Acetyl hypoiodite, oxidation

The synthesis of the four monocarboxylic acids of dibenzothiophene has been recorded in the previous review. However, several modified preparations have since been described. Ethyl 1-dibenzothiophene-carboxylate has been synthesized from 2-allylbenzo[6]thiophene (Section IV,B, 1) hydrolysis afforded the 1-acid (57% overall). In a similar manner, 3-methyl-1-dibenzothiophenecarboxylic acid was obtained from the appropriately substituted allyl compound. This method is now the preferred way of introducing a carbon-containing substituent into the 1-position of dibenzothiophene. 2-Dibenzothiophenecarboxylic acid has been prepared by oxidation of the corresponding aldehyde or by sodium hypoiodite oxidation of the corresponding acetyl compound. Reaction of 2-acetyldibenzothiophene with anhydrous pyridine and iodine yields the acetyl pyridinium salt (132) (92%), hydrolysis of which yields the 2-acid (85%). The same sequence has been carried out on 2-acetyldibenzothiophene 5,5-dioxide. The most efficient method of preparing the 2-acid is via carbonation of 2-lithio-... 

Rather rare examples of the oxidation of tertiary alcohols are the degradation of 3-ethyl-3-pentanol to 3-pentanone and iodoethane in respective yields of 90 and 84% by acetyl hypoiodite in acetic acid and chlorobenzene under irradiation for 1 h at 20-25 °C [780 and the conversion of trflnj-9,10-dihydroxy-l,4,5,8,9,10-hexahydronaphthalene into 3,8-cyclodecadiene-l,6-dione and its tetramethylacetal by lead tetraacetate (equation 274) [447. ... 

Oxidation of acetyl- and acetylnitro-substituted thienothiophenes 1 and 2 with ferricyanide or hypoiodite to the corresponding acids was used primarily to confirm the site of electrophilic substitution at position 2 in the thienothiophenes. " Permanganate degrades the thieno[3,2-A]-thiophene (2) ring system, while potassium hypobromite produced bromo derivatives of thieno[2,3-6]thiophene-2-carboxylic acid. ... 

On oxidation (with hypoiodite) to the corresponding aldonic acid, of the disaccharide obtained by partial hydrolysis of chitin, and acetylation with sodium acetate in acetic anhydride, the product undergoes /3-elimination, to give the bionic acid derivative 2-acetamido-4-0-(2-acetamido-tri-0-acetyl-2-deoxy- -D-glucopyranosyl)-6-0-acetyl-2,3-dideoxy-D-erj/(firo-hex-2-enono-1,5-lactone (90). In the original work, the determination of the site... 

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