- 著者
- 藤井 達也 西田 裕 阿比留 佳明 山本 雅司 黄瀬 正博
- 出版者
- The Pharmaceutical Society of Japan
- 雑誌
- Chemical and Pharmaceutical Bulletin (ISSN:00092363)
- 巻号頁・発行日
- vol.43, no.11, pp.1872-1877, 1995-11-15 (Released:2008-03-31)
- 参考文献数
- 13
- 被引用文献数
- 7 19
Diisopropylamine (DIPA), N, N-diisopropylethylamine (DIPEA), tributylamine (TNBA) and 7-(1-piperazinyl)-4-quinolone-3-carboxylic acid (2) were titrated in water-dimethylformamide (DMF) mixtures containing 45-98% DMF. Apparent pKa values in anhydrous DMF (pKDMF) were calculated by extrapolation from the variation in the half-neutralization pH values in aqueous DMF. The validity of the relative basicity derived from the pKDMFs was confirmed by examination of the kinetics of esterification of a derivative of 2 with 4-(bromomethyl)-5-methyl-1, 3-dioxol-2-one (DMDO-Br). Relative basicities in DMF were : the carboxylate anion of 2»DIPA>DIPEA>TNBA >the amino group in the piperazinyl part of 2. This order is clearly different from that observed in water.We concluded that DIPEA is a suitable agent to suppress the undesired esterification during the reaction to mask the amino group of 2 with a DMDO group, because it does not remove a proton from the carboxyl group, but only from the protonated amino group.