I2-DMSO-Mediated Cascade Cyclization of β-Ketosulfoxonium Ylides and β-Enaminones: Synthesis of Quaternary-Carbon-Centered 2-Hydroxy-pyrrol-3(2H)-ones

A novel I₂-DMSO-mediated cascade cyclization approach for synthesizing 2-hydroxy-pyrrol-3(2H)-one scaffold from readily accessible β-ketosulfoxonium ylides and β-enaminone derivatives has been developed. Under metal-free and mild conditions, this cascade transformation facilitates the formation of one C−C bond and one C−N bond in a single reaction vessel, exhibiting a wide range of functional group compatibility. In addition, this method added an active hydroxyl group to a quaternary carbon center.     

Direct Synthesis of β-Alkyl N-Aryl Aza Baylis-Hillman Adducts via Nitroso-Ene Reaction

A new approach for the direct Fe-catalyzed synthesis of β-alkyl N-aryl aza Baylis-Hillman (ABH) adducts is reported. This approach involves the formation of a C-N bond via a nitroso-ene reaction. This is a simple, fast, and best alternate method to overcome the substrate scope limitations of the ABH reaction, which converts allyl esters and carbonyl compounds to novel ABH adducts. A variety of arylhydroxylamines reacted with esters, aldehydes, ketone, and nitriles to yield the corresponding products in moderate to excellent yields.     

Facile and Stereoselective Synthesis of N-Substituted Benzotriazole with Baylis-Hillman Adducts

Benzotriazole derivatives are a class of useful intermediates in organic synthesis because of the easy introduction and elimination of the auxiliary benzotriazole. The syntheses and application of benzotriazole derivatives have been much developed, especi…     

Improved Synthesis of Icaritin and Total Synthesis of β-Anhydroicaritin

Natural products icaritin and β-anhydroicaritin with P-glycoprotein(P-gp) inhibitory activities were ciently synthesized in nine steps from commercially available phloroglucinol. A modified Algar-Flynn-Oyamada cyclization and relay Claisen-Cope rearrangement were employed in this concise route. Oiir synthesis offers opportunities to synthesize various icariin analogues for biological and pharmacological investigations.     

Spectral Differences of the Molecule-ion Adducts of β-Cyclodextrin and Lithium Carbonate

A small shielding effect on the hydrogen atoms of chiral carbons of β-cyclodextrin (β-CD) was detected by ¹H nuclear magnetic resonance, but a large environmental change of the chiral carbon atoms at high concentration ratios of lithium carbonate (Li₂CO₃) to β-CD was observed by polarimetry in aqueous solution. These findings urged us to investigate whether different formation conditions of the molecule-ion system between Li₂CO₃ and β-CD in solid state were involved in different spectral performances. To answer the question, we prepared three adducts of Li₂CO₃ to β-CD, i.e., samples 1, 2, and 3, by magnetic stirring, solvothermal and grinding conditions, respectively. Powder X-ray diffraction and Fourier transformation infrared spectroscopy provided the information of formation of the three molecule-ion adducts. Besides, scanning electron microscope images provided different surface information of the three adducts. Further, significant spectral differences in thermal behavior of these adducts were found by thermogravimetry and derivative thermogravimetry.     

Synthesis of N-(2-chloroethyl)isatins and their β-ethyleneacetals and β-thiosemicarbazones

The nitrogen atoms of isatin, its 5-bromoderivative, and their -ethyleneacetals are alkylated by 1,2-dichloroethane in K₂CO₃–DMF and LiH(NaH)-DMF.Institute of Biological Protection of Plants and Institute of Chemistry of the Moldovan Academy of Sciences, Kishinev 2058. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 907–909, July, 1999.     

