2,4,4,6-Tetrabromo-2,5-cyclohexadienone (TABCO), N-Bromosuccinimide (NBS) and Bromine as Efficient Catalysts for Dithioacetalization and Oxathioacetalization of Carbonyl Compounds and Transdithioacetalization Reactions
作者:Nasser Iranpoor、Habib Firouzabadi、Hamid Reza Shaterian、M. A. Zolfigol
DOI:10.1080/10426500211712
日期:2002.5.1
6-tetrabromo-2,5-cyclohexadienone (TABCO), N-bromosuccinimide (NBS), and bromine as efficient catalysts for conversion of carbonyl compounds to their cyclic and acyclic dithioacetals and 1,3-oxathiolanes under mild reaction conditions are described. These catalysts are also used for efficient transdithioacetalization of acetals, diacetals, ketals, acylals, enamines, hydrazones, and oximes with high
An efficient and chemoselective deprotection of aryl- and styrenyldithioketals (acetals)
作者:Eng-Chi Wang、Chien-Huang Wu、Shih-Chang Chien、Wen-Chang Chiang、Yueh-Hsiung Kuo
DOI:10.1016/j.tetlet.2007.08.054
日期:2007.10
In this Letter, an efficient and chemoselective deprotection of aryl- and styrenyldithioketals (acetals) is described. After being carefully examined, 10% Pd/C and Amberlite 120 in refluxing methanol was found to be an excellent condition for the chemoselective deprotection of aryl- and styrenyldithioketals (acetals) in good yields. Under this condition, no deprotection and no reduction of alkyldithioketals
2,6-Dicarboxypyridinium Chlorochromate. An Efficient and Selective Reagent for the Mild Deprotection of Acetals, Thioacetals, and 1,1-Diacetates to Carbonyl Compounds
chlorochromate (2,6- DCPCC ) was found to be an efficientreagent for the conversion of acetals, thioacetals, and 1,1-diacetates to their corresponding carbonyl compounds under neutral and anhydrous conditions in good to excellent yields. Selectivedeprotection of acetals or 1,1-diacetates in the presence of thioacetals at room temperature is also observed with this reagent.
Deprotection of Thioacetals Using K2S2O8/[bmim]Br as a Mild and Efficient Reagent under Solvent-Free Conditions
作者:Abdol R. Hajipour、Majid Mostafavi、Arnold E. Ruoho
DOI:10.1007/s00706-007-0650-1
日期:2007.6
A straightforward and effective procedure for the deprotection of thioacetals to the corresponding carbonyl compounds using potassium persulfate and the ionic liquid [ bmim ]Br undersolvent-freeconditions is reported. A variety of aliphatic and aromatic 1,3-dithiolanes or 1,3-dithanes was deprotected to the corresponding carbonyl derivatives by this procedure.
A mild process using a combination of TMSCl and NaI in acetonitrile is used to regenerate carbonyl compounds from a variety of dithiane and dithiolane derivatives. This easy to handle and inexpensive protocol is also efficient to deprotect oxygenated and mixed acetals as 1,3-dioxanes, 1,3-dioxolanes and 1,3-oxathianes quantitatively. As a possible extension of this method, it was also showed that
在乙腈中使用 TMSCl 和 NaI 组合的温和工艺用于从各种二噻烷和二硫戊环衍生物中再生羰基化合物。这种易于操作且价格低廉的方案还可以有效地将含氧和混合缩醛作为 1,3-二氧六环、1,3-二氧戊环和 1,3-氧杂环己烷进行定量脱保护。作为该方法的可能扩展,还表明作为腙、N-甲苯磺酰腙和酮时的氮化底物在这些条件下反应良好,以高产率得到预期的酮。本文提出的方法是现有方法的一个很好的替代方案,因为它不使用金属、氧化剂、还原剂、酸性或碱性介质,并且以高产率获得酮产物。