Thioacrolein

Methylbenzthiazole ethiodide /3-Ethyl thioacrolein diethyl acetal... 

For the practical design of hypersurfaces, i.e. cuts through the (3n-6)dimensional hyperspace, some hints are outlined. The main purpose, however, is to illustrate the usefulness of hypersurface calculations especially for the detection, identification and characterization of unstable molecules. Examples chosen comprise the structure of RS-C=C-SR, the relative stability of thioacroleine isomers C,H S, the structural changes accompanying the oxidation of hydrazine and some of its derivatives, the isomerization of tetrahedrane to cyclobutadiene both thermally as well as on oxidation, the predicted existence of F SS and nonexistence of CI2SS or H2SS, and, finally, some aspects of the thermal decomposition of methyl and vinyl azides. 

From this hypersurface survey, incomplete with respect to approxir mate barriers for kinetic aspects e.g. concerning the ready polymerization of thiocarbonyl derivatives (19g), we tentatively concluded that the PE spectroscopic detection of thioacroleine (18) should be feasible, that it would be less stable than its oxygen analogue, acroleine, and that it could be identified by its PE spectroscopic ionization pattern because of the considerable differences in MNDO eigenvalue sequences to all nearby C4H3S isomers (Figure 2). 

The violet thioacroleine readily dimerizes and can be isolated as a white crystalline mixture of 2-vinyl-1,3-dithiine( AHf ° =... 

Thietes are easily polymerized to different types of macromolecules that often turn up as undesired by-products. The fused compound 149 is easily transformed into a thioacrolein (Eq. 70), which polymerizes to a glassy solid. ... 

As highly reactive heterocycles, the thietes are well suited for the formation of metal complexes. Takahashi and Dittmer both individually and in collaboration have been involved with the interaction of thietes and iron or cobalt carbonyls. During the thermally or photochemically induced complexation process, ring opening takes place so that the resultant thioacrolein is the actual ligand in the organometallic compound (Scheme i7)/ 3-203,204... 

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). 

Gas-phase reactions. Thioacrolein most stable C3H4S isomer and its PE spectroscopic gas-phase detection. ... 

A 1,3-dithiane was also obtained by the reaction of indanone with LR in 95% yield. Presumably, this product was formed via [4-1-2] cycloaddition of thioindanone and a thiocarbonyl-containing condensation product, to which the 1,3-dithiane fragmented upon heating (Equation 75) <1999HAC369>. A similar self-condensation of thioacrolein has been reported as well <2000JOG6601>. 

A similar oxidation of the thioacrolein cobalt (22a,b,d) and iron complexes (23a-c, see Scheme 8) led to complexes of the corresponding 5-oxides. H202/acetic acid or m-chloroperbenzoic acid was used as the oxidant. The oxidation of 22b was achieved by heating the compound in air.147... 

Block and Zhao reported the thermal transformation of diallyl sulfoxide (92) into 3,4-dihydro-2//-thiopyrans, the thioacrolein Diels-Alder adducts, in good to excellent yields385 (equation 97). 

The parent compound, thioacrolein, affords similar cycloadducts which are present in garlic and show potent antithrombotic activity479 480. 

The sulfine 91 obtained from the room-temperature dimerization of thioacrolein. Y-oxide was characterized by key NMR data <1997TL1385> and by comparison with chemical shift data for the 3,4-dihydro-2//-thiopyran-l-oxide <1985AJC119>. 

A novel synthesis of a-unsaturated sulfines has been introduced by Bra-verman et al. [99]. Et3N or DABCO treatment of allylic and benzylic tri-chloromethyl sulfoxides triggered the elimination of chloroform and formation of the sulfines. It must be stressed that these sulfines are thermally relatively stable, and this stands in high contrast to the corresponding thio-carbonyl compounds unsaturated thioaldehydes cannot be monitored under the same experimental conditions and have to be used at very low temperature or trapped in situ. The first synthesis of thioacrolein S-oxide was achieved by flash vacuum thermolysis of an anthracene allyl sulfoxide [100], and both isomers in a (Z E) ratio of 78 22 were characterised by NMR spectroscopy at -60 °C. 

The Franck-Condon factors determination is of special interest when the two electronic states, involved in the transition exhibit very different geometries. This is especially the case of electronic transition in the valence shell such as n — tt, which induces conjugation change, as well as geometrical change, in the molecular system. This phenomenon was studied in the fluorescence spectra of acetaldehyde and acetone [62,63], and in the phosphorescence spectra of thioacrolein and thioacetaldehyde [64,65] and thioacetone [66]. 

Reaction of thietes with iron carbonyls or cyclopentadienyl cobalt dicarbonyl affords thioacrolein complexes 57 and 58. On gentle heating or... 

On the other hand, doubly metallated 2-propanethiol (thioacrolein dianion) reacts preferentially (7 0 ratio = 70 30, Scheme 16, entries b and d) at its -position - with alkyl and benzyl chlorides and bromides and with epoxides. The cis stereochemistry found in the 7-adduct suggests that the organometallic is internally chelated as shown in Scheme 16. The nature of the metal (Li or K) does not affect the percentages of the alkylated vinyl sulfides,whereas addition of HMPA to the dilithio derivative inverts the regioisomeric ratio obtained (Scheme 16, entry c, compare to entries b and d). ... 

Dilithium-thioacrolein dianion with 2 equiv tetramethylethylenediamine (TMED). 

Dilithium derivatives of delocalized dianions of thioacrolein and Li2(CH2CRCHS) homologues, formed by metallation of the corresponding allylmercaptans in the presence of 2 equiv tetramethylethylenediamine (TMED) react with Br2Mg OEt2 in THE (0°C,... 

Cases in which the attacking nucleophile is present in the silene molecule itself have also been reported. The ring closure of the silicon analogues of an acrolein derivative and thioacrolein to silaoxetenes232 and silathietenes233, which immediately undergo a 2 + 2 cleavage to yield an acetylene and a silanone or silanethione, has been proposed to account for the results of flash vacuum pyrolysis of silylated ketenes and thioketenes (equation 110). 

FIGURE 19. Photoelectron spectra illustrating the synthesis of thioacrolein (54) from its Diels-Alder dimer 55. 

---