25844-13-7Relevant academic research and scientific papers
O-Methylarenehydroxamates as Ortho-Lithiation Directing Groups. Ti(III)-Mediated Conversion of O-Methyl Hydroxamates to Primary Amides
Fisher, Lawrence E.,Caroon, Joan M.,Jahangir,Stabler, S. Russell,Lundberg, Scott,Muchowski, Joseph M.
, p. 3643 - 3647 (2007/10/02)
Reaction of O-methyl benzohydroxamates 2a-c with sec-butyllithium in the presence of TMEDA at -40 deg C regiospecifically generates the highly reactive N,ortho-dilithiated species (e.g. 3).These dilithio species react avidly with a wide spectrum of electrophilic reagents, including alkyl halides, givind adducts which on reduction with TiCl3 are converted into ortho-substituted primary benzamides in excellent yields.Ortho lithiation of O-methyl benzohydroxamates is thus formally equivalent to ortho lithiation of primary benzamides themselves.The utility of these synthetic operations is enhanced by the well-known facility with wich the primary amide moiety can be transformed into other useful functional groups.The conversion of O-methyl hydroxamates to primary amides is shown to be general, as exemplified by transformation of 14a-f to 15a-f.O-Methyl-2-methylbenzohydroxamate (4a) undergoes regiospecific dilithiation on nitrogen and on the methyl group when treated with sec-butyllithium at -70 deg C.These dilithio species react with DMF or "Weinreb-type" amides to give condensation products wich cyclize to N-methoxyisoquinolin-1(2H)-ones under mildly acidic conditions.Removal of the N-methoxy moiety under conditions analogous to those used for O-methyl benzohydroxamate provides N-unsubstituted isoquinolin-1(2H)-ones with high overall efficiency.This process is exemplified by the synthesis of isoquinolin-1(2H)-one 9a, its 3-n-butyl congener 9b, and the tricyclic isoquinolin-1(2H)-ones 20a and 20b from O-methyl 2-methylbenzohydroxamate (4a).
Preparation of carboxylic acids from salts of nitroketones
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, (2008/06/13)
A method of preparing carboxylic acids is provided by contacting an ammonium, Group IA or Group IIA metal salt of a nitroketone in an aqueous medium. The method is preferably undertaken in the presence of an acidic mineral acid salt.
