A Synthesis of 2-(6′-Carboxy-2′-cis-Hexenyl)-4-Hydroxycyclopent-2-EN-1-ONE,a Prostagiandin Intermediate1

Several recent publications² report the synthesis of prostaglandin E₁ (PGE₁, 2) and some of its derivatives by conjugate addition reactions to ether-ester forms of hydroxycyclopentenone acid 1.³ The simplicity of this approach makes its application to the preparation of prostaglandins of the PG₂- and PG₃ - series (cis-Δ⁵)⁴ an attractive alternative to the existing elegant methods.⁵ We now wish to report a five-step synthesis of the requisite hydroxycyclopentenone precursor 3 from the readily available⁶ lactone 4.     

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.     

A Practical Synthesis of 4′-Methylbiphenyl-2-carbonitrile as a Key Intermediate of Angiotensin II Antagonists

A new and practical synthesis of 4′-methylbiphenyl-2-carbonitrile, a key intermediate of angiotensin II antagonists is described. The key step is Pdcatalyzed dehydrogenation of the compound 6, which proceeds selectively by utilizing hydrogen acceptor such as maleic diester or oxygen.     

A Facile Synthesis of 4-(3β -Methoxy-5α-androstan-17β-YL)-3-pyrrolin-2-one

The title compound was prepared in 4 steps from 3β-methoxy-21-hydroxy-5α-pregnan-20-one (1). The required intermediate (4) was obtained using lithium enolate derived from t-butyl acetate. Interesting enough, p-tosyl chloride in pyridine quantitatively converted compound 1 into the α-chloro ketone derivative (2).     

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.     

Synthesis of 2-(Substituted Benzylideneamino)-4-(4′-hydroxyphenyl) Thiazoles and Their O-Glucosides

2-Amino-4-(4′-hydroxyphenyl) thiazole 1a was prepared from reaction between p-hydroxyacetophenone, thiourea, and iodine; compound 1a was treated with several (aryl/hetro aryl) aldehydes to form 2-(substituted benzylideneamino)-4-(4′-hydroxyphenyl) thiazoles 2a–j, which were glucosylated by using acetobromoglucose as a glucosyl donor to afford 2-(substituted benzylideneamino)-4-(2, 3, 4, 6-tetera-o-acetyl-4′-o-β-d-glucosidoxyphenyl) thiazoles 3a–j, which further on during deacetylation produced 2-(substituted benzylideneamino)-4-(4′-o-β-d-glucosidoxyphenyl) thiazoles 4a–j. These compounds were evaluated for biological activity, and their structure was confirmed by IR, NMR, mass spectra, elemental, and chemical analysis.

     

A Facile Synthesis of 5-(2′-Oxoalkyl)-2-Cyclopenten-1-Ones

In spite of the fact that a number of methods are available for the preparation of C-5-monoalkylated (simple alkyl) cyclopentenones¹, general synthetic routes leading to cyclopentenones possessing an activated side chain at C-5 remain virtually unknown². In connection with our synthetic studies on iridoids³, we have developed a convenient synthesis of the title compounds which we wish to report herein.     

Ionic-Liquid Salt-Mediated Synthesis of 4′-(Pyridyl)-terpyridines

One-pot reactions to produce isomeric 4′-(pyridyl) 2,2′:6′,2″-terpyridine under moderate conditions are described using imidazolium-based ionic liquid and quaternary ammonium-based molten salts as solvent media. The use of eutectic molten salts as a reaction media proved effective in sequential aldol and Michael addition reactions, leading to substituted terpyridines. The desired product was obtained in reasonable yield via a simple, one-pot reaction.     

