Sulfinate decomposition

According to Figure 3, hydroperoxides are reduced to alcohols, and the sulfide group is oxidized to protonic and Lewis acids by a series of stoichiometric reactions. The sulfinic acid (21), sulfonic acid (23), sulfur trioxide, and sulfuric acid are capable of catalyzing the decomposition of hydroperoxides to nonradical species. 

The branching of the adduct decomposition was studied by measuring the pKa of the mixtures. Thus for pulse radiolysis of N20-saturated methyl phenyl sulfoxide the results yield a p/Ca obs value of 1.50 while the values for methane sulfinic and benzene sulfinic acids are 2.28 and 1.29, respectively. The fraction of each branch can be calculated from the equation,... 

The H and 13C CIDNP studies have shown that not only the sulfone 14, but also the sulfmic ester 15, is generated as cage products from the phenyl/p-toluenesulfonyl radical pair during the thermal decomposition of phenylazo aryl sulfone (13)54 (Scheme 2). The cross-termination of arenesulfonyl and triethylgermyl radicals was found to occur exclusively via the formation of germyl sulfinate, ArS(0)0GeEt333. 

N, O-Diacylated or O-alkylated N-hydroxysulfonamides release nitroxyl (HNO) upon hydrolysis or metabolic dealkylation, as determined by gas chromatographic identification of nitrous oxide in the reaction headspace [27-29, 38]. Scheme 7.5 depicts the decomposition of a representative compound (7) to a C-acyl nitroso species that hydrolyzes to yield HNO. Either hydrolysis or metabolism removes the O-acyl or O-alkyl group to give an N-hydroxy species that rapidly decomposes to give a sulfinic acid and an acyl nitroso species. This C-acyl nitroso species (8) hydrolyzes to the carboxylic acid and HNO (Scheme 7.5). These compounds demonstrate the ability to relax smooth muscle preparations in vitro and also inhibit aldehyde dehydrogenase, similar to other HNO donors [27, 29]. 

Second, partial decomposition of an aryl thiolsulfinate specifically labeled (35S) at the sulfinyl sulfur indicates (a) some incorporation of label in ArSSAr, which would not be expected if (75) were the only path for formation of disulfide (b) a significantly unequal distribution of label beween the two sulfurs of ArS02SAr [in its simple form (76) predicts both sulfurs should be equally labeled] (c) some incorporation of label into the sulfenyl sulfur of the recovered unreacted thiolsulfinate. The specific reactions responsible for these variations of the 35S-distribution from the pattern predicted by (74)-(76) cannot be pinpointed with certainty, although Koch et al. (1970) considered that a homolytic decomposition (80) of sulfenyl sulfinate [20], competitive with its... 

One of the earliest known reactions of sulfinic acids, and one that is in many instances responsible for their slow decomposition on standing at room temperature, is their disproportionation (106). The mechanism of this reaction has been worked out in detail for aromatic sulfinic acids (Kice et al., 1966a,b,... 

The displacement of both alkoxy groups at sulfur in 239 with predominant inversion of configuration can be explained by the simultaneous formation of two different intermediates (or transition states) 242 and 243, which undergo decomposition before pseudorotation. In this context, it is interesting to note that the formation and decomposition of only one such sulfurane intermediate would give two sulfinate products with inverted and retained configuration at sulfur. 

Also of interest are the cumulative systems of sulfines and of carbon disulfide which react with nitrile oxides to give 5H-1,4,2-oxathiazole S-oxide (220) <77JCS(P1)1468> and 1,4,2-oxathiazol-5-one derivatives (221), respectively <66JOC24l7>. The latter is formed from the primary spiro bis adduct (222) by further decomposition (see also Section 4.14.5.6). 

Flash vacuum pyrolysis (FVP) represents a special method for inducing decomposition of thietane compounds. Block et al. succeeded for the first time in the preparation of methylene sulfine in the gas phase, applying this method to thietane 1-oxide. The reaction starting at 600°C was followed by mass and microwave spectroscopy. 

Pyrazino sulfolenes 495 have been derived from a cycloaddition reaction of intermediate 494 with SO2. This intermediate is produced by the thermal decomposition of the sulfine 493 (Scheme 39) <2000JOC3395>. 

Compound 26, prepared as described in Section 10.09.9.1.2, was shown to undergo the novel hydrolytic decomposition shown in Scheme 5 <2000JHC191>. Treatment with aqueous acid presumably initiates a hydrolysis to give compound 27. Further hydrolysis then results in loss of the glyoxylate fragment to give sulfinic acid 28, self-condensation of which will provide sulfoxide 29. Finally, loss of water will give the observed lOrt-aromatic product 30. 

