Structural studies of seven homoisoflavonoids, six thiohomoisoflavonoids, and four structurally related compounds

¹H and ¹³C NMR chemical shifts have been determined and assigned based on PFG ¹H, ¹³C HMQC, and HMBC experiments for 3-(4′-X-benzyl)-4-chromenones (Ia, X = CN and Ib, X = NO₂), 3-(4′-X-benzyl)-4-thiochromenones (IIa, X = Cl and IIb, X = Br), (E)-3-(4′-X-benzylidene)-4-chromanones (IIIa–IIIe, X = OCH₃, CH₃, Cl, N(CH₃)₂, Br), (Z)-3-(4′-X-benzylidene)4-thiochromanones (IVa–IVd, X = Cl, Br, F, OCH₃), 2-benzyl-1,2,3,4-tetrahydro-1-naphthol (V), 2-benzyl- and (E)-2-benzylidene-1-tetralones (VI and VII), and (E)-2-benzylidene-1-benzosuberol (VIII). The crystal structures have been determined for the following seven compounds: derivatives of 4-chromanones (IIIa–IIId), 1-tetrahydronaphtol (V), and 1-tetralones (VI and VII). The molecular features and intermolecular interactions in crystal state have been discussed.     

Synthesis and characterization of novel 2-(1-benzyl-3-[4-fluorophenyl]-1H-pyrazol-4-yl)-7-fluoro-4H-chromen-4-one derivatives

Novel 1-benzyl-3-(4-fluorophenyl)-1H-pyrazole-4-carbaldehydes 3a to 3e were synthesized via Vilsmeier-Haack reaction of the appropriate 1-benzyl-2-(1-(4-fluorophenyl)ethylidene)hydrazines, derived from 4-fluoroacetophenone 1 with substituted 2-benzylhydrazines 2a to 2e . The base catalyzed condensation of 1-benzyl-3-(4-fluorophenyl)-1H-pyrazole-4-carbaldehydes 3a to 3e with 1-(4-fluoro-2-hydroxyphenyl)ethanone 4 gave (E)-3-(1-benzyl-3-(4-fluorophenyl)-1H-pyrazol-4-yl)-1-(4-fluoro-2-hydroxyphenyl)prop-2-en-1-ones 5a to 5e . On cyclization with dimethyl sulfoxide (DMSO)/I₂, compounds 5a to 5e gave 2-(1-benzyl-3-(4-fluorophenyl)-1H-pyrazol-4-yl)-7-fluoro-4H-chromen-4-ones 6a to 6e . Structures of all novel compounds were confirmed by infrared (IR), proton nuclear magnetic resonance (¹H NMR), carbon nuclear magnetic resonance (¹³C NMR), and mass spectral data. All the synthesized compounds were screened for their antibacterial activities.     

Synthesis of stereoregular heteropolysaccharides having amino-groups by ring-opening copolymerization of 1,6-anhydro-azido-sugar derivatives

The cationic, ring-opening copolymerization of 1,6-anhydro-2-azido-3,4-di-0-benzyl-2-deoxy-(2-ABG), -3-azido-2,4-di-0-benzyl-3-deoxy- (3-ABG), -4-azido-2,3-di-0-benzyl-4-deoxy-β-D -glucopyranose (4-ABG) with 1,6-anhydro-2,3,4-tri-0-benzyl-β-D -glucopyranose (LGTBE) was investigated with phosphorus pentafluoride as catalyst at low temperatures, giving highly stereoregular, (1→6)-α-linked copolymers with number-average molecular weights of 3.90 × 10⁴?9.27 × 10⁴. Structure and composition of the copolymers were determined by ¹H- and ¹³C-NMR spectroscopies and elemental analysis, which indicated that copolymerization occurred in a stereoregular manner to give azido groups containing (1→6)-α-linked glucopyranan derivatives. The differences in polymerizability among the three azido monomers are discussed. Regioselective reduction of three kinds of heteropolysacharide derivatives which had different quantities of azido groups at C-2, -3, or -4 position with lithium aluminum hydride and subsequent debenzylation of the copolymers with sodium in liquid ammonia produced amino-group-containing heteropolysaccharides.     

