- 1,3-Dipolar cycloadditions of new mesoionic compounds. Synthesis of 1H-pyrrolo[1,2-c]thiazoles, pyrrolizines and 5,6,7,8-tetrahydroindolizines
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We studied the 1,3-dipolar cycloaddition reactions between alkyne dipolarophiles and the new mesoionic compounds 2H,5H,7H-thiazolo[4,3-b]oxazol-2-one (12), 2H,5H,7H-pyrrolo[2,1-b]oxazol-2-one (13) and 2H,5H,7H-oxazolo[3,2-a]pyridin-2-one (14). These 1,3-dipoles were prepared in situ by means of cyclodehydration with acetic anhydride of the corresponding α-substituted 4-oxo-3-thiazolidine- (9), 2-oxo-1-pyrrolidine- (10) and 2-oxo-1-piperidineacetic acids (11). The cycloaddition reactions with alkyne dipolarophiles afforded single 1H-pyrrolo[1,2-c]thiazole, pyrrolizine and 5,6,7,8-tetrahydroindolizine derivatives, or a mixture of the two possible regioisomers, depending on whether symmetrical or unsymmetrical alkynes.
- Dalla Croce, Piero,La Rosa, Concetta
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p. 1843 - 1857
(2007/10/03)
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- Azomethine ylide generation via the dipole cascade
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A series of N-acyl 2-diazo-3-oxobutanoates, when treated with a catalytic quantity of a rhodium(II) carboxylate, were found to afford substituted pyrroles derived from an azomethine ylide intermediate. The initial reaction involves generation of the expec
- Padwa, Albert,Dean, Dennis C.,Hertzog, Donald L.,Nadler, William R.,Zhi, Lin
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p. 7565 - 7580
(2007/10/02)
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- Synthesis, Chemical Reactivity, and Antileukemic Activity of 5-Substituted 6,7-Bis(hydroxymethyl)pyrrolothiazole Biscarbamates and the Corresponding Sulfoxides and Sulfones
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A series of bis(N-methylcarbamate) and bis derivatives of 5-substituted 6,7-bis(hydroxymethyl)pyrrolothiazoles was prepared.The compounds were tested for activity in vivo against P388 lymphocytic leukemia, and the chemical reactivities of the compounds were compared by using the model nucleophile 4-(4-nitrobenzyl)pyridine (NBP).The 5-(3,4-dichlorophenyl)-substituted biscarbamates 6b, 8b, and 12b were inactive and unreactive toward NBP.The 5-methyl-substituted bicarbamates 6a, 7a, 8a, 9a, 12a, and 13a were all active against murine P388 lymphocytic leukemia.The chemical reactivities of the active compounds depended on the oxidation state of the sulfur.The reactivity toward NBP followed the order S > SO >> SO2.The sulfones 12a and 13a are the most active compounds in this series, and their lack of reactivity toward NBP led to the suggestion that 12a and 13a are activated in vivo.
- Anderson, Wayne K.,Mach, Robert H.
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p. 2109 - 2115
(2007/10/02)
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