A Facile Synthesis of 1-Substituted β-Carboline Derivatives via Minisci-Reaction

A mild and efficient one-pot reaction for the synthesis of 1-substituted β-carboline derivatives via the Minisci reaction has been developed with good yields and selectivity. In addition, the mechanism of the 1-substituted β-carboline derivatives by means of the nucleophilic radical is described.     

Syntheses of 1,3,4-Thia（oxa）diazole-substituted Pyrazole Derivatives and Their Fungicidal Activities

A series of 1,3,4-oxadiazole or 1.3.4-thiadiazole-substituted pyrazole derivatives were synthesized from 4-pyrazole formhydrazide; their biological activities were studied. The structures of all the new compounds were confirmed by means of spectroscopic methods and microanalyses. The preliminary bioassay results indicate that some compounds of them have a good fungicidal activity against Phoma asparagi and Physalospora piricola Nose.     

A Facile Stereoselective Synthesis of Ether-Linked β-D-Maltosyl- and β-D-Lactosyl-glycerolipids via Peracetylated Disaccharide α-Phosphoramidates

The reaction of 1-O-hexadecyl-2-O-methyl-sn-glycerol with 2,3,6,2′,3′,4′,6′-hepta-O-acetyl-α-lactosylphosphoramidate or α-maltosylphos-phoramidate in the presence of trimethylsilyl triflate and molecular sieves afforded 1-O-hexadecyl-2-O-methyl-3-O-(2,3,6,2′,3′,4′,6′-hepta-O-acetyl-β-lactosyl)-sn-glycerolipid or β-maltosyl-sn-glycerolipid stereoselectively in moderate yields after column chromatography. Alkaline hydrolysis of the O-peracetyl glycerolipids gave the desired β-glycolipids 1 and 2.     

Catalytic Access to Chiral δ-Lactams via Nucleophilic Dearomatization of Pyridine Derivatives

Nitrogen-bearing rings are common features in the molecular structures of modern drugs, with chiral δ-lactams being an important subclass due to their known pharmacological properties. Catalytic dearomatization of preactivated pyridinium ion derivatives emerged as a powerful method for the rapid construction of chiral N-heterocycles. However, direct catalytic dearomatization of simple pyridine derivatives are scarce and methodologies yielding chiral δ-lactams are yet to be developed. Herein, we describe an enantioselective C4-dearomatization of methoxypyridine derivatives for the preparation of functionalised enantioenriched δ-lactams using chiral copper catalysis. Experimental ¹³C kinetic isotope effects and density functional theory calculations shed light on the reaction mechanism and the origin of enantioselectivity.     

Facile Entry to 4‐ and 5‐Hydroxybenzofuran and to Their Amino Derivatives

An innovative one‐step procedure for the synthesis of 4‐hydroxybenzofuran and an improved synthesis of 5‐hydroxybenzofuran is reported. Such compounds were also transformed into their amino derivatives via Smiles rearrangement with good to high overall yields.     

Heterocyclic Synthesis with Nitriles: Synthesis of Some New Thiophene,Pyridazine, Oxazine,Thiopyran, Pyrrole,and Pyrrolo[1,2‐b]pyridazine Derivatives

2‐Phenyl‐1,1,3‐tricyanopropene[α‐(cyanomethyl)benzylidene‐malononitrile] undergoes bromination with N‐bromosuccinimide (NBS) to afford 2‐phenyl‐1,1,3‐tricyano‐3‐bromopropene: [α(bromocyanomethyl)benzylidene malononitrile]. This bromo derivative undergoes reactions with sodium hydrogen sulfide, hydrazine hydrate, phenyl hydrazine, hydroxylamine hydrochloride, ethyl thioglycollate, urea derivatives, and cyanacetohydrazide to afford thiophene, 4H‐pyridazines, 4H‐oxazine and 4H‐thiopyran, N‐substituted pyrrole, and pyrrolo[1,2‐b]pyridazine derivatives respectively.     

Synthesis, Mesogenic and Spectroscopic Properties of 2,5-Disubstituted Thiophene Derivatives

Two series of 2,5-disubstituted thiophene derivatives （series 1： 2,5-bis（p-alkoxyphenylethynyl）thiophene and series 2： 2,5-bis[p-（p-alkoxyphenylethynyl）（phenylethynyl）]thiophene） were synthesized and characterized by ^1H NMR, ^13C NMR, HRMS and elemental analysis. The relationship between the structure and the mesogenic and spectroscopic properties has been discussed. The results show that compounds 1a-1f all exhibited an enantiotropic nematic mesophase, which was confirmed by the polarized optical microscopy （POM）, differential scanning calorimeter （DSC） and variable temperature powder X-ray diffraction （PXRD）. In contrast, the extended conjugated analogues 2a-2b had no liquid crystal properties. As for the spectroscopic properties, incorporating more phenylethynyl units results in red-shifted absorption and emission spectra, greatly enhanced quantum efficiency.     

New Routes to β-Iminophosphonates,Phosphineoxides, and Sulfides

Abstract

Two synthetic methods leading to β-iminophosphonates, phosphineoxides, and sulfides 2 are reported. The first method involves the reaction of imines with chlorophosphines and phosphites followed by oxidation or sulfurization. The second one utilizes the reaction of imines with diethylchlorophosphate and thiophosphate. The stereochemistry of the obtained products is discussed, and their structure is confirmed by NMR (¹H, ³¹P, ¹³C) and IR spectroscopies, and by mass spectrometry.

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.

