N1-Substituted Hypoxanthine Derivatives from the Reaction of 6-Halopurines with Michael Acceptors Under the Conditions of Heck Reaction

2000 ◽  
Vol 65 (5) ◽  
pp. 797-804 ◽  
Author(s):  
Martina Havelková ◽  
Martin Studenovský ◽  
Dalimil Dvořák
Keyword(s):  
Methyl Methacrylate ◽  
Butyl Acrylate ◽  
Heck Reaction ◽  
Conjugate Addition ◽  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Acetate Anion ◽  
Methyl Vinyl ◽  
Michael Acceptors

The reaction of 6-iodo-, 9-benzyl-6-chloropurine and 7-benzyl-6-chloropurine with butyl acrylate, acrylonitrile, methyl vinyl ketone or methyl methacrylate under conditions of the Heck reaction in the presence of TlOAc or AgOAc afforded N1-alkylhypoxanthine derivatives. Formation of these unexpected products can be rationalised as a Tl+- or Ag+-assisted substitution of halogen with acetate anion. The 6-acetoxypurine derivative thus formed then eliminates ketene and gives 7-benzyl- or 9-benzylhypoxanthine. Conjugate addition of these compounds onto Michael acceptors furnishes the N1-substituted hypoxanthine derivatives.

Aprotic Conjugate Addition Reactions of Lithiated Allylic Sulfoxides With Acyclic Enones; a Breakdown of the trans-Decalyl Transition State

1989 ◽  
Vol 42 (10) ◽  
pp. 1785 ◽  
Author(s):  
RK Haynes ◽  
AG Katsifis ◽  
LM King ◽  
SC Vonwiller
Keyword(s):  
Transition State ◽  
Conjugate Addition ◽  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Mesityl Oxide ◽  
Addition Reactions ◽  
State Characteristic ◽  
Methyl Vinyl ◽  
Cyclic Enones ◽  
Carbonyl Addition

The reactions of lithiated 1-(t-butylsulfinyl)prop-2-ene, 1-(t-butylsulfinyl)-3-methylbut-2-ene, 1-(t-butylsulfinyl)but-2-ene, 1-(phenylsulfinyl)but-2-ene and 2-methyl-1-(phenylsu1finyl)prop- 2-ene with methyl vinyl ketone, mesityl oxide and crotonaldehyde give largely carbonyl addition products arising from reaction through C1 or C3 of the allyl system. In the case of methyl crotonate, conjugate addition through C3 is observed. The initially formed diastereomers of the C1 adducts, allylic sulfoxides, are configurationally unstable. Only the lithiated 1-(t-butylsulfinyl)-3-methylbut-2-ene undergoes conjugate addition with methyl vinyl ketone to give an (E)-vinyl sulfoxide whose formation may involve the trans-decalyl transition state characteristic of the reactions of lithiated allylic sulfoxides with cyclic enones.

CROSS-LINKING OF COPOLYMERS FROM METHYL VINYL KETONE AND n-BUTYL ACRYLATE

1956 ◽  
Vol 34 (3) ◽  
pp. 387-405 ◽  
Author(s):  
W. Cooper ◽  
E. Catterall
Keyword(s):  
Zinc Oxide ◽  
Butyl Acrylate ◽  
Oxide System ◽  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Cross Linking ◽  
Unsaturated Ketone ◽  
Methyl Vinyl ◽  
Or Groups ◽  
Cross Links

Copolymers of n-butyl acrylate and methyl vinyl ketone can be cross-linked by a combination of sulphur and zinc oxide; the reaction is associated with the methyl vinyl ketone units in the polymer chain. From studies on the copolymers and model compounds, it is suggested that adjacent pairs or groups of methyl vinyl ketone units in the polymer cyclize to give αβ unsaturated ketone groups. These contain reactive hydrogen which is attacked by sulphur; disulphide or zinc mercaptide cross-links are then formed. Water is produced in the cyclization reaction and hydrolyzes some of the ester groups; additional cross-links are thus formed by reaction of the acid groups with zinc oxide. The ease of cyclization and, therefore, the extent of cross-linking is dependent on the method of preparing the copolymers, emulsion copolymers being much more reactive than those prepared in solution. A comparison has been made between the sulphur + zinc oxide system and other cross-linking agents which may be used for polyacrylates.

scholarly journals Gas-phase selective conjugate addition of methanol to acetone for methyl vinyl ketone over SnO2 nanoparticle catalysts

2005 ◽  
Vol 16 (3b) ◽  
pp. 607-613 ◽  
Author(s):  
Humberto V. Fajardo ◽  
Luiz F. D. Probst ◽  
Antoninho Valentini ◽  
Neftalí L. V. Carreño ◽  
Adeilton P. Maciel ◽  
...  
Keyword(s):  
Gas Phase ◽  
Conjugate Addition ◽  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Methyl Vinyl ◽  
Nanoparticle Catalysts ◽  
Sno2 Nanoparticle
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