New rearrangement of oxazolium salts into Δ3-pyrrolin-2-ones

The possibility of recyclizing oxazolium salts into ³-pyrrolin-2-ones by the action of base has been shown for the first time.Omsk State University, Omsk 644077. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 979–980, July, 1997.     

Pictet–Spengler reactions of oxetan-3-ones and related heterocycles

Pictet–Spengler reactions of oxetan-3-ones and azetidin-3-ones with tryptamine and tryptophan derivatives produce spirocyclic tetrahydro-β-carbolines in good yields. Molecular iodine (5 mol %) is an effective catalyst in most cases and high levels of diastereoselectivity are witnessed using 2-substituted oxetan-3-ones.     

Synthesis of 2-aryl-3H-indol-3-ones via trapping reaction in singlet oxygenation of 2-arylindoles

2-Aryl-3H-indol-3-ones (3a-o) have been synthesized via methanol trapping reaction in singlet oxygenation of 2-arylindoles (1a-o), followed by thermal decomposition of the resultant 2-aryl-2-methoxy-3-oxo-2,3-dihydroindoles (2a-o) in good yields.     

A Versatile Approach for the Asymmetric Synthesis of 3-Alkyl-isoindolin-1-ones

3 Ｓｕｂｓｔｉｔｕｔｅｄｉｓｏｉｎｄｏｌｉｎ 1 ｏｎｅｓ (2 ,3 ｄｉｈｙｄｒｏ 1Ｈ ｉｓｏｉｎｄｏｌｉｎ 1 ｏｎｅｓ)ｏｆｇｅｎｅｒａｌｓｔｒｕｃｔｕｒｅ (1)ｃｏｎｓｔｉｔｕｔｅｔｈｅｋｅｙｓｔｒｕｃｔｕｒａｌｆｅａｔｕｒｅｏｆａｌａｒｇｅｎｕｍｂｅｒｏｆｂｉｏａｃｔｉｖｅｍｏｌｅｃｕｌｅｓｏｆｎａｔｕｒａｌｏｒｓｙｎｔｈｅｔｉｃｏｒｉｇｉｎ .Ｆｏｒｅｘａｍｐｌｅ ,ｌｅｎｎｏｘａｍｉｎｅ (2 ) ,1ｎｕｅｖａｍｉｎｅａｎｄｃｈｉｌｅｎｉｎｅａｒｅａｌｋａｌｏｉｄｓｉｓｏｌａｔｅｄｆｒｏｍｖａｒｉｏｕｓ…     

SbCl3-catalyzed solvent-free Friedel–Crafts reaction of phenols with mandelic acids to 3-aryl benzofuran-2(3H)-ones: Synthesis of spirocyclic 2,3-dihydrobenzofuran-2-ones

A facile, SbCl₃-catalyzed, one-pot, tandem Friedel–Crafts/lactonization reaction of phenols and mandelic acids has been developed under solvent-free conditions to afford 3-aryl benzofuran-2(3H)-ones in good to high yields (52–90%). Additionally, the utility of 3-aryl benzofuran-2(3H)-ones is demonstrated by using them as precursors in the synthesis of a new class of spirocyclic benzofuran-2-ones using classical synthetic methodologies.     

Structure-Activity Relationship of Insecticidal Steroids. V. 3β-Benzoyloxystigmastan-6-ones

The toxicity of steroid benzoates 4-10 for Colorado beetle (Leptinotarsa decemlineata Say.) larvae was studied by a contact-intestinal method. The most active growth and development regulator for this insect is 3-benzoyloxy-5-hydroxy-⁷-6-ketosteroid 9a.     

Synthesis of Enantiopure Dehydropiperidinones from α-Amino Acids and Alkynes via Azetidin-3-ones

Chiral dehydropiperidinones were synthesized in enantiopure form from α-amino acids and alkynes via azetidin-3-ones.     

Stereochemistry of the asymmetric alkylation of Δ9,10-octahydroquinolin-4-ones

The asymmetric character of the alkylation of a series of metallated bicyclic enaminoketones has been established and its stereoselectivity has been investigated. The enantiomers of (3S*)-methyl- and (3S*)- and (3R*)-3-methyl-3-butyl-^9,10-octahydroquinolin-4-ones have been obtained. The possibility of inducing chirality at the 3 position of the enaminoketone molecule during methylation in the presence of chiral lithium amides has been established in principle.M. V. Lomonosov Moscow State University, Moscow 119899. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1531–1542, November, 1995. Original article submitted November 10, 1995     

Efficient One-Pot Synthesis of β-Unsaturated Isoxazol-5-ones and Pyrazol-5-ones Under Ultrasonic Irradiation

4-Arylmethylidene-3-isopropylisoxazol-5-ones and 4-arylmethylidene-1-phenyl-3-isopropylpyrazol-5-ones have been prepared from the reactions of hydroxylamine and phenylhydrazine with methyl 4-methyl-3-oxovalerate and aromatic aldehydes in an aqueous medium at room temperature in the presence of pyridine under ultrasonic irradiation. The simple and facile method produced products in good yields.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Synthesis of 4-Halo-3-isopropoxyfuro[3,4-с]-pyridin-1(3H)-ones

Russian Journal of Organic Chemistry - The reaction of 4-halo-3-hydroxyfuro[3,4-c]pyridin-1(3H)-ones with propan-2-ol leads to the formation of 4-halo-3-isopropoxyfuro[3,4-c]pyridin-1(3H)-ones. The...     

