79265-31-9Relevant academic research and scientific papers
Reactions of Trimethylsilylthiazoles with Ketens: A New Route to Regioselective Functionalisation of the Thiazole Ring
Medici, Alessandro,Pedrini, Paola,Dondoni, Alessandro
, p. 655 - 656 (1981)
2-Trimethylsilylthiazole (2) and 2,5-bis(trimethylsilyl)thiazole (6) undergo ipso-substitution of the 2-SiMe3 group with various ketens affording the thiazolyl-trimethylsiloxy-ethylenes (3) and (7), respectively, which are hydrolysed to the 2-acylthiazoles (4), whereas 5-trimethylsilylthiazole (8) undergoes attack at C-2 by dichloroketen giving the Michael-type adduct 2-dichloroacetyl-5-trimethylsilylthiazole (9c).
Synthesis of (Trimethylsilyl)thiazoles and Reactions with Carbonyl Compounds. Selectivity Aspects and Synthetic Utility
Dondoni, Alessandro,Fantin, Giancarlo,Fogagnolo, Marco,Medici, Alessandro,Pedrini, Paola
, p. 1748 - 1761 (2007/10/02)
Synthetic routes to all possible regioisomeric mono- and bis(trimethylsilyl)thiazoles as well as to the tris(trimethylsilyl) derivative via lithiation-silylation sequences of the thiazole ring followed by selective protodesilylation in some cases are described. (Trimethylsilyl)thiazoles serve as thiazolyl donor synthons upon reaction with carbonyl compounds (ketenes, acyl chlorides, aldehydes) for the preparation of mono- and bis-substituted thiazoles in very good yields.Carbodesilylation occurs more readily at the 2- than 5-position, whereas no reaction takes place at the 4-position.A mechanism via a thiazolium 2-ylide as an intermediate is suggested for the carbodesilylation at the 2-position.
NEW PERSPECTIVES IN THIAZOLE CHEMISTRY
Dondoni, Alessandro
, p. 1 - 38 (2007/10/02)
Carbon-carbon bond forming reactions at C-2 of the thiazole ring have been carried using two strategies, one involving the addition of organometallic reagents (lithium carbanions of esters, Grignard salts, silyl enol ethers, silyl ketene acetals, silylazoles) to N-acylthiazolium salts; the other involving the addition of carbon electrophiles (ketenes, acyl chlorides, anhydrides, aldehydes) to N-acylthiazolium ylides generated in situ.The reactions have been applied to 1,3-thiazole and 2-trimethylsilyl-1,3-thiazole, the latter being more reactive than the former toward electrophiles.This methodology constitutes a new entry to a variety of functionalized thiazoles and thiazolines which are potential building blocks for the synthesis of natural compounds and analogues of biologically active molecules (penems, arylpropionic acids).Some ring transformations of thiazoles induced by carbon-sulfur bond cleavage are also described.The fundamental role played by the sulfur atom of the thiazole ring in the observed reactions is pointed out and briefly discussed.
