The title compounds, the P(3)‐axially and P(3)‐equatorially substituted cis‐ and trans‐configured 9‐benzyl‐3‐fluoro‐2,4‐dioxa‐9‐aza‐3‐phosphadecalin 3‐oxides (=9‐benzyl‐3‐fluoro‐2,4‐dioxa‐9‐aza‐3‐phosphabicyclo[4.4.0]decane 3‐oxides=7‐benzyl‐2‐fluorohexahydro‐4H‐1,3,2‐dioxaphosphorino[4,5‐c]pyridine 2‐oxides) were prepared (ee >99%) and fully characterized (Schemes 2 and 4). The absolute configurations were deduced from that of their precursors, the enantiomerically pure ethyl 1‐benzyl‐3‐hydroxypiperidine‐4‐carboxylates and 1‐benzyl‐3‐hydroxypiperidine‐4‐methanols which were unambiguously assigned. Being configuratively fixed and conformationally constrained phosphorus analogues of acetylcholine, the title compounds represent acetylcholine mimetics and are suitable probes for the investigation of molecular interactions with acetylcholinesterase. As determined by kinetic methods, all of the compounds are moderate irreversible inhibitors of the enzyme. 相似文献
The synthesis of α‐benzamido‐α‐benzyl lactones 23 of various ring size was achieved either via ‘direct amide cyclization’ by treatment of 2‐benzamido‐2‐benzyl‐ω‐hydroxy‐N,N‐dimethylalkanamides 21 in toluene at 90 – 110° with HCl gas or by ‘ring transformation’ of 4‐benzyl‐4‐(ω‐hydroxyalkyl)‐2‐phenyl‐1,3‐oxazol‐5(4H)‐ones under the same conditions. The precursors were obtained by C‐alkylations of 4‐benzyl‐2‐phenyl‐1,3‐oxazol‐5(4H)‐one ( 15 ) with THP‐ or TBDMS‐protected ω‐hydroxyalkyl iodides. Ring opening of the THP‐protected oxazolones by treatment with Me2NH followed by deprotection of the OH group gave the diamides 21 , whereas deprotection of the TBDMS series of oxazolones 25 with TBAF followed by treatment with HCl gas led to the corresponding lactones 23 in a one‐pot reaction. 相似文献
Summary: The ring‐opening polymerization of N‐carboxy anhydrides (NCA) of γ‐benzyl‐L ‐glutamate and β‐benzyl‐L ‐aspartate was studied in the presence of an ammonium chloride‐functionalized poly(ethylene oxide) macroinitiator, which possibly prevents side reactions such as NCA deprotonation. Although polymerization initiated by such macroinitiators was found to be quite slow, well‐defined conjugates of poly(ethylene oxide)‐block‐poly(γ‐benzyl‐L ‐glutamate) and poly(ethylene oxide)‐block‐poly(β‐benzyl‐L ‐aspartate) with polydispersity indexes as low as 1.05 were prepared. Moreover, the presence of ammonium chloride chain ends significantly prevented end‐group cyclization of poly(γ‐benzyl‐L ‐glutamate) after polymerization.
Gel permeation chromatograms recorded for the diblock copolymers of poly(ethylene oxide)‐block‐poly(γ‐benzyl‐L ‐glutamate) prepared by N‐carboxy anhydride polymerization initiated either by PEO‐NH2 macroinitiator or PEO‐NHequation/tex2gif-stack-1.gifCl− macroinitiator. 相似文献
The title compounds, the P(3)‐axially and P(3)‐equatorially substituted cis‐ and trans‐configured 8‐benzyl‐3‐fluoro‐2,4‐dioxa‐8‐aza‐3‐phosphadecalin 3‐oxides (=8‐benzyl‐3‐fluoro‐2,4‐dioxa‐8‐aza‐3‐phosphabicyclo[4.4.0]decane 3‐oxides=2‐fluorohexahydro‐6‐(phenylmethyl)‐4H‐1,3,2‐dioxaphosphorino[5,4‐c]pyridine 2‐oxides) were prepared (ee>98%) and fully characterized (Schemes 2 and 3). The absolute configurations were established from that of their precursors, the enantiomerically pure cis‐ and trans‐1‐benzyl‐4‐hydroxypiperidine‐3‐methanols which were unambiguously assigned. Being configuratively fixed and conformationally constrained phosphorus analogues of acetyl γ‐homocholine (=3‐(acetyloxy)‐N,N,N‐trimethylpropan‐1‐aminium), they are suitable probes for the investigation of molecular interactions with acetylcholinesterase. As determined by kinetic methods, all of the compounds are weak inhibitors of the enzyme. 相似文献
