Nucleophilic reactions of 1-methyl-2-methoxy-2-phenyl-3-oxo-2,3-dihydroindole

The title compound (1) was prepared via methylene blue (MB)-sensitized photooxy-genation of l-methyl-2-phenylindole (2d) in methanol. Acid-catalyzed nucleophilic substitution of 1 with nucleophiles gave 1,2,2-trisubstituted 3-oxo-2,3-dihydroindoles (3-6). Reduction of 1 with lithium aluminum hydride, followed by acidic workup yielded 4d and 2d, whereas the same reduction reaction of 1, followed by neutral workup gave l-methyl-2-phenyl-3-hydroxy-2,3-dihydroindole (15), together with 3. The reaction pathways of nucleophilic substitution and reduction of 1 were discussed.     

Highly Stereoselective Synthesis of trans-3-Aryl-4-carbethoxy-2,3-dihydro-2-fur-2＇-oyl-5-methylfurans

Multi-substituted dihydrofurans are valuable intermediates for the synthesis of natural products and pharmaceuticals. Considerable attention has been focused on the development of efficient and regioselective methods for their preparation. Using K2CO3 as a base, with the reaction of fur-2-oylmethyltriphenylarsonium bromide 1 and ethyl 2-acetyl-3-arylacrylate 2 in tetrahydrofuran at room temperature, we found an efficient protocol was achieved to synthesize trans-3-aryl-4-carbethoxy-2,3-dihydro-2-fur-2＇-oyl-5-methylfurans 3 in good yield with high stereoselectivity. The structure of compound 3 was confirmed by IR, ^1H NMR, MS and HRMS. The mechanism for the formation of 3 was proposed.     

Investigations of 2,3′-biquinolyl. 9. Reaction of 1′,4′-dihydro-2,3′-biquinolyl with organolithium compounds

The 1,4-dihydro-2,3-biquinolyl reacts with organolithium compounds to form the mixture of 4-R-1,4-dihydro-2,3-biquinolyls and 2-R-1,2-dihydro-2,3-biquinolyls in the ratio analogous to the conversion in the series of 2,3-biquinolyl. The utilization of the complex, the organolithium compound-TMEDA, in this process leads, after treatment of the reaction mixture with water, exclusively to 2-R-1,2-dihydro-2,3-biquinolyls. Treatment with methyl iodide leads to 1-methyl-2-R-1,2-dihydro-2,3-biquinolyls.     

Oxiranyl β-Aminovinyl Ketones. 7. Synthesis of 5-Hydroxy-3-(1-oxo-2,3-epoxyalkyl)benzofurans

5-Hydroxy-3-(1-oxo-2,3-epoxyalkyl)benzofurans were obtained with yields of up to 81% by the reaction of p-benzoquinone with oxiranyl -dimethylaminovinyl ketones in acetic acid.     

Synthesis and characterization of transition metal complexes of N′-[(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)methylene]thiophene-2-carbohydrazide

A hydrazone ligand (HL) containing the thiophene moiety has been prepared via condensation of thiophene-2-carbohydrazide with 1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazole-4-carbaldehyde. The complexes of copper(II), nickel(II), cobalt(II), manganese(II), zinc(II), palladium(II), iron(III), ruthenium(III), uranyl(VI), and titanium(IV) with the ligand were prepared in good yield from the reaction of the ligand with the corresponding metal salts. The ligand and complexes were characterized using infrared, mass spectra, nuclear magnetic resonance, electronic absorption spectra, electron spin resonance, and magnetic moment measurements as well as elemental and thermal analyses. The results showed that the complexes are enolic by nature, whilst the ratio between the metal ion and the ligand depends on the acidity of the metallic ions and their oxidation numbers.     

Investigations of 2,3′-biquinolines 23. Synthesis of 1′-R-1′,4′-dihydro-2,3′-biquinolin-4′-ones by Claisen condensation

A method has been developed for the synthesis of 1′-R-1′,4′-dihydro-2,3′-biquinolin-4′-ones based on the interaction of quinaldine with N-alkyl-N-formylanthranilic acid methyl esters under the conditions of the Claisen condensation. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 409–410, March 2008.     

