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…     

Synthesis, Structure and Dielectric Property of Ba_(1- x)Sr_xZr_yTi_(1- y)O_3

ＩｎｔｒｏｄｕｃｔｉｏｎＢａＴｉＯ３ｉｓａｓｔｒｏｎｇｄｉｅｌｅｃｔｒｉｃｍａｔｅｒｉａｌ，ｗｈｉｃｈｉｓｗｉｄｅｌｙｕｓｅｄｉｎｔｈｅｐｒｏｄｕｃｔｉｏｎｏｆｅｌｅｃｔｒｉｃｃｏｍｐｏｎｅｎｔｓｓｕｃｈａｓｃｅｒａｍｉｃｃａｐａｃｉｔｏｒ，ＰＴＣ，ｍｅｄｉｕｍａｍｐｌｉｆｅｒ［１］．Ｉｔｈａｓｔｈｅｈｉｇｈｅｓｔｄｉｅｌｅｃｔｒｉｃｃｏｎｓｔａｎｔａｔ１２０℃（ｃａ．１０４），ｗｈｉｌｅｉｔｓｄｉｅｌｅｃｔｒｉｃｃｏｎｓｔａｎｔａｔｒｏｏｍｔｅｍｐｅｒａｔｕｒｅｉｓｏｎｌｙ１／６ｏｆｔｈｅＣｕ…     

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…     

Synthesis of 1-N-(β-D-Glucopyranosyl)- and 1-N-(1-Deoxy-2,3,4,5,6-penta-O-acetyl-D-galactit-1-yl)ascorbigens

The 1-N-carbohydrate-containing ascorbigens 1-N-(-D-glucopyranosyl)ascorbigen and 1-N-(1-deoxy-2,3,4,5,6-penta-O-acetyl-D-galactit-1-yl)ascorbigen were synthesized.     

Synthesis and ozonization of (+)-4α-(1-trimethylsilyloxyethen-1-yl)-2-carene

(+)-4-(1-Trimethylsilyloxyethen-1-yl)-2-carene was synthesized, and the products of its ozonization were identified.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1984–1987, October, 1995.     

Crystal structure and properties of (Z)-N′-((E)-2-(hydroxyimino)-1-phenylethylidene) isonicotinohydrazide

Compound I contains in its molecule pyridyl, monoxime and hydrazone functions. A non-merohedral twin crystal of the compound with two reciprocal lattices differently oriented and giving rise to double diffraction spot sets with the 0.5:0.5 ratio of the twin components was studied. The hydrazone and oxime units are approximately planar. The dihedral angles between this plane and the planes of the pyridine and phenyl rings are 30.79(19)° and 18.43(13)°, respectively. Both the oxime and hydrazone units in I have an E configuration. The molecules of I are linked via C-H⋯O and O-H⋯N hydrogen bonds forming a 3D framework. The compound was also characterized by IR, ¹H NMR and elemental analyses.     

Stereoselective Synthesis and Characterization of (Z)-(−)-4-(1′-Alkoxyl-1′-alkyloxycarbonyl-methylidene)-5(R)-[(1R)-menthyloxy]-γ-butyrolactones

Abstract

A series of enantiomerically pure (Z)-(?)-4-(1′-alkyloxy-1′-alkyloxycarbonyl-methylidene)-5(R)-[(1R)-menthyloxy]-γ-butyrolactones were synthesized and characterized in good to excellent yields via O-alkylation of (4R,5R)-(?)-4-ethoxyoxalyl-5-[(1R)-menthyloxy]-γ-butyrolactone with alkyl halides in the presence of K₂CO₃ in acetone at room temperature.     

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.     

Synthesis and Anti-HIV Activity of Further Examples of 1-[3-Deoxy-3-(N-hydroxyamino)-β-d-threo-(and β-d-erythro)-pentofuranosyl]thymine Derivatives1

Abstract

Upon sodium cyanoborohydride reduction followed by de-O-silylation, the O-methyloxime and N-benzylnitrone of 5′-TBDMS-3′-ketothymidine gave resolvable epimeric mixtures of 1-[2,3-dideoxy-3-(N-methoxyamino)-β-d-threo-and β-d-erythro-pentofuranosyl]thymine and 1-[3-(N-benzyl-N-hydroxyamino)-2,3-dideoxy-β-d-threo- and β-d-erythro-pentofuranosyl]thymine respectively. These compounds were inactive against HIV. On the other hand, 1-[2,3-dideoxy-3-(N-hydroxyamino)-5-O-TBDMS-β-d-threo-pentofuranosyl]thymine, upon treatment with acetone, then de-O-silylation, gave the bicyclonucleoside analogue 15, slightly more active against HIV in vitro than DDI.     

Synthesis and Crystal Structure of N′-(4-fluorobenzylidene)-2-(1H-1,2,4-triazole-1-yl)acetohydrazide

IntroductionBoth triazole derivatives and Schiff base have beenreported to possess significant antifungal[1—3]and plantgrowth regulatory activities[4—6].Triazole drugs are alsovery common in the medical field,which has given animmense impetus to the res…     

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.     

