A new, efficient and highly enantioselective synthesis of methyl p-nitrophenyl alkylphosphonates 4 a-c is described. Alkylphosphonic dichloride 1 a-d reacted successively with L-proline ethyl ester and p-nitrophenol to afford phosphoramidates 3 a-d in 97% de. Boron trifluoride catalysed methanolysis gave 4 a-c with 93% ee. Absolute configurations of compounds 4 c and 3 c were established by correlation with the X-ray structure of HPL-colipase-(-)-4 c complex. 31P NMR studies indicates that monochloro phosphoramidates (R p )- and (S p)-2 c undergo fast epimerisation. The observed diastereoselectivity in favour of (S p)-3 c results from a faster reaction of (R p)-2 c as compared to its epimer, according to the Curtin-Hammett principle.
Synthesis, antimicrobial, and surfactant activity of octameric cyclic esters of alkylphosphonic acids
作者:S. N. Aminov、Z. F. Tanaeva、L. É. Korneva、L. A. Savitskaya、V. Kim
DOI:10.1007/bf01151184
日期:1987.11
the approach of the other molecule of the nucleophile will be stericaily hindered. The replacement of one chlorine atom in the dichloroanhydride molecule by an alkoxy group results in a greater electron density on the phosphorus atom which lowers the molecule's reactivity. Thus, the steric and electron factors enhance the formation of a cyclic product regardless of the molar ratio of the starting reagents
在给定的反应中,三乙醇胺是试剂和 HCl 受体,因此使用过量。在研究该反应时,我们发现 [i] APA 二氯酸酐和三乙醇胺之间的相互作用仅导致形成环状产物,而与起始试剂的摩尔相关性无关。这显然与亲核试剂对四面体磷原子的攻击更依赖于空间因素而不是平面羰基化合物的攻击这一事实有关。我们知道,反应速率不仅取决于与取代基团对应的酸的 pKa 大小,还取决于其体积 [6]。APA 二氯酸酐中两个氯原子的置换速率不同,因此一旦一个氯原子发生反应,亲核试剂的另一个分子的接近就会受到空间阻碍。烷氧基取代二氯酸酐分子中的一个氯原子会导致磷原子上的电子密度更大,从而降低分子的反应性。因此,无论起始试剂的摩尔比如何,空间和电子因素都会促进环状产物的形成。
Inhibition of human gastric and pancreatic lipases by chiral alkylphosphonates. A kinetic study with 1,2-didecanoyl-sn-glycerol monolayer
potential inhibitors of human gastric lipase (HGL) and human pancreatic lipase (HPL). The inhibitory properties of each enantiomer have been tested with the monomolecular films technique in addition to an enyzme linked immunosorbent assay (ELISA) in order to estimate simultaneously the residual enzymatic activity as well as the interfacial lipase binding. With both lipases, no obvious correlation between