New phenyl-carboxyl compounds useful in the preparation of 6-halo-3,4-dihydroxy-L-phenylalanine

摘要

Phenyl-carboxyl compounds (I), are new. Phenyl-carboxyl compounds of formula (I), are new. R1>optionally substituted 3-6C alkyl (preferably tert-butyl); R2>alkyloxycarbonyl, formyl, alkylcarbonyl, optionally substituted trityl, phenyl or diphenylene, where the alkyl group is optionally substituted by 1-6C alkyl, preferably tert-butyloxycarbonyl; R3>, R4>alkyloxycarbonyl, alkyloxymethyl or alkyloxyethyl, where the alkyl group is optionally substituted by 1-6C alkyl, optionally substituted 3-8C cycloalkyl, optionally substituted 3-8C cycloalkenyl, tetrahydrofuranyl or tetrahydropyranyl, preferably tert-butyloxycarbonyl; and R5>optionally substituted 1-6C alkyl, preferably butyl. Independent claims are included for: (1) the preparation of (I); and (2) use of (I) for the preparation of a phenyl-halogen compound of formula (IIa), by reacting (I) with X-containing compound and subsequently with an optionally substituted 1-6C alkylcarboxylic acid or a mixture containing an unsubstituted 1-6C alkylcarboxylic acid. X : F, 1>8>F, I, I-123, I-125 or I-131. [Image] [Image].