Synthesis of extended, π-conjugated isoindolin-1-ones

The synthesis and characterization of extended, conjugated molecules containing isoindolinone units was explored. Nucleophilic cyclizations between an amide and an alkyne were found to be an efficient method of producing the desired isoindolin-1-ones in high yields. A variety of derivatives were synthesized, demonstrating that a number of structural alterations could be made while maintaining good regio- and stereospecificity in the cyclized product.     

Studies of 2-Substituted 1,3-Oxazolidin-5-ones and 1,3-Oxazinan-6-ones as Precursors for the Synthesis of N-Alkyl-β-Amino Acids

1,3-Oxazolidin-5-ones and 1,3-oxazinan-6-ones have been shown to be useful precursors for the synthesis of N-methyl α- and β-amino acids, respectively. The methodology has now been expanded to allow for the synthesis of N-alkyl-β-amino acids.     

Synthesis of spirocyclic 1,3-dioxolan-4-ones fromα-hydroxyamides

It is shown that ,-dihydroxypiperidine-4-carboxyamides in reaction with formaldehyde in concentrated sulfuric acid is converted to the corresponding 1,3-dioxolan-4-ones.Belorus State University, Minsk 220080. Translated from Khimiya Geterotsiklicheskikh Soedinenii No. 9, pp. 1216–1218, September, 1994. Original article submitted June 2, 1994.     

B(C6F5)3-Catalyzed Aza-Friedel–Crafts Reaction of Indolizines with 2-Aryl-3H-indol-3-ones

A Friedel–Crafts reaction of indolizines with 2-aryl-3H-indol-3-ones catalyzed by B(C₆F₅)₃ is described. This protocol gives access to indolizine derivatives that are valuable building blocks in synthetic and pharmaceutical chemistry. The reaction proceeds under mild conditions, affording various C2-quaternary indolin-3-ones based on indolizine with high yields and regioselectivities. Moreover, the synthetic transformations of the target products were realized by N-methylation and trifluoromethane sulfonation.     

β-Chlorocinnamonitriles in a New Synthesis of 3-Functionally Substituted 6-amino-1,2-Dihydropyridin-2-ones

β-Chlorocinnamonitriles react with methylene-active compounds containing N-substituted carboxamide group in DMSO solution in the presence of potassium hydroxide, forming 3-functionally substituted 1,2-dihydropyridin-2-ones.     

Oxidation of α-Benzoyl-O-hydroxyacetophenones Using Iodobenzene Diacetate in Methanolic Potassium Hydroxide: A New Synthesis of 2-Benzoylcoumaran-3-ones

The oxidation of α-benzoyl-o-hydroxyacetophenones (3a-d) using iodobenzene diacetate in methanolic potassium hydroxide provides a new direct method for the synthesis of 2-benzoylcoumaran-3-ones (4a-c) in good yields. The formation of 4a-d is explained by neighb uring group participation.     

Lewis acid mediated functionalization of β-lactams: mechanistic study and synthesis of C-3 unsymmetrically disubstituted azetidin-2-ones

A convenient and efficient route to novel unsymmetrically disubstituted azetidin-2-ones is described. β-Lactam carbocation equivalents of type 1 and active aromatic substrates in the presence of a Lewis acid promote a facile and stereoselective C-3 substitution to provide monosubstituted β-lactams (3,4) and symmetrically disubstituted β-lactams (5). cis-3-(4′-Methoxyphenyl)-3-phenylthioazetidin-2-ones (4) undergo further substitution with active aromatic substrates mediated by a Lewis acid to afford unsymmetrically disubstituted azetidin-2-ones (7).     

Synthesis of 3-methyleneisoindolin-1-ones via palladium-catalyzed C–Cl bond cleavage and cyclocarbonylation of ortho-chloro ketimines

PdCl₂(PCy₃)₂-catalyzed cyclocarbonylative coupling of ortho-chloro arylketimines with CO has been investigated to develop an efficient method for the synthesis of isoindolin-1-ones. The developed synthetic method has the advantages of having easily available starting materials, high atom-economy, and high selectivity.     

Stereoselective α,α'-annelation reactions of 1,3-dioxan-5-ones

Pyrrolidine enamines derived from three 1,3-dioxan-5-ones undergo α,α'-annelation reactions with methyl α-(bromomethyl)acrylate to produce bridged 2,4-dioxabicyclo[3.3.1]nonane ring systems with complete stereocontrol. Stereochemical outcomes have been rationalized based on steric and stereoelectronic interactions in intermediate boat-like conformations of the 1,3-dioxane ring and subsequent kinetic protonation to set an axial ester group on the cyclohexanone ring. Base-mediated ester epimerization provides the stereochemical array found in the highly oxygenated cyclohexane ring of phyllaemblic acid and glochicoccins B and D.