Pyridinophane Bridging Group Chemistry: Synthesis and Reactions of 1,2,9,10-Tetra-chloro[ 2,2](2,6)pyridinophane-1,9-diene

1979 ◽  
Vol 32 (6) ◽  
pp. 1241 ◽  
Author(s):  
HJJB Martel ◽  
S McMahon ◽  
M Rasmussen
Keyword(s):  
Nucleophilic Addition ◽  
Good Yield ◽  
Substitution Reactions ◽  
Valence Tautomerism ◽  
Vacuum Pyrolysis ◽  
High Yields

Oxidation and polychlorination of 2,11-dithia[3,3](2,6)pyridinophane (II) gives high yields of the corresponding octachloro bissulfone (14) which, on vacuum pyrolysis, readily loses SO2 and Cl2 sequentially, giving eventually a good yield of orange 1,2,9,10-tetrachloro[2,2](2,6)pyridinophane-1,9-diene (4). Nucleophilic addition and substitution reactions of the dichloroethene bridges of (4) are described. None of the [2,2]metacyclophane diene systems undergoes spontaneous or photoinduced valence tautomerism to a 10b,10c-diazapyrene (2).

scholarly journals Regio- and stereoselective synthesis of new ensembles of diversely functionalized 1,3-thiaselenol-2-ylmethyl selenides by a double rearrangement reaction

2020 ◽  
Vol 16 ◽  
pp. 515-523 ◽  
Author(s):  
Svetlana V Amosova ◽  
Andrey A Filippov ◽  
Nataliya A Makhaeva ◽  
Alexander I Albanov ◽  
Vladimir A Potapov
Keyword(s):  
Nucleophilic Substitution ◽  
Nucleophilic Addition ◽  
Stereoselective Synthesis ◽  
Ring Expansion ◽  
Nucleophilic Attack ◽  
Substitution Reactions ◽  
Ring Contraction ◽  
Rearrangement Reaction ◽  
High Yields ◽  
Alkyl Propiolates

The reaction of 2-(bromomethyl)-1,3-thiaselenole with potassium selenocyanate proceeded via a rearrangement with ring expansion, leading to a six-membered 2,3-dihydro-1,4-thiaselenin-2-yl selenocyanate (kinetic product) which in turn underwent rearrangement with ring contraction to a 1,3-thiaselenol-2-ylmethyl selenocyanate (thermodynamic product). These rearrangements occurred by a nucleophilic attack of the selenocyanate anion at two different carbon atoms of the seleniranium intermediate. The efficient regioselective synthesis of alkyl, allyl, 2-propynyl, benzyl, 4-fluorobenzyl, and 2-pyridinylmethyl 1,3-thiaselenol-2-ylmethyl selenides was developed based on the generation of sodium 1,3-thiaselenol-2-ylmethylselenolate from 1,3-thiaselenol-2-ylmethyl selenocyanate or bis(1,3-thiaselenol-2-ylmethyl) diselenide followed by nucleophilic substitution reactions. Sodium 1,3-thiaselenol-2-ylmethylselenolate underwent nucleophilic addition to alkyl propiolates in a regio- and stereoselective manner affording 1,3-thiaselenol-2-ylmethyl vinyl selenides in high yields predominantly with Z-configuration. Not a single representative of the 1,3-thiaselenol-2-ylmethyl selenide scaffold has been previously described in the literature.