Debromination of N‐benzyl 4‐ or 5‐substituted α‐bromo‐α‐p‐toluenesulfonylglutarimides is achieved with 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) to give the N‐benzyl 4‐ or 5‐substituted α‐p‐toluenesulfonylglutarimides. The DBU/THF system is applied to a new methodology for the synthesis of bicyclic glutarimide skeleton in moderate yields. 相似文献
Silica-supported polyphosphoric acid (PPA-SiO2) was found to be an efficient catalyst for the multi-component condensation reaction of benzaldehydes, 2-naphthol, and methyl/benzyl carbamate to afford the corresponding N-[α-(β-hydroxy-α-naphthyl)(benzyl)] O-alkyl carbamate derivatives in good to excellent yields. This new approach consistently has the advantage of short reaction time, high conversions, clean reaction profiles, and simple experimental and work-up procedures. 相似文献
In this paper, aliphatic polyesters functionalized with pendant carboxylic groups were synthesized via several steps. Firstly, substituted cyclic ketone, 2‐(benzyloxycarbonyl methyl)cyclopentanone (BCP) was prepared through the reaction of enamine with benzyl‐2‐bromoacetate, and subsequently converted into the relevant functionalized δ‐valerolactone derivative, 5‐(benzyloxy carbonylmethyl)‐δ‐valerolactone (BVL) by the Baeyer‐Villiger oxidation. Secondly, the ring‐opening polymerization of BVL with ε‐caprolactone was carried out in bulk using stannous octoate as the catalyst to produce poly(ε‐caprolactone‐co‐δ‐valerolactone) bearing the benzyl‐protected carboxyl functional groups [P(CL‐co‐BVL)]. Finally, the benzyl‐protecting groups of P(CL‐co‐BVL) were effectively removed by H2 using Pd/C as the catalyst to obtain poly(ε‐caprolactone‐co‐δ‐valerolactone) bearing pendant carboxylic acids [P(CL‐co‐CVL)]. The structure and the properties of the polymer have been studied by Nuclear Magnetic Resonance (NMR), Fourier Infrared Spectroscopy (FT‐IR) and Differential Scan Calorimetry (DSC) etc. The NMR and FT‐IR results confirmed the polymer structure, and the 13C NMR spectra have clearly interpreted the sequence of ε‐caprolactone and 5‐(benzyloxycarbonylmethyl)‐δ‐valerolactone in the copolymer. When the benzyl‐protecting groups were removed, the aliphatic polyesters bearing carboxylic groups were obtained. Moreover, the hydrophilicity of the polymer was improved. Thus, poly(ε‐caprolactone‐co‐δ‐valerolactone) might have great potential in biomedical fields. 相似文献
2,3‐Dihydro‐6‐hydroxy‐5‐methoxy‐7H‐dibenzo[de,h]quinolin‐7‐one, 6‐hydroxy‐5‐methoxy‐7H‐dibenzo[de,h]quinolin‐7‐one, and 2‐(6,7‐dimethoxy‐3,4‐dihydroisoquinolin‐1‐yl)benzyl benzoate, easily available by a Bischler–Napieralski cyclization, were used as starting materials to afford 6‐oxoisoaporphine and 2,3‐dimethoxy‐5,6,8,12b‐tetrahydroisoindolo[1,2‐a]isoquinoline as the main products. However, the catalytic hydrogenation of the benzyl benzoate derivative afforded, under mild conditions, 1,2,3,4‐tetrahydro‐6,7‐dimethoxy‐1‐(2‐methylphenyl)isoquinoline. 相似文献
Treatment of 2‐(methyl 3‐O‐benzyl‐4,6‐O‐benzylidene‐2‐deoxy‐α‐d‐altropyranosid‐2‐yl)ethanal (3) with malononitrile in the presence of aluminium oxide provided 2‐cyano‐4‐(methyl 3‐O‐benzyl‐4,6‐O‐benzylidene‐2‐deoxy‐α‐d‐altropyranosid‐2‐yl)crotononitrile (4). Starting from 4, cyclization with sulphur and triethylamine yielded 2‐amino‐5‐(methyl 3‐O‐benzyl‐4,6‐O‐benzylidene‐2‐deoxy‐α‐d‐altropyranosid‐2‐yl)thiophene‐3‐carbonitrile (5). Further cyclization could be achieved with triethyl orthoformate/ammonia to furnish 4‐amino‐6‐(methyl 3‐O‐benzyl‐4,6‐O‐benzylidene‐2‐deoxy‐α‐d‐altropyranosid‐2‐yl)thieno[2.3‐d]pyrimidine (8). 相似文献