The crude -acetaminobenzene sulfonyl chloride (p. 3) obtained from 67.5 g. (0.5 mole) of acetanilide is shaken for two hours with a solution of 250 g. (1 mole) of crystallized sodium sulfite (Na2S03 7H2O) in 500 cc. of water. The reaction mixture is kept slightly alkaline by the addition at intervals of small portions of 50 per cent sodium hydroxide solution. The total volume of alkali used varies from 10 to 50 cc. After the alkaline mixture has been shaken for the two-hour period (Note 1) it is filtered, and the filtrate is acidified with 60 per cent sulfuric acid. If the acid is added slowly, the sulfinic acid comes down in fine crystals which after filtering and drying, melt at 1550 with decomposition (Note 2). The yield is 50-55 g. (43-47 per cent of the theoretical amount based on the acetanilide used). 

An indirect strategy consisting of the slow decomposition of sulfines 140 into ketones has been investigated by Metzner409,410 (equation 151). 

A third method of access to sulfines is the oxidation of thiocarbonyl compounds. When the starting material is available it is an attractive route. There has been some dispute in the past whether enethiolisable thiocarbonyl derivatives would lead to the corresponding sulfines or to divinyl disulfides [101, 102]. It is now clear from our research that, even if the C=S molecules bear highly acidic a-protons, oxidation occurs on C=S and does not touch the a-protons. There are many examples of this behaviour. The most easily enethiolised compounds are thioketones. We have shown that their reaction with a peroxycarboxylic acid, mCPBA, is very fast at 0°C and quantitatively provides the corresponding sulfines [103]. In many examples the aliphatic sulfines are not very stable and have to be used in subsequent reactions that will be faster than their decomposition (t1/2 from some hours to days). 

Thiazolyl sulfamic acids, rearrangement of sulfonic acid, 70 rearrangement to sulfonic acid, 75 by sulfonation, 75 2-Thiazolyl sulfenyl chloride, transformation to, thiazolyl disulfides. 412 2-Thiazolyl sulfide, in hydrocarbon synthesis, 406 oxidation of, with m-chloroperbenzoic acid, 415 with CrOj, 415 with Hj02,405,415 with KMn04,415 physical properties, infrared, 405 NMR, 404 pKa, 404 ultraviolet, 404 preparation of, from 2-halothiazoles and 5-Thiazolyl sulfides, bis-5-thiazolyl sulfide, oxidation of, 415 general, 418 5-(2-hydroxythiazolyl)phenyl sulfide case, 418 physical properties, 418 preparation of, 417-418 table of compounds, 493-496 uses of. 442 2-Thiazolyl sulfinic acid, decomposition of, 413 preparation of, from 2-acetamidothiazole sulfonyl chloride, 413 from A-4-thiazoline-2-thione and H, 0, 393,413 table of compounds, 472-473 5-Thiazolyl sulfinic add, preparation of,... 

Moreover the diastereomeric excess can be easily and accurately determined in each case by H NMR analysis of the crude mixtures, because of the differences in chemical shifts of H-l and H-2 in the two diastereomeric sulfinate esters ( Table 21). All of the sulfinate esters obtained up to now are stable and can be stored for several days in the refrigerator without any decomposition. An interesting and common feature of all of these sulfinate esters is the sign of specific rotation (R)-sulfinates are dextrorotatory, while (S)-sulfinates are /evorotatory. 

Other retrocycloadditions may occur in the decomposition of /3-sultines, obtained by reaction of triplet sulfur dioxide with alkenes, to ketones and sulfines (or a carbene and sulfur monoxide) and in the decomposition of 1,2-oxathietane-4-one 2-oxides to carbon dioxide and a sulfine. The mass spectrum of 1,2-oxathietane 2-oxide shows a fragment attributed to sulfine. ... 

These decompositions are rationalized on the basis of expansion of the three-mem-bered episulfone ring to a four-membered cyclic sulfinate or a five-membered... 

The dioxide rearranges to the sulfinate ester and eliminates SO to close the dibenzofuran ring. This mode of decomposition closely parallels the behaviour under electron impact. 

Sulfinic acids are thought to be produced by a side reaction during the homogeneous first-order decomposition of thiosulfonates, and were then postulated to decompose to sulfur dioxide and hydrocarbons by a free radical mechanism . 

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