Lipase-Catalyzed Acetylation of 3-Substituted 2,3-Dihydro-1<i>H</i>-1,4-benzodiazepin-2-ones: Effect of temperature and conformation on enantioselectivity and configuration
作者:Amir Avdagić、Andreja Lesac、Zsuzsa Majer、Miklòs Hollòsi、Vitomir Šunjić
DOI:10.1002/hlca.19980810558
日期:——
due to the binding to the enzyme, in absolute (P)-conformation. Temperature dependence of enantioselectivity revealed inverse correlation of the E value of rac-9, and ee values for prochiral 16, with T[K], indicating prevalent contribution of the enthalpy term to enantioselection. Absolute conformation (M/P) and absolute configuration at C(3) of all products was determined by combining CD and 1H-NMR
由醋酸乙烯酯/ AcOEt中通过固定化的催化乙酰化的对映选择性南极假丝酵母脂肪酶(诺维信435)。研究了外消旋-3-(羟甲基)-1,4-苯并二氮杂-2-酮7,9,14(Ñ数目; = 1 CH 2基团在链中的C(3)),20(n = 2)和前手性3,3-双(羟甲基)衍生物16。对映体过量(ee [%])与底物的构象特性(相对构象,两个船状基态构象之间的能量差,环反转势垒)相关,如DNMR和MM2计算所确定。优先形成乙酸酯(+)- 8,(+)- 10,(+)- 15和(+)- 21的(3S)-对映体。在乙酸盐(-)- 17(ee 90.2%)的情况下,有利于(3R)-对映异构体的形成。在rac - 3(n = 0)中具有类人血样特性的C(3)OH基团不能被23种测试的脂肪酶和4种酯酶中的任何一种乙酰化。外消旋醇7,9,14,和20,优选的acetylationof(3小号) -对映体,存在于绝