Efficient synthesis of (−)-(R)- and (+)-(S)-rolipram

A novel, efficient and protecting group free enantioselective synthetic approach of (?)-(R)-1 and (+)-(S)-rolipram 2 is described employing the organocatalyzed asymmetric Michael addition, Henry condensation, Wittig olefination and reductive lactamization reactions as key steps.     

Synthesis and Study of Spectroscopic Properties of 5-(1-Oxido-3-pyridyl)-10,15,20-triphenyl Porphyrin and Its Zn(Ⅱ) Complex

Two novel sensitizers with pyridine-N-oxide zinc porphyrin and its zinc porphyrin as the anchor group and electron acceptor have been synthesized. The structures have been characterized by UV, elemental analyses and ~1H NMR. UV and fluorescence spectra show that they have good light absorbing properties in the range of visible light and suggest that they have potential applications in dye-sensitized solar cells.     

Total Synthesis of (-)-Kaerophyllin,(-)-Hinokinin and (±)-Isohinokinin

Kaerophyllin (1) ,hinokinin (2 )andtheiranalogue isohinokinin (3)belongtothedibenzylbutyrolactone lig nans .Kaerophyllin (1)wasisolatedfromtherootofspot tedcowparsley (ChaerophyllummaculatumWilld .) 1andhinokinin (2 )wasisolatedfromtheheartwoodofLiboce drusformosanaFlorin .2 AccordingtoMacRaeandTow ers ,3afivememberedlactoneringandamethylenedioxylgroupwereimportantstructuralcharacteristicswhichcon tributetotheactivityoflignansasantitumoragents .More over ,anunsaturateddoublebondbetweenC3—…     

Efficient synthesis of (S)-(−)- and (R)-(+)-enantiomers of 15-deoxyspergualin (15-DSG)

An efficient synthesis of the (S)-(−)- and (R)-(+)-enantiomers of 15-deoxyspergualin (15-DSG) is reported. The synthesis involves preparative HPLC separation and subsequent hydrogenolysis of two diastereoisomers 10a and 10b of fully protected 15-DSG penultimates. Alternatively, diastereomerically pure amide 10b (97% de) was also prepared from acid 8b (97% de), which was obtained via crystallization of a 1:1 diastereomeric mixture of 8a and 8b.     

Structural and bonding investigation of an unbridged donor-acceptor complex 1-(2,2′-bipyrimidine)-1-(t-butyl)-2, 3-bis(trimethylsilyl) -2,3-dicarba-1-galla-closo-heptaborane(6)

The reaction between thecloso-gallacarborane, 1-(t-C₄H₉)-1-Ga-2,3-(SiMe₃)₂-2,3-C₂B₄H₄ (1), and 2,2-bipyrimidine in a molar ratio of 11 in dry benzene produced the unbridged donor-acceptor complex 1-(2,2-C₈H₆N₄)-1-(t-C₄H₉)-1-Ga-2,3-(SiMe₃)₂-2, 3-C₂B₄H₄ (2) as a pale-yellow crystalline solid in 81% yield. The spectroscopic data of2 are almost identical to those of the bridged species 1,1-(2,2-C₈ H₆N₄)-[1-(t-C₄H₉)-1-Ga-2,3-(SiMe₃)₂-2,3-C₂ B₄H₄]₂ (3). However, the single-crystal X-ray structure of2 reveals that the complex consists of only one distorted gallacarborane unit and a bipyrimidine molecule, that acts as a bidentate ligand. The apical gallium in2 is displaced further away from the centroidal position above the carborane than it is in 1. Despite the steric hindrance imposed by the bulky trimethylsilyl groups on the cage carbons, the Ga-C_(t-buty) bond is tilted toward the cage carbon atoms. Complex2 crystallizes in the monoclinic space groupP2₁ witha=11.279 (3),b=10.060 (3),c=11.911 (3) Å,=94.94 (2)°,V=1346.5 (6) ų,Z=2,D _x=1.24g cm^–3, (MoK) F(000)= 528, andT=220 K. Full-matrix least-squares refinement for2 converged at R=0.036 andRw= 0.045 for 3032 observed reflections. Molecular orbital calculations showed that antibonding interactions between the gallium and carborane cage carbons, induced by base complexation, are a contributing factor to the gallium's slip distortion that is found in2.     

Preparation of α-Ketophosphonate Derivatives and Their Application in the Synthesis of 1-(N-Alkylcarbamoyl)-1-(diethoxyphosphoryl)alkyl Benzoates via Passerini Reaction

Abstract

The Passerini reaction of α-ketophosphonates, isocyanides, and benzoic acid derivatives leads to 1-(N-alkylcarbamoyl)-1-(diethoxyphosphoryl)alkyl benzoates in one step at room temperature. The structures of products were assigned on the basis of their ¹H NMR, ¹³C NMR, ³¹P NMR, and IR spectroscopic data.

GRAPHICAL ABSTRACT