An efficient synthesis of 4-chromanones

A two step efficient and practical synthesis of a variety of 4-chromanones is described. Phenols undergo a Michael addition to acrylonitriles in the presence of catalytic amounts of potassium carbonate and tert-butanol to generate the corresponding 3-aryloxypropanenitriles in 50-93% yields. Treatment of the resulting aryloxypropionitriles with 1.5 equiv of TfOH and 5 equiv of TFA, followed by an aqueous work up afforded 4-chromanones in moderate to excellent yields.     

Crystal structure and quantum chemical calculations of (E)1-benzyl-3-((4-methoxyphenyl)imino)-5-methylindolin-2-one

The known Schiff base compound, (E)1-benzyl-3-((4-methoxyphenyl)imino)-5-methylindolin-2-one, was prepared as before by reacting 1-benzyl-5-methylindoline-2,3-dione with 4-methoxyaniline. The product was unambiguously characterized using elemental analysis, ¹H and ¹³C-NMR spectroscopy, and its new single-crystal X-ray structural analysis. Molecular orbital calculations were conducted in order to investigate the structures and relative stabilities of the (E) and (Z) isomers of 1-benzyl-3-([4 methoxyphenyl]-imino)-5-methylindolin-2-one. Specific attention was paid to the (E) isomer. The available crystallographic experimental data for the latter ensured also validation of the model structures computationally derived at the theoretical B3LYP/6-31G(d,p) level.     

A facile synthesis of 3-alkylchromanones and chromones

A simple and high yielding route to 3-alkylchromanones and 3-alkylchromones has been achieved from 3-alkyl-3-phenyl-sulphonyl-4-chromanones.

A simple and high yielding route to 3-alkylchromanones and 3-alkylchromones has been achieved from 3-alkyl, 3-phenylsulphonyl-4-chromanones.     

<Emphasis Type="Italic">trans</Emphasis>-4-amino-3-hydroxypiperidines. Regio- and stereoselective synthesis

trans-4-Amino-1-benzyl-3-hydroxypiperidines were synthesized by regio- and stereoselective amination of a series of 1-benzyl-3,4-epoxypiperidines with primary and secondary aliphatic, aromatic, and heterocyclic amines in the presence of lithium perchlorate. The regio- and stereoselectivity of the amination process is ensured by specific activation of the oxirane ring in epoxypiperidine derivatives. Lithium cation is coordinated simultaneously at the piperidine nitrogen atom and oxirane oxygen atom, which leads to greater extension of the C⁴-O bond as compared to C³-O, so that nucleophilic attack is directed at the C⁴ atom of the piperidine ring.     

Some reactions of 5-benzyl-2,3,5-trichloro-4,4-dimethoxy-cyclopent-2-en-1-one and its derivatives

5-Benzyl-2,3,5-trichloro-4,4-dimethoxycyclopent-2-en-1-one and 2-benzyl-2,4,5-trichlorocyclopent-4-ene-1,3-dione were subjected to dehydrochlorination by the action of 1,4-diazabicyclo[2.2.2]octane, selective dechlorination at C⁵ by the action of CrCl₂, and Ad_NE replacement of the chlorine atom at C³ by the action of secondary amines. The reduction of 2-benzyl-2,4-dichloro-5-morpholinocyclopent-4-ene-1,3-dione with sodium tetrahydridoborate in methanol and ethanol gave different products.     

新型2H-噻唑[3,2-b][1,2,4]三嗪-3,7-二酮的超声辅助一锅法合成及乙酰胆碱酯酶抑制活性研究

以取代苯甲醛、溴乙腈和6-苄基-3-硫代-3,4-二氢-1,2,4-三嗪-5(2H)-酮为起始原料,在超声辅助下,一锅合成了9个新型6-苄基-2-亚苄基-2H-噻唑[3,2-b][1,2,4]三嗪-3,7-二酮类化合物,结构经_¹H NMR,_¹³C NMR和MS（ESI）表征并对其合成机理进行了初步研究。测试了目标化合物(4a~4i)的体外乙酰胆碱酯酶的抑制活性,其中4a和4d抑制活性最好,有进一步研究的价值。     

