Manske modification

The Manske Modification Using hydrazine to release the primary amine. 

A commonly used modification of the Gabriel synthesis is the Ing-Manske procedure.10 Instead of removal of the phthaloyl group with aqueous base or acid, the Ing-Manske modification utilizes hydrazinolysis. It has been used in the synthesis of optically active a-amino acids 17, as illustrated by Guifa and Lingchong.11... 

As well as amines, the Ing-Manske modification has also been used to synthesise O-substituted hydroxy lam ines, for example, 20.12 The hydroxyamines thus obtained were subsequently condensed with steroids to form O-alkyloximes. 

B. Gabriel Condensation and Ing-Manske Modification 13-S. Preparation of a, Diaminoadipic Add... 

For the sake of applicability, the preparation of a,(5-diaminoadipic acid using the Ing-Manske modification is given here, although the same reference indicates that, at least in this case, the Gabriel condensation and hydrolysis affords a higher yield. 

Gabriel condensation, 124-126 Ing-Manske modification, 124-126 Gattermann condensation, 50 Goldberg reaction, 93 Grignard coupling, 14-15,17 Grignatd method, 54-56 Grignard reaction, 31,50, 59,94,176,187, 246-248... 

The alcohol must be perfectly dry. Any water present causes immediate saponification of the ester with a consequent loss of yield. An excellent method for preparing really anhydrous alcohol is that of Smith (J. Chera. Soc. ig27, 1288), or the modification proposed by Manske (J. Am. Chem. Soc. 53, 1106... 

This procedure is a modification of the method described by Manske and coworkers.4 Syringic aldehyde has also been obtained by numerous other procedures from pyrogallol-1,3-dimethyl ether M.v,a and from gallic acid.9 1CU1... 

Another method for the preparation of primary amines involves the alkylation of potassium phthalimide according to procedures of Gabriel to give A-alkylphthalimides, which, on hydrolysis, afford the primary amine and phthalic acid. Since the hydrolysis is sometimes difficult, Ing and Manske [18] developed a modification in which the decomposition of the A-alkylphthalimide is carried out in the presence... 

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