Hydroxyl reaction with sulfite

The reactions of thionyl chloride with organic compounds having hydroxyl groups are important. Alkyl chlorides, alkyl sulfites, or alkyl chlorosulfites form from its reaction with aUphatic alcohols, depending on reaction conditions, stoichiometry, and the alcohol stmcture ... 

In terms of the reaction catalyzed, molybdopterin-containing enzymes can be divided in two groups those that mediate oxygen atom transfer, such as dimethyl sulfoxide (DMSO) reductase and sulfite oxidase (SO), and those that catalyze hydroxylation reactions of aromatic heterocyclic compounds and aldehydes [116], for instance xanthine oxidoreductase (XOR) and aldehyde oxidoreductase (AOR). However, this functional classification does not coincide with structural properties that suggest that the enzymes should be grouped into five families, whose most representative members are (1) DMSO reductase (2) XOR (3) SO (4) aldehyde-... 

The catalyst can also be sulfated at lower temperature by a complex series of reactions with sulfur dioxide, and the catalyst can contain up to 3% of combined sulfur under normal operating conditions. It has been snggested that sulfur dioxide is strongly chemisorbed by snrface hydroxyl gronps to give a sulfite intermediate. This reacts with sulfur vapor to give a thiosulfate intermediate that reacts, in tnm, with a neighboring hydroxyl to form snlfate. This does not necessarily deactivate the catalyst. 

E. Vedejs (1978) developed a general method for the sterically controlled electrophilic or-hydroxylation of enolates. This uses a bulky molybdenum(VI) peroxide complex, MoO(02)2(HMPTA)(Py), which is rather stable and can be stored below 0 °C. If this peroxide is added to the enolate in THF solution (base e.g. LDA) at low temperatures, oneO—O bond is broken, and a molybdyl ester is formed. Excess peroxide is quenched with sodium sulfite after the reaction has occurred, and the molybdyl ester is cleaved to give the a-hydroxy car-... 

A common reaction sequence is shown in the schemes printed above. The sulfosuccinate monoesters are produced by a two-step reaction. In the first step 1 mol of maleic anhydride is reacted with a hydroxyl group-bearing component. In the second step the monoester is reacted with sodium sulfite (or sodium bisulfite) to form the disodium alkyl sulfosuccinate. At the so-called halfester stage, there are two possibilities for an electrophilic attack [61] (Michael-type reaction) at the double bond (Scheme 6). Reactivity differences between the two vinylic carbons should be very small, so that probably an exclusive formation of one single regioisomer can be excluded. 

The indium-mediated allylation carried out with allylstannanes in combination with indium chloride in aqueous medium was reported by Marshall et al.113 Allylindium was proposed as the reaction intermediate. Various aldehydes can be alkylated very efficiently with 3-bromo-2-chloro-l-propene mediated by indium in water at room temperature. Subsequent treatment of the compound with ozone in methanol followed by workup with sodium sulfite provided the desired hydroxyl ester in high yield.114... 

Direct proof for the existence of O-glycosidic linkages involving the hydroxyl groups of serine and threonine was provided simultaneously from three laboratories. Anderson et al. (39) reported partial losses of serine and threonine after treatment with 0.52V NaOH (or 0.452V KOH) at 4°C or room temperature for about 20 hours. Subsequent reduction with platinum showed formation of some alanine and < -aminobutyric acid. Harbon et al (40) treated ovine submaxillary glycoprotein at pH 12.8 for 45 minutes at 70 °C. The serine and threonine content decreased by 78 and 60%, respectively. Treatment of this product with 0.1M sulfite, (pH 9, 24 hours, room temperature) caused a conversion of the dehydroserine residues to cysteic acid, but had no action on the dehydrothreonine residues. This reaction has been further studied by Simpson et al. (41). 

It is not possible to dissolve the asphaltenes in water by treatment of the halo derivatives with aqueous sodium hydroxide or with aqueous sodium sulfite (II). The hydrolyzed products remained insoluble even in a strongly alkaline solution. The decreased (H + Cl)/C ratios and the increased O/C ratios of the products relative to those of the parent halo-asphaltenes indicate that partial reaction occurs. The infrared spectra of the products showed a broad band centered at 3450 cm 1, a region assigned to the presence of hydroxyl groups in the products, but it was not possible to establish conclusively the presence of sulfonic acid group(s) in the product from the sodium sulfite reaction by assignment of infrared absorption bands to this particular group. 

The furo[2,3-fusion process without a catalyst gave the glycoside (25) in 93% yield. Addition of water to the reaction mixture yields glycosides which are unprotected at the C-2 hydroxyl group <88CAR(180)233>. 

Neutral and Alkaline Sulfite Pulping In neutral sulfite pulping the most important reactions of lignin are restricted to phenolic lignin units only. The first stage always proceeds via the formation of a quinone methide with simultaneous cleavage of an a-hydroxyl or an a-ether group (Fig. 7-12). At least in noncyclic structures, the quinone methide is readily attacked by a... 

The carbon atoms in cyclic sulfates and sulfites are highly reactive towards nucleophilic reagents [50], which allows us to use such functionalities as the epoxide substitutes in many reactions. The 3,5-sulfites having the neighboring free hydroxyl group were used for preparation of anhydronucleosides. Thus, D-xy/o-furanoside nucleoside 66 reacted with SOCI2 in p)Tidine to afford the cyclic sulfite 67, which upon treatment with sodium bicarbonate furnished the 2,3-anhydro-nucleoside 68 (O Scheme 21). 

M-dihydroxybenzene or resorcinol forms white crystals, which become pink on exposure to light. It has a m.p. of 110°C and a b.p. of 276.5°C. Being a skin irritant, when absorbed through skin may cause toxic effects. It is chemically very reactive due to the reinforcing influence of the two hydroxyl groups— this explains many reactions such as easy ammination with aqueous ammonia at 200° C to m-amino phenol and with ammoniacal ammonium sulfite solution to m-phenylenediamine... 

The Diels-Alder reaction was utilized to construct bicyclo [2.2 1]heptane or bicyclo[2 2 l]heptene structures The reaction of isopropylidenecyclopentadiene with maleic anhydride produced the endo and exo configurational isomers of 8-isopropylidenebicyclo[2.2.1] hept-2-ene-5,6-dicarboxylic anhydride Similar reactions were applied to unsubstituted and l-(methoxycarbonyl)cyclopentadienes to give the corresponding anhydrides The anhydrides were reduced to alcohols, which were then allowed to react with thionyl chloride or tosyl chloride to give cyclic sulfites or tosylates Reaction of the tosylates with lithium chloride gave chlorinated compounds Hydration of the double bonds of the chlorinated compounds was accomplished by hydroboration-oxidation Diol 31 thus obtained was converted to 5,6-bis(chloromethyl)-7-isopropylidene-bicyclo[2 2 1] heptan-2-one [33] by chromium trioxide oxidation of the secondary hydroxyl group followed by dehydration at the C-7 substituent. 

Prolonged exposure to light, or failure to control exothermic reactions in prior steps, results in a sticky product which smells of pyridine. No method for purifying partly decomposed MoOPH has been found, and "sticky" product should not be used for enolate hydroxyl ation. Suspect material can be decomposed by stirring with aqueous sodium sulfite (Na2S03) solution. 

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