Synthesis and crystal structure of β-hexanitrohexaazaisowurtzitane

A polycyclic caged compound with high strain—hexanitrohexaazaisowurtzitane (HNIW)—has been synthesized via a three-step reaction: condensation, hydrogenolysis debenzylation and nitrolysis, starting with benzylamine and glyoxal. HNIW is the most powerful high energy density compound (HEDC) ever tested. β-HNIW possesses a caged structure consisting of two five-membered rings and one six-membered ring with a nitro group attached to each of the six bridging nitrogens. The nitro group lies basically within a plane. The lengths of C—C bonds of β-HNIW range from 0. 156 nm to 0.159 nm, 0.002–0.005 nm longer than the sp³ C-C bond. The β-HNIW’s crystal belongs to orthorhombic system and space groupPca2₁ with parameters:a = 0.9670 (2),b = 1.1616 (2),c = 1.3032 (3) nm;V = 1.4638(5) nm³,Z = 4; D_c = 1.989 g/cm³ and D_m = 1.982 g/cm³. Project supported by the Advanced Research Funds (12060451867) from the Commission of Science and Technology for National Defence.     

Synthesis and biology of N-thiolated β-lactams

N-Thiolated β-lactams are an interesting new family of bioactive agents having antibacterial, antifungal, and anticancer capabilities. Our interest in these β-lactams stems from their highly unusual structure–activity profiles and selectivity toward only a few genera of pathogenic bacteria, including Staphylococcus aureus, Bacillus anthracis, and Micrococcus. Here, we provide a complete outline on our work in the discovery and ongoing development of these compounds, starting from our initial, unexpected finding of antimicrobial activity for one of the lead compounds, to a more complete understanding of their chemical and biological mode of action and potential utility as antibacterial compounds.     

Synthesis and crystal structure of β-hexanitrohexaazaisowurtzitane

A polycyclic caged compound with high strain——hexanitrohexaazaisowurtzitane (HNIW)——has been synthesized via a three-step reaction: condensation, hydrogenolysis debenzylation and nitrolysis, starting with benzylmine and glyoxal. HNIW is the most powerful high energy density compound (HEDC) ever tested. β-HNIW possesses a caged structure consisting of two five-membered rings and one six-membered ring with a nitro group attached to each of the six bridging nitrogens. The nitro group lies basically within a plane. The lengths of C--C bonds of β-HNIW range from 0.156 nm to 0.159 nm, 0.002--0.005 nm longer than the sp~3 C-C bond. The β-HNIW's crystal belongs to orthorhombic system and space group Pca2_1 with parameters: a=0.9670 (2), b=1.1616 (2), c=1.3032 (3) nm; V=1.4638(5) nm~3, Z=4; D_c=1.989 g/cm~3 and D_m=1.982 g/cm~3.     

RETRACTED ARTICLE: Synthesis and characterization of new D-π-D type Schiff base ligands

Two Schiff bases of D-p-D type (L₁ and L₂) have been successfully synthesized by the reaction of 3,3′-dimethylnapthide and 3,3′,5,5′-tetramethylbenzidine with 4-(dimethylamino)cinnamic aldehyde. The ligands L₁ and L₂ have been characterized by IR, UV-visible, ¹H NMR and fluorescence spectra, as well as, TGA-DSC-DTG, elemental analyses and mass spectra.     

Synthesis,Crystal Structure,and Studies on Mechanism of D-π-A Ferrocene Derivative

Russian Journal of Coordination Chemistry - Microwave-assisted solvent-free synthesis of new (D-π-A) chromogenes, 2-ferrocenyl-1,1-dicyanobuta-1,3-diene derivatives (II), have been...     

