High regiocontrol in the nucleophilic ring opening of 1-aralkyl-3,4-epoxypiperidines with amines—a short-step synthesis of 4-fluorobenzyltrozamicol and novel anilidopiperidines
摘要:
Nucleophilic ring-opening reactions of three 1-aralkyl-3,4-epoxypiperidines with a series of aliphatic and aromatic amines have been investigated. Reactions in protic solvents, preferably 2-propanol, gave rise to 3-amino-piperidin-4-ols in ratios up to 20:1. Accordingly, 4-fluorobenzyltrozamicol, a highly potent ligand for the vesicular acetylcholine transporter was obtained directly from an epoxide ring opening in one step, without the need of chromatographic separation. Reactions in acetonitrile assisted by Li-salts, most suitable with LiBr, led regioselectively to trans-4-amino-piperidin-3-ols in high yields. N-Phenethyl substituted anilino-piperidinols as easily obtained by this method were converted into a series of new beta-hydroxy substituted anilidopiperidines. (C) 2011 Elsevier Ltd. All rights reserved.
High regiocontrol in the nucleophilic ring opening of 1-aralkyl-3,4-epoxypiperidines with amines—a short-step synthesis of 4-fluorobenzyltrozamicol and novel anilidopiperidines
摘要:
Nucleophilic ring-opening reactions of three 1-aralkyl-3,4-epoxypiperidines with a series of aliphatic and aromatic amines have been investigated. Reactions in protic solvents, preferably 2-propanol, gave rise to 3-amino-piperidin-4-ols in ratios up to 20:1. Accordingly, 4-fluorobenzyltrozamicol, a highly potent ligand for the vesicular acetylcholine transporter was obtained directly from an epoxide ring opening in one step, without the need of chromatographic separation. Reactions in acetonitrile assisted by Li-salts, most suitable with LiBr, led regioselectively to trans-4-amino-piperidin-3-ols in high yields. N-Phenethyl substituted anilino-piperidinols as easily obtained by this method were converted into a series of new beta-hydroxy substituted anilidopiperidines. (C) 2011 Elsevier Ltd. All rights reserved.
An ion-pair complex [FBzPy][Ni(mnt)2], where [FBzPy]+ = 1-(4â²-fluorobenzyl)pyridinium and mnt2â = maleonitriledithiolate, forms a discrete stacking column and shows a peculiar magnetic transition from paramagnetic to diamagnetic around 90 K.
离子对复合物[FBzPy][Ni(mnt)2](其中[FBzPy]+ = 1-(4â²-氟苄基)吡啶鎓,mnt2â = 马来酰亚胺二硫酸盐)形成了一个离散的堆积柱,并在 90 K 左右出现了从顺磁性到二磁性的奇特磁性转变。
New ion-pair nickel(III) complexes containing [Ni(‘S2’)2] (‘S2’2−=1,2-benzenedithiolate) fragments: synthesis, crystal structure and properties
Two new ion-pair complexes [1-(4'-fluorobenzyl)pyridinium][Ni(bdt)(2)] (1) and [1-(4'-bromobenzyl)pyridinium][Ni(bdt)(2)] (2), in which bdt(2-) = 1,2-benzenedithiolate ('S-2(,2-)), have been prepared and characterized. X-ray structural analyses showed that 1 and 2 are isostructural, and the anions are centrosymmetric. The 2 non-equiv. anions form different uniform-spaced stacking pattern in I and 2. The magnetic measurements of 1 and 2 indicate ferromagnetic behavior in the antiferromagnetic exchange system, which may arise from spin canting. Cyclovoltammetry revealed two quasi-reversible one-electron steps for I and 2, which are attributed to Ni(IV/III) and Ni(III/II) redox couples. (C) 2002 Elsevier Science Ltd. All rights reserved.
High regiocontrol in the nucleophilic ring opening of 1-aralkyl-3,4-epoxypiperidines with amines—a short-step synthesis of 4-fluorobenzyltrozamicol and novel anilidopiperidines
Nucleophilic ring-opening reactions of three 1-aralkyl-3,4-epoxypiperidines with a series of aliphatic and aromatic amines have been investigated. Reactions in protic solvents, preferably 2-propanol, gave rise to 3-amino-piperidin-4-ols in ratios up to 20:1. Accordingly, 4-fluorobenzyltrozamicol, a highly potent ligand for the vesicular acetylcholine transporter was obtained directly from an epoxide ring opening in one step, without the need of chromatographic separation. Reactions in acetonitrile assisted by Li-salts, most suitable with LiBr, led regioselectively to trans-4-amino-piperidin-3-ols in high yields. N-Phenethyl substituted anilino-piperidinols as easily obtained by this method were converted into a series of new beta-hydroxy substituted anilidopiperidines. (C) 2011 Elsevier Ltd. All rights reserved.