An Efficient Synthesis of the Anti-asthmatic Agent T-440: A Selective N-Alkylation of 2-Pyridone.
作者:Masakatsu SUGAHARA、Yasunori MORITANI、Tooru KURODA、Kazuhiko KONDO、Hideshi SHIMADZU、Tatsuzo UKITA
DOI:10.1248/cpb.48.589
日期:——
6, 7-Diethoxy-1-[1-(2-methoxyethyl)-2-oxo-1, 2-dihydropyridin-4-yl]naphthalene-2, 3-dimethanol [T-440, (1)]is a potential anti-asthmatic agent based on selective phosphodiesterase 4 inhibition. It was necessary for the further evaluation of 1 to develop an efficient synthetic route for 1, especially the construction of the 1-(2-methoxyethyl)-2-pyridone moiety. We examined an N-selective alkylation of pyridone derivative (2) in basic media, 2-Methoxyethylation of 2 with 2-methoxyethyl iodide utilizing LiH as the base gave predominantly an N-alkyl pyridone derivative (3a) in 82% yield (N/O-alkylation=92/8), which is compatible with an ab initio calculation of transition-state structures for the methylation of 2-pyridone. Single crystallization of a crude mixture of 3a and 4a furnished pure 3a, which is a key synthetic intermediate of 1.
6,7-二乙氧基-1-[1-(2-甲氧基乙基)-2-氧代-1,2-二氢吡啶-4-基]萘-2,3-二甲醇[T-440,(1)]是一种基于选择性磷酸二酯酶 4 抑制作用的潜在抗哮喘药物。为了对 1 进行进一步评估,有必要开发出 1 的高效合成路线,特别是 1-(2-甲氧基乙基)-2-吡啶酮分子的结构。我们研究了吡啶酮衍生物(2)在碱性介质中的 N-选择性烷基化反应,利用 LiH 作为碱,用 2-甲氧基乙基碘化物对 2 进行 2-甲氧基乙基化反应,主要得到了一种 N-烷基吡啶酮衍生物(3a),收率为 82%(N/O-烷基化=92/8),这与 2-吡啶酮甲基化过渡态结构的 ab initio 计算结果相符。对 3a 和 4a 的粗混合物进行单结晶,得到了纯净的 3a,它是 1 的关键合成中间体。