Regioselectivity in SNH reactions of some 3-nitro-1,5-naphthyridines with chloromethyl phenyl sulfone

2004 ◽  
Vol 82 (5) ◽  
pp. 567-570 ◽  
Author(s):  
Maria Grzegożek ◽  
Barbara Szpakiewicz
Keyword(s):  
Nmr Spectroscopy ◽  
Nucleophilic Substitution ◽  
Key Words ◽  
High Yield ◽  
Vicarious Nucleophilic Substitution ◽  
H Nmr ◽  
Phenyl Sulfone ◽  
Convenient Synthesis ◽  
Key Words 3 ◽  
Hydrogen Substitution

3-Nitro-1,5-naphthyridine and its 2-substituted derivatives react with the carbanion of chloromethyl phenyl sulfone to give hydrogen-substitution products at position 4 in high yield. The intermediacy of 4-(phenylsulfonyl)chloromethyl σ adducts of 2-R-3-nitro-1,5-naphthyridines (R = H, D, Cl, OC2H5, NHCH3, OH) was established by 1H NMR spectroscopy. A convenient synthesis of 2-N-methylamino-3-nitro-1,5-naphthyridine is reported. Key words: 3-nitro-1,5-naphthyridines, anionic (phenylsulfonyl)chloromethyl σ adducts, vicarious nucleophilic substitution.

Nine- and Eight-Vertex Polyhedral Dicarbaborane Chemistry: New arachno and hypho Dicarbaboranes from arachno-4,5-C2B7H13: Isolation and Characterization of the [arachno-4,5-C2B7H12]- and [hypho-7,8-C2B6H13]- Anions, and of the Neutral Ligand Derivatives exo-6-(MeNC)-arachno-4,5-C2B7H11 and exo-5-L-hypho-4,9-C2B7H13 (L = NMe3 and NEt3)

1994 ◽  
Vol 59 (7) ◽  
pp. 1584-1595 ◽  
Author(s):  
Tomáš Jelínek ◽  
Josef Holub ◽  
Bohumil Štíbr ◽  
Xavier L. R. Fontaine ◽  
John D. Kennedy
Keyword(s):  
Nmr Spectroscopy ◽  
Selective Removal ◽  
High Yield ◽  
Two Dimensional ◽  
Neutral Ligand ◽  
Tertiary Amines ◽  
Proton Sponge ◽  
H Nmr ◽  
Isolation And Characterization

Deprotonation of neutral arachno-4,5-C2B7H13 (1) either with 1, 8-(NMe2)2C10H6 (proton sponge, PS) or with a mixture of aqueous K2CO3 and [NMe4]Cl leads to the isolation in high yield of the [arachno-4,5-C2B7H12]- anion (2). Isostructural with this anion is the ligand derivative exo-6-(MeNC)-arachno-4,5-C2B7H11 (3), which is prepared in 20% yield from the reaction between arachno-4,5-C2B7H13 and MeNC in dichloromethane. Under comparable conditions compound 1 with tertiary amines gives the first representatives of the nine-vertex hypho family of dicarbaboranes, the ligand derivatives exo-5-(NR3)-hypho-4,9-C2B7H13 (4a and 4b, where R = Me and Et, respectively) in moderate yields (20 - 55%), whereas the reaction between 1 and aqueous NaCN results in the selective removal of one boron vertex to yield the eight-vertex [hypho-7,8-C2B6H13]- anion (5) in 61% yield. All compounds isolated were characterized by 11B and 1H NMR spectroscopy, with two-dimensional and selective decoupling techniques giving unambiguous assignments.

Reactions of organic anions. 174. Vicarious Nucleophilic Substitution of hydrogen (VNS) in nitrobenzofuroxans and the Boulton–Katritzky rearrangement of the VNS products

1990 ◽  
Vol 68 (12) ◽  
pp. 2239-2241 ◽  
Author(s):  
Stanisław Ostrowski ◽  
Krzysztof Wojciechowski
Keyword(s):  
Nucleophilic Substitution ◽  
Organic Anions ◽  
Nucleophilic Substitution Of Hydrogen ◽  
Tert Butyl ◽  
Vicarious Nucleophilic Substitution ◽  
Phenyl Sulfone

The Vicarious Nucleophilic Substitution of hydrogen in 4-nitrobenzofuroxan derivatives by carbanions of chloromethyl phenyl sulfone, chloromethyl p-tolyl sulfone, chloromethyl tert-butyl sulfone, and N,N-dimethyl chloromethane sulfonamide proceeds at positions 5 and 7. In some cases the Boulton–Katritzky rearrangement of the products obtained, leading to more stable 7-substituted isomers, was observed. Keywords: carbanions, nitrobenzofuroxans, sulfones, Vicarious Nucleophilic Substitution, Boulton–Katritzky rearrangement.

Preparation and alkylation reactions of 4-nitrobenzyl and 5-nitrofurfuryl sulfones

1988 ◽  
Vol 53 (4) ◽  
pp. 851-856 ◽  
Author(s):  
Josef Prousek
Keyword(s):  
Nmr Spectroscopy ◽  
Dimethyl Sulfoxide ◽  
Mass Spectroscopy ◽  
Substitution Reaction ◽  
Reaction Medium ◽  
Polyethylene Glycols ◽  
H Nmr ◽  
Phenyl Sulfone ◽  
Alkylation Reactions

