioglycolic acid in the presence of AcONa and Ac 2 O. Esterification of 3 with alcohols gave 3-[5'-(2'-alkoxycarbonyl)thienyl]benzo[5,6]-coumarins ( 4a , b ). The chemical behavior of 4 toward nucleophilic reagents (such as ammonia, hydroxyl amine, and hydrazine derivatives) is described. The electron impact ionization mass spectra of compounds 4b , 5 , and 8a , b show a weak molecular ion peak and a base peak of m / z 278 resulting from a cleavage fragmentation. In contrest compounds 3 and 4a show a base peak of m / z 250 and m / z 74 resulting from fragmentation. Compounds 9 and 10 give a characteristic fragmentation pattern with a very stable fragment of m / z 305.     

Synthesis of Spiro[1,4-benzothiazine-2,2′-pyrroles] by Reaction of Pyrrolo[1,2-c][4,1]benzoxazepinetriones with 2-Aminobenzenethiol

Russian Journal of Organic Chemistry - 3-Aroylpyrrolo[1,2-c][4,1]benzoxazepine-1,2,4-triones reacted with 2-aminobenzenethiol to give...     

Reaction of tert-Butylcyanoketene with 2′-Cyclohexylspiro [Fluorene-9,3′-Oxaziridine]

Although the reactions of ketenes and three-membered heterocycles containing one hetero atom are well known,^1,2 only one investigation of similar recations with three-membered rings containing two hetero atoms has been reported.³ The reaction of 2-ethyl-3-phenyloxaziridine with diphenylketene was found to afford among other minor products an oxazolidinone derivative (1) and benzaldehyde in yields of 38% and 50% respectively.     

Synthesis of Macroheterocycles by Reaction of N,N′-(1,4-Phenylene)bis[N′-(4,4-diethoxybutyl)urea] with Resorcinol and Its Derivatives

An efficient procedure has been developed for the synthesis of macroheterocycles by acid-catalyzed reaction of N,N′-(1,4-phenylene)bis[N′-(4,4-diethoxybutyl)urea] with resorcinol, 2-methylresorcinol, and pyrogallol. The structure of the isolated compounds was proved by spectral methods.

     

Synthesis of Spiro[[1,2,5]oxadiazolo[3,4-b]pyrazine-5,2′-pyrroles] by Reaction of Pyrrolooxazinetriones with Diaminofurazan

Russian Journal of Organic Chemistry - The reaction of 8-aroyl-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-1,6,7-triones with 3,4-diamino­furazan afforded...     

A Simple Synthesis of 2′,5′-Disubstituted-Spiro [Dihydroacridine 9(10H), 4′-Thiazolines] by the Reaction of Corresponding 3-(Acridin-9-Yl)-Thioureas with Methyl Bromoacetate and Bromoacetonitrile

A convenient method has been devised for the preparation of the spirodihydro-acridinethiazolines 5a-j by the treatment of thioureas 3a-e with methyl bromoacetate and bromoacetonitrile via non-isolable isothioureas 4a-j and their subsequent cyclization with methanolic sodium methoxide.     

Synthesis and structural characterization of copper(II) complexes with the 2′-[1-(2-pyridinyl)ethylidene]oxalohydrazide ligand

The octahedral copper(II) complex with two 2-[1-(2-pyridinyl)ethylidene]oxalohydrazide molecules was synthesized from bis(acetylacetonato)copper(II) and 2-[1-(2-pyridinyl)ethylidene]oxamohydrazide (Hapsox). The complex is unstable when not in solution. X-ray analysis confirmed the tridentate coordination of the ligands in the monoanionic form. In addition, the stable tetrahedral copper(II) complex with one ligand molecule coordinated as a tridentate in the dianionic form was prepared by direct synthesis from Cu(NO₃)₂·3H₂O and Hapsox, and characterized by elemental analysis, magnetic measurements and by i.r. and u.v./vis. spectrophotometry.     

