Rongalite

Sodium formaldehyde sulfoxylate dihydrate (sodium hydroxymethylsulHnate, Rongalite)... 

In the presence of sodium bicarbonate, sodium formaldehyde sulfoxylate (Rongalite) converts perfluoroalkyl iodides and bromides to the corresponding carboxylates Less decarboxylation to the monohydroperfluoroalkanes occurs when the bromides are used [16] (equation 17)... 

Direct perfluoroalkylation of heteroaromatics occurs with RFI when sodium hydroxymethane sulfinate (Rongalite) is present. 3-Perfluoroal-kylcoumarins can be obtained (90CC1781). The distribution of isomers from substituted pyridines is compatible with a radical reaction (90TL2711). 

The electrophilic character of sulfur dioxide does not only enable addition to reactive nucleophiles, but also to electrons forming sulfur dioxide radical anions which possess the requirements of a captodative" stabilization (equation 83). This electron transfer occurs electrochemically or chemically under Leuckart-Wallach conditions (formic acid/tertiary amine - , by reduction of sulfur dioxide with l-benzyl-1,4-dihydronicotinamide or with Rongalite The radical anion behaves as an efficient nucleophile and affords the generation of sulfones with alkyl halides " and Michael-acceptor olefins (equations 84 and 85). 

Dibenzyl telluride (typical procedure) Rongalite (18.0 g, 0.5 mol) is added under N2 at 80°C to a suspension of Te (2.56 g, 20 mmol) in a solution of NaOH (12 g, 0.3 mol) in 125 mL of H2O. After stirring for 1 h, a solution of benzyl chloride (1.26 g, 10 mmol) in a small volume of EtOH is added dropwise at room temperature to the almost colourless telluride solution. After stirring for an additional hour, the mixture is extracted with ether, and the ethereal solution dried (MgS04) and evaporated. The residue is recrystalUzed from petroleum ether (40-60°C) under red light, giving the telluride as yellow needles (1.09 g (70%) m.p. 49-57°C). 

Cyclic tellurides, including some with a steroidal structure, - have been prepared by the Rongalite method. 

The Rongalite method (see Section 3.1.1.1b,i) can be successfully applied to the preparation of diaryl tellurides from aryl iodides. This method seems to be advantageous compared to the preceding one because of the higher yields and milder experimental conditions. 

Some concurrent reactions sometimes observed in the above methods (dehydrohalo-genation with the tellurium/Rongalite method and formation of tellurocarbamates RTeC(0)NMe2 with the tellurium/NaH/DMF method) that decrease the yields of the desired tellurides can be avoided by a modified procedure, where sodium telluride is generated by heating elemental tellurium and NaH in NMP. The deep purple solution of the reagent prepared under these conditions can be stored for many days (in contrast to the use... 

Under aqueous conditions (Na2Te/Rongalite method) no reduction occurs, the thioke-tone being converted into the ketone. ... 

Epoxides bearing a leaving group in a suitable position, such as chloromethyl epoxides, react with sodium telluride (prepared by the Rongalite method), giving allyhc alcohols. ... 

Methods and Since elemental tellurium is separated during the reaction, the debromination can be performed using only catalytic amounts of tellurium, the reagent being continuously regenerated at the expense of excess Rongalite (method E) and (Et0)2P(0)Na (method E). 

Alkyl aryl sulphones (typical procedure). Method A. A solution of NajTe (prepared by heating a mixture of Te (0.13 g, 1 mmol), Rongalite (0.79 g, 5 mmol) and aqueous 1 M NaOH (15 mL)) is added dropwise to a stirred solution of TsCl (1 mmol) and BzEtjN+CF (0.022 g, 0.1 mmol) in THF (10 mL) at room temperature under Nj. An instantaneous reaction occurs and the colour of the mixture changes to deep black. After stirring for 5 min. 

The reducing agent e.g. sodium formaldehyde sulfoxylate (Rongalite, C, BASF) must be selected in accordance with the legislation of the corresponding country. 

Various hyposulphite compounds are used for industrial purposes including stable aldehyde compounds. Of these the formaldehyde compound (Formosul) is tie most important, since it is the reducing agent almost universally employed in applying vat dyes by printing methods to textile materials. The less stable sodium hydrosulphite is used in dyeing with vat dyes. Stable zinc compounds (Rongalite) are also on the market. 

Hydrosulphite B 50 grams of hydrosulphite N F cone, or of hyral-dite C extra or of rongalite C are dissolved in 500 c.c. of water and the solution then acidified with 2 c.c. of acetic acid. 

A selection of the results obtained 29) for the emulsion copolymerization of 1 with styrene at 10 °C using sodium lauryl sulphate as emulsifying agent and Rongalit / H202/Fe2+ as initiator are given in Table 3.4. 

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