Synthesis and Crystal Structure of Ethyl 4-（2-Chloro-4-fluorophenyl）-6-hydroxy-3-oxo-1,3-dihydro-5-isobenzofurancarboxylate

The crystal structure of the title compound(C17H12ClFO5,Mr=350.72) was determined by single-crystal X-ray diffraction.The crystal belongs to monoclinic,space group P21/c,with a=7.693(1),b=15.767(1),c=12.986(1),β=97.23(1)°,V=1562.6(2)3,Z=4,Dc= 1.491 g/cm3,λ(MoKα)=0.71073,F(000)=720,μ(MoKα)=0.280 mm-1,R=0.0563 and wR=0.1674.A total of 3592 unique reflections were collected,of which 2462 with Ⅰ2σ(Ⅰ) were observed.Five-membered lactone rings and hydroxyl-substituted phenyl rings are approximately coplanar with their dihedral angle of 4.1°.The dihedral angle between two different phenyl rings is 71.3°.To our interest,intramolecular O(1)-H(1)···O(4) hydrogen bonds could be found in each molecule.Intramolecular hydrogen bonds and intermolecular van der Waals force contribute to the stability of the structure.     

The Kornblum Reaction of α-Substituted 3-Benzyl-1,2-dihydro-2-oxoquinoxalines. Synthesis and Structure of 3-Benzoyl-2-oxo-1,2-dihydroquinoxaline

A method has been developed for the preparation of 3-benzoyl-2-oxo-1,2-dihydroquinoxaline by the reaction of 3-(-chlorobenzyl)-1,2-dihydroquinoxaline under Kornblum reaction conditions to the corresponding -azido derivative and then acid fission of the latter. The structure of the target ketone has been confirmed by X-ray analysis.     

Synthesis and Crystal Structure of Ethyl 3-（4-Chlorophenyl）-3,4-dihydro-6-methyl-4-oxo-2- （pyrrolidin-1-yl）furo[2,3-d]pyrimidine-5-carboxylate

The crystal structure of the title compound ethyl 3-（4-chlorophenyl）-3,4-dihydro-6- methyl-4-oxo-2-（pyrrolidin-1-yl）furo[2,3-d]pyrimidine-5-carboxylate （C20H20ClN3O4, Mr= 401.84） has been prepared and determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/n with a = 20.6215（9）, b = 8.5311（4）, c = 21.6886（9） A^°, β = 91.607（1）°, V = 3814.0（3）A^°^3, Z = 8, Dc = 1.400 g/cm^3, F（000） = 1680, μ = 0.233 mm^-1, R = 0.0718 and wR = 0.1545 for 6717 observed reflections with I 〉 2σ（I）. X-ray diffraction analysis reveals two crystallographically independent molecules in the asymmetric unit.     

Synthesis of 2-Tert-butylimino-3-hepta-O-benzoyl-β-D-lactosylimino-4-S-benzyl-6-arylimino-2,3-dihydro-1,3,5-thiadiazines

A new series of synthesis of 2-tert-butylimino-3-hepta-O-benzoyl-β-D-lactosylimino-4-S-benzyl-6-arylimino-2,3-dihydro-1,3,5-thiadiazines (hydrochloride) were synthesized by the interaction of 1-aryl-5-hepta-O-benzoyl-β-D-lactosyl-2-S-benzyl-2,4-isodithiobiurets with tert-butyl isocyanodichloride. The identities of these newly synthesized N-lactosides have been established on the basis of usual chemical transformations and infrared, ¹H NMR, and mass spectral analysis.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

4-hydroxy-2-quinolenes. 24. Improved synthesis and biological properties of hydrochlorides ofβ-dialkylaminoalkylamides of 1-alkyl-2-oxo-4-hydroxyquinoline-3-carboxylic acids

High-purity hydrochlorides of-dialkylaminoalkylamides of 1-R-2-oxo-4-hydroxyquinoline-3-carboxylic acids have been obtained from N-alkyl-2-carbalkoxyanilides of malonic acid. The synthesized compounds have been tested for certain forms of pharmacological activity.For Communication 23, see [1].Ukrainian Pharmaceutical Academy, Khar'kov 310002. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1400–1405, October, 1994. Original article submitted November 8, 1994.     

Exploring the synthetic versatility of the Lewis acid induced decomposition reaction of α-diazo-β-hydroxy esters. The case of ethyl diazo(3-hydroxy-2-oxo-2,3-dihydro-1H-indol-3-yl)acetate

Ethyl diazo(3-hydroxy-2-oxo-2,3-dihydro-1H-indol-3-yl)acetate was prepared by aldol-type condensation of ethyl diazoacetate with isatin. A systematic and mechanistic study on the Lewis acid induced decomposition reaction of this valuable diazo precursor was carried out with the aim to gain new insights into the mechanistic aspects of the reaction as well as to further understand the factors and experimental conditions which affect the relative product distribution. The reaction, which may proceed via cationic and noncationic mechanisms, was found to be significantly influenced by the reaction environment determined by the characteristics of the Lewis acid employed, by the ability of the Lewis acid to form a complex with the alcohol functionality of the α-diazo-β-hydroxy ester, and by the polarity and nucleophilicity of the solvent used.     

