A Useful and Environmentally Benign Synthetic Protocol for Dethiolization by Employing Vanadium Pentoxide Catalyzed Oxidation of Ammonium Bromide by Hydrogen Peroxide
作者:Ejabul Mondal、Gopal Bose、Priti Rani Sahu、Abu T. Khan
DOI:10.1246/cl.2001.1158
日期:2001.11
presence of olefin and aromatic ring as well as other protecting groups to carbonyl compounds by employing V2O5 catalyzedoxidation of ammonium bromide by H2O2 in CH2Cl2–H2O solvent system; mild conditions, high selectivity, good yield, and no side products such as bromination or oxidation are some of the major advantages.
A Highly Efficient Procedure for Regeneration of Carbonyl Groups from their Corresponding Oxathioacetals and Dithioacetals Using Sodium Nitrite and Acetyl Chloride in Dichloromethane
作者:Abu T. Khan、Ejabul Mondal、Priti R. Sahu
DOI:10.1055/s-2003-37115
日期:——
A wide variety of oxathioacetals 1 as well as dithioacetals 2 can be chemoselectively deprotected to the corresponding carbonyl compounds 3 in good yields by employing NaNO2-AcCl and H2O in CH2Cl2 at 0 °C to room temperature. Some of the major advantages of this procedure are: mild conditions, easy to handle, highly chemoselective and efficient, high yields and inexpensive reagents. In addition, no acetylation occurs at the hydroxyl group nor chlorination takes place at the double bond.
An Expedient and Efficient Method for the Cleavage of Dithioacetals to the Corresponding Carbonyl Compounds Using Organic Ammonium Tribromide (OATB)
作者:Ejabul Mondal、Gopal Bose、Abu T. Khan
DOI:10.1055/s-2001-14579
日期:——
A variety of dithioacetals of aldehydes or ketones 1 can be easily cleaved into the parent carbonyl compounds 2 at 0-5 °C in very high yields by employing organic ammonium tribromides such as cetyltrimethyl-ammonium tribromide (CetTMATB) or tetrabutylammonium tribromide (TBATB) in dichloromethane.
通过使用有机三溴化铵,如二氯甲烷中的十六烷基三甲基三溴化铵 (CetTMATB) 或四丁基三溴化铵 (TBATB),各种醛或酮的二硫代乙醛 1 可在 0-5 °C 的温度下轻松裂解成母体羰基化合物 2,而且产率非常高。
Nickel(II) chloride as an efficient and useful catalyst for chemoselective thioacetalization of aldehydes
作者:Abu T. Khan、Ejabul Mondal、Priti R. Sahu、Samimul Islam
DOI:10.1016/s0040-4039(02)02771-5
日期:2003.1
A wide variety of acyclic and cyclic dithioacetals can be prepared chemoselectively from the corresponding aldehydes by employing a catalytic amount of nickel(II) chloride in dry CH2Cl2-MeOH (5:1) at room temperature in good yields. Some of the major advantages of this procedure are high chemoselectivity, ease of operation, high yields and also compatibility with other protecting groups. (C) 2003 Elsevier Science Ltd. All rights reserved.
Cobalt(II)chloride catalyzed chemoselective thioacetalization of aldehydes
作者:Surya Kanta De
DOI:10.1016/j.tetlet.2003.11.082
日期:2004.1
A mild and chemoselective dithioacetalization procedure for the protection of various aldehydes in the presence of catalytic amount of cobalt(II)chloride is described. (C) 2003 Elsevier Ltd. All rights reserved.