79265-41-1

Upstream product

• 288-47-1 1,3-thiazole 
• 79-36-7 dichloroacethyl chloride 
• 4591-28-0 dichloroketene 
• 79265-30-8 2-(trimethylsilyl)thiazole 
• 79265-33-1 2-(2,2-Dichloro-1-trimethylsilanyloxy-vinyl)-thiazole 
• 79265-38-6 2-dichloroacetyl-5-trimethylsilylthiazole 
• 24295-03-2 2-Acetylthiazole 
• 112969-86-5 2,2-Dichloro-1-(4-trimethylsilanyl-thiazol-2-yl)-ethanone 

Relevant academic research and scientific papers

Solvent-free preparation of α,α-dichloroketones with sulfuryl chloride

An efficient and facile method is reported for the synthesis of a series of α,α-dichloroketones. The direct dichlorination of methyl ketones and 1,3-dicarbonyls using an excess amount of sulfuryl chloride affords the corresponding gem-dichloro compounds in moderate to excellent yields. Moreover, the protocol features high yields, broad substrate scope, and simple reaction conditions without using any catalysts and solvents.

Synthesis of (Trimethylsilyl)thiazoles and Reactions with Carbonyl Compounds. Selectivity Aspects and Synthetic Utility

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

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.

Additions and Cycloadditions of Ketenes to 1,3-Thiazole and Its Alkyl Derivatives

1,3-Thiazole and its 4-methyl and 5-methyl derivatives react with tert-butylcyanoketene (TBCK) and dichloroketene (DCK), affording Michael-type addition products at C2, viz., 2-acylthiazoles, and 2:1 cycloadducts (with TBCK only) which proved by X-ray analysis to be bicyclic systems constituted by a thiazoline and a piperidine-1,3-dione ring condensed across the C-N bond. 2-Ethyl- and 2-isopropyl-1,3-thiazole undergo acylation by DCK at the Cα of the alkyl chain.The latter thiazole gives also a 2:1 cycloadduct, which X-ray analysis showed to be a bicyclic system constituted by a thiazoline and an oxazinone ring condensed across the C-N bond.A mechanism is envisaged involving the quaternization of the thiazole nitrogen by the ketene to give an N-thiazolium enolate system which owing to proton exchange between the C2 of the ring or the Cα of the 2-alkyl chain and its enolate portion is in equilibrium with an N-acylthiazolium ylide or zwitterion, respectively.Subsequent reactions of these active intermediates with the ketene lead to the final products.

Reactions of Trimethylsilylthiazoles with Ketens: A New Route to Regioselective Functionalisation of the Thiazole Ring

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).