Intramolecular N to N acyl migration in conformationally mobile 1′-acyl-1-benzyl-3′,4′-dihydro-1′<Emphasis Type="Italic">H</Emphasis>-spiro[piperidine-4,2′-quinoline] systems promoted by debenzylation conditions (HCOONH<Subscript>4</Subscript>/Pd/C)

We report an efficient and useful synthesis of new attractive spiropiperdine scaffolds 4 based on an intramolecular acyl transfer process in 1′-acyl-1-benzyl-3′,4′-dihydro-1′H-spiro[piperidine-4,2′-quinolines] 3 using simple and mild debenzylation reaction conditions (HCOONH₄/Pd/C). The compounds 3 were prepared by acylating 1-benzyl-4′-methyl-3′,4′-dihydro-1′H-spiro[piperidine-4,2′-quinolines] 2 that are easily available from 1-benzyl-4-piperidone 1. The intramolecular character of this process was proven primarily through a crossover experiment technique. Through an examination of all spectroscopic information (¹H, ¹³C NMR, VT-¹H NMR, and ²D NMR) it was possible to correctly predict amide configurations and piperidine ring conformations of starting and final spiropiperidine compounds.      

Synthesis and coordinating properties of 5-phenyl- and 5-pyridylmethylidene-substituted 2-selenohydantoines and 2-selenoimidazol-4-ones

2-Selenoimidazolidin-4-ones and 2-selenoimidazol-4-ones containing phenylor pyridylmethylidene substituent at position 5 were synthesized. The structure of 3-benzyl-2-selenohydantoine was confirmed by X-ray crystallography. A series of 2-(methylseleno)imidazol-4-ones was obtained by alkylation of 3,5-disubstituted selenohydantoines with methyl iodide. The synthesized selenohydantoines and 3-benzyl-5-pyridylmethylidene-2-(methylseleno)imidazol-4-ones were examined in the complexation reactions with CoCl₂, NiCl₂, CuCl₂, and Cu^I(CH₃CN)₄ClO₄; electrochemical investigations showed that reduced forms of the copper-containing complexes were stable     

Synthesis of N6-substituted adenines from 3-methylxanthine

A series of 6-arylalkyl(hetarylalkyl, cycloalkyl, carboxyalkyl)amino-7-benzyl-2-chloropurines have been synthesized from 3-methylxanthine via the reaction of the intermediate 7-benzyl-2,6-dichloropurine with amines and aminoacids. N⁶-benzyladenine, N⁶-(-furfuryl)adenine (kinetin), and N-(purinyl)glycine have been obtained via the catalytic hydrogenation of 7-benzyl-6-benzyl(furfuryl, carboxymethyl)amino-2-chloropurines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, 529–532, April, 2000.     

Synthesis of spiropyrazoline [5.3′] 4′-chromanones

Synthesis of a series of novel 1,3-diphenyl-4-aryl spiropyrazolines [5.3′] 4′-chromanones has been accomplished in good yields by regioselective 1,3-dipolar cycloaddition of diphenylnitrilimine to 3-arylidene-4-chromanones. X-ray crystal structure analysis of one of the products 4a confirms the structure and the regiochemistry of cycloaddition. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:327–332, 1998     

Preparation of trans Diequatorial 2,3-Pyruvate Acetals in a Di- and a Trisaccharide Related to the K-Antigen from E. Coli 0101:K103:H−

Abstract

Using methyl 2,2-bis(ethylthio)propionate as acetalating agent and triflic acid-sulfuryl chloride as catalyst, synthesis of 2,3-trans diequatorial pyruvate ketal was achieved. Starting from D-galactose and L-rhamnose derivatives, methyl 2,3,4,6-tetra-O-benzyl-α-D-galactopyranosyl-(1→4)-6-O-benzyl-2,3-O-(1-methoxycarbonyl)ethylidene- α-D-galactopyranosyl-(1→3)-2,4-di-O-benzyl-α-L-rhamnopyranoside and methyl 4,6-di-O-benzyl-2,3-O-(1-methoxy-carbonyl)ethylidene-α-D-galactopyranosyl-(1→3)-2,4-di-O-benzyl-α-L-rhamnopyranoside were synthesized. Removal of the protecting groups from the former, afforded the trisaccharide repeating unit of the K-antigen from E.coli O101:K103:H^? in the form of its methyl glycoside methyl ester.     