Substitution reaction of 5-nitrofurfuryl bromide (I) with sodium thiophenoxide and 4-chlorothiophenoxide in dimethyl sulfoxide at 20 °C and oxidation with dimethyl sulfoxide in the reaction medium afforded 5-nitrofurfuryl phenyl sulfone (IVa) and 5-nitrofurfuryl 4-chlorophenyl sulfone (IVb), respectively. Similarly, 4-nitrobenzyl bromide reacted with sodium 4-chlorothiophenoxide to give 4-nitrobenzyl 4-chlorophenyl sulfone (VII) and with sodium phenylsulfinate to afford 4-nitrobenzyl phenyl sulfone (IX). The sulfide intermediates were not isolated. The sulfone IX was used as substrate in alkylation reactions, catalysed by polyethylene glycols. Derivatives IVb and VII were identified by IR and mass spectroscopy, alkylation products by 1H NMR spectroscopy.

scholarly journals 4-[(3,5-Dimethyl-1H-pyrazol-1-yl)methyl]-4-methyl-2-phenyl-4,5-dihydrooxazole

Molbank ◽  
10.3390/m1074 ◽  
2019 ◽  
Vol 2019 (3) ◽  
pp. M1074
Author(s):  
Hajib ◽  
Alami ◽  
Faraj ◽  
Aouine
Keyword(s):  
Nmr Spectroscopy ◽  
Dimethyl Sulfoxide ◽  
Nucleophilic Substitution ◽  
Elemental Analysis ◽  
Substitution Reaction ◽  
Nucleophilic Substitution Reaction ◽  
High Yield

The compound, 4-[(3,5-dimethyl-1H-pyrazol-1-yl)methyl]-4-methyl-2-phenyl-4,5-dihydrooxazole 2 was prepared in high yield, through nucleophilic substitution reaction of the O-tosyl oxazoline derivative 1, by heating in dimethyl sulfoxide (DMSO) and in presence of KOH as base. The structure of the synthesized compound was established on the basis of NMR spectroscopy (1H, 13C), MS data and elemental analysis.

Novel chiral fluorescent chemosensors for malate and acidic amino acids based on two-arm thiourea and amide

2008 ◽  
Vol 86 (2) ◽  
pp. 170-176 ◽  
Author(s):  
Xiao-Huan Huang ◽  
Yong-Bing He ◽  
Zhi-Hong Chen ◽  
Chen-Guang Hu ◽  
Guang-Yan Qing
Keyword(s):  
Amino Acids ◽  
Nmr Spectroscopy ◽  
Key Words ◽  
Fluorescent Chemosensors ◽  
Enantioselective Recognition ◽  
H Nmr ◽  
Acidic Amino Acids ◽  
Recognition Ability

The charge neutral anthracene based chiral fluorescent receptors 4a and 4b containing thiourea and amide groups were synthesized by simple steps in good yields, and their enantioselective recognition for chiral dicarboxylic anions (L/D-malate, L/D-aspartate, and L/D-glutamate) were examined by UV–vis, fluorescence, and 1H NMR spectroscopy. The sensor 4a exhibited an excellent enantioselective recognition ability towards malate (Kass (L)/Kass (D) = 9.65).Key words: enantioselective recognition, chiral chemosensor, fluorescence, malate.

Sedum alkaloids. XI. Synthesis of sedinone and sedacrine by application of anodic oxidation

1991 ◽  
Vol 69 (2) ◽  
pp. 211-217 ◽  
Author(s):  
Frank Driessens ◽  
ClaUDE Hootelé
Keyword(s):  
Nucleophilic Substitution ◽  
Key Words ◽  
Anodic Oxidation ◽  
Methoxy Group ◽  
High Yield ◽  
Piperidine Alkaloids ◽  
Piperidine Derivative ◽  
Sedum Acre ◽  
Anodic Methoxylation

α-Methoxycarbamate 12, synthetic precursor of the 2,6-disubstituted alkaloids of Sedum acre, was obtained in high yield from 2-phenacylpiperidine 5; the key step of the synthesis rests on the anodic methoxylation, which allows the functionalization of carbon 6. Nucleophilic substitution of the methoxy group by an acetonyl chain leads, after the required transformations, to sedinone 23. Bromomethoxylation of the enecarbamate 19 followed by dehydrohalogenation and nucleophilic substitution of the methoxy group leads to sedacrine 33. In both cases, the nucleophilic substitution of the methoxy group leads to a cis 2,6-disubstituted piperidine derivative. Key words: synthesis, piperidine alkaloids, anodic methoxylation

Ketone coordination chemistry of the diborane t-BuCH=C[B(C6F5)2]2

1998 ◽  
Vol 76 (9) ◽  
pp. 1249-1255 ◽  
Author(s):  
Katrin Köhler ◽  
Warren E Piers
Keyword(s):  
Coordination Chemistry ◽  
Nmr Spectroscopy ◽  
Low Temperature ◽  
Temperature Dependence ◽  
Key Words ◽  
Lewis Acidity ◽  
High Yield ◽  
Lewis Bases ◽  
Equilibrium Yield ◽  
Boron Center

Reactions of the bifunctional borane t-BuCH=C[B(C6F5)2]2, 1, with simple Lewis bases were investigated to probe its Lewis acidity. Ethereal bases (Et2O, THF) bind very weakly, if at all, as no adducts were detectable in solution. Certain ketones, however, were observed to bind to 1. Acetone forms an adduct, 2, reversibly in solution (Keq at 293 K = 69.1), and the temperature dependence of this equilibrium yield thermodynamic parameters of H° = -59.5 ± 2.0 kJ mol-1; S° = -167 ± 4 J K-1 mol-1. Low temperature NMR spectroscopy suggests that the acetone binds to the more sterically accessible boron center trans to the t-Bu group. Ketone binding is strengthened when 2,3-diphenylcyclopropenone is reacted with 1, irreversibly forming an isolable adduct, 4, in high yield (95%). The availability of a resonance form incorporating the aromatic cyclopropenyl cation contributes to the added stability of this adduct in comparison to 2.Key words: organoboranes, diboranes, ketone complexes.

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