A new method for preparation of 1-(4-substituted phenyl)-6-phenyl-2-thiouracils via cyclization of N-(4-substituted phenyl)-N'-3-phenylpropenoylthioureas and Dimroth rearrangement of 2-(4-substituted phenylimino)-6-phenyl-5,6-dihydro-4H-1,3-thiazin-4-ones

1987 ◽  
Vol 52 (9) ◽  
pp. 2260-2265 ◽  
Author(s):  
Milan Dzurilla ◽  
Peter Kutschy ◽  
Dušan Koščík
Keyword(s):  
Boron Trifluoride ◽  
Lithium Hydride ◽  
New Method ◽  
Dimroth Rearrangement ◽  
Reaction Conditions

N-(4-Substituted phenyl)-N'-3-phenylpropenoylthioureas treated with lithium hydride afforded 1-(4-substituted phenyl)-6-phenyl-2-thiouracils; these could also be obtained by Dimroth rearrangement of 2-(4-substituted phenylimino)-6-phenyl-5,6-dihydro-4H-1,3-thiazin-4-ones under the same reaction conditions. 2-(4-Substituted phenylimino)-6-phenyl-5,6-dihydro-4H-1,3-thiazin-4-ones were synthesized from the corresponding thioureas under catalysis of boron trifluoride in chloroform.

A Novel and Efficient Alkoxylselenenylation of Alkenes

2019 ◽  
Vol 41 (6) ◽  
pp. 1039-1039
Author(s):  
Yingguo Fang and Jie Yan Yingguo Fang and Jie Yan
Keyword(s):  
Room Temperature ◽  
Electrophilic Addition ◽  
New Method ◽  
Reaction Conditions ◽  
Selenium Species

A novel and efficient alkoxylselenenylation from alkenes, diselenides, and alcohols mediated by iodine is developed, with which a series of β-alkoxy selenides are synthesized. In this procedure, firstly, I2 reacts with diselenide to form in situ the active electrophilic selenium species RSeI, then following an electrophilic addition of it to alkenes provides β-alkoxy selenides with high regioselectivity and in good yields. This new method for achieving β-alkoxy selenides has some advantages over other methods such as using available and cheap iodine as the oxidizing species at room temperature, which makes this reaction has milder reaction conditions and simpler procedure.

Zur Reaktion von 1-Sila-2,4-cyclohexadien mit tert-Butyllithium/Trimethylchlorsilan / On the Reaction of 1-Sila-2,4-cyclohexadiene with tert-Butyllithium/Trimethylchlorosilane

1984 ◽  
Vol 39 (10) ◽  
pp. 1368-1374 ◽  
Author(s):  
Peter Jutzi ◽  
Gabriele Berg ◽  
Cornelius Otto ◽  
Thomas Wippermann
Keyword(s):  
Nucleophilic Substitution ◽  
Bond Cleavage ◽  
Lithium Hydride ◽  
Pure Form ◽  
Reaction Conditions ◽  
Carbon Bond ◽  
Nmr Data ◽  
Silicon Carbon ◽  
System 1 ◽  
C Nmr

In the system 1-sila-2,4-cyclohexadiene (l)/tert-butyllithium/trimethylchlorosilane the following reaction types have been observed: nucleophilic substitution, metallation, addition of tert-butyllithium to the diene fragment, addition of lithium hydride to the diene fragment, silicon-carbon bond cleavage, and transmetallation. The resulting products 2-11 have been characterised by their 1H and 13C NMR data; the compounds 2, 3, 6, 8 and 10 could be isolated in a pure form. The relative quantities obtained of the compounds 2-11 depend on the reaction conditions (solvent, temperature, order of addition).

Plasma cholinesterase phenotyping with use of visible-region spectrophotometry.

1986 ◽  
Vol 32 (1) ◽  
pp. 194-197 ◽  
Author(s):  
M H Abernethy ◽  
P M George ◽  
J L Herron ◽  
R T Evans
Keyword(s):  
Cholinesterase Activity ◽  
Visible Region ◽  
Plasma Cholinesterase ◽  
Choline Oxidase ◽  
New Method ◽  
Absorption Curve ◽  
Differential Inhibition ◽  
Reaction Conditions ◽  
Activity Measurements

Abstract A method that overcomes the difficulties of the 240-nm benzoylcholine method for phenotyping plasma cholinesterases has been developed. After a timed reaction, under the same reaction conditions as in the classic procedure, choline is detected at 500 nm by use of choline oxidase coupled with the peroxidase/phenol/aminoantipyrine system. Cholinesterase activity measurements, calibrated by use of choline iodide as standard, are linearly related to results obtained with propionylthiocholine as substrate at 25 degrees C (y = 0.14x + 0.17, n = 30, r = 0.98). Results of differential inhibition with dibucaine and fluoride are virtually identical with those obtained by the ultraviolet method (y = 0.97x + 4.3, r = 0.995, and y = 0.93x - 0.5, r = 0.987, respectively) and give the same classification of homo- and heterozygotes for the usual, atypical, and fluoride-resistant variants. The new method has substantial advantages in that it eliminates the difficulties associated with measuring small changes in high absorbances at a suboptimal wavelength on a steep portion of the absorption curve.

A New Method of Dimroth Rearrangement in Fused Triazolo[1,5-d]-1,2,4-triazine

2014 ◽  
Vol 52 (5) ◽  
pp. 1411-1414 ◽  
Author(s):  
B. E. Ezema ◽  
L. E. S. Akpanisi ◽  
C. G. Ezema ◽  
A. E. Onoabedje
Keyword(s):  
New Method ◽  
Dimroth Rearrangement

A New Method for the Synthesis of Bishydroperoxides Based on a Reaction of Ketals with Hydrogen Peroxide Catalyzed by Boron Trifluoride Complexes.

ChemInform ◽  
2004 ◽  
Vol 35 (1) ◽  
Author(s):  
Alexander O. Terent'ev ◽  
Alexander V. Kutkin ◽  
Maxim M. Platonov ◽  
Yuri N. Ogibin ◽  
Gennady I. Nikishin
Keyword(s):  
Hydrogen Peroxide ◽  
Boron Trifluoride ◽  
New Method

Aminomethylation of BINOL with methyleneiminium salts

2011 ◽  
Vol 89 (11) ◽  
pp. 1319-1324 ◽  
Author(s):  
Gennady Shustov ◽  
Vladimir Khlebnikov
Keyword(s):  
Enantiomeric Excess ◽  
New Method ◽  
Reaction Conditions

A new method for synthesizing chiral 3,3′-bis(N,N-dialkylaminomethyl)-1,1′-bi-2-naphthols with high enantiomeric excess is described. The procedure consists of bis-lithiation of diprotected (S)- or (R)-1,1′-bis(2-naphthol) followed by treatment of the intermediate with methyleneiminium salts. Mild reaction conditions prevent racemization and provide 3,3′-bis(N,N-dialkylaminomethyl)-1,1′-bi-2-naphthols or 3-(N,N-dialkylaminomethyl)-1,1′-bi-2-naphthols with an enantiomeric excess >99%.

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