Synthesis of 4-arylethyl-6-arylpyrimidine-2-thiols through aza-Michael addition/nucleophilic addition/aromatization tandem reactions

2018 ◽  
Vol 24 (1) ◽  
pp. 23-26
Author(s):  
Zheng Li ◽  
Wenli Song ◽  
Jiaojiao He ◽  
Yan Du ◽  
Jingya Yang
Keyword(s):  
Efficient Method ◽  
Michael Addition ◽  
Nucleophilic Addition ◽  
Tandem Reactions ◽  
Reaction Conditions ◽  
High Yields ◽  
Work Up

Abstract An efficient method for the synthesis of the title compounds by reactions of divinyl ketones with thiourea is described. This protocol has the advantages of high yields, mild reaction conditions and simple work-up procedure.

scholarly journals Applications of tert-butanesulfinamide in the asymmetric synthesis of amines

2003 ◽  
Vol 75 (1) ◽  
pp. 39-46 ◽  
Author(s):  
J. A. Ellman
Keyword(s):  
Amino Acids ◽  
Asymmetric Synthesis ◽  
Nucleophilic Addition ◽  
Amino Alcohols ◽  
Wide Range ◽  
Aldehydes And Ketones ◽  
Directing Group ◽  
High Yields ◽  
Direct Condensation

tert-Butanesulfinamide is prepared using catalytic enantioselective methods in two steps from the extremely inexpensive oil waste by-product, tert-butyl disulfide. Direct condensation of tert-butanesulfinamide with aldehydes and ketones provides tert-butanesulfinyl imines in uniformly high yields. The tert-butanesulfinyl group activates the imines for the addition of many different classes of nucleophiles, serves as a powerful chiral directing group, and after nucleophilic addition is readily cleaved by treatment with acid. A wide range of highly enantioenriched amines, including α-branched and α,α-dibranched amines, α- and β-amino acids, 1,2 and 1,3-amino alcohols and α-trifluoromethyl amines are efficiently synthesized using this methodology.

Analysis of wood vacuum pyrolysis solid residues by diffuse reflectance infrared Fourier transform spectrometry

1989 ◽  
Vol 67 (2) ◽  
pp. 310-314 ◽  
Author(s):  
H. Pakdel ◽  
J. L. Grandmaison ◽  
C. Roy
Keyword(s):  
Fourier Transform ◽  
Diffuse Reflectance ◽  
Process Development ◽  
Liquid Fuels ◽  
Solid Residue ◽  
Vacuum Pyrolysis ◽  
Development Unit ◽  
Diffuse Reflectance Infrared ◽  
High Yields ◽  
Increasing Temperature

Vacuum pyrolysis of wood furnishes high yields of oils which are a source of liquid fuels and chemicals. Wood charcoal is a solid residual by-product. Solid residues produced at 200, 263, 327, 363, 401, and 448 °C in a Process Development Unit were analyzed using wet chemical methods and chromatography and infrared spectrometry.A Diffuse Reflectance Infrared Fourier Transform (DRIFT) study of the solid residues which contained various proportions of organic polymeric constituents consisting of unconverted lignin, polysaccharides, and recondensed materials was performed. Polysaccharide contents were determined by hydrolysis in trifluoroacetic acid followed by derivatization and gas-chromatographic analysis. The DRIFT study showed that the solid residue retained its wood nature below 263 °C. Significant degradation, decomposition, and recondensation reactions occurred with increasing temperature and coal-like nature prevailed above 327 °C. Occurrence of a new band at 1700 cm−1 in samples produced at 363 °C and above was found to be indicative of a new carbonyl group, presumably in recondensed material.A series of equations were also developed to predict semiquantitatively Klason residue, glucose and xylose content of the solid residues. The usefulness of each equation is discussed in the article. Keywords: wood, vacuum pyrolysis, solid residue, DRIFT, spectrometry.

Asymmetric synthesis of β-amino ketones by using cinchona alkaloid-based chiral phase transfer catalysts

2018 ◽  
Vol 16 (45) ◽  
pp. 8704-8709 ◽  
Author(s):  
Weihua Li ◽  
Yifeng Wang ◽  
Danqian Xu
Keyword(s):  
Asymmetric Synthesis ◽  
Nucleophilic Addition ◽  
Phase Transfer ◽  
Cinchona Alkaloid ◽  
Reaction Products ◽  
Chiral Phase ◽  
Phase Transfer Catalysts ◽  
Chiral Phase Transfer Catalysts ◽  
The Mannich Reaction ◽  
High Yields

A highly enantioselective nucleophilic addition of ketones to versatile imines catalyzed by chiral PTC has been developed, and the process affords the Mannich reaction products with tertiary stereocenters in good to high yields and excellent enantioselectivities. This protocol is effective for gram scale reaction.

