Thiophene 1-oxides Research Articles

The Latest Advances in Chemistry of Thiophene 1-Oxides and Selenophene 1-Oxides

Immediately after we had reviewed the chemistry of thiophene 1-oxides in 1996 (Sulfur Reports, 16), very rapid and important progress was achieved in this field. The present article provides a supplement to the above review. The chemistry of thiophene sulfilimines (1-imino-1, 1-dihydrothiophenes) as well as that of selenophene 1-oxides is also reviewed.

1-Oxides and 1,1-Dioxides of Thiophenes and Selenophenes and Related Compounds

Abstract The first topic of the present article involves recent advances in the chemistry of thiophene 1-oxides. Next is the chemistry of the parent thiophene 1,1-dioxide, which is followed by that of congested thiophene 1,1-dioxides, where emphasis is placed on their syntheses and synthetic applications. The chemistry of 1-imino, 1,1-diimino, and 1-imino-1-oxo derivatives of thiophenes is then described. Finally, the newborn chemistry of selenophene 1-oxides and 1,1-dioxides is discussed.

Synthesis of (4-chlorophenyl)-(1-oxo-1λ 4-benzo[b]thien-2-yl)methanone and study of its reactivity towards sulfur- and oxygen-containing nucleophiles

(4-Chlorophenyl)-(1-oxo-1λ 4-benzo[b]thien-2-yl)methanone 2a was synthesized by oxidation of the corresponding benzo[b]thiophene derivative 2 with the oxidative system H 2O 2 TFA . This benzo[b]thiophene sulfoxide undergoes Michael-type nucleophilic addition of sulfur- and oxygen-containing nucleophiles either under basic conditions leading to 2,3-dihydro-3-substituted-benzo[b]-thiophene 1-oxides or in acidic media leading then to rearomatized 3-substituted-benzo[b]thiophenes. This method provides an easy two-step functionalization of 2-acyl-benzo[b]thiophene derivatives.

Synthesis and Characterization of Thiophene 1-Oxides Kinetically Stabilized by Bulky Substituents at the 3- and 4-Positions

Abstract Oxidation of 3,4-di-t-butyl- and 3,4-di-1-adamantyl-, and 2,4-di-t-butylthiophenes with an equimolar amount of m-chloroperbenzoic acid in the presence of BF3•Et2O gave the corresponding thiophene 1-oxides in good yields, which are stable enough to be isolated in pure crystalline form. An X-ray single crystal structure analysis led to the conclusion that thiophene 1-oxides would not be aromatic.

The Chemistry of Thiophene 1-Oxides

An exhaustive literature survey has been made of the chemistry of thiophene 1-oxides (thio- phene S-oxides). Syntheses, structures, and reactions of thiophene 1-oxides are described to understand the present status of this chemistry. The chemistry of selenophene 1-oxides is also described briefly.

Enantioselective dioxygenase-catalysed formation and thermal racemisation of chiral thiophene sulfoxides

Substituted chiral thiophene 1-oxides and their cycloadducts of variable enantiopurity have been isolated as products of dioxygenase-catalysed sulfoxidation of the corresponding thiophenes using intact cells of Pseudomonas putida; thermal racemization (ΔG‡= 25.1 kcal mol–1) of the enantiopure metabolite (1R)-2-methylbenzo[b]thiophene 1-oxide has been observed.

Base hydrolysis of ruthenium(II) thiophene complexes and reactions of the coordinated ligands

This paper describes the acid/base reactivity of a series of ruthenium thiophene complexes. In the acid form the starting compounds (ring)Ru(C[sub 4]R[sub 4]S)[sup 2+] are reactive toward 2 equiv of aqueous base, first as an OH- acceptor and next as a proton donor. The first and the second conjugate bases exist in at least two isomeric forms whose interconversions we have examined. The present results are related to previous work where we showed that one C-S bond in (C[sub 5]Me[sub 5])Rh(C[sub 4]R-4S)[sup 2+] undergoes base hydrolysis by attack of 2 equiv of OH-. C-S cleavage occurs upon deprotonation of the intermediate [(C[sub 5]Me[sub 5])-Rh([eta][sup 4]-C[sub 4]R-4S-2-OH)][sup +], giving rise to a neutral acyl thiolato complex. Furthermore NMR measurements indicated that the resulting acyl thiolates were dynamic in a manner that was poorly understood. We also showed that the initial attack of (excess) base results in formation of the thiophene 1-oxide complex [(C[sub 5]Me[sub 5])Rh([eta][sup 4]-C[sub 4]R[sub 4]S-1-O)], but intermediates in the formation of this S-oxide were not observed. Our studies of related ruthenium systems have uncovered the following: (i) evidence that S-hydroxythiophene complexes are precursors to the thiophene 1-oxides and C[sub 4]R[sub 4]S-2-OH complexes, (ii) an explanation of the dynamicmore » properties of the acyl thiolates, and (iii) the stereochemical course of the protonation of the acyl thiolates. 23 refs., 2 figs.« less

2,3-Dihydronaphtho[1,2-b]thiophene 1-oxides in the synthesis of 2,3-dihydronaphtho- and naphtho[1,2-b]thiophenes

2,3-Dihydronaphtho[1,2-b]thiophene 1-oxides, obtained by thermolysis of alkyl 1-naphthyl sulfoxides, are reduced by lithium aluminum hydride to 2,3-dihydronaphtho [1,2-b]thiophenes, whereas under the influence of acetic and trifluoroacetic anhydrides they form naphtho[1,2-b]thiophenes.

Photoreactivity of 2- and 3-substituted benzo[b]thiophene 1-oxides in solution

Photoreactivity of 2- and 3-substituted benzo[b]thiophene 1-oxides in solution