NMR of enaminones. Part 7<sup>1</sup>H-,<sup>13</sup>C-, and<sup>17</sup>O-NMR and X-ray structure determinations of 1,2-disubstituted conjugated 3-[(<i>tert</i>-Butyl)amino]enones
作者:Jin-Cong Zhuo、Kurt Schenk
DOI:10.1002/hlca.19970800713
日期:1997.11.3
1,N-anti conformations A and B, respectively. The structures of the (E)- and (Z)-form are confirmed by X-ray crystal-structure determinations of 3 and 4. The shielding of the carbonyl O-atom in the 17O-NMR spectrum by intramolecular H-bonding (ΔλHB) ranging from −28 to −41 ppm, depends on the substituents at C(l) and C(2). Crystals of 3 at 90 K are monoclinic. with a = 9.618(2) Å, b = 15.792(3) Å, c
1 H-,13 C-和17为2-取代的烯胺酮的MeC O型NMR谱(O)C(Me)的CHNH(吨-Bu)(1),ETC(O)C(Me)的CHNH(吨-报告了Bu)(2),PhC(O)C(Me)CHNH(t -Bu)(3)和MeC(O)C(Me)CHNH(t -Bu)(4)。这些数据表明,3主要以(E)形式存在,4以(Z)形式存在,1和2作为两种形式的混合物存在。极性溶剂偏爱(E)形式。(Z)-和(E)形式分别存在于1,2- syn,3,N-anti和1,2- anti,1,N-anti构象A和B中。(E)和(Z)形式的结构通过X射线晶体结构3和4的确定得到确认。通过分子内H键对17 O-NMR光谱中羰基O原子的屏蔽( Δλ HB)为-28至-41 ppm时,取决于取代基在C(l)和C(2)。在90 K时3的晶体是单斜晶的。其中a = 9.618(2)Å,b = 15.792(3)Å,c =