Sulfinyl acetic acid

Fig.l Frequency of detection of herbicides (red bars) and their transformation products (blue bars) in samples collected from 51 US Midwestern streams during late spring runoff (A) and harvest season runoff (B) [34]. ESA - ethane sulfonic acid OXA - oxanilic acid SAA - sulfinyl acetic acid... 

The Pummerer rearrangement was reported by Rudolf Pummerer in 1909 when he published a paper in Chemische Berichte. Earlier in the same year, Smythe had reported the reaction of dibenzyl sulfoxide 3 with acetic anhydride and hydrochloric acid to give benzaldehyde 4 and thioacetal 5, among other products. Smythe was apparently unable to explain the product distribution, which was then left to Pummerer do so in his much-cited paper later that year. Pummerer published the reaction of sulfinyl acetic acid 6 with hydrochloric acid to give glyoxylic acid 7. The formal oxidation of the... 

Among the oxyacids of sulfur the predilection to form an anhydride with a sulfur-sulfur bond, rather than one with an oxygen bridge between the two sulfurs, is not restricted to sulfenic acids. We will see in a subsequent section that sulfinic acids also do this. Their anhydrides have the sulfinyl sulfone structure. RS(0)S02R, rather than RS(0)0S(0)R. What is unique about the sulfenic acid-thiolsulfinate system, however, is the fact that the anhydride (thiolsulfinate) is strongly preferred thermodynamically over the acid at equilibrium. With any other type of common acid the reverse is true, of course. The uniqueness of the sulfenic acid-thiolsulfinate situation can perhaps best be appreciated by realizing that, if the same stability relationship between acid and anhydride were to exist for carboxylic acids, acetic acid would spontaneously dehydrate to acetic anhydride ... 

Equilibrium constants for sulfinyl sulfone formation from aromatic sulfinic acids at 21 °C in acetic acid containing 1 to 5% H20 ... 

In (65) only electrophilic catalysis of the scission of the S-S bond is involved, a situation also encountered in the acid-catalyzed hydrolysis in weekly nucleophilic media (acetic acid-1% water) of certain aryl sulfinyl sulfones substituted with electron-donating substituents (66)164, viz. 

Sulfoxides and sulfones can be prepared on cross-linked polystyrene by oxidation of thioethers. The most commonly used reagent for this purpose is MCPBA in DCM [8,12,32,57,80-82] or dioxane [50,83] (Table 8.6), but other oxidants such as H2O2 in acetic acid [34], oxone (Entry 7, Table 8.6), or oxaziridines [84] have also been used. PEG-bound thioethers have been converted into sulfones by oxidation with MCPBA in DCM [52,54] or with Os04/NMO [85], The oxidation of thioethers to sulfoxides requires careful control of the reaction conditions to prevent the formation of sulfones. Sulfones have also been prepared by S-alkylation of polystyrene-bound sulfi-nates (Entries 8 and 9, Table 8.6), by a-alkylation of sulfones (BuLi, THF, alkyl halide [86]), and by addition of sulfinyl radicals to resin-bound alkenes or alkynes (Entry 11, Table 8.6). 

Sulfinyl chlorides.1 These reagents are generally prepared by reaction of sulfinic acids with thionyl chloride. They can be prepared more conveniently by reaction of the readily available disulfides in acetic acid with sulfuryl chloride yields are nearly quantitative. 

The 3-(benzhydrylthio)acethylhydroxamic acid, dissolved in anhydrous CH3COOH, is reacted with H202. The mixture is left at 40°-45°C for about 1.5 h, the acetic acid is evaporated and the residue is taken up in 50 ml of ethyl acetate the 2-[(diphenylmethyl)sulfinyl]-N-hydroxyacetamide (CRL 40028) crystallises (recrystallised from isopropanol). 

Kinetic Order of the Reaction. The decomposition of the hydroperoxide had an initial slow reaction or induction period followed by a faster main reaction. The induction period was unaffected by the addition of dilauryl sulfinyl dipropionate or by carrying out the reaction in an atmosphere of nitrogen but was eliminated by the addition of acetic acid. The length of the induction period decreased as the initial concentration of both hydroperoxide or sulfur compound increased. 

Amidine 79 reacts with /V-sulfinyl p-toluenesulfonamide (80) to give 81 in 94% yield. Subsequent acid hydrolysis in refluxing acetic acid gave the benzothiadizine 82.48... 

The stereochemistry of oxidation of 3-substituted thietanes has been discussed. Both thermodynamic and kinetic determination of products are observed. For example, oxidation of 3-t-butylthietane with dinitrogen tetroxide gives a cis trans ratio of 82 18 (the cis isomer is more thermodynamically stable than the trans, provided the sulfinyl oxygen prefers an equatorial configuration) whereas oxidation with hydrogen peroxide-acetic acid gives a cis trans ratio of 43 57. ... 

The chlorination of an alkyl 2,4-dinitrobenzenesulfenate (180) in acetic acid leads to an intimate sulfoxonium ion pair (181) which may lose a sulfinyl chloride fragment before or after solvation174 177. The chloride-acetate ratio decreases sharply in the presence of added lithium perchlorate, a manifestation of a special salt effect. Since... 

SoUadid has introduced a-sulfinyl acetates as reagents for asymmetric aldol reactions.Compound (211) is prepared in good optical purity from the menthyl ester of p-tolylsulfinic acid. The magnesium enolate of (211), prepared by reaction of the sulfrnyl ester with r-butylmagnesium bromide, reacts with aldehydes and ketones to give diastereomeric mixtures of a-sulfinyl-3-hydroxy esters (Scheme 13). No... 

A simple method of preparing sulfinic esters consists of oxidative chlorination of aliphatic thiols, thiophenols, or disulfides with chlorine in glacial acetic acid, followed by alcoholysis of the resulting sulfinyl chlorides 626... 

Benzo[2,l-c 3,4-c ]bisisothiazole (495), benzol[l,2-c 3,4-c ]bisisothiazole (496), and benzo[l,2-c 4,3-c ]bisisothiazole (497) have been prepared from easily available dimethylanilines as depicted in Scheme 38. The 2,5-dimethyl-aniline (490) was easily cyclized to the benzisothiazole (493) which upon nitration with a mixture of nitric and sulfuric acids and further reduction with iron and dilute acetic acid, yielded the aminobenzisothiazole (494). Treatment of (494) with IV-sulfinyl-methanesulfonamide afforded the benzo[2,l-c 3,4-c ]bisisothiazole (495). Analogously, (496) and (497) have been prepared from 2,4-dimethylaniline (491) and l,4-diamino-2,3-dimethylbenzene (492), respectively <80JHC533>. 

When the use of nucleophiles other than water in the presence of terminal alkenes under Pd(II) catalysis Wacker-type products frequently predominate. Use of White s electrophilic ftts-sulfinyl Pd(ll) acetate catalyst with terminal alkenes in the presence of acetic acid enabled the preparation of terminal acetoxylated olefins via allylic C—H oxidation and subsequent regioselective nucleophilic trapping of a Pd 7i-allyl complex (Table 3.3). The substrates screened afforded the desired end products with high levels of fi-selectivity and in moderate yields with excellent linear branched ratios. Recent updates to this method include the use of A-tosylcarbamates as nucleophiles. ... 

---