Synthesis and urease inhibition studies of some new quinazolinones

In this study, novel quinazolinones were designed, synthesized, characterized by FT-IR, ¹H-NMR, ¹³C-NMR spectral data, and LC–MS. New compounds inhibitory activities on urease were assessed. All of the compounds exhibited potent urease inhibitory activities. Especially in the synthesized compounds, 2-benzyl-3-({5-[(4-nitrophenyl)amino]-1,3,4-thiadiazol2-yl}methyl)quinazolin-4(3H)-one has the best inhibitory effect against Jack bean urease with IC₅₀ = 3.30 ± 0.09 μg/mL. And also, N-(4-nitrophenyl)-2-[(4-oxoquinazolin-3(4H)-yl)acetyl] hydrazinecarbothioamide, N-(4-fluorophenyl)-2-[(4-oxoquinazolin-3(4H)-yl)acetyl] hydrazinecarbothioamide, and 2-benzyl-3-({5-[(4-fluorophenyl)amino]-1,3,4-thiadiazol-2yl} methyl)quinazolin-4(3H)-one have best activities among the synthesized compounds.     

C-Glycoside Analogues of N4-(2-Acetamido-2-deoxy-β-D-glucopyranosyl)-L-asparagine: Synthesis and conformational analysis of a cyclic C-glycopeptide

The synthesis of C-glycosidic analogues 15–22 of N⁴-(2-acetamido-2-deoxy-β-D -glucopyranosyl)-L -asparagine (Asn(N⁴GlcNAc)) possessing a reversed amide bond as an isosteric replacement of the N-glycosidic linkage is presented. The peptide cyclo(-D -Pro-Phe-Ala-CGaa-Phe-Phe-) (CGaa = C-glycosylated amino acid; 24 ) was prepared to demonstrate that 3-[(3-acetamido-2,6-anhydro-4,5,7-tri-O-benzyl-3-deoxy-β-D -glycero-D -guloheptonoyl)amino]-2-[(9H-fluoren-9-yloxycarbonyl)amino]propanoic acid ( 22 ) can be used in solid-phase peptide synthesis. The conformation of 24 was determined by NMR and molecular-dynamics (MD) techniques. Evidence is provided that the CGaa side chain interacts with the peptide backbone. The different C-glycosylated amino acids 15–21 were prepared by coupling 3-acetamido-2,6-anhydro-4,5,7-tri-O-benzyl-3-deoxy-β-D -glycero-D -gulo-heptonic acid ( 4 ) with diamino-acid derivatives 8–14 in 83–96% yield. The synthesis of 4 was performed from 2-(acetamido-3,4,6-tri-O-benzyl-2-deoxy-β-D -glucopyranosyl) tributylstannane ( 2 ) by treatment with BuLi and CO₂ in 83% yield. Similarly, propyl isocyanat yielded the glycoheptonamide 7 in 52% from 2 . Compound 2 was obtained from 2-acetamido-3,4,6-tri-O-benzyl-2-deoxy-D -glucopyranose ( 1 ) by chlorination and addition of tributyltinlithium in 74% yield. A procedure for a multigram-scale synthesis of 1 is given.     

Synthesis of 1-benzyl-3,6-diazahomoadamantane

By condensation of 4-phenylbutan-2-one with tetramethylenediethylenetetramine 1-benzyl-3,6-diazahomoadamantan-9-one was synthesized. Further nitration of 1-benzyl-3,6-diazahomoadamantan-9-one yielded 1-(4-nitrobenzyl)-3,6-dia?ahomoadamantan-9-one. The modification of the nitro and carbonyl groups resulted in the formation of 1-benzyl-3,6-diazahomoadamantane and its derivatives with functional groups in the benzene ring and at the bridge carbon atom C⁹.     

