Thietes structure

Thiete structures have been suggested as fragmentation products in the mass spectra of a thietane fused to a 3-lactam, an ortho disulfide of a thiolbenzoate ester, -propanethiol, thiirane carboxylic acid esters, isothiazoles, thiazoles, 1,3-dithiole 2-thiones, 1,3-dithiolene-2-ones, S-ethyl thio-benzoate, and thianaphthene sulfones. Tetramethylthiete may have been formed on thermolysis of the p-toluenesulfonyl-hydrazone of 2,2,4,4-tetramethyl-3-thietanone. " Thiete 2-thione may be an intermediate in the decomposition of 1,2-ditholium salts by the action of bases. " 2,2-Diphenyl-2H-thiete is suggested as an intermediate in the reaction of diphenyldiazomethane with 1,2,3-benzo-thiadiazole which yields 9-phenylthioxanthene and three other products. ... 

In view of the limited capacity of the sulfur atom in the sulfoxide and sulfone functional groups to transmit conjugative effects due to the insulating effect of the LUMO sulfur d-orbitals45,46,56, the application of the UV technique even in the case of the cyclic vinyl sulfones (e.g. thiete dioxides 6b) cannot be expected to find extensive use. UV spectra of substituted thiete dioxides in which an extended conjugated system (e.g. 194) exists in the molecule, did provide useful information for structure elucidation231. However, the extent... 

The preparation and investigation of the thietane oxide system (5a) is largely associated with stereochemical and conformational studies . The investigation of the thietane dioxides (5b) is substantially related to the chemistry of sulfenes , the [2 -I- 2] cycloaddition of which with enamines is probably the method of choice for the synthesis of 5b . The study of the thiete dioxide system (6) evolved, at least in part, from the recognition that the unstable thiete system 183 can be uniquely stabilized when the sulfur in the system is transformed into the corresponding sulfone , and that the thiete dioxide system is very useful in cycloadditions and thermolytic reactions. The main interest in the dithietane oxides and dioxides (7) appears to lie in the synthetic challenge associated with their preparation, as well as in their unique structural features and chemical behavior under thermolytic conditions . ... 

Cycloadditions of nitrones, nitrile oxides or diazo compounds to thiete dioxides do not show the high stereoselectivity observed with acyclic vinyl sulfones, and mixtures of the two possible adducts are formed . The charge-transfer stabilization energy calculated according to the Klopman-Salem perturbational approach is able to account for the experimental trends of the isomer ratio in terms of the major stereochemical structural differences between the acyclic vinyl sulfones and the four-membered ring sulfones (see Section IV.B.3). 

X-Ray analysis of the red-orange crystalline thioacrolein complex 272, which is derived from the dimeric thioacrolein derivative by way of thermal elimination of carbon monoxide (Scheme 17), has revealed a structure with an essentially square FejSs array. Analogous reactions with iron carbonyls have been carried out by McCaskie et who used thiete 1,1-dioxide instead of thiete (Scheme 18). 

Structure of 1,3-dimethyl-3",4 -diphenylimidazolidine-2-spiro-2 (2 jff) thiete-4,5-dione. ... 

H-Benzo[6]thiete synthesis, 4, 824 Benzothietes ring opening, 7, 423 synthesis, 4, 824 Benzothietide anions stability, 7, 419 1H-1 A4-1 -Benzothiins pxidation, 4, 969 stability, 3, 926 structure, 3, 894 Benzothiins, dihydrodisproportionation, 3, 908 lH-2-Benzothiin, 3,4-dihydro-2,2-dioxide... 

Thiabicyclo[3.1,0]hex-3-ene synthesis, 4, 784 9-Thiabicyclo[3,3. l]nonane 9,9-dioxide bond, angles, 7, 409 - 5-Thiabicyclo-2-pentene, 1,2,3,4-tetrakis(trifiuoromethyl)-rearrangement, 7, 153 2H-l,2-Thiaborin dibenzo fused, 1, 658 1-Thia[2.2.2]cyclazines, 4, 479 5-Thia[2.3.3]cyclazines, 4, 481 Thiacyclobutadienes — see 1H-1A4-Thietes l-Thia-4-cycloheptyne, 3,3,6,6-tetramethyl-structure, 7, 555 synthesis, 7, 574... 

This chapter continues this work covering the literature of the last 10 years, that is, from 1996 until 2005. The preparation of this review was based on a literature search through SCOPUS and the Beilstein Database, which revealed 104 important papers published within this period. This chapter is organized in accordance with the general structure of CHEC-III, which includes a division into 12 sections including the same aspects as in CHEC-II(1996). For some aspects of thietane and thiete chemistry, such as their synthesis from six- and seven-membered rings, no new papers were published within the discussed period. 

The literature describing theoretical studies on monocyclic thietanes and thietes until 1995 has been fully covered in CHEC-II(1996). However, the described papers were confined to semi-empirical or molecular orbital(MO) calculations. During the last decade, computational abilities have increased dramatically, and several papers have appeared dealing with ab initio calculations of thietane structures. Extensive ab initio calculations have been carried out in order to establish the isotropic shielding constant a and chemical shifts 8 of 14 variously substituted thietanes 1 <2000MRC468>. These values have been computed using the HF/6-31++G and geometries for this purpose... 

