Calcium hypochlorite secondary alcohols

During the course of a kinetic study on the oxidation of tnuu-stilbene with peroxyphosi oric acid (HsPOs), Ogata and coworkers observed the unexpected oxidation of the reaction solvent tetrahydrofuran to y-butyrolactone. However, although n-butyl ether was also oxidized by this reagent, tetrahydropy-ran and dioxane were apparently inert. Ethers undergo oxidation on treatment with 4-nitroperbenzoic acid in chloroform. Moderate yields of esters and lactones are obtained when simple ethers are treated with calcium hypochlorite. 7 At room temperature, reaction times of 4-16 h are necessary. However, primary and secondary alcohols are readily oxidized under these conditions. 

Hypochlorites are very good oxidizers of alcohols and are frequently selective enough to oxidize secondary alcohols in preference to primary alcohols see equations 288-291). Solutions of sodium hypochlorite in acetic acid react exothermically with secondary alcohols within minutes [693]. Calcium hypochlorite in the presence of an ion exchanger (IRA 900) oxidizes secondary alcohols at room temperature in yields of 60-98% [76 5]. Tetrabutylammonium hypochlorite, prepared in situ from 10% aqueous sodium hypochlorite and a 5% dichloromethane solution of tetrabutylammonium bisulfate, oxidizes 9-fluorenol to fluorenone in 92% yield and benzhydrol to benzophenone in 82% yield at room temperature in 35 and 150 min, respectively [692]. Cyclohexanol is oxidized to cyclohexanone by teit-butyl hypochlorite in carbon tetrachloride in the presence of pyridine. The exothermic reaction must be carried out with due precautions [709]. 

In the experiments that follow, several representative oxidations of alcohols using hypochlorous acid will be performed. In the first experiment, cyclodode-canol (1), a secondary alcohol, is oxidized to cyclododecanone (2) using sodium hypochlorite or commercial household bleach (Eq. 16.20). In the second experiment, 4-chlorobenzyl alcohol (3) is oxidized directly to 4-chlorobenzoic acid (4) using calcium hypochlorite (Eq. 16.21). 

Spot test This test has been used universally as rapid, nrm-specific means for detecting the presence of certain unspecified lichen substances. This test is most convenient and simple to perform, even under field conditimis. However, this is only a preliminary step in the process of identification of lichens or its substances. In order to identify accurately the secondary metabolite present in the lichen thaUus, one has to perform more sensitive test such as TLC or HPLC. Spot test is carried out by placing a small drop of reagent on the lichen thallus, either directly on the upper surface (cortex) or on the medulla. In the later case, the cortex is scraped or superficially cut with the help of a blade. The reagents used are 10 % aqueous KOH solution (K), saturated aqueous solution of bleaching powder (NaOCla) or calcium hypochlorite (Ca(OCl)2) (called as Q and 5 % alcoholic... 

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