Acylation of spiro(1-pyrazoline-3,1′-cyclopropanes) to form 1-acyl-3-(2-chloroethyl)-2-pyrazolines and transformation of bicyclic 2-pyrazolines into 1,4,5,6-tetrahydropyridazines

Strained polycyclic spiro(1-pyrazoline-3,1-cyclopropanes) react with acetyl or benzoyl chlorides at 0–15 °C regioselectively to give in high yields corresponding 1-acyl-3-(2-chloro-ethyl)-2-pyrazolines. Under the same conditions 6-ethenyl-4,5-diazaspiro[2,4]hept-4-ene gives a mixture of two pyrazolines resulting from the acyl group attack directed at different nitrogen atoms. Bicyclic pyrazolines-2 obtained by acylation of the cycloaddition products of diazocyclopropane with 3,3-disubstituted cyclopropenes transform under the action of hydrogen chloride to 1,4,5,6-tetrahydropyridazines in high yields.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2208–2211, November, 1995.The work was carried out with financial support of the Russian Foundation for Basic Research (Grant No. 94-03-08902).     

Formation of Unsymmetrical 2-(Diacylmethylene)-2,3-dihydro-1H-benzimidazoles During Acidolysis of 1-Benzoyl-2-(β-benzoyloxy-β-phenylvinyl)-1H-benzimidazole

The reaction of 1-benzoyl-2-(-benzoyloxy--phenylvinyl)-1H-benzimidazole with carboxylic acids was investigated. A convenient method was developed for the synthesis of unsymmetrical 2-(diacylmethylene)-2,3-dihydro-1H-benzimidazoles. 2-(4-Pyrazolyl)-1H-benzimidazoles were obtained by the reaction of 2-(benzoylformylmethylene)-2,3-dihydro-1H-benzimidazole with hydrazine.     

Asymmetric Conjugate Addition of Alcohols to (R)-(-)-5-[(1R,2S,5R)-Menthyloxy]-2-(5H)-Furanone

(R)-(-y5-[(IR,2S,5R)-menthyloxy](1)isausefulchiralsynthonreadilypreparedonatWo-stepprocedure-l']FindingsoffuranoneringsexistingascomponentSofsomenaturalproductSI'laswellastheiractivereactivityl']havestimu1atedeXtensiveresearchofitSasymmetricreactionswhichincludeDiels-Alderreactions,l']l,3-dipo1arcycloadditions,['1Michaelauditionsl5]andconjugateedditionsofaminesl']andmercaPtans.g4:,::7f:7':theseadductsledtovariousmultifunctionalhomochiralbuildingblockssuchas2-alkyl-l,4-butanediols,I'l2-aI…     

Comeplexes of 1-(2′-hydroxybenzyl)-2-(2′-hydroxyphenyl)-benzimidazole with U(VI) and Ce(IV)

Some new U(VI) and Ce(IV) complexes of 1-(2′-hydroxybenzyl)-2-(2′-hydroxyphenyl)-benzimidazole have been prepared and characterized by spectrg magnetic and conductance studies. IR spectral data suggests that the ligand in all the complexes is monodenate through the tertiary nitrogen and that the phenolic oxygen is free from coordination. Conductivity measurements indicate that the nitrate and acetate complexes of U(VI) are non-electrolytes, whereas the nitrate complex of Ce(IV) is a 1:1 electrolyte.     

Stereoselective synthesis of s-(2-deoxy-α-D-glycosyl)- phosphorodithioates1 and of their (2R)-2-deoxy-2-deuterio- analogues. Novel route to C-2 d

Addition of 0,0-dialkylphosphorodithioic acids to fully protected 1,2-unsaturated hexo- and pentopyranoses gives S-(2-deoxy-glycosyl)-phosphorodithioates in quantitative yield and high stereoselectivity with respect to the α-isomer. The stereochemistry of this reaction is “cis” as demonstrated by the addition of deuterated 0,0-dialkylphosphorodithioic acids to 3,4,6-tri-O-acetyl-D-glucal which gives exclusively the α-dithiophosphates of (2R)-2-deoxy-2-deuterio-D-arabinohexopyranose. This result provides an efficient and fully stereoselective method of labeling of the deoxy function in 2-deoxy monosaccharides and their glycosylic derivatives.     

Synthesis of 2-(3-hydroxy-2-methyl-1-alkenyl)-1-pyrrolines and 2-(3-hydroxybutyl)-1-pyrroline using α-lithiated 2-methyl-1-pyrroline

Condensation of 2-methyl-1-pyrroline with chloroacetone or 3-chloro-2-butanone using LDA in THF afforded novel 2-(3-hydroxy-2-methyl-1-alkenyl)-1-pyrrolines via a peculiar reaction mechanism instead of the anticipated 2-(3-oxobutyl)-1-pyrrolines. The intermediacy of 2-(2,3-epoxy-2-methylalkyl)-1-pyrrolines in the latter transformation was demonstrated by immediate reductive epoxide ring opening utilizing lithium aluminium hydride in diethyl ether. Furthermore, 2-(3-oxobutyl)-1-pyrroline was prepared via an alternative approach through alkylation of 2-methyl-1-pyrroline with 3-chloro-2-(methoxymethyloxy)-1-propene using LDA in THF, followed by acid hydrolysis. Reduction of 2-(3-oxobutyl)-1-pyrroline by sodium borohydride in methanol afforded the corresponding 2-(3-hydroxybutyl)-1-pyrroline in good yield.     