Size-Controlled Synthesis of β(1→4)-GlcNAc Oligosaccharides Using an Endo-Glycosynthase

Chitin and peptidoglycan fragments are well recognized as pathogen associated molecular patterns (PAMPs). Long-chain oligosaccharides of β(1→4)-linked N-acetyl-D-glucosamine (GlcNAc) units indeed activate plants and mammals innate immune system. However, the mechanisms underlying PAMPs perception by lysine motif (LysM) domain receptors remain largely unknown because of insufficient availability of high-affinity molecular probes. Here, we report a two-enzyme cascade to synthesize long-chain β(1→4)-linked GlcNAc oligomers. Expression of the D52S mutant of hen egg-white lysozyme (HEWL) in Pichia pastoris at 52 mg L⁻¹ provided a new glycosynthase catalyzing efficient polymerization of α-chitintriosyl fluoride. Selective N-deacetylation at the non-reducing unit of the glycosyl fluoride donor by Sinorhizobium meliloti NodB chitin-N-deacetylase abolished its ability to be polymerized by the glycosynthase but not to be transferred onto an acceptor. Using NodB and D52S HEWL in a one-pot cascade reaction allowed the synthesis on a milligram scale of chitin hexa-, hepta- and octasaccharides with yields up to 65 % and a perfect control over their size.     

Synthesis of Certain 2′-Deoxy-3′,5′-di- O -benzyl-4′-thio-nucleosides Using Natural Phosphate Doped with Trifluoromethanesulfonic Acid as Catalyst

A series of 2′-deoxy-4′-thionucleosides are synthesized by coupling 1-O-acetyl-2-deoxy-3,5-di-O-benzyl-4-thio-D-erythro-pentufuranose to trimethylsilylated nucleobases using natural phosphate doped with trifluoromethanesulfonic acid as catalyst. The detail of this one-pot method and the comparison between the percentage of α and β -2′-deoxy-4′-thionucleosides with those described previously are also reported.     

Antimicrobial Activities of a Series of Diphenyl (4′-(Aryldiazenyl)Biphenyl-4-Ylamino)(Pyridin-3-YL)Methylphosphonates

Abstract

A series of diphenyl (4′-(aryldiazenyl)biphenyl-4-ylamino)(pyridin-3-yl)methyl- phosphonates 2–7 was synthesized in high yields and their antimicrobial activities were investigated. Some compounds showed high antimicrobial activities against Escherichia coli as a gram-negative bacterium, Bacillus subtilis and Staphylococcus aureus as gram-positive bacteria, and Candida albicans and Schccaromycies cerevisiae as fungi and at low concentrations (10–1000 μg/mL). Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Spectrophotometric Determination of Carbon Disulfide Using Bis(4-(4′-Nitrophenyl)azo-2-Nitrophenyl) Disulfide

Bis(4-(4-nitrophenyl)azo-2-nitrophenyl) disulfide (NADS) has been synthesized for the first time and proposed for the indirect photometric determination of carbon disulfide by dithiocarbamic acid. The reaction, which involves the breaking of the disulfide bond with the formation of colored azothio anions, is carried out in a mixture of dimethylsulfoxide and n-butanol. The high value of the apparent molar absorptivity (2 × 10⁵) is probably due to the autocatalytic character of the reaction. Using NADS, procedures for the determination of carbon disulfide in the atmospheric air of populated areas and in the model gas mixtures designed for the calibration of gas analyzers have been developed and certified. The procedures show high sensitivity and good reproducibility.     

Synthesis and some transformations of 2-(2′-thienyl)benzothiazole

Condensation of ortho-aminothiophenol with 2-thenoyl chloride in 1-methyl-2-pyrrolidone was used to synthesize 2-(2′-thienyl)benzothiazole. Its reactions of electrophilic (nitration, bromination, oxymethylation, formylation, acylation) and radical (nitration, arylation) substitution were studied.     

Synthesis of 2-(hydroxyphenylamino)- and 2-(aminophenylamino)-4-methylquinolines and N,N′-bis(4-methylquinolin-2-yl)benzenediamines

2-(Hydroxyphenylamino)- and 2-(aminophenylamino)-4-methylquinolines and N,N′-bis(4-methylquinolin-2-yl)benzenediamines were synthesized by reactions of 2-chloro-4-methylquinolines with o-, m-, and p-aminophenols and o-, m-, and p-phenylenediamines.     

