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Synthesis of 4‐Amino Derivatives of 5‐Oxoproline

“…[14] It has been found that interaction of (2S,4RS)-1 and dibenzylamine results not only in the target product 4, but also in the product of the γ-elimination of HBr, dimethyl (Z)-1-phthalimidocyclopropane-1,2-dicarboxylate (6, Scheme 3), similar to a previous report. [15] Scheme 3.…”

“…The 1 H NMR spectrum is identical to the literature data. [15] HPLC [LiChrosorb Si-60 (4 ϫ 250 mm, 5 µm), A/B/C = 80:0.7:0.3]: t R = 15.9 min. C 15 H 13 NO 6 (303.27): calcd.…”

Natural Occurrence, Syntheses, and Applications of Cyclopropyl-Group-Containing α-Amino Acids. 1. 1-Aminocyclopropanecarboxylic Acid and Other 2,3-Methanoamino Acids

“…Protected forms of racemic 2,3-methanovaline 378 , ( Z )-2,3-methanophenylalanine ( Z )- 379 , norcoronamic acid ( Z )- 380 , and ( Z )-aspartic acid ( Z )- 381 were prepared by base-induced cyclization of the corresponding γ-bromo-substituted amino acid derivatives 374 − 377 (Scheme ), which had been synthesized by regioselective bromination of the correspondingly protected underlying amino acids leucine, homophenylalanine, norvaline, and glutamic acid. , An anlogous transformation of the brominated β,γ-didehydrovaline derivative 382 afforded the protected 1-amino-2-methylenecyclopropanecarboxylic acid 383 (Scheme ) . According to this method, enantiopure 2,3-methanovaline was obtained by introduction of an additional stereocenter into the N -phthaloyl protecting group (Scheme ) …”

Synthesis and properties of 1-aminocyclopropane-1,2-dicarboxylic acid and compounds incorporating it

“…of AlCl 3 in the presence of NaI, esters 75a,b are converted either into monoalkyl esters of 1-phthalimidocyclopropane-1,2-dicarboxylic acid or into a free diacid. According to X-day diffraction analysis, 69 1 H NMR and 13 C NMR spectroscopic and GC/MS data, 70 dialkyl esters 75a,b represent individual isomers with a trans-configuration of ester groups relative to the cyclopropane ring, although the starting bromo derivatives 76a,b were used as a mixture of diastereomers.…”

“…HPLC studies have shown 70 that (2S,4S)-isomers of compounds 76 react with bases much more slowly than (2S,4R)isomers. This reaction is accompanied by epimerisation at the C(4) atom of glutamic acid.…”