Synthesis,Structure and Biological Activities of 2-(1H- 1,2,3-Benzotriazol-1-yl)-1-(4-methylphenyl)-2- (1H-1,2,4-triazol-1-yl)-1-ethanone

IntroductionTriazole derivatives have become the most rapidlyexpanding group of antifungal compounds with advanta-ges of lowtoxicity, high oral bioavailability and broad-spectrum antifungal activity, which can be used againstfungi including most yeasts an…     

Cyclization of 1-(4,4-diethoxybutyl)-3-aryl(thio)ureas to 2-arylpyrrolidines and 2,3´-bipyrrole derivatives

A reaction of 1-(4,4-diethoxybutyl)-3-phenylthiourea with resorcinol, 2-methylresorcinol, pyrogallol, and hydroquinone in chloroform in the presence of trifluoroacetic acid leads to 2-aryl-1-(N-phenylcarbamothioyl)pyrrolidines. 1-(4,4-Diethoxybutyl)-3-arylureas and 1-(4,4diethoxybutyl)-3-arylthioureas in the presence of an acid catalyst undergo intramolecular cyclization and dimerization with the formation of 1,1´-bis(N-arylcarbamo(thio)yl)-2,3´-bipyrrole derivatives.     

Reactions of Methyl 1-(Bromoacetyl)azulene-3-carboxylate with 2-Hydroxy-benzaldehydes: Synthesis of 1-(Benzofuran-2-yl)-3- methoxycarbonylazulenes

A few compounds containing the 2-arylbenzofuran nucleus, have been isolated from plants.[1] For example,moracins A and B, egonol, homoegonol and (±)-machicendiol are well known.     

Molecular Structure of 1- (Diisopropyl )amino-2-(p-methyl )phenyl-3-methyl-phosphetane 1-oxided

lINTR0DUCTIONThechemistryofstablephospheniumcati0n[Rl-P-R2j hasbeenextensivelyknowntl-3).Wereportedsynthesesandreactions0fthephospheniumcati0nsfeatur-ingwithanS-P-Nlinkage.(4-8)Recentlywefoundthatphospheniumion[i-Pr2N-P-Clj [AlC'j-canregiOselectivelyinsertintophenylcyclopropaneringattwocycliccarbon-carbonb0ndsadjacenttophenylgr0uptogivel-(diisopropyl)amin0-2-(p-methyl)phenyl-3-methyl-phosphetanel-oxide(1).Inordertodisclosetherelativesterelchemistry,itssinglecrystalwasobtainedfromn-he…     

Synthesis of propyl O-(α-L-rhamnopyranosyl)-(1→3)-[2,4-di-O-(2s-methylbutyryl)-α-L-rhamno-pyranosyl]-(1→2)-(3-O-acetyl-β-D-glucopyranosyl)-(1→2)-β-D-fucopyranoside,the tetrasaccharide moiety of Tricolorin A

Propyl O-(α-L-rhamncpyranosyl)-(1→3)-[2,4-di-O-(2s-methylbutyryl)-α-L-rham-nopyranosyl]-(1→2)-(3-O-acetyl-β-D-glucopyranosyl)-(1→2)-β-D-fucopyranoside (1), the tetrasac-charide moiety of Tricolorin A, was synthesized in total 23 steps with a longest linear sequence of 10 steps, and overall yield of 3.7% from D-Glucose. The isomerization of the dioxolane-type berzyli-dene in the presence of NIS/AgOTf was observed. Tetrasaccharide 1 exhibited no activity against the cultured P388 cell as Tricolorin A did.     

Investigation of supramolecular inclusion complexes with β-cyclodextrin of 1-(2-ethoxyethyl)-4-(pentyn-1-yl)-4-hydroxypiperidine and 1-(2-ethoxyethyl)-4-(pentyn-1-yl)-4-benzoyloxypiperidine oxalate by NMR spectroscopy

A comparative analysis of ¹H and ¹³C NMR spectra of 1-(2-ethoxyethyl)-4-(pentyn-1-yl)-4-hydroxypiperidine, 1-(2-ethoxyethyl)-4-(pentyn-1-yl)-4-benzoyloxypiperidine oxalate and their inclusion complexes with β-cyclodextrin was performed. The differences in values of chemical shifts of ¹H and ¹³C nuclei of the substrates and the receptor in the inclusion complexes were determined. It was found that the formation of complexes of 1-(2-ethoxyethyl)-4-(pentyn-1-yl)-4-hydroxypiperidine and 1-(2-ethoxyethyl)-4-(pentyn-1-yl)-4-benzoyloxypiperidine oxalate with β-cyclodextrin was accompanied by insertion of one N-ethoxyethyl fragment of the substrate molecule into the inner sphere of one molecule of the receptor.     