GRAPHICAL ABSTRACT      

A Simple Route to β,β-Trehalose via Trichloroacetimidates

Abstract

The reaction of 2,3,4,6-tetra-O-acetyl-β-D-glucopyranose with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl trichloroacetimidate in CH₂Cl₂ promoted by BF₃;OEt₂ gives β,β-octaacetyltrehalose in up to 58% isolated yield, which is readily deacetylated to β,β-trehalose. The corresponding 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl penta-fluorophenylimidate is configurationally stable and inert to coupling under mild conditions.     

A New and Efficient Synthesis of Wedelolactone Derivatives

A new and facile method based on an intermolecular cycloaddition was described for the synthesis of wedelolactone derivatives.     

Ceric(IV)-mediated Oxidative Addition of 1, 3-Dicarbonyl Compounds to MCPs: A Facile Access to Dihydrofuran Derivatives Incorporating Cyclopropyl Groups

A variety of simple cyclopropane-containing compounds have been of synthetic interest due to their biological activity1. The dihydrofuran ring system is found prevalently at the central position of diverse classes of naturally occurring and biologically a…     

Ceric（Ⅳ）-mediated Oxidative Addition of 1, 3-Dicarbonyl Compounds to MCPs： A Facile Access to Dihydrofuran Derivatives Incorporating Cyclopropyl Groups

Alkylidenecyclopropanes undergo ceric（Ⅳ） ammonium nitrate （CAN）-mediated addition reaction with 1,3-dicarbonyl compounds leading to dihydrofuran derivatives incorporating cyclopropyl groups in moderate yields.     

Synthesis and Stereostructure of New β-Lactam Derivatives of1,5-Benzothiazepines

Becauseoftheimportanceofbenzothiazepinederivatives,whichexhibitversatilebiologicalactivities.thechemistryofbenzothiazepinehasarousedinterestforalongtime'-'.Inourpreviouspapers.wehavereportedthesynthesisandelucidationofthestereostructureoftwokindsofl,5-benzothiazepine-6-lactams'-'.InordertoelucidatetheinfluenceofthesizeofthesubstituentatC-2ontheconfigurationof0-lactammoietyandfurtherstudythestereochemistryofthecycloadditionreaction.wepreparedaseriesofnewfi-lactamderivativesofI.5-benzothiazepine…     

Access to C-protected β-amino-aldehydes via transacetalization of 6-alcoxy tetrahydrooxazinones and use for pseudo-peptide synthesis

Efficient access to masked β-amino-aldehydes was performed starting from 6-alcoxy tetrahydrooxazinone 6a–d (6-ATO). Transacetalization leads to the opening of the cycle to form either unsymmetric acetal 7 or symmetric acetals 16–18. These amino acetals are key compounds, obtained with 99% ee, which can be engaged in efficient peptide coupling. This method could easily provide peptides aldehydes or small amido aldehydes as exemplified with the formal synthesis of ent-Maraviroc.     

Facile and Green Method for the Synthesis of β-Aminoketone Derivatives in Aqueous Media

Three-component reaction of aromatic aldehyde, 2-naphthalenamine, and 1,2-diphenylethanone in aqueous media catalyzed by triethylbenzylammonium chloride (TEBAC) at 90 °C gave 3-aryl-3-(naphthalen-2-ylamino)-1,2-diphenylpropan-1-one derivatives. The enol form of 1,2-diphenylethanone was tentatively proposed to participate in the formation of the products. Compared with previous methods, this three-component reaction has the advantages of green solvent, good yields, and operational simplicity.     

Efficient Synthesis of Highly Substituted Furan,Thiophene, Pyrrole and 2‐Aminothiazole Derivatives

Ethyl cyanoacetate dimer (1) undergoes bromination with N‐bromosuccinimide (NBS) to afford 3‐amino‐4‐bromo‐2‐cyano‐pent‐2‐enedioic acid diethyl ester (2). This bromo derivative reacts with potassium carbonate, sodium hydrogen sulfide, aromatic amines, ammonium thiocyanate, thiourea, N‐phenylthiourea, and thiosemicarbazide to afford highly substituted furan, thiophene, pyrrole, and 2‐aminothiazole derivatives. Mechanistic explanations as well as structure elucidations are discussed.     

A New Application of Dimethyl Trithiocarbonate. Methylthiothiocarbonylation of 2,4-Pentanedione and Some β-Oxoesters

2,4-Pentanedione, ethyl acetoacetate, benzoyl acetate and diethyl malonate 1a-d react with sodium acetate and dimethyl trithiocarbonate in dimethylformamide to afford methyl-β,β′-dicarbonyldithiocarboxylate derivatives 2a-d in moderate yield.     

New Approach to 4‐ and 5‐Aminopyrazole Derivatives

3‐Oxo‐3‐(pyrrol‐2‐yl)‐propanenitrile 1 coupled with aromatic diazonium salts to yield the corresponding 2‐arylhydrazones 2a–c. The latter products reacted with chloroacetonitrile and ethyl chloroacetate to yield 4‐aminopyrazole derivatives 5a–f. Reaction of 2 with hydrazine hydrate led to formation of 5‐amino‐4‐arylazopyrazole 6a–c. Compound 1 reacted also with trichloroacetonitrile to yield enamine 7, which in turn reacted with hydrazine hydrate to yield 5‐amino‐3‐(pyrrol‐2‐yl)‐pyrazole‐4‐carbonitrile 8.     

Facile Synthesis of Monofluoro γ-Lactones and Pyrrolidine Derivatives via Electrophilic Fluorination of Allenoic Acids and Amides

A convenient method to synthesize a series of monofluoro γ-lactones and pyrrolidine derivatives in moderate to good yields via the electrophilic fluorination of γ-allenoic acids and tosylamides using Selectfluor was developed.