Sodium hydrosulfite ketones

Garcia et al. has extended the Batcho-Leimgruber procedure to the synthesis of 2-substituted indoles. Treatment of 36 with o-fluorobenzoyl chloride 37, followed by in situ hydrolysis and deformylation gave ketone 38. Reduction of nitroarylketone 38 with sodium hydrosulfite then furnished indole 39. Similarly, bromoacetylation of 36 gave an acylenamine which was converted into the phthalimido derivative 40. Hydrolysis and deformylation gave phthalimidoketone 41 which underwent reductive cyclization to furnish indole 42. 

The mash from the Streptomyces aureofaciens fermentation broth is acidified and filtered. The filtrate is adjusted to the desired pH, usually 7-8.5, and various flocculating or chelating agents may be added (e.g., vinyl acetate-maleic anhydride copolymer, sodium EDTA, ammonium oxalate, Arquad). The precipitate is (1) stirred with filter aid, filtered, stirred with HC1, refiltered, mixed with 2-ethoxyethanol, filtered, washed, and the filtrates are combined, acidified with HC1, NaCl is added, and the crystals are collected, washed with 2-ethoxyethanol, water, and ethanol, and dried (67), or (2) extracted into methyl isobutyl ketone, the extracts are combined, filtered, and acidified with HC1, and the crystals are collected and washed with water, 2-ethoxyethanol, and isopropanol, and vacuum-dried. If the crystals are greenish, they are treated with sodium hydrosulfite at pH 1.8, filtered, washed, and dried as in (1) above (68). 

Use Reduction of various organic compounds purification of aldehydes and ketones, iodine, sodium hydrosulfite antiseptic source of sulfurous acid, particularly in brewing analytical chemistry tanning bleaching straw and textile fibers chemical preservative in foods (except meats and other sources of vitamin B,). 

Dehalogenation of a-halo ketones. a-Halo ketones can be dehalogenated by treatment with pyridine in acetone followed by addition of sodium hydrosulfite yield 50-75%. The method involves formation of a pyridinium salt, which is then reduced in acetic acid to a 1,4-dihydropyridine derivative this fragments spontaneously to the ketone and pyridine. ... 

Although a variety of chemical methods that include reagents such as sodium hydrosulfite (Na2S204), sodium metal (Na) dissolved in liquid ammonia (NHs )) in the presence of an alcohol (which is the ultimate proton donor), and even sodium (Na° and the other alkali metals [Li°, K° and Rb°]) in alcohol (e.g., ethanol, CH3CH2OH) itself have been used over the years to reduce ketones to alcohols (Scheme 9.15). Newer methods appear to be preferred for their selectivity, ease of use, and success in avoiding unwanted side products. 

The first total synthesis of the intricate Stemona alkaloid (+ /—)-isostemofoline (224) was reported by Kende and coworkers 81) starting from 1,2-hexanediol (225) which was straightforwardly converted to 227 (Scheme 22) 82). Reductive cycUzation with sodium hydrosulfite in refluxing aqueous ethanol, and protection of the unstable pyrrole as tert-butyl carbamate, afforded 228 in five steps with 12% overall )deld. The key bicyclic ketone 231 was assembled by [4 + 3] cycloaddition of pyrrole 228 and diazoester 229 promoted by rhodium octanoate dimer, followed by enol silane deprotection, exo-specific hydrogenation, and nucleophilic decarboxylation (47% overall yield). Sodium methoxide-catalyzed aldol condensation of ketone 231 and furfural provided the Q-j/i-unsaturated ketone 232 whose olefin configuration was established by nOe studies. Allylation of 232 provided a 2.4 1 mixture of ketone 234 and the corresponding allylic enol ether 233, which could be converted to the former via a stereoselective Claisen rearrangement. 

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