Gusakova G V, Denisov G S, Smolianskiĭ A L, Charykov A K
Antibiotiki. 1984 Aug;29(8):576-80.
The association and conformational structure of the molecule of erythromycin in solutions of CCl4, C2Cl4 and CHCl3 were studied by the IR spectra in the region of v OH and vC = O. The analysis of the concentration and temperature changes showed that the erythromycin association was accounted for by the hydrogen linkage of OH ... O = C to the ester group. In the monomer molecule of erythromycin, all hydroxyl groups participated in the intramolecular hydrogen linkage. Band 3513 cm-1 belonged to the OH group in the five-membered cycles of OH ... O. Components 3500, 3530 and 3560 cm-1 of the wide band vOH were assigned to the cycles with OH ... N and OH ... O linkages of a larger size. The association was due to a break in a part of the intramolecular hydrogen linkages. Addition of strong acceptors of proton-hexamethanol and trioctylphosphinoxide to the solution resulted in attenuation of these bands and appearance of a strong band vOH of the erythromycin-acceptor complexes. In the presence of monochloroacetic acid in the solution of CHCl3 stoichiometric protonization of erythromycin was observed. The total acid was in the form of anion (vaCO-2 1610 cm-1) up to a ratio of 1:1. The protonization proceeded according to the nitrogen atom since the antibiotic spectrum in the region of vC=O did not change. Propionic acid titrated erythromycin in methanol solution and in mixtures of water and methanol up to a ratio of 1:5 (v/v). However, in the solution of CHCl3 equilibrium between the neutral and ionized molecules of the acid was seen.
通过在v OH和vC = O区域的红外光谱研究了红霉素分子在CCl4、C2Cl4和CHCl3溶液中的缔合和构象结构。对浓度和温度变化的分析表明，红霉素的缔合是由OH…O = C与酯基的氢键作用引起的。在红霉素的单体分子中，所有羟基都参与了分子内氢键作用。3513 cm-1谱带属于OH…O五元环中的OH基团。宽谱带vOH的3500、3530和3560 cm-1成分被归属于具有较大尺寸的OH…N和OH…O键合的环。缔合是由于部分分子内氢键的断裂。向溶液中加入强质子受体六甲醇和三辛基氧化膦会导致这些谱带减弱，并出现红霉素 - 受体复合物的强vOH谱带。在CHCl3溶液中存在一氯乙酸时，观察到红霉素的化学计量质子化。直至比例为1:1时，总酸呈阴离子形式（vaCO - 2 1610 cm-1）。由于在vC = O区域抗生素的光谱没有变化，质子化是根据氮原子进行的。丙酸在甲醇溶液以及水和甲醇的混合物中滴定红霉素，直至比例为1:5（v/v）。然而，在CHCl3溶液中可以看到酸的中性分子和离子化分子之间的平衡。
