“…It is assumed that the two populations have reached equilibrium with respect to the above processes. Takahata (1983) studied that rate of approach to equilibrium conditions for the finite island model and found that it is approximately equal to the mutation rate.…”
“…It is assumed that the two populations have reached equilibrium with respect to the above processes. Takahata (1983) studied that rate of approach to equilibrium conditions for the finite island model and found that it is approximately equal to the mutation rate.…”
“…222 The type of substituents in the reactants determined the relative amounts of the products.222 The semicyclic ketene S,N-acetals, for example 215, reacted with an aryl isothiocyanate to give 216 or 217, depending on the reaction conditions (Scheme 20). 223,224 Similarly, 6-aminouracils with isothiocyanates furnished 5-substituted thiocarbamoyl derivatives which were manipulated to yield various fused pyrimidines, some of which were found to be biologically active (Scheme [225][226][227] The reaction of isothiocyanates with carbon bases, generated by metalation of heterocycles and other suitable systems, does not seem to have been properly studied and it would be worthwhile to explore further its synthetic utility.…”
“…S -Alkylation of tertiary thioamides having α,α hydrogen atom(s) gives rise to the formation of ketene S , N -acetals 205 and 206 (Figure ), also known as alkylthio derivatives of enamines. − These compounds readily react with electrophilic agents. Moreover, an intramolecular heterocyclization with elimination of the S -alkyl group may occur when a nucleophilic center is also present in the reacting compound (Figure ).…”
Section: Reactions Of Ketene Sn-acetals With
Electrophilesmentioning
confidence: 99%
“…Thus, high yields of pyrimidine-2,4-diones 207 (Scheme ) or azacycloalkano[2,3- d ]pyrimidines 208 (Scheme ) were obtained in the reaction of the ketene S , N -acetals 205a and 206a with 2 mol of an aryl isocyanate or an aryl isothiocyanate in refluxing toluene . However, if the reaction between 206a and an aryl isothiocyanate is carried out at room temperature in diethyl ether, it is possible to isolate the primary products 209 and to obtain in that way new thioamides preserving much of the framework of the starting one (Scheme ). ,, In the reaction with another molecule of aryl isocyanate or aryl isothiocyanate, compounds 209 undergo cyclization to yield the uracil derivatives 210 (Scheme ). , 8 54 55 …”
Section: Reactions Of Ketene Sn-acetals With
Electrophilesmentioning
in 1972 with a M.S. in chemical technology. In 1977 he received his Ph.D. degree in organic chemistry from Lomonosov State University in Moscow, Russia; his doctoral thesis, "Synthesis of condensed heterocycles from indolylurethanes", was completed under the supervision of Prof. A. N. Kost. From 1977 to 1991, he conducted research on thioamide chemistry and taught organic chemistry at Technical University of Szczecin. He received his habilitation degree in 1991 from Warsaw University of Technology for research on synthesis, reactions, and properties of the thioamide derivatives of benzene and some fivemembered heterocycles.
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