A simple, green and efficient method for the DHP protection of various alcohols and phenols and the subsequent removal of the corresponding protective group in the presence of a catalytic amount of the activated carbo...A simple, green and efficient method for the DHP protection of various alcohols and phenols and the subsequent removal of the corresponding protective group in the presence of a catalytic amount of the activated carbon supported H2SO4 is described.展开更多
The deprotection of 1,3-dibenzyl-5-（N,N-dimethylamino）-6-phenyl-ethyluracil I was investigated. A practical, regioselective N3 deprotection of compound I was performed with excellent yield using cyclohexene as a hyd...The deprotection of 1,3-dibenzyl-5-（N,N-dimethylamino）-6-phenyl-ethyluracil I was investigated. A practical, regioselective N3 deprotection of compound I was performed with excellent yield using cyclohexene as a hydrogen donor.展开更多
t-Butyldimethylsilyl (TBDMS) ether can be cleaved upon refluxing in acetone/H2O (95 : 5) in the presence of a catalytic amount of copper (II) chloride dihydrate (5 mmol %).
An efficient and selective method for the deprotection of primary alcoholic tert-butyl-dimethylsilyl (TBS) ethers using SnCl_2·2H_2O as catalyst is described. The reaction conditionsallow primary alcoholic TBS et...An efficient and selective method for the deprotection of primary alcoholic tert-butyl-dimethylsilyl (TBS) ethers using SnCl_2·2H_2O as catalyst is described. The reaction conditionsallow primary alcoholic TBS ethers to be desilylated chemoselectively in the presence of phenolicTBS ethers, secondary and tertiary alcolholic TBS ethers, and the extensively used TBDPS-,acetyl-, benzyloxycarbonyl-, p-toluenesulfonyl- and benzyl protective groups.展开更多
A mild, efficient and fast method for direct oxidation of trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds using trinitratocerium（Ⅳ） bromate （TNCB） supported on...A mild, efficient and fast method for direct oxidation of trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds using trinitratocerium（Ⅳ） bromate （TNCB） supported on NaHSO4.H2O under solvent-free conditions is reported.展开更多
An efficient and clean preparation of acylals from aromatic aldehydes in the presence of synthetic phosphates (flourapatite and hydroxyapatite doped with ZnCl2 and ZnBr2) and acetic anhydride was achieved easily in hi...An efficient and clean preparation of acylals from aromatic aldehydes in the presence of synthetic phosphates (flourapatite and hydroxyapatite doped with ZnCl2 and ZnBr2) and acetic anhydride was achieved easily in high yields (86% - 97%) at room temperature under solvent-free conditions. Deprotection of the resulting acylals has also been attained by using the same catalysts under microwave irradiation. This method consistently has advantage of excellent yields (82% - 96%) and a short reaction time (3 - 4 min).展开更多
When the mixture of CpTiCl_3-KI is used, many acetals and ketals, which are difficuitly deprotected with CpTiCl_3 alone, can be easily converted to the corresponding carbonyl compounds in high yield at 30℃ in Et_2O.
Boc protection group could be readily removed in a very mild mechanochemical conditions. In a short reaction time, ball milling of Boc-protected amines with p-toluenesulfonic acid in solvent-free conditions affords co...Boc protection group could be readily removed in a very mild mechanochemical conditions. In a short reaction time, ball milling of Boc-protected amines with p-toluenesulfonic acid in solvent-free conditions affords corresponding amine p-TsOH salts.展开更多
As an important protective group of amines and amino acids,tert-butoxycarbonyl(Boc) group was extensively used in organic synthesis.Though many mild and selective reagents could be used,there is still a need for the d...As an important protective group of amines and amino acids,tert-butoxycarbonyl(Boc) group was extensively used in organic synthesis.Though many mild and selective reagents could be used,there is still a need for the development of a more simple and convenient method for deprotection.In this paper,a new method for the deprotection of N-Boc group with silica gel in refluxing toluene was reported.The reactions were mostly achieved in 5 h with high yields(75%-98%).N-Boc protected indoline and benzylamine,which are not deprotected with other mild method,could be deprotected with our method in good yields(89% and 95%,respectively).Additionally the deprotection of other carbamates such as Cbz,Fmoc and ethyl carbamate wasn′t observed under same conditions.展开更多
基金the special research project of the National 973 Foundation of China(No.2006CB708606)the National Natural Science Foundation of China(No.20562010)
文摘A simple, green and efficient method for the DHP protection of various alcohols and phenols and the subsequent removal of the corresponding protective group in the presence of a catalytic amount of the activated carbon supported H2SO4 is described.
基金Supported by the National Natural Science Foundation of China(No.20672008) "985" Program of the Ministry of Edu-cation of China
文摘The deprotection of 1,3-dibenzyl-5-（N,N-dimethylamino）-6-phenyl-ethyluracil I was investigated. A practical, regioselective N3 deprotection of compound I was performed with excellent yield using cyclohexene as a hydrogen donor.
基金Financial support by National Natural Science Foundation of China !(Grant No. 29972002) isgreatly acknowledged.
文摘t-Butyldimethylsilyl (TBDMS) ether can be cleaved upon refluxing in acetone/H2O (95 : 5) in the presence of a catalytic amount of copper (II) chloride dihydrate (5 mmol %).
文摘An efficient and selective method for the deprotection of primary alcoholic tert-butyl-dimethylsilyl (TBS) ethers using SnCl_2·2H_2O as catalyst is described. The reaction conditionsallow primary alcoholic TBS ethers to be desilylated chemoselectively in the presence of phenolicTBS ethers, secondary and tertiary alcolholic TBS ethers, and the extensively used TBDPS-,acetyl-, benzyloxycarbonyl-, p-toluenesulfonyl- and benzyl protective groups.
文摘A mild, efficient and fast method for direct oxidation of trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds using trinitratocerium（Ⅳ） bromate （TNCB） supported on NaHSO4.H2O under solvent-free conditions is reported.
文摘An efficient and clean preparation of acylals from aromatic aldehydes in the presence of synthetic phosphates (flourapatite and hydroxyapatite doped with ZnCl2 and ZnBr2) and acetic anhydride was achieved easily in high yields (86% - 97%) at room temperature under solvent-free conditions. Deprotection of the resulting acylals has also been attained by using the same catalysts under microwave irradiation. This method consistently has advantage of excellent yields (82% - 96%) and a short reaction time (3 - 4 min).
文摘When the mixture of CpTiCl_3-KI is used, many acetals and ketals, which are difficuitly deprotected with CpTiCl_3 alone, can be easily converted to the corresponding carbonyl compounds in high yield at 30℃ in Et_2O.
基金The financial support of this work by the Croatian Science Foundation(grant No.9310)is acknowledged.
文摘Boc protection group could be readily removed in a very mild mechanochemical conditions. In a short reaction time, ball milling of Boc-protected amines with p-toluenesulfonic acid in solvent-free conditions affords corresponding amine p-TsOH salts.
文摘As an important protective group of amines and amino acids,tert-butoxycarbonyl(Boc) group was extensively used in organic synthesis.Though many mild and selective reagents could be used,there is still a need for the development of a more simple and convenient method for deprotection.In this paper,a new method for the deprotection of N-Boc group with silica gel in refluxing toluene was reported.The reactions were mostly achieved in 5 h with high yields(75%-98%).N-Boc protected indoline and benzylamine,which are not deprotected with other mild method,could be deprotected with our method in good yields(89% and 95%,respectively).Additionally the deprotection of other carbamates such as Cbz,Fmoc and ethyl carbamate wasn′t observed under same conditions.
