Imbuing Aqueous Solubility to Amphotericin B and Nystatin with a Vitamin
作者:Timothy P. Day、Diptesh Sil、Nikunj M. Shukla、Asokan Anbanandam、Victor W. Day、Sunil A. David
DOI:10.1021/mp100363f
日期:2011.2.7
primary amines under entirely aqueous conditions and at physiologic pH, while no reaction was observed for secondaryamines; the basis of the exceptional stability appears to be a consequence of favorable H-bond interactions of the imine nitrogen with the 5-OH group of PLP. Amphotericin B and nystatin in their native forms display marked aqueous insolubility and possess lone primary amines. We were
目前临床使用的许多药物的水溶解度非常低,需要经常出现肠胃外给药问题的制剂,包括由于使用的赋形剂引起的毒性。认识到药理活性化合物通常含有胺,我们询问磷酸吡哆醛 (PLP),一种无害的水溶性维生素,是否可用于通过形成亚胺或亚胺加合物来形成前药样复合物,以及该维生素是否会赋予增溶作用这种复合物的性质。使用模型伯胺和仲胺获得的直接光谱和晶体学数据表明,PLP 在完全水性条件和生理 pH 值下与伯胺形成稳定的亚胺加合物,而没有观察到仲胺的反应;异常稳定性的基础似乎是亚胺氮与 PLP 的 5-OH 基团之间有利的 H 键相互作用的结果。天然形式的两性霉素 B 和制霉菌素显示出明显的水不溶性,并具有单独的伯胺。我们能够利用 PLP 实现这两种抗真菌剂的出色溶解,超过 100 mg/mL 的水溶解度。在体外生物测定中,PLP 加合物形式的两种多烯都显示出减弱的抗真菌效力,这归因于“前药样”复合物。这些结果表明两性霉素
Electrosynthesis of 15N-labeled amino acids from 15N-nitrite and ketonic acids
15N isotope-labeled aminoacids (15N-amino acids) are crucial in the fields of biology, medicine, and chemistry. 15N-amino acids are conventionally synthesized through microbial fermentation and chemical reductive amination of ketonic acids methodologies, which usually require complicated procedures, high temperatures, or toxic cyanide usage, causing energy and environmental concerns. Here, we report
15 N 同位素标记的氨基酸(15 N-氨基酸)在生物学、医学和化学领域至关重要。15 N-氨基酸传统上是通过微生物发酵和化学还原胺化酮酸的方法合成的,这些方法通常需要复杂的程序、高温或使用有毒的氰化物,从而引起能源和环境问题。在这里,我们报告了在可再生电力驱动的环境条件下,从现成的 15 N-亚硝酸盐 ( 15 NO 2 ) 和生物质衍生的酮酸合成15 N-氨基酸的可持续途径。机理研究表明15 N-亚硝酸盐→15 NH 2 OH→ 15 N-丙酮酸肟→ 15 N-丙氨酸合成15 N-丙氨酸的反应途径。此外,这种电化学策略可以合成 6 个15 N-氨基酸,产率为 68%-95%。此外,最常用的肝炎治疗药物15 N-硫普罗宁的15 N-标记药物是使用15 N-甘氨酸作为结构单元制造的。令人印象深刻的是,15 N 源可以通过15 NH 4 +电氧化为15 NO 2进行回收方法经济。这项工作为15
Electron Paramagnetic Resonance Study of the Imino Ascorbyl Radicals Formed in the Photochemical Reaction in the Presence of Nitrite between Ascorbic Acid and the Amino Compounds DL-Alanine, Methylamine, Ethylamine, Glycine, Ammonia or Hydrazine.
作者:Carl Lagercrantz、Alexander Senning、Xiaoxin Qiao、Robert A. Pascal, Jr.、Allen J. Bard、George W. Francis、József Szúnyog、Bengt Långström
DOI:10.3891/acta.chem.scand.52-0037
日期:——
Irradiation with UV light at room temperature of a mixture of the amino compounds DL-alanine, methylamine, ethylamine, glycine, ammonia or hydrazine, and sodium nitrite-ascorbic acid dissolved in alkaline water solution gave rise to radicals detectable by EPR spectroscopy. The observed radicals were considered to be mono imino or mono hydrazine ascorbyl radicals formed by a one-electron oxidation of the corresponding imino or hydrazyl derivatives formed in the nucleophile reaction between the amino compounds and an oxo group of ascorbic acid. The reactions are believed to be promoted by a photoexcited state of the nitrite ion.
Synthesis of α-amino and α-hydroxy acids under volcanic conditions: implications for the origin of life
Facile synthesis of alpha-hydroxy and alpha-amino acids is observed at temperatures from 145 to 280 degrees C with catalytic Ni2+, with cyano ligands as source for C and N, and with CO as a reductant and as a source for C. Implications for the problem of the origin of life are discussed, (C) 2009 Elsevier Ltd. All rights reserved.
Solvent-dependent conformational distributions of some dipeptides