105526-85-0Relevant articles and documents
Novel Compounds 002
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Page/Page column 98, (2009/04/24)
Compounds of Formulae I, or pharmaceutically acceptable salts thereof: wherein R1, R2 and Y are as defined in the specification as well as salts and pharmaceutical compositions including the compounds are prepared. They are useful in therapy, in particular in the management of pain.
Electrophilic fluorination of pyroglutamic acid derivatives: Application of substrate-dependent reactivity and diastereoselectivity to the synthesis of optically active 4-fluoroglutamic acids
Konas,Coward
, p. 8831 - 8842 (2007/10/03)
Electrophilic fluorination of enantiomerically pure 2-pyrrolidinones (4) derived from (L)-glutamic acid has been investigated as a method for the synthesis of single stereoisomers of 4-fluorinated glutamic acids. Reaction of the lactam enolate derived from 9 with NFSi results in a completely diastereoselective monofluorination reaction to yield the monocyclic trans-substituted α-fluoro lactam product 21. Unfortunately, a decreased kinetic acidity in 21 and other structurally related monofluorinated products renders them resistant to a second fluorination. In contrast, the bicyclic lactam 12 is readily difluorinated under the standard conditions described to yield the α,α-difluoro lactam 24. The difference in reactivity between the two types of related lactams is attributed mainly to the presence or lack of a steric interaction between the base used for deprotonation and the protecting group present in the pyrrolidinone substrates. This conclusion was reached based on analysis of the X-ray crystal structure of 21, molecular modeling, and experimental evidence. The key intermediates 21 and 24 are converted to (2S,4R)-4-fluoroglutamic acid and (2S)-4,4-difluoroglutamic acid, respectively.
Syntheses of 2-[(1S,3S)-1-amino-3-carboxy-3-hydroxypropyl]-thiazole-4-carboxylic acid and the tripeptide skeleton of nosiheptide containing the acid
Shin,Nakamura,Yamada,Yonezawa,Umemura,Yoshimura
, p. 3151 - 3160 (2007/10/03)
The stereoselective synthesis of an amino acid component called Fragment D, N,O-diprotected 2-[(1S,3S)-1-amino-3-carboxy-3-hydroxypropyl]thiazole-4-carboxylic acid of a macrobicyclic peptide antibiotic nosiheptide, was achieved by two routes. The dipeptide, Fragment B-C, 2-[(Z)-1-(N,O-isopropylidene-L-threonylamino)-1-propenyl]thiazole-4-ca rboxylic acid was also synthesized by the thiazole ring formation from (Z)-2-(N,O-diprotected L-threonylamino)-2-butenethioamide with ethyl bromopyruvate. The coupling of two components by using a condensing agent gave the expected tripeptide 2, which is an important partial skeleton of the nosiheptide.
