1 -Aminocyclopentane-1 -carboxylic

Amino-1-cyclopentanecarboxylic acid CAS 52-52-8 EINECS/ELINCS 200-144-6 Synonyms ACPC 1-Aminocyclopentane-1-carboxylic acid Cycloleucine... 

Aminocyclopentane-1-carboxylic acid. See 1-Amino-1-cyclopentanecarboxylic acid... 

The commercially available lactam 76 is usable for amino acid synthesis as a chiral cyclic building block. 4-Fluoro- and 4,4-difluoro-3-aminocyclopentane carboxylic acids 79 and 81, potential inhibitors of y-aminobutanoic acid (GABA) aminotransferase, were synthesized as shown in Scheme 9.19 [39]. In this process, replacement of hydroxyl or carbonyl groups with fluorine was achieved by the use of DAST. Interestingly, the stereochemistry in substitution with DAST is retained [40], although it is by inversion in most cases [26]. Hydrolysis of 78 gave 80. 

The major isomer (1 R,2S,3 R)-79 (39% yield, i.e. 78% of the theoretical maximum) was crystallized, subjected to hydrogenolysis (Pd-mediated N-debenzylation), then hydrolysis to afford (lR,2S,3R)-3-methyl-2-aminocyclopentane carboxylic acid (ds-pentacin) 80 in >98% ee. Epimerization of 79 under basic (t-BuOK/t-BuOH) conditions and subsequent deprotection gave the (1S,2S,3R)-3-methyl-2-aminocyclopentane carboxylic acid (traus-pentacin). 

CgHiaNOa, 1-Aminocyclopentane carboxylic acid monohydrate, 38B, 171 CgHiflClNOa, 1-Aminocyclopentanecarboxylic acid hydrochloride monohydrate, 44B, 117... 

London, D. R., and Segal, S., 1967, Differences in the uptake and efflux of two nonutilizable amino acids, a-aminoisobutyric and 1-aminocyclopentane carboxylic acid in the cut" rat diaphragm, Biochim. Biophys. Acta 135 179. 

The effect of C ,C -disubstituted amino acids (aaAAs) on peptide secondary structure has been studied in recent years.2a d While longer side-chain C ,C -di-n-alkyl amino acids promote extended peptide conformation,23 alicyclic aaAAs, in which the Ca carbon forms a cyclic bridge with itself, such a 1-aminocyclopentane-l-carboxylic acid (Ac5c) and 1-aminocyclohexane-l-carboxylic acid (Ac6c), have helix-forming characteristics similar to those of 1 -aminoisobutyric acid (Aib).2ax... 

Decarboxylative condensation of N-unsubstituted tx-amino acids with benzaldehyde as an aromatic aldehyde requires somewhat harsher conditions. Benzaldehyde and oc-amino acids are heated under reflux in DMF together with N-phenylmaleimide. The azomethine ylides 108 generated can be captured as mixtures of several stereoisomeric cycloadducts (84CC180). 1-Aminocyclopentane-l-carboxylic acid undergoes a similar reaction with pyridine-3-carbaldehyde in the presence of N-phenylmaleimide to afford a spirocyclic cycloadduct, the maleimide cycloadduct of azomethine ylide 109 (84CC182). 

Aminocyclopentane-l-carboxylic acid undergoes a similar reaction with pyridine-3-carbaldehyde in the presence of N-phenylmaleimide to afford a spirocyclic cycloadduct, the maleimide cycloadduct of azomethine ylide 109 (84CC182). 

Phosphonylmethylaminocyclopentane-l-carboxylic acid 1 was obtained in a good yield of 86% by reacting aminocyclopentane-l-carboxylic acid, cycloleuicin, paraformaldehyde, and diethyl H-phosphonate [92],... 

Imidazoleacetic acid 3-Aminopropanesulfonic acid ( )-fmn5-3-Aminocyclopentane-1 -carboxylic acid ( )-cis-3-Aminocyclopentane-1 -carboxylic acid Bicuculline... 

Subsequent conversion of the acid moiety to an amide was followed by rearrangement to IS,3R-3-aminocyclopentane-l-carboxylic acid (7.35). An alternative synthesis converted norbomanol to dicarboxylic acid 7.39 by oxidative cleavage with permanganate. This was then converted to 7.38. Dicarboxylic acid 7.39 was also converted to the trans- acid (7.40) by literature procedures and the same reaction sequence as before was used to prepare /rrinj-3-aminocyclo-pentane-1-carboxylic acid, 7.27. >20... 

Alkenes are important vehicles for incorporating functionality into a ring. An example is the Michael addition of ammonia to 1-cyclopentene-l-carboxylic acid (7.42) to give 2-aminocyclopentane-l-carboxylic acid (7.43), as a mixture of cis- and rra s-isomers.2 The yield in this particular case was rather low, however. Hydrogenation of cycloalkene carboxylic acid derivatives is a convenient route to the... 

As in other chapters of this book, particularly chapter one, P-lactams are important precursors to non-a-amino acids. In this section, bicyclic P-lactam derivatives will be used to prepare cyclic amino acids. In a typical example, reaction of cyclo-pentene with chlorosulfonyl isocyanate (CSI) gave a P-lactam and treatment with basic potassium iodide cleaved the sulfonyl group to give 7.86. Acid hydrolysis gave cjj-2-aminocyclopentane-l-carboxylic acid, 7.87. Another method used... 

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