Preparation and Structure of Oligolides from (<i>R</i>)-3-Hydroxypentanoic Acid and comparison with the hydroxybutanoic-acid derivatives: A small change with large consequences
作者:Dieter Seebach、Torsten Hoffmann、Florian N. M. Kühnle、Urs D. Lengweiler
DOI:10.1002/hlca.19940770727
日期:1994.11.2
P9(3-HB) and P(3-HV) derived from stretch-fibre X-ray scattering. Crystals of a water-containing NaSCN complex of the triethyl triolide 3 were obtained in good quality for X-ray analysis. The structure (Figs. 12, 13, and Table 6) contains an interesting array of CO and H2O O-atoms around the Na+ ions along a channel-type tube (a-axis of the crystal) which may be relevant to the role of P(3-HB) and P(3-HV)
Cyclische Oligomere von (<i>R</i>)-3-Hydroxybuttersäure: Herstellung und strukturelle Aspekte
作者:Diemar A. Plattner、Andreas Brunner、Max Dobler、Hans-Martin Müller、Walter Petter、Peter Zbinden、Dieter Seebach
DOI:10.1002/hlca.19930760518
日期:1993.8.11
Cyclic Oligomers of (R)-3-Hydroxybutanoic Acid: Preparation and Structural Aspects
(R)-3-羟基丁酸的环状低聚物:制备和结构方面。
High-Yield Synthesis of 20-, 24-, and 28-Membered Macropentolide, -hexolide, and -heptolide, Respectively, from (<i>R</i>)- or (<i>S</i>)-3-hydroxybutanoic acid under<i>Yamaguchi</i>'s macrolactonization conditions
oligomers formed in ca. 50% yield from enantiomerically pure 3-hydroxybutanoic acid under Yamaguchi's macrolactonizationconditions. The FAB mass spectra of the MH+, M Na+, and MCs+ are reported (Figs. 2, 3, 5, and 6). No cyclic tetramer is detected. The 1H-NMR spectra of the cyclic oligomers, of the monomer, and of the polymer (PHB) are very similar (Fig. 4). Directed synthesis of the open-chain dimer and
大环戊内酯1,己内酯2和庚内酯3构成ca。形成在所述低聚物的80%约 在山口的大环内酯化条件下,对映体纯的3-羟基丁酸的收率为50%。报道了M H +,M Na +和M Cs +的FAB质谱图(图2、3、5和6)。未检测到环状四聚体。环状低聚物,单体和聚合物(PHB)的1 H-NMR谱图非常相似(图4)。3-羟基丁酸的开链二聚体和四聚体的直接合成和尝试的环化作用不会导致环状四聚体的分离。
On the Macrolactonization of β-Hydroxy Acids. Crystal structures of the pentolide and the hexolide from (<i>R</i>)-3-hydroxybutanoic acid. Molecular modeling studies of the tetrolide
from (R)- or (S)-3-hydroxybutanoicacid under Yamaguchi's macrolactonization conditions (2,4,6-trichlorobenzoyl chloride/base) was studied. While the content of hexolide 2 in the product mixture is almost invariably ca. 35%, the amounts of pentolide 1 and of the larger rings strongly depend upon the temperature employed (Fig.1). Cyclic oligomers (5,6) are also obtained from 3-hydroxypentanoic acid. Enantiomerically