1,3-Dipolar Cycloaddition of Substituted Benzonitrile Oxide to 5-(R)-(l-Menthyloxy)-2(5H)-furanone

Isoxazoline compounds as key intermediates for construction of natural products have been developed very fast as an hot area in organic synthesis1. 5-(R)-(l-menthyloxy)- 2(5H)-furanone as a valuable chiral synthon has been recently studied for its high stereoselectivity in many reactions2. In this paper, we focused on its reactivity and regioselectivity of the 1,3-dipolar cycloaddition with the substituted benzonitrile oxide3 and several isoxazoline compounds were obtained and characterized…     

Modular synthesis of 1-α- and 1-β-(indol-2-yl)-2'-deoxyribose C-nucleosides

A simple two-step method for the selective preparation of anomerically pure 1α- and 1β-(indol-2-yl)deoxyribose derivatives was developed. The synthesis was based on the Sonogashira reaction of 1α- and 1β-ethynyldeoxyribose and 2-haloanilines followed by a Pd-complex catalyzed cyclization to the corresponding indolyldeoxyribosides.     

A Facile Synthesis of an Advanced Glycosylation Endproduct 2-(2′-furoyl)-4(5)-(2′-furanyl)-1H-imidazole

Abstract: A three step synthesis of the advanced glycosylation endproduct 2-(2′-furoyl)-4(5)-(2′-furanyl)-1H-imidazole (4, FFI) has been achieved from 2-acetylfuran. The key step in the synthesis was the rearrangement of the hydrazinium bromide 3 in refluxing methanol.     

Synthesis and Crystal Structure of 1-(o-methylphenyl)-2-(p-methoxyphenyl)-1,3,2-diazaphospholidin-4-thione-2-sulfide

11NTRODUCTIoNThederivativesofdiazaphospholidinoneorthecorrespondingthionesareknowntopossessinterestingbiologicalproperties,suchasherbicidalactivity"'2i.Inrecentyears,itwasreportedthatthel,4,2-diazaphospholindine-5-thione-2havegoodselectiveherbicidalactivity"'41.Tolookformoreeffectiveherbicideswithlowtoxicity,aseriesofnovel1-(o-methylphenyl)-2-(p-methoxyphenyl)-phospholidin-4-thione-sulfideshavebeensynthesizedandtheirmolecularstructuresstudied.PreliminarybioassaysshowthatthesecomPoundshaveg…     

Intramolecular Cyclization of 1-(ω-Phenylalkyl)-2-(nitromethylene)pyrrolidines in Triflic Acid

1-(ω-Phenylalkyl)-2-(nitromethylene)pyrrolidines in triflic acid undergo a C,O-diprotonation, followed by loss of water, to form conjugated iminium–hydroxynitrilium dications, which react with the tethered phenyl ring by electrophilic aromatic substitution to afford tricyclic iminium compounds as triflate salts. The scope and mechanism of this reaction are discussed.     

Synthesis of Two Isomeric Tetrasaccharides 0-α-L-Fucopyranosyl-(1→3) and (1→4)-0-(2-Acetamido-2-Deoxy-β-D-Glucopyranosyl)-(1→3)-0-(β-D-Galactopyranosyl)-(1→4)-D-Glucopyranose and a Related Tetrasaccharide 0-α-L-Fucopyranosyl-(1→3)-0-(2-Acetamido-2-Deoxy-β-D-Glucopyranosyl-(1→6)-0-(β-D-Galactopyranosyl)-(1→4)-D-Glucopyranose

ABSTRACT

Synthesis of three tetrasaccharides, namely, 0-α-L-fucopyranosyl-(1→3)-0-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-(1→3)-0-(β-D-galactopyranosyl)-(1→4)-β-D-glucopyranose (7), 0-α-L-fucopyranosyl-(1→4)-0-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-(1→3)-0-(β-D-galactopyranosyl)-(1→4)-D-glucopyranose (9), and 0-α-L-fucopyransoyl-(1→3)-0-(2-acetamido-2-deoxy-β-D-glucopyransoyl)-(1→6)-0-(β-D-galactopyranosyl)-(1→4)-D-glucopyranose (15) has been described. Their structures have been established by ¹³C NMR spectroscopy.     

Hydrolysis Reactions and Resolution of (±)-2-Acetamido-3-hydroxy-1-(4-nitrophenyl)-1-propanone

IntroductionChloramphenicol,which was isolated fromStreptomyces venezuelae in 1 947[1] ,is used as abroad- spectrum antibiotic possessing activityagainst many Gram- negative and Gram- positivemicroorganisms. (± ) - 2 - Acetamido- 3 - hydroxy- 1 -(4- nitrophenyl) - 1 - propanone[(± ) - 1 ]is one of theintermediates of producing chloramphenicol.Petrow et al.[2 ] reported some transformations of(± ) - 1 in hydrolysis reactions. However,thereaction products were complicated under multiplehydr…