Novel enantioselective synthesis of (S)-ketamine using chiral auxiliary and precursor Mannich base

2019 ◽  
Vol 97 (5) ◽  
pp. 331-336 ◽  
Author(s):  
Seyed Jamaladdin Gohari ◽  
Abdollah Javidan ◽  
Abolghasem Moghimi ◽  
Mohammad Javad Taghizadeh ◽  
Maryam Iman
Keyword(s):  
Acid Solution ◽  
Nucleophilic Addition ◽  
Grignard Reagent ◽  
Mannich Base ◽  
Enantioselective Synthesis ◽  
Chiral Auxiliary ◽  
Chiral Auxiliaries ◽  
Anesthetic Drug ◽  
Directing Group ◽  
High Yields

Ketamine has been extensively used as an anesthetic drug. Chiral auxiliaries such as tert-butanesulfinamide (TBSA) can be used for the asymmetric synthesis of (S)-ketamine. Condensation of TBSA with ketones provides tert-butanesulfinylimines in consistently high yields. The tert-butanesulfinyl group actuates the imine for nucleophilic addition, is a potent chiral directing group, and after nucleophilic addition is easily dissociated by intervention with acid solution. To prepare 2-(N-piperidinomethyl)-1-phenylcyclohexylamine (1), we started with the cyclohexanone and using Mannich reaction achieved an aminoketone. Then, we made the sulfiniylamin (2) by the condensation of TBSA with aminoketone. By using salts such as Ti(OEt)4, we obtained N-tert-butanesulfinylketimine in 85% yield. Next, we provided a new chiral center (3) using Grignard reagent as nucleophile at −78 °C (80% yield). Finally, after many steps, the (S)-ketamine synthesized under ozonolysis conditions, with good yield and enantioselectivity (75% yield and 75% ee).

scholarly journals Functionalization of N-arylmaleimides by sp3 C–H bonds of hydroacridines(qinolines)

2020 ◽  
pp. 165-170
Author(s):  
N.V. Smetanin ◽  
◽  
A.V. Mazepa ◽  
Keyword(s):  
1H Nmr ◽  
Spectral Methods ◽  
Good Yield ◽  
Single Step ◽  
Main Direction ◽  
Facile Synthesis ◽  
Nmr Spectrum ◽  
Type Reaction ◽  
Catalyst Free ◽  
High Yields

The catalyst-free sp3 C–H functionalization of tetrahydroacridine(quinolines) derivatives has been achieved using a Michael-type reaction with N-arylmaleimides. This method enables the facile synthesis of biologically important N-aryl bearing tetrahydroacridine(quinolines) moieties in a single step with high yields. The reaction occurs under non-catalytic conditions by heating of hydroacridines(quinolines) in DMSO within 4 h at 100–1200C. The reaction between starting compounds allows synthesizing (3S/4R)-3-[(3R/4S)-9-chloroacridine(quinoline)-4-yl]-1(-N-aryl)pyrrolidine-2,5-diones with a good yield. The structure of compounds was proved by spectral methods of analysis. The 1H NMR spectrum shows characteristic signals of protons of the CH-groups in acridine(quinoline) (3.4–3.5 ppm) and pyrrolidine (3.8–3.9 ppm) cycles. It is interesting to note that the main direction of the fragmentation is the Michael retro-reaction, which is accompanied by the elimination of 1-(2-nitrophenyl)-1H-pyrrole-2,5-dione and leads to the formation of m/z ions of starting chloroacridines(quinolines).

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