Thioamide dianions derived from N-arylmethyl thioamides: Generation and application as carbon nucleophiles adjacent to the nitrogen atom

2010 ◽  
Vol 82 (3) ◽  
pp. 541-554 ◽  
Author(s):  
Toshiaki Murai
Keyword(s):  
Nitrogen Atom ◽  
Electronic Properties ◽  
Cyclization Reaction ◽  
Carbon Nucleophiles ◽  
Ready Availability

This review illustrates the ready availability of thioamide dianions and their versatility as carbon nucleophiles adjacent to the nitrogen atom. The products derived from the addition of thioamide dianions to a range of electrophiles can participate in a cyclization reaction to form nitrogen-containing heterocycles. The electronic properties of thioamide dianions are also considered.

A highly stereoselective preparation of syn-1,2-diols from secondary α-allenic alcohols via iodocyclization. Synthesis of (±)-threo-L-factor and (±)-disparlure

1994 ◽  
Vol 72 (8) ◽  
pp. 1857-1865 ◽  
Author(s):  
Richard W. Friesen ◽  
André Giroux
Keyword(s):  
Nitrogen Atom ◽  
Cyclization Reaction ◽  
Reaction Sequence ◽  
Terminal Olefin ◽  
Isomeric Mixture ◽  
Silver Carbonate ◽  
Synthetic Utility ◽  
Vinyl Iodide ◽  
Hydrolysis Of ◽  
Initial Process

The iodocyclization of the N-tosyl carbamates 5 of secondary α-allenic alcohols 4 is described. The reaction sequence involves the addition of iodine to the terminal olefin of the allene moiety of 5 resulting in the formation of an isomeric mixture of Z and E diiodides 6 and 7. This initial process is followed, in the same pot, by reaction of the diiodides with silver carbonate. Hydrolysis of the resulting trans imino carbonates 8 provides syn-1,2-diols 10 in a highly diastereoselective (>50:1) and regioselective (>20:1) fashion. Oxazolidinones 9 are minor products that arise from the participation of the carbamate nitrogen atom in the cyclization reaction. The regioselectivity of the cyclization reaction from 6/7 to 8 is highly dependent upon the reaction solvent with the optimum results being obtained in ether/MeCN mixtures (10:1 to 50:1) or CH2Cl2. The synthetic utility of the vinyl iodo diols 10 is demonstrated by the synthesis of (±)-threo-5-hydroxy-4-decanolide (17) ((±)-threo-L-factor) and (±)-cis-7, 8-epoxy-2-methyloctadecane (24) ((±)-disparlure). The key step in each synthesis involves the conversion of the vinyl iodide moiety of 10 into the alkynes 15 or 18 (from 10j and 10k, respectively) via a high-yielding dehydrohalogenation reaction.

Electronic versus steric control in palladium complexes of carboranyl phosphine-iminophosphorane ligands

2019 ◽  
Vol 48 (2) ◽  
pp. 486-503
Author(s):  
José Luis Rodríguez-Rey ◽  
David Esteban-Gómez ◽  
Carlos Platas-Iglesias ◽  
Antonio Sousa-Pedrares
Keyword(s):  
Nitrogen Atom ◽  
Electronic Properties ◽  
Palladium Complexes ◽  
Imine Nitrogen ◽  
Imine Nitrogen Atom ◽  
Fine Control ◽  
Donor Ability ◽  
Pd Complexes ◽  
Steric Control

Subtle changes in the electronic properties of C- and B3-carboranyl phosphineiminophosphoranes allows a fine control of the donor ability of the imine nitrogen atom, which results in Pd complexes with the ligands providing (P,N)-chelating or P-terminal coordination.

scholarly journals Synthetic Strategy and Structure Characterization of a New [1,3]Thiazolo[3,2-b][1,2,4]Triazolium Cationic Surfactant

2021 ◽  
Vol 11 (6) ◽  
pp. 13885-13892
Keyword(s):  
Electronic Structure ◽  
Nitrogen Atom ◽  
Cationic Surfactant ◽  
Nmr Spectra ◽  
Structure Characterization ◽  
Cyclization Reaction ◽  
Semiempirical Calculations ◽  
Synthetic Strategy ◽  
Strategy And Structure

Here, we present a synthetic strategy to access a new [1,3]thiazolo[3,2-b][1,2,4]triazolium-based cationic surfactant via the use of proton-induced heterocyclization method for quaternization of a nitrogen atom. The two-step synthesis of 2-heptyl-6,6-dimethyl-3-phenyl-5,6-dihydro-3H-[1,3]thiazolo[3,2-b][1,2,4]triazol-7-ium perchlorate is described in details. The analysis of NMR spectra unequivocally proved the formation of the 1,3-thiazolinium ring upon cyclization reaction. PM7 semiempirical calculations testify to the similar electronic structure of the newly synthesized surfactant cation and 1-heptylpyridinium cation.

Structural properties of GaAs/InGaAs/GaAs (001) and InGaAs/GaAs (001) heterostructures and correlation with electronic properties

1990 ◽  
Vol 48 (4) ◽  
pp. 602-603
Author(s):  
J.M. Bonar ◽  
R. Hull ◽  
R. Malik ◽  
R. Ryan ◽  
J.F. Walker
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Gaas Substrate ◽  
Critical Thickness ◽  
Lattice Mismatch ◽  
Band Offset ◽  
Misfit Dislocations ◽  
Gaas Substrates ◽  
Gaas Structure ◽  
Low X

In this study we have examined a series of strained heteropeitaxial GaAs/InGaAs/GaAs and InGaAs/GaAs structures, both on (001) GaAs substrates. These heterostructures are potentially very interesting from a device standpoint because of improved band gap properties (InAs has a much smaller band gap than GaAs so there is a large band offset at the InGaAs/GaAs interface), and because of the much higher mobility of InAs. However, there is a 7.2% lattice mismatch between InAs and GaAs, so an InxGa1-xAs layer in a GaAs structure with even relatively low x will have a large amount of strain, and misfit dislocations are expected to form above some critical thickness. We attempt here to correlate the effect of misfit dislocations on the electronic properties of this material.The samples we examined consisted of 200Å InxGa1-xAs layered in a hetero-junction bipolar transistor (HBT) structure (InxGa1-xAs on top of a (001) GaAs buffer, followed by more GaAs, then a layer of AlGaAs and a GaAs cap), and a series consisting of a 200Å layer of InxGa1-xAs on a (001) GaAs substrate.

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