Synthesis of substituted 2,3-dihydro-1H-boroles by transmetalation of aluminacyclopent-2-enes with BF3·Et2O

A procedure was developed for selective synthesis of 4,5-dialkyl-1-fluoro-2,3-dihydro-1H-boroles via transmetalation of the corresponding aluminacyclopent-2-enes with BF₃·Et₂O. 4,5-Dialkyl-1-fluoro-2,3-dihydro-1H-boroles were isolated as complexes with BEtF₂. 4-Alkyl-5-dimethylaminomethyl-1-fluoro-2,3-dihydro-1H-boroles were synthesized for the first time.     

A facile synthesis of 2-substituted-2,3-dihydro-4(1H)-quinazolinones in 2,2,2-trifluoroethanol

2-Substituted-2,3-dihydro-4(1H)-quinazolinones were obtained in high yields by condensation of anthranilamide with aryl, alkyl or heteroaryl aldehydes or ketones in the refluxing 2,2,2-trifluoroethanol without any catalyst.     

Synthesis of 3-Phenyl-6-formyl-3, 4-dihydro-2H-1, 3-benzoxazine

Benzoxazine is a novel class of thermosetting resins, which possesses lots of outstanding properties such as no by-products and near-zero shrinkage during polymerization as well as good molecular design flexibility1-2. Furthermore, polybenzoxazines (PBZs)…     

Synthesis and crystal structure of β-N-(5-methyl-4-oxo-5,6-dihydro-4H-1,3-thiazin-2-yl)isonicotinohydrazide

In the presence of amines under mild conditions, β-N-(methacryloylcarbamoythioyl)isonicotinohydrazide underwent intramolecular heterocyclization to give β-N-(5-methyl-4-oxo-5,6-dihydro-4H-1,3-thiazin-2-yl)isonicotinohydrazide, the spatial structure was confirmed by X-ray crystallography.     

Reactions of 3,3-dialkyl-2,3-dihydro-6-trifluoromethyl-4-pyrones with hydroxylamine. Synthesis and structures of 5-(1,1-dialkyl-2-hydroxyethyl)-5-hydroxy-3-trifluoromethyl-Δ2-isoxazolines

The reactions of 3,3-dialkyl-2,3-dihydro-6-trifluoromethyl-4-pyrones with hydroxylamine hydrochloride afforded regioisomeric 3(5)-(1,1-dialkyl-2-hydroxyethyl)-5-hydroxy-5(3)-trifluoromethyl-Δ²-isoxazolines depending on the reaction conditions. The title compounds were also prepared from 2,2-dialkyl-5-amino-1-hydroxy-6,6,6-trifluorohex-4-en-3-ones. The above dihydropyrones reacted with hydroxylamine (base) to yield 3-(1,1-dialkyl-2-hydroxyethyl)-5-hydroxy-5-trifluoromethyl-Δ²-isoxazolines. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1334–1339, July, 1999.     

Efficient synthesis of 1-oxo-3-aryl-1H-isochromene-4-carbaldehydes from enaminoketones of 2′-carboxamidodeoxybenzoins

The efficient synthesis of enaminoketones of 2′-carboxamidodeoxybenzoins and subsequent transformation into 1-oxo-3-aryl-1H-isochromene-4-carbaldehydes via an intermolecular cyclization under weakly acidic conditions has been demonstrated. Mild reaction conditions, a simple work-up procedure, short reaction times and high yields are the advantages of the presented method.     

Investigations in the region of 2,3′-biquinoline. 3. Synthesis of 2′-alkyl(aryl)-1′,2′-dihydro-2,3′-biquinolines and 2′-alkyl(aryl)-2,3′-biquinolines

A method was developed for the synthesis of 2-alkyl(aryl)-1,2-dihydro-2,3-biquinolines, based on the addition of organolithium compounds to 2,3-biquinoline in the presence of tetramethylethylenediamine. Their oxidation with manganese dioxide led to 2-alkyl(aryl)-2,3-biquinolines.For Communication 2, see [1].Stavropol State University, Stavropol 355009, Russia. Russian Chemical-Technology University, Moscow 125190. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 350–354, March, 1998.     

Triheterocyclic Thiadiazepine Derivatives of Pharmacological Interest: Synthesis of 2-Aryl-4-[p-(2,3-dihydro-5-methyl-2-oxo-1,3,4-oxadiazol-3-yl)phenyl]-6-(un)substituent-1",2",4"-triazolo[3",4"-b]-1',3',4'-thiadiazepine

Synthesis of novel thiadiazepine derivatives based on the reactivity of 4-acetylphenylsydnone (1) was reported. The structures of the newly synthesized compounds have been proved by their physical, analytical, IR, ¹H NMR, ¹³C NMR and mass spectral data.