Preparation and Polymerization of 2-(Phthalimido)ethyl 10′-(Methacryloyloxy)decyl Hydrogen Phosphate

The preparation and polymerization of 2-(phthalimido)ethyl 10′-(methacryloyloxy)decyl hydrogen phosphate are described. This monomer was polymerized with 2, 2′-azobisisobutyro-nitrile (AIBN). The properties of the resultant polymer are also described.     

Synthesis of 2′,3′-Dideoxy-2′-Fluorokanamycin A

2′,3′-Dideoxy-2′-fluorokanamycin A (23) was prepared by condensation of 6-azido-4-0-benzoyl-2,3,6-trideoxy-2-fluoro-α-D-ribo-hexopyranosyl bromide (13) and a protected disaccharide (19). Methyl 4,6-0-benzylidene-3-deoxy-β-D-arabino-hexopyranoside (5) prepared from methyl 4,6-0-benzylidene-3-chloro-3-deoxy-β-D-allo-hexopyranoside (1) by oxidation with pyridinium chlorochromate followed by reduction with Na₂ S₂O₄ was fluorinated with the DAST reagent to give methyl 4,6-O-benzylidene-2,3-dideoxy-2-fluoro-β-D-ribo-hexopyranoside (7). Successive treatment of 7 with NBS, NaN₃ and SOBr₂ gave 13. The structure of the final product (23) was determined by the ¹H and ¹⁹F and shift-correlated 2D NMR spectra.     

Synthesis and Crystal Structure of 1′-Methyl-4′- (4-chlorophenyl)-1H-indole-3-spiro-2′-pyrrolidine- 3′-spiro-4'-(2'-phenyloxazole)-2,5'(3H,4'H)-dione

The title compound (C26H20ClN3O3) has been synthesized by 1,3-dipolar cycloaddition reaction from isatin, sarcosine and (Z)-4-(4-chlorobenzylidene)-2-phenyloxazol-5(4H)-one through a one-pot procedure, and its structure was confirmed by IR, 1H NMR, elemental analysis and single-crystal X-ray diffraction analysis. The crystal belongs to the triclinic system, space group P1, with a = 9.3903(19), b = 11.398(2), c = 12.603(3) , α = 83.495(3), β = 68.988(3), γ = 67.178(3)°, V = 1160.1(4) 3, Z = 2, Mr = 457.90, Dc = 1.311 g/cm3, μ = 0.198 mm-1, F(000) = 476, the final R = 0.0489 and wR = 0.1144 for 3109 observed reflections with I > 2σ(I).     

Stereoselective Synthesis of 2-(4-Hydroxyphenyl)-3-hydroxymethyl-1,4-benzodioxane-6-aldehyde—The Key Intermediate of Sinaiticin

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CRYSTAL STRUCTURES OF [N′-(2- OXIDOBENZYLIDENE)-N-(PROP-2-EN-1-YL)- CARBAMOHYDRAZONOTHIOATO(2-)](1,10- PHENANTHROLINE)COPPER AND [N′-(2- OXIDOBENZYLIDENE)-N-(PROP-2-EN-1-YL)- CARBAMOHYDRAZONOTHIOATO(2-)](2,2′- BIPYRIDINE)COPPER HEMIHYDRATES

Journal of Structural Chemistry - The crystal structures and biological properties of [N′-(2-oxidobenzylidene)-N-(prop-2-en-1-yl)-carbamohydrazonothioato(2-)](1,10-phenanthroline)copper...     

Efficient Synthesis of 1-(4′-Methylbenzoyl)- 3,3-Diethylthiourea Under Microwave Irradiation Using Potassium Fluoride on Alumina

1,1-diethylthiourea and 4-methylbenzoic acid were condensed to 1-(4′-methylbenzoyl)-3,3-diethylthiourea in open vessels under microwave irradiation using an unmodified domestic microwave oven. The synthesis was carried out in the presence of alumina impregnated with potassium fluoride and catalytic amounts of N,N-dimethylformamide. The yields are noticeably improved in comparison with classical methods.