Bisulfite adducts oxidation

The principal additive shrink-resist treatment uses the polymer Synthappret BAP (Bayer AG) which is a polypropylene oxide polyurethane containing reactive carbamoyl sulfonates (or isocyanate bisulfite adduct groups, —NHCOSO —Na" ). An aqueous solution of this polymer is padded onto woven fabrics, which are immediately dried. Other polymers may be appHed at the same time to modify the handle. 

Some internal oxidation-reduction reactions have been reported with the bisulfite adducts of naphtho[l,2-c]furoxan " and some... 

RCH(NH2)COOH - RCHO. Tryptophane is oxidized to indole-3-acetalde-hyde by Chlorox in C6H6 at 50-55°. The crude aldehyde thus obtained (33-60% yield) is purified via a bisulfite adduct. The overall yield of pure product is 60%. Careful control of the pH to > 7.7 is essential since the substrate is unstable to base. 

Tertiary alcohols are oxidized in water-dioxane-NaOH to alkoxy radicals, wliich fragmentate to ketone and alkyl radicals R- (Eq. (216) ). The relative rate of cleavage decreases with R in the order sec -butyl > isopropyl > ethyl > propyl > pentyl > isobutyl > methyl 46 8). Likewise, the bisulfite adduct of cyclohexanone is converted in 20% yield to 4-hydroxyhexanoic acid lactone (160) and 3-hydroxycyclohexanoic acid lactone (161) by anodic fragmentation (Eq. (222) ) 469 ... 

Aldehyde bisulfite adducts are oxidized by dimethyl sulfoxide/acetic anhydride and converted to simple amides in good yield. ... 

Surprisingly, this TEMPO-mediated oxidation process, followed by the formation of the crystalline sodium bisulfite adduct scaled up in the pilot plant (100 L and 600 L) afforded the sodium bisulfite adduct with variable yields (48% and 71%). Careful investigation of what happened during the pilot-plant synthesis reveals that the lower yield was linked to the contact time between the... 

An attractive variant is to utilise certain products of reversible addition to 3//-indolium cations, such as the the indole bisulfite adduct (section 17.1.1), or where there has been an intramolecular nucleophilic addition such compounds, though they are indolines, are still at the oxidation level of indoles, needing only mild acid treatment to regenerate the aromatic system. ... 

Wuts, P. G. M. Bergh, C. L. The Oxidation of Aldehyde Bisulfite Adducts to Carboxylic Acids and their Derivatives with Dimethyl... 

The coupling of allgrl halides with Cu(i) nucleophiles has proved to be a powerful method, enabling both Csp -Csp and Csp -Csp disconnections. Such a strategy was demonstrated in a 2001 publication from Abbott Laboratories (Scheme 11.63). °° Use of a Cu(i)-catalysed Grignard alleviation allowed the use of readily available starting materials and enabled the synthesis of a key y-arylbutanal (isolated as its sodium bisulfite adduct 51) in only two steps. In contrast, alternative routes exemplified in the literature required multiple steps for C-C bond construction and oxidation state adjustment. 

Bisulfite adducts of aldehydes, RCH(0H)S03Na, are conveniently oxidized to car-boxyUc acid derivatives by treatment with a mixture of dimethylsuUbxide and acetic anhydride [241]. The important intermediate in this reaction is an a-ketosuUbnate. Its sulfonate fragment can easily be displaced by nucleophiles such as water, alcohol or amine, giving the corresponding acids, esters, or amides, respectively. 

The action of sulfur nucleophiles like sodium bisulfite and thiophenols causes even pteridines that are unreactive towards water or alcohols to undergo covalent addition reactions. Thus, pteridin-7-one smoothly adds the named S-nucleophiles in a 1 1 ratio to C-6 (65JCS6930). Similarly, pteridin-4-one (73) yields adducts (74) in a 2 1 ratio at C-6 and C-7 exclusively (equation 14), as do 4-aminopteridine and lumazine with sodium bisulfite. Xanthopterin forms a 7,8-adduct and 7,8-dihydropterin can easily be converted to sodium 5,6,7,8-tetrahydropterin-6-sulfonate (66JCS(C)285), which leads to pterin-6-sulfonic acid on oxidation (59HCA1854). 

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