Manganese(III)–Arsenic(III) Reaction Catalyzed by Some Antidotic Oxime Iodides

Manganese(III)–arsenic(III) reaction in the presence of sulfuric acid is proposed in this work as an indicator reaction for the kinetic determination of some antidotic oxime iodides. As 2-hydroxyiminomethyl-1-benzyl-3-methylimidazolium iodide, 2-hydroxyiminomethyl-3-benzyl-1-[3-(2-hydroxyiminomethyl-3-benzyl-1-imidazolio)-2-oxapropyl]-imidazolium diiodide, and 2-[(hydroxyimino)methyl]-1-methylpyridinium iodide catalyze the proposed reaction, a kinetic method for their determination in the range from 1.0 × 10⁻⁸to 8.0 × 10⁻⁸mol dm⁻³was developed. The effect of some other antidotic oximes on the accuracy of these determinations was investigated.     

Synthesis of Four Spacer-Containing Trisaccharides with the 4-0-(β-L-Rhamnopyranosyl)-D-glucopyranose Unit in Common,Representing Fragments of Capsular Polysaccharides from Streptococcus Pneumoniae Types 2, 7F, 22F,and 23F

Abstract

The synthesis is reported of 3-aminopropyl 3-O-[4-O(β-L-rhamnopyranosyl)-β-D-glucopyranosyl]-α-L-rhamnopyranoside (34), 3-aminopropyl 2-acetamido-3-O-[4-0-(β-L-rhamnopyranosyl)-β-D-glucopyranosyl]-2-deoxy-β-D-galactopyranoside (37), 3-aminopropyl 3-O-[4-O-(β-L-rhamnopyranosyl)-α-D-glucopyranosyl]-α-D-galactofuranoside (41), and 3-aminopropyl 4-O-[4-O-(β-L-rhamnopyranosyl)-β-D-glucopyranosyl]-β-D-galactopyranoside (45). These are spacer-containing fragments of the capsular polysaccharides of Streptococcus pneumoniae type 2, 7F, 22F, and 23F, respectively, which are constituents of Pneumovax^© 23. 2,3,4-Tri-O-benzyl-α-L-rhamnopyranosyl bromide was coupled to l,6-anhydro-2,3-di-(O-benzyl-β-D-glucopyranose (3). Opening of the anhydro ring, removal of AcO-1, and imidation of l,6-anhydro-2,3-di- O-benzyl-4-O-(2,3,4-tri-O-benzyl-β-L-rhamnopyranosyl)-β-D-glucopyranose (4β) afforded 6-O-acetyl-2,3-di-O-ben-zyl-4-O-(2,3,4-tri- O-benzyl-β-L-rhamnopyranosyl)-αβ-D-glucopyranosyl trichloroacet-imidate (7αβ). Condensation of 7αβ with 3-N-benzyloxycarbonylaminopropyl 2-O-ben-zyl-5,6-O-isopropylidene-α-D-galactofuranoside (26), followed by deprotection gave 41 Opening of the anhydro ring of 4 p followed by debenzylation, acerylauon, removal of AcO-1, and imidation yielded 2,3,6-tri-(9-aceryl-4-O-(2,3,4-tri-0-acetyl-P-L-rharnnopyran-.-osyl)-α-D-glucopyranosyl trichloroacetimidate (11). Condensation of 11 with 3-N-bcn-zyloxycarbonylaminopropyl 2,4-di-O-benzyl-α-L-rhamnopyranoside (18), with 3-N-bcn-zyloxycarbonylaminopropyl 2-acetamido-4,6-O-benzylidene-2-deoxy-β-D-galactopyran-oside (21), or with 3-N -benzyloxycarbonylaminopropyl 2-O-acetyl-3-O-allyl-6-O-benzyl-β-D-galactopyranoside (31), followed by deprotection afforded 34, 37, and 45, respectively.     

A Facile and Practical Procedure for the Synthesis of 8-Hydroxy-4-oxochroman Derivatives

Abstract: Novel 8-hydroxy-4-oxochroman derivatives were prepared from appropriate 4-chromanones via the Baeyer-Villiger oxidation followed by an intramolecular Fries rearrangement.