Spectropolarimetry II. The optical rotatory dispersion of α‐amino‐acids and α‐hydroxy‐acids

Abstract

The rotatory dispersion of 26 amino-acids and 5 hydroxy-acids was studied.I t was found that the carboxyl absorption-band at about 205 nm to 210 nm is optically active. L-Amino-acids as well as L-hydroxy-acids show a positive Cotton effect. For a number of amino-acids a correlation exists between peakheight and molecular structure. Except for proline, hydroxy-proline and cystine. all acids studied show very similar rotatory dispersion curves.

Circular dichroism of monocyclic and bicyclic lactones. Restricted and rigid model compounds for the ester chromophore

“…Reduction of 2-PhenyI-l-indanone and 2-Phenyl-l,3-indandione (10,1).-Separation of 2-phenylindan (11) and 2-phenylindene (12) was achieved by column chromatography. From the petroleum ether fraction, 11 was obtained as a colorless oil, which was distilled in vacuo at 100-110°( 0.1 mm).…”

Excitatory amino acid receptor antagonists: Resolution, absolute stereochemistry, and pharmacology of (S)‐ and (R)‐2‐amino‐2‐(5‐tert‐butyl‐3‐hydroxyisoxazol‐4‐yl)acetic acid (ATAA)

“…The CD curves of the ATAA enantiomers in Figure 6B clearly demonstrated that the two compounds are enantiomers, and a virtually identical mirrorimage relationship is seen in Figure 7B for the AMAA enantiomers. 16 In both cases, the (S)-enantiomer, as expected for (S)-amino acids in acidic solution, [28][29][30] showed a relatively strong positive Cotton effect at 220 nm (⌬⑀ = +1.0m 2 /mol).…”

AMPA receptor agonists: Resolution, configurational assignment, and pharmacology of (+)-(S)- and (-)-(R)-2-amino-3-[3-hydroxy-5-(2-pyridyl)-isoxazol-4-yl]-propionic acid (2-Py-AMPA)

“…The positive Cotton effect of (S)-APPA at 210-220 nm is in agreement with the empirical correlation between the absolute configuration and the CD spectra of (S)-amino acids in acidic solution, stating that (S)-amino acids, most likely due to a forbidden n → * transition of the ␣-carboxylic acid, show a positive Cotton effect near 220 nm. [36][37][38] The CD spectra of (+)-and (−)-2-Py-AMPA (Fig. 5C) clearly illustrate that the two compounds are enantiomers.…”