151838-56-1Relevant articles and documents
Total synthesis of actinophenanthroline A via double Doebner–Miller reaction
Ghosh, Suman Kr,Nagarajan, Rajagopal
, p. 4009 - 4011 (2016)
Total synthesis of actinophenanthroline A, a marine actinomycete within the family of Streptomycetaceae (strain CNQ-149) is reported. Both the racemic and enantiopure actinophenanthroline A have been synthesized with good overall yields. Highlight of the synthesis contains the classical and economical double Doebner–Miller reaction to access the 1,7-phenanthroline core followed by a modified EDCI coupling.
Compounds And Compositions for the Treatment of Ocular Disorders
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Paragraph 0502, (2017/04/11)
The disclosure describes prodrugs and derivatives of prostaglandins, carbonic anhydrase inhibitors, kinase inhibitors, beta-adrenergic receptor antagonists and other drugs, as well as controlled delivery formulations containing such prodrugs and derivatives, for the treatment of ocular disorders.
Hydrogen-bond-mediated folding in depsipeptide models of β-turns and α-helical turns
Gallo, Elizabeth A.,Gellman, Samuel H.
, p. 9774 - 9788 (2007/10/02)
The folding of several depsipeptides constructed from α-amino acids [L-proline (P) and L-alanine (A)] and α-hydroxy acids [L-lactic acid (L) and glycolic acid (G)] has been examined in methylene chloride solution by variable- temperature IR spectroscopy. Additional studies have been conducted in some cases, involving variable-temperature 1H NMR spectroscopy and molecular mechanics calculations. The depsipeptides include three-residue molecules (PLL, ALL, and PLG) that can form a 13-membered-ring amide-to-amide hydrogen bond, which, for a peptide backbone, would correspond to a single turn of an α-helix. These depsipeptides can also form 10-membered-ring amide-to-ester hydrogen bonds, which would correspond to β-trun formation for a peptide backbone. For PLL and PLG, distinct N-H stretch bands can be identified for three folding patterns: non-hydrogen-bonded, β-turn, and α-helical turn. IR-based van't Hoff analyses for PLL indicate that the α-helical turn and the β-turn are both modestly enthalpically favored relative to the non-hydrogen-bonded state, but neither turn is enthalpically preferred over the other. For PLG, in contrast, the α-helical turn appears to be enthalpically preferred over both of the alternative folding patterns. Comparison between PLL and ALL indicates that the N-terminal proline residue favors α-helical turn formation. The strengths of amide-to-amide and amide-to-ester hydrogen bonds have been compared in the context of a β-turn geometry by analyzing LG and AG in CH2Cl2. The amide-to-amide hydrogen bond is enthalpically favored by ca. 1.6 kcal/mol, but formation of this enthalpically stronger intramolecular hydrogen bond is more costly entropically. Extrapolation from the behavior of these depsipeptides leads us to predict that for tripeptides in a nonpolar environment, a β-turn will generally be enthalpically preferred over an isolated α-helical turn. β-Turn folding has previously been widely studied in model peptides and depsipeptides; however, the present report appears to represent the first experimental effort to model formation of a single α-helical turn.
