1998 carboxylic acid esters

carboxylic acid esters (benzene compounds)Q 0530

35 - 136Esters of Sterically Hindered Carboxylic Acids. — The synthesisof hardly accessible esters of sterically hindered aromatic acids is presented.Reaction of primary aliphatic nitramines (II) with sodium nitrite generatesthe corresponding carbenium ions which are able to attack the carboxylicoxygen to form the ester bond. A similar reaction proceeds in the presenceof trifluoroborane etherate. This method is not suitable for the introductionof a trinitroethoxy group due to the fast decomposition of the correspondingcation. However, use of trinitroethyl sulfuric acid (VI) as esterification agentprovides access to the target trinitroethyl esters of aromatic carboxylic andpolycarboxylic acids [cf. (IX), (XI)]. — (BAGAL, M. L.; ISHCHENKO, M. A.;NIKOLAEV, V. D.; Zh. Org. Khim. 33 (1997) 12, 1814-1822; St. Peterburgskiigos. tekhnol. inst., St. Petersburg 198013, Russia; RU)

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1998 carboxylic acid esters

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