The crystal structure of 9α-(3-azabicyclo[3,3,1]nonanyl)-2'-cyclopentyl-2'-hydro-xyl-2'-thienylacetate (C16H27NO3S, Mr = 349.48) has been determined by single-crystal X-ray diffraction analysis. The crystal belongs to orthorhombic, space group P212121 with a = 14.937(3), b = 8.1673(16), c = 15.423(3) (A), V = 1881.5(6) (A)3, Z = 4, Dc =1.234 g/cm3, μ = 0.188 mm-1, F(000) = 752, the final R = 0.0468 and wR = 0.1251. The bicyclo[3,3,1]nonane ring system adopts the most favored twin-chair conformation. The crystal structure shows the existence of intramolecular O-H…O hydrogen bonds by which a one-dimensional chain struc- ture is formed. 相似文献
An efficient asymmetric synthesis of (S)‐2,3‐dihydrobenzo[b]furan‐3‐carboxylic acid ( 8 a ) and (S)‐5‐chloro‐2,3‐dihydrobenzo[b]furan‐3‐carboxylic acid ( 8 b ) was established. Key to the success was the highly stereoselective enzymatic kinetic resolution of the corresponding methyl or ethyl esters that was further developed into a dynamic process. As a reliable and fast tool for analysing the enantiomeric excess, HPLC coupled with a CD detector was utilized. The route was completed by a Friedel–Crafts acylation of ethyl (S)‐5‐chloro‐2,3‐dihydrobenzo[b]furan‐3‐carboxylate ( 7 c ) followed by saponification leading to (S)‐5‐chloro‐2,3‐dihydrobenzo[b]furan‐3‐carboxylic acid ( 2 ), an analgesic agent. 相似文献
A short and enantioselective formal synthesis of (R)-selegiline has been achieved using Jacobsen's hydrolytic kinetic resolution (HKR) of phenyl propylene oxide.
N. B. K. thanks the Council of Scientific and Industrial Research, New Delhi, for the award of a senior research fellowship. Financial support in the form of a research grant from the Department of Science and Technology, New Delhi, is gratefully acknowledged. 相似文献
Feel the pinch! Planar–chiral, cationic, ruthenium–palladium complexes based on η6,η1‐coordinated ECE′ pincer ligands are synthesized as racemic mixtures by reacting ECE′–palladium complexes and [Ru(C5R5)(MeCN)3]+ arenophiles (R=H or Me). Chiral resolution of the cationic complexes was achieved by using the chiral counterion [Δ‐TRISPHAT]?, and solving the X‐ray crystal structure of one diastereoisomer (shown here).
This document describes a simple and robust process for the synthesis of olmesartan medoxomil. This tailored process allows us to synthesize olmesartan medoxomil on a large scale with 50% overall yield. Also, our process has excellent control of the impurity profile in all the stages. 相似文献
Both enantiomers of inherently chiral calixarene carboxylic acids with ABCD substitution patterns have been prepared by the benzoylation of 25-propoxy-27-(R)-N-(α-phenylethyl)amidomethyloxycalix[4]arene followed by resolution of the diastereomers formed, monobromination of them and removal of the benzoyl and α-phenylethylamide auxiliary groups. The absolute configuration of the calixarenes obtained has been established by X-ray analysis. Preliminary study of the chiral recognition properties of calixarene carboxylic acid was performed. 相似文献
In this article, we describe our efforts on the total synthesis of bolivianine ( 1 ) and isobolivianine ( 2 ), involving the synthesis of onoseriolide ( 3 ). The first generation synthesis of bolivianine was completed in 21 steps by following a chiral resolution strategy. Based on the potential biogenetic relationship between bolivianine ( 1 ), onoseriolide ( 3 ), and β‐(E)‐ocimene ( 8 ), the second generation synthesis of bolivianine was biomimetically achieved from commercially available (+)‐verbenone in 14 steps. The improved total synthesis features an unprecedented palladium‐catalyzed intramolecular cyclopropanation through an allylic metal carbene, for the construction of the ABC tricyclic system, and a Diels–Alder/intramolecular hetero‐Diels–Alder (DA/IMHDA) cascade for installation of the EFG tricyclic skeleton with the correct stereochemistry. Transformation from bolivianine to isobolivianine was facilitated in the presence of acid. The biosynthetic mechanism and the excellent regio‐ and endo selectivities in the cascade are well supported by theoretical chemistry based on the DFT calculations. 相似文献