Several bond lengths and bond angles for various fused thietanes and thietes and their derivatives were determined by X-ray crystallography, microwave spectroscopy, and electron diffraction, and are presented in CHEC(1984) and CHEC-II(1996). Since 1995, the following structures have been published 5-(2,5-dimethylphenyl)-3,3-diphe-nyl-l-thia-5-aza-spiro[3.4]octan-6-one 3 <2003CC2218> (+)(Ay,4/ )-4-methyl-l,6-diphenyl-2-thia-6-azabicy-... 

The mass spectral fragmentation patterns of a variety of fused and spiro thietanes and thietes were presented in CHEC(1984) and CHEC-II(1996). Only more recent data are included here. The mass spectrometry (MS) spectra of thietanes 10 and 11 show molecular ion peaks at m/z 330 and 270, respectively, corresponding to the molecular weights of thiobarbiturates used for their preparation by photolysis in acetonitrile <2003H(59)303>. The structures of different derivatives (substituted in the thietane ring by CH3, Ph, or OC2H5 groups) of 5,7,7,9-tetramethyl-l-thia-... 

An attempted synthesis of thiete by thermolysis (300°) of a Diels-Alder adduct with anthracene was unsuccessful, no doubt because of the thermal instability of thiete.Thiete derivative 215 was obtained by other methods, and structure 217 was suggested as an intermediate in the desulfurization of 216. The unusual dithiolactone 218b is formally derived from a cycloaddition of carbon disulfide with acetylene 218a. " A 2-substituted-3,4-diphenyl-2H-thiete is obtained by treatment of the ylide, 8-methyl-1,3-diphenyldibenzo [e, h]-8-thiazulene, with diphenylcyclo-propenethione. 2-Methoxy-3,4-diphenyl-2H-thiete is one of several products obtained on photolysis of diphenylcyclopropenethione in methanol. ... 

An x-ray structural analysis has been done on thiete 1,1-dioxide (248), naphtho[l,8-bc]thiete 1,1-dioxide (205b),and rrans-2,5-dibromo-7-thiabicyclo-[4.2.0]-l(6)-octene 7,7-dioxide (249). A microwave spectrum of thiete sulfone has been obtained for which an O-S-0 angle of 120.1° was preferred, which differs from the value of 115.5° found in the x-ray analysis. 

An iron tetracarbonyl complex (295) ° and a platinum bis(triphenylphosphine) complex of thiete 1,1-dioxide have been prepared. Platinum complexes of 3-phenyl- and 3-(p-bromophenyl) thiete 1,1-dioxide also have been prepared. No complex was obtained with the 3-t-butyl derivative. The pale-yellow, crystalline iron complex decomposes in refluxing hexane in the presence of excess sulfone to Fe2S2(CO)9, indicating a drastic structural rearrangement. Other carbon-containing fragments were not observed. The bis(triphenylarsine)platinum complex of 3-02-bromophenyl) thiete sulfone is decomposed photochemically to the thiete sulfone. The same result is achieved on treatment of the complex with tetra-cyanoethylene. ... 

In another group of (2 + 2)-cycloaddition reactions, the heterocyclic nucleus reacts via an electron-deficient carbon-carbon or carbon-nitrogen double bond with electron-rich aminoacetylenes (ynamines). For instance, thiete 1,1-dioxides, JV-benzylmaleimide, and 2,3-bis(methoxycarbonyl)-7-oxabicyclo( 2.2.1 lhepta-2,5-diene reacted with 1-diethylamino-l-propyne and with 1 -phenyl-2-( 1 -pyrrolidinyl)-acetylene to give the (2 + 2)-cycloadducts 48, 49, and 50, respec-tively.35,37,53 The latter product was thermally rather unstable, and its structure was identified on the basis of its conversion with 2,4,6-tri-methylbenzonitrile oxide into 51.53 (2 + 2)-Cycloaddition via a carbon-nitrogen double bond has been reported to take place in the reactions of 3,3-dimethyl-3//-indoles and 3,4-dihydroisoquinoline with ynamines, e.g., l-dimethylamino-2-phenylacetylene, in the presence of boron trifluoride.54 The (2 + 2)-cycloadducts 52 and 53 were not isolated, but... 

Formation.—Phenyl-, 2-naphthyl-, 2-thienyl-, and 2-furanyl-thiets are prepared from aryl methyl ketones, dimethylamine, and methanesulphonyl chloride. X-K y crystal structures establish that the compounds arising from the cycloaddition of alkynes to thioxanthones are thiets, and not spiro-dihydropyrans, as originally proposed. Additional work shows that alkynyl sulphides also give thiets with thioxanthone, and that the adduct (104) is in rapid equilibrium with the open form (105) in solution, although they can be isolated separately. Thiet (106) was isolated after thermolysis of a Dewar thiophen—azide adduct. ... 

Treatment of thiets with di-iron enneacarbonyl yields complexes, e.g. (177), of thioacrolein. X-Ray analysis of thioacrolein triphenylphosphine dicarbonyliron (178) established the structure. ... 

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