Total Synthesis of Q-Chamigrene and β-Chamigrene

Spirocyclicsesquiterpenes,agrouPofspecialsesquiterpenoidwhichhaveaspiro[4,5]-decaneoraspiro[5,51-undecanestrUctureasthebasicskeleton,areattrctivetargetfortotaISynthesisbecauseof,inadditiontotheuniquestereostrUctUralfeatUrs,theirexcellentphysiologicalactivihesandexten-sivelyoccurringinnatUre.Inthisfamily,Q-chamigreneandD-chamigrene,isolatedfromSChisan-drachinensisI1]andChamaeoparistatwanesisl'],respectively,arecharacteristicmembers.lnthispa-per,wereportedtotalsynthesisof(t)-Q-chamigreneand…     

Synthesis of Vinyl and β-Phthalimido Ketones

Vinyl ketones are prepared by reaction of an aldehyde with a vinyl Grignard reagent followed by a Swern oxidation. β-Phthalimido ketones are then obtained by 1,4-addition of phthalimide.     

Selective Reduction of ortho-Acylated β-Enaminones of Homoveratryamine and Their Cyclization to 1,2,3,4-Tetrahydroisoquinolines with β-Enaminone Moiety

Enaminones are very stable compounds and can be prepared from cheap and easily available starting materials. Therefore they are excellent starting materials in organic synthesis. The selective reduction of ortho-acylated β-enaminones under mild conditions, keeping the enaminone moiety intact, is reported. The appropriated conditions for cyclization of newly obtained hydroxienamides were found. Novel 1-substituted 1,2,3,4-tetrahydroisoquinolines with potential anticonvulsic activity were synthesized.     

Synthesis and biological investigation of the β-thiolactone and β-lactam analogs of tetrahydrolipstatin

The synthesis of β-thiolactone and β-lactam analogs of tetrahydrolipstatin is described from a common late-stage β-lactone derivative. These analogs, and a cis-disubstituted β-lactone analog of tetrahydrolipstatin, were screened for activity against porcine pancreatic lipase and for inhibition of cell growth of a panel of four human cancer lines.     

Synthesis based on β-phenylethylamines. IX. Synthesis of sulfides of β-phenylethylamines and of N-benzyltetrahydroisoquinolines

New bimolecular sulfur-containing -phenylethylamines and N-benzyltetrahydroisoquinolines have been synthesized from formyl derivatives of diaryl sulfides. The possibility of using metals as catalysts for obtaining diaryl sulfides in the reaction of ortho-substituted benzaldehydes with SCl₂ has been shown for the first time.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 731–735, September–October, 1995. Original article submitted November 11, 1994.     

Stereoselective Synthesis of Novel Diels–Alder Adducts of p-Substituted Methyl Thiocinnamates and Cyclopentadiene

This article describes the Diels–Alder reaction between methyl thiocinnamates, substituted at the para position by electron-donating and electron-withdrawing groups, with cyclopentadiene in the presence of catechol boron bromide (CBB) as a Lewis acid catalyst. The adduct configuration was confirmed by ¹H NMR coupling constants and single-crystal x-ray diffraction. Total endo stereoselectivity was observed in all reactions and was attributed to the effective secondary interaction between the boron atom and the incipient double bond in the norbonene resulting from the planar geometry of the catalyst. ¹³C NMR chemical shifts of the coordinated dienophile carbonyl carbons with CBB compared to those of the non coordinated thiocinammates suggest a strong complexation with the catalyst.     

Synthesis and properties of a blue bipolar indenofluorene emitter based on a D-π-A design

Through a rational design, a novel Donor-Acceptor π-conjugated (D-π-A) blue fluorescent indenofluorene dye, DA-DSF-IF, has been synthesized for application in single-layer Small Molecule Organic Light Emitting Diodes (SMOLEDs). This new blue emitter possesses bipolar properties as well as good morphological and emission color stabilities and has been successfully used in a blue emitting single-layer SMOLED, with performances impressively magnified compared to a nonbipolar indenofluorene emitter.     

Synthesis of N-formylated β-lactams using nano-sulfated TiO2 as catalyst under solvent-free conditions

An easily accessible catalyst, nano-sulfated titania, efficiently catalyzes the N-formylation of β-lactams and all types of amines (primary, secondary, aromatic, and aliphatic) in solvent-free conditions at room temperature.