Nomoto Y, Takai H, Ohno T, Nagashima K, Yao K, Yamada K, Kubo K, Ichimura M, Mihara A, Kase H
Pharmaceutical Research Laboratories, Fuji, Kyowa Hakka Co., Ltd., Shizuoka, Japan.
J Med Chem. 1996 Jan 5;39(1):297-303. doi: 10.1021/jm950197j.
We previously reported that (+/-)-6-(4-(benzylamino)-7-quinazolinyl)-4,5- dihydro-5-methyl-3(2H)-pyridazinone (+/-)-1, KF15232) showed potent cardiotonic activity with a strong myofibrillar Ca(2+)-sensitizing effect. As an extension of our work, we attempted to synthesize optically active 1. (+/-)-4-(4-(Benzylamino)-7-quinazolinyl)-3-methyl-4-oxobutyric acid (-)-menthyl ester (6) was separated into both diastereoisomers, and each was converted to optically pure 1 (> 99% ee) in an enantioselective manner. In order to determine the absolute configuration of the isomers, an alternative synthesis of optically active 1 was employed. The precursor of (-)-1 ((+)-9) was obtained by enantioselective synthesis from (R)-D-alanine. Consequently, we concluded that the absolute configuration of (-)-1 at the 5-position of the pyridazinone ring was R. The cardiotonic effects and inhibitory activities to PDE III and V of racemic 1 and (-)-1 were more potent than those of (+)-1. These compounds also demonstrated greater vasorelaxant effects in guinea pig aorta. In contrast, (+)-1 showed only weak cardiotonic and vasodilating effects, although the compound displayed potent Ca(2+)-sensitizing activity. Racemic and (-)-1 attracted our interest for the treatment of congestive heart failure.
我们之前报道过(±)-6-(4-(苄基氨基)-7-喹唑啉基)-4,5-二氢-5-甲基-3(2H)-哒嗪酮(±)-1，KF15232)具有强大的强心活性以及强烈的肌原纤维Ca(2+)致敏作用。作为我们工作的拓展，我们尝试合成光学活性的1。(±)-4-(4-(苄基氨基)-7-喹唑啉基)-3-甲基-4-氧代丁酸(-)-薄荷酯(6)被拆分为两种非对映异构体，并且每种异构体都以对映选择性方式转化为光学纯的1(对映体过量>99%)。为了确定异构体的绝对构型，我们采用了另一种光学活性1的合成方法。(-)-1的前体((+)-9)通过对映选择性合成从(R)-D-丙氨酸获得。因此，我们得出结论，(-)-1在哒嗪酮环5位的绝对构型为R。外消旋1和(-)-1对PDE III和V的强心作用及抑制活性比(+)-1更强。这些化合物在豚鼠主动脉中也表现出更强的血管舒张作用。相比之下，(+)-1仅表现出微弱的强心和血管舒张作用，尽管该化合物具有强大的Ca(2+)致敏活性。外消旋体和(-)-1在治疗充血性心力衰竭方面引起了我们的兴趣。
