Sulphine intermediates

Photolysis of thiet 1,1-dioxides (179), either at 235 nm or at 350 nm with a sensitizer, yields unsaturated ketones (181) by loss of sulphur monoxide from a vinyl sulphine intermediate (180). A small amount of cyclohexadiene... 

The participation of sulphine intermediates has been reported in the periodate-promoted oxidative rearrangement of C-sulphonylthioform-amides to S-sulphonylthiourethanes, and in the formation of a-toluenesul-phinic acid or benzhydryl benzyl sulphone by the reaction of benzhydryl benzyl sulphoxides with sulphuryl chloride. ... 

Condensation of Nitriles and Dialkyl Sulphites. (Type C).—A novel isothiazole synthesis involves the interaction of phenylacetonitrile anion, generated in the presence of sodamide, and diethyl sulphite. The main product of the reaction, 4,5-diphenylisothiazol-3-ol (17) (47%), is accompanied by a-cyano-a-(4,5-diphenylisothiazol-3-yl)benzyl phenyl thione (18) (up to 15%). The use of other dialkyl sulphites produces the same isothiazolol (17), but in much reduced yields (9—18%). The reaction may possibly proceed by way of the sulphine intermediate (15), as outlined in Scheme 1, terminating with loss of hydrogen cyanide from (16). ... 

Phenylsulphine prepared in situ from phenylmethanesulphinyl chloride and triethyl-amine reacted with 1 -morpholinocyclohexene to form the addition product 169 having the enamine structure218. A similar experiment with phenylsulphine and 2-pyrrolidinocyclo-hexene gave only 2-phenylmethanesulphinyl cyclohexanone 170. The latter is most probably formed by hydrolysis of the corresponding enamine sulphoxide upon isolation. The reaction of sulphines with enamines is apparently a stepwise process involving the transient formation of the dipolar intermediate 171 which is stabilized by proton transfer, giving the enamine sulphoxide. 

When photolysis (> 290 nm) was carried out in Z-butanol, the identified products were purine, hypoxanthine and purine-6-sulphonic acid. Again, reaction occurred only in the presence of oxygen. The sulphonic acid was thought to arise from the sulphinic acid, but this intermediate could not be detected [150]. 

The formation of thioamides from amines (methylamine, dimethylamine and morpholine) and dithioester sulphines, prepared from dithio esters and peracids, is thought to proceed via the intermediates shown in equation 102325. 

The direct reaction of [TCO4] in ethanolic solution with dppe and oxalic acid produces the red Tc" complex [Tc(ox)(dppe)2] (552). Attempts to prepare similar complexes with succinic acid, phthalic acid, or salicylic acid failed, or the complexes were stable in solution only. " Similarly, cationic complexes of Tc" are produced by reaction of the versatile precursor [TcO(OH)(dppe)2] (204) with various dithiocarbamates, which produces several complexes of general formula [Tc(dtc)(dppe)2] (553). For this reaction the reductant formamidine sulphinic acid (510) was required in an alkaline solution. The X-ray crystal structure of [Tc(S2CNMe2)(dppe)2] (554) shows a distorted octahedral geometry. Cyclic voltammetry reveals a reversible reduction wave Tc"/Tc couple at —0.53 V, and a reversible oxidation at +0.3 V for the Tc" /Tc" couple. The same compound (554) was also prepared from the thiourea precursor [TcO(tmtu)4] + (91).The reaction of this precursor in dmf in the presence of dppe produced a mixture of brown [TcO(dtc)(tmtu)2] and the Tc" complex (553). The first compound is probably an intermediate... 

Retinol Derivatives. Aryl sulphones have been used in two new syntheses in the vitamin A series. Reaction of /8-cyclocitryl phenyl sulphone (102) with the bromo-compound (103) gives the intermediate sulphone (104), which on base-catalysed elimination affords methyl retinoate (98). Alternatively retinol (99) has been prepared in high yield by condensation of the C15 bromide (105) with the C5 hydroxy-sulphone (106), followed by elimination of sulphinic acid. The syntheses... 

The lower members of the homologous series of 1. Alcohols 2. Aldehydes 3. Ketones 4. Acids 5. Esters 6. Phenols 7. Anhydrides 8. Amines 9. Nitriles 10. Polyhydroxy phenols 1. Polybasic acids and hydro-oxy acids. 2. Glycols, poly-hydric alcohols, polyhydroxy aldehydes and ketones (sugars) 3. Some amides, ammo acids, di-and polyamino compounds, amino alcohols 4. Sulphonic acids 5. Sulphinic acids 6. Salts 1. Acids 2. Phenols 3. Imides 4. Some primary and secondary nitro compounds oximes 5. Mercaptans and thiophenols 6. Sulphonic acids, sulphinic acids, sulphuric acids, and sul-phonamides 7. Some diketones and (3-keto esters 1. Primary amines 2. Secondary aliphatic and aryl-alkyl amines 3. Aliphatic and some aryl-alkyl tertiary amines 4. Hydrazines 1. Unsaturated hydrocarbons 2. Some poly-alkylated aromatic hydrocarbons 3. Alcohols 4. Aldehydes 5. Ketones 6. Esters 7. Anhydrides 8. Ethers and acetals 9. Lactones 10. Acyl halides 1. Saturated aliphatic hydrocarbons Cyclic paraffin hydrocarbons 3. Aromatic hydrocarbons 4. Halogen derivatives of 1, 2 and 3 5. Diaryl ethers 1. Nitro compounds (tertiary) 2. Amides and derivatives of aldehydes and ketones 3. Nitriles 4. Negatively substituted amines 5. Nitroso, azo, hy-drazo, and other intermediate reduction products of nitro com-pounds 6. Sulphones, sul-phonamides of secondary amines, sulphides, sulphates and other Sulphur compounds... 

