Succinic acid
Succinic acid
disodium succinate
Phthalocyanine pigment
Compound dyes
Compound green
Composite blue
Process for the preparation of chiral succinic acid(cas:110-15-6) derivatives
Release time:2016/8/2 16:58:45

Preparation of optically active 1-023-cyclopentyl-2(R)-021(R)-(hydroxycarbamoyl)-2-(3,4,4-trimethyl-2,5- dioxo-1-imidazolidinyl)ethyl05propionylpiperidine of formula (I) comprises reaction of a cyclopentenyl-alkoxycarbonyl-succinic acid(cas:110-15-6) ester of formula (II) with 3-bromomethyl-1,5,5-trimethylhydantoin in the presence of base to give a tricarboxylic acid derivative of formula;

Hydrogenolysis of (III) in the presence of metal catalyst and decarboxylation in the presence of base, to give the succininc acid(cas:110-15-6) compound of formula (IV), and purification of (IV) in the presence of a further, salt-forming, base to give (IV) in the form of its salt; (c) reaction of (IV) with piperidine, under activation of the carboxylic acid, to give the amide of formula (V) (where (V) is either (Va) with R1 = tert. butyl or (Vb) with (R1 not tert. butyl); and either (d) reaction of (Va) with a benzylhydroxylamine hydrochloride (A), where (A) is activated with alkylmagnesium halide, to give 1-022(R)-021(R)-benzyloxycarbamoyl-2-(3,4,4-trimethyl-2,5-dioxo-1-imidaz olidinyl)ethyl05-3-cyclopentyl-propionyl05piperidine (VII), and hydrogenolysis of (VII) to give (I); or (e) removing the tert. butyl ester group of (Va) using mineral acid and carboxylic acid and/or its ester, and optionally removing the alkyl ester R1 group of (Vb) using alkali or alkaline earth hydroxide, to give 1-022(R)-021(R)-carboxy-2-(3,4,4-trimethyl-2,5-dioxo-1-imidazolidinyl)et hyl05-3-cyclopentyl-propionyl05piperidine (VI); and either converting (VI) to (VII) and then to (I) as in (d); or reacting (VI) with trimethylsilyl-hydroxylamine or tetrahydropyranyl-hydroxylamine, and removing the trimethylsilyl or tetrahydropyranyl group by standard methods, to give (I). R1 = methyl, ethyl, propyl, butyl, pentyl, hexyl or tert.-butyl; R2 = a group that can be released by hydrogenolysis. (II)-(VII) are new.

Also new are intermediates for (II), of formula (XII). X = H or SO2R3; R3 = CF3 or phenyl (optionally substituted by NO2 or halo).

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