Reaction of [VO(OPr)3] with hexamethyldisylthiane in the presence of β-diketones

The reaction of [VO(OPr)₃] (Pr is n-propyl) with hexamethyldisylthiane Me₃SiSSiMe₃ in the presence of β-diketones (acetylacetone (HAcac), hexafluoroacetylacetone (Hfac), and dipivaloylmethane (Dpm)), is studied. In all cases, vanadium(IV) and vanadium(III) β-diketonate complexes of different types are formed. New crystalline modification [V(Acac)₃] is obtained in the reaction with HAcac. The mixedligand vanadium(III) complex of the composition [V₂(Hfac)₂(μ-OPr)]₂ is formed with Hfac. In the presence of Dpm, the known vanadium(IV) complex [V₂O₂(Dpm)₂(μ-OPr)₂] is obtained in which two vanadyl groups VO²⁺ are linked by two bridging propoxy groups. The structures of all products are determined by X-ray diffraction analysis.     

Reaction of Pyrrolooxazinetriones with Diphenylguanidine. Synthesis of Substituted Spiro[imidazole-4,2′-pyrroles]

Russian Journal of Organic Chemistry - 8-Aroyl-3,4-dihydropyrrolo[2,1-c][1,4]oxazine-1,6,7(1H)-triones reacted with 1,3-diphenylguani­dine to give...     

Synthesis of 2-(2-Thienyl)benzimidazoles by the Reaction of 2-(Mercaptomethyl)benzimidazole With β-Electrophilic Esters

New 2-(2-di- and tetrahydrothienyl)benzimidazole compounds were prepared by the ring closure reactions of 2-(mercaptomethyl)benzimidazole^1,2 (1) and α,β-unsaturated compounds activated with electron-withdrawing groups.     

Memory of Chirality in the Asymmetric Synthesis of Piperidines with Vicinal Stereocenters by Intramolecular Sn2′ Reaction

Intramolecular Sn 2′ cyclization of α-amino ester enolates provided piperidine derivatives with vicinal quaternary-tertiary stereocenters with excellent diastereo- and enantioselectivity via memory of chirality and the Thorpe-Ingold effect. DFT calculations provided a mechanistic rationale for the increase in chirality preservation via the Thorpe-Ingold effect. This new method has the potential to be integrated into concise asymmetric synthesis of bioactive molecules containing multisubstituted piperidine moieties.     

Reaction of 4-(2′-Hydroxyaryl)-1,3-dithiolium Salts with Sodium Sulfide. A Selective Synthesis of 2′-Hydroxyacetophenones

Abstract

The treatment of 4-(2′-hydroxyaryl)-2-(N,N-dialkylamino)-1,3-dithiolium perchlorates (1a–g) with sodium sulfide nonahydrate in ethanol at room temperature affords the corresponding 1,3-dithiole-2-thiones (2a–g). When these reactions are conducted in boiling ethanol, 2′-hydroxyacetophenones (3a–g) have been obtained in good to excellent yield. A tentative mechanism for the formation of 3a–g shows that this reaction is regioselective, this being established by the presence of hydroxyl group in 2′-position. That has been confirmed in a control experiment, 4-phenyl-2-(piperidin-1-yl)-1,3-dithiolium perchlorate affording a mixture of condensation products of acetophenone and phenylacetaldehyde, under similar reaction conditions.     

Applying an Aza-Wittig Reaction for the Synthesis of Novel Thieno[3′,2′:5,6] Pyrido[4,3-d]pyrimidinone Derivatives

A series of new 2-substituted tetrahydrobenzo[4′,5′]thieno[3′,2′:5,6]pyrido[4,3-d] pyrimidin-4(3H)-ones 5 has been designed and synthesized via an aza-Wittig reaction. Iminophosphorane 3a or iminophosphorane 3b reacted with 4-Cl-phenyl(or 4-F-phenyl) isocyanate to give carbodiimide 4a or carbodiimide 4b , which were further treated with phenols to cyclize to give compounds 5 in presence of a catalytic amount of K₂CO₃. The structures of compound 5 have been confirmed by ¹H NMR, EI-MS, IR spectroscopy, and elemental analyses.     

Synthesis of 2.2′-azobis[2-methylpropionitrile] labeled with radioactive carbon (C14)

Summary The synthesis is described of 2.2-azobis[2-mediylpropionitrileI labeled with radioactive carbon.