Alcohols barium manganate

By Oxidation of Alcohols.—Barium manganate is readily available and stable, and has been recommended for the oxidation of primary and secondary alcohols to aldehydes and ketones respectively. Chromic acid adsorbed on to silica geP and the recyclable poly[vinyl(pyridinium chromate)] effect the same changes, while acid-stable primary and secondary alcohols are oxidized rapidly using potassium dichromate, sulphuric acid, methylene chloride, and a phase-transfer catalyst." Benzeneseleninic anhydride is an alternative reagent for the oxidation of alcohols under essentially neutral conditions. ... 

Barium manganate (BaMn04) was a little known oxidant in organic synthesis till Firouzabadi et al. published in 1978 83 two foundational papers76 showing that it behaves against alcohols in a similar way as active MnC>2. 

Benzylic and Propargylic Alcohols in Presence of Saturated Alcohols, using Barium Manganate (BaMn04)... 

A suspension of ca. 5 20 equivalents—typically 10 equivalents—of dry powdered barium manganate (BaMn04, MW = 256.28) in a ca. 0.02-0.08 M solution of the alcohol in dry CH2Cl2,a is stirred at room temperature1 under an inert atmosphere till most of the starting compound is consumed.0... 

Keywords allylic alcohol, manganese dioxide, barium manganate, aldehyde, ketone... 

Barium manganate, BaMn04, is commercially available. The dark-blue crystals are obtained from aqueous solutions of barium chloride and potassium permanganate [552, 555]. It oxidizes alcohols, especially benzylic alcohols, to carbonyl compounds [552, 555] hydroquinone to quinone [555] benzylamines to benzaldehydes [555] aromatic amines to azo compounds [555] and phosphines to phosphine oxides [555],... 

The oxidation of diols having alcoholic groups of the same nature, for example, both alcoholic groups are primary, secondary, allylic, or benzylic, is usually carried out at both groups to yield dialdehydes [832] or diketones [552], Such reactions are achieved by chromium trioxide [582], barium manganate [832], dimethyl sulfoxide activated with acetic anhydride [1013], and others (equations 284 and 285). 

A second total synthesis of ascididemin (323) was achieved by Moody et al. in 1990 in two steps starting from l,10-phenanthroline-5,6-quinone (331) (Scheme 38) (155,156). The quinoneimine 333 was first prepared by reaction between the quinone 331 and the sodium salt of diethyl N-(2-iodophenyl)-phosphoramidate (332). Photocyclization of 333 in cone, sulfuric acid gave ascididemin (323). Because of the low yield of especially the first step, 10%, preparation of 333 was carried out via a different route in two steps. The reaction of epoxide 334 with 2-iodoaniline 335 gave the amino alcohol 336, which was readily oxidized with barium manganate to the desired intermediate 333. 

New dry media reagents have been introduced Ferric chloride adsorbed on silica gel, an easily controllable multipurpose reagent, has been used for high yield selective dehydration of alcohols and basic silica gel for the conversion of aliphatic nitro into oxo compounds (modified Nef reaction) Barium manganate has been recommended as an oxidant for alcohols high yields of oxo compounds, e.g. o-dial-... 

The readily available and stable compound barium manganate has been shown to be an efficient oxidizing agent for the oxidation of primary and secondary alcohols to carbonyl compounds. It has similar activity to manganese dioxide but is claimed to be better for the preparation of certain aldehydes e.g. the furan aldehyde (11) is produced in 80% yield whereas with Mn02 the yield is less than 20%. 

---