Polyhydroxy- phenols. amino acids, di- and polyamino compounds, amino alcohols. Sulphonic acids. Sulphinic acids. Salts. sulphinic acids, aminosulphonic acids and sulphonamides. Some diketones and /3-keto esters. Ethers and acetals. Lactones. Acyl halides. Diaryl ethers. intermediate reduction products of nitro compounds. Sulphones, sulphonamides of secondary amines, sulphides, sulphates and other sulphur compounds. 

One special case is that of the reactive intermediates, the sulphenes (252), and the isolable compounds, the sulphines (253). In the first place, cycloadditions of these species... 

Calculations227 indicate thatthese intermediates have very similar HOMO and LUMO energies and that their LUMO coefficients are very similar to each other so we cannot look to these features to explain the striking difference in the reactivity of these two species. The former (252) cannot be isolated when sulphonyl chlorides are treated with base instead the intermediate sulphene (e.g. 254) rapidly dimerizes.228 By contrast, sulphines (e.g. 255 and 256) are an easily isolated class of compound.226,229 The same... 

Thiosulphonate ArS02SAr was supposed to be formed from the disproportionation of the intermediate sulphinic acid. These results were confirmed later by other workers49. 

Scheme 52 outlines a sequence of reaction steps of an unusual nature in which an alka-1,2-dienylphosphonic diester is subjected to initial lithiation followed by silylation at this stage the silylated carbanion 424 may be protonated to yield the [l-(trimethylsilyl)alk-2enyl]phosphonate (425). However, 424 also reacts with SO2 to yield the thienyl-2-phosphonic diester 427 the intermediate in this process has been identified as the sulphine 426 ... 

The synthon (51) is derived from the optically active C22-allenic apocarotenal 49 which is prepared via a Wittig condensation of the Ci5-allenic aldehyde 23b with the Cv-skeleton phosphonium chloride 48 (Scheme 10). The compound 23b (97% e.e.) is synthesized starting from the TMS ether 47 of 36 through intermediates 4 and 31 according to the known route (Scheme 7), with minor modifications. Reduction of the aldehyde group in 49 (a mixture of (IIZ)- and (1 l )-isomers) with NaBH4, followed by acetylation, yields the acetate 50, which is converted into the sulphone 57 by heating under reflux with sodium sulphinate in propan-2-ol and water. 

Other Ligands.—Reactions of platinum(n) complexes PtHX(PR3>2 with azides, which give amido-complexes, may proceed by attack at the co-ordinated hydride. In Friedel-Crafts sulphination of Fe(butadiene)-(CO)s, attack is both at the metal and at the diene ligand, for an X-ray study has revealed that the structure of the intermediate is (49). ... 

Thiols can be oxidised further using more forcing conditions. For example, MBT above with excess H2O2 gives a sulphinic acid, which can eliminate SO2 in acid to give benzothiazole [230]. A reaction analogous to this is used to make clomethiazole, an intermediate in vitamin Bi manufacture [231]. In alkali, sulphinic acids are oxidised further by H2O2 to sulphonic acids [232]. 

Thermolysis of Thiet Dioxides, In the vapour phase at 400 °C or in solution at 220 °C, thiet 1,1-dioxide (80) gave the cyclic sulphinate (81), the intermediate vinylsulphene in this rearrangement (Scheme 12) being... 

Sulphines with electron-withdrawing substituents appeared to be the most reactive dienophiles, and the reaction was found to occur largely stereo-specifically. The methylene-blue-sensitized photo-oxygenation of sulphines resulted in the formation of the corresponding ketone and sulphur dioxide. This reaction was considered to involve singlet oxygen as the reactive species and to proceed via the cyclic intermediate (118), and is... 

A possible route to 2- and 3-t-aminophenothiazines is afforded by the reaction of chloro-lO-alkylphenothiazines with sodium or lithium derivatives of secondary amines. Thus, treatment of 1-chloro- or 2-chloro-lO-methylphenothiazine with sodium amide-morpholine leads to the same product, i.e. 2-morpholino-lO-methylphenothiazine, presumably by way of the same phenothiazyne intermediate (121). 3-Chloro- and 4-chloro-lO-methylphenothiazine react similarly giving, as expected, the same 3-mor-pholino-derivative via an analogous phenothiazyne intermediate. The phenazathionium cation (122), generated oxidatively in situ with ferric chloride, reacts readily with toluene-p-sulphinic acid, nitrite, or thiourea to... 

Reactions of sulphur dioxide with [Fe( -allylX -QH6XCO)2] are known to afford S-bonded sulphinate complexes. It is generally accepted that these reactions proceed via dipolar metal-alkene intermediates, and low-temperature n.m.r. studies have now provided evidence for this reaction intermediate (8). The rates of re-... 

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