Sulfuric Acid Adsorbed on Silica Gel: An Efficient Catalyst for the Protection and Deprotection of Alcohols with Dihydropyran.

Content Provider	Semantic Scholar
Author	Heravi, Majid M. Bigdeli, Mohammad Ali Nahid, Navidjouy Ajami, Dariush
Copyright Year	2000
Abstract	3, 4-Dihydro-2H-pyran (DHP) has been widely utilized as a protective group for hydroxy compounds requiring protic or Lewis acids as typical promoters' . More recently the tetrahydropyranylation process (THP ethers) has been perfomled under environmentally friendly conditions with minimum purfication requi rements . These include use of heterogenous catalysts such as montmorillon ite K-I 0, sulfonated charcoal, H-Y zeolite, zinc chlorides, envirocat EPZG and natural kao linite cla/ . Moreover a bentonitic clay has been used to deprotect THP ethers. However, none of these catalysts is claimed to give protection as well as deprotection of hydroxy compounds but one . Taking into account the increasing demand for new and cleaner chemical process we undertook a study directed towards discovering new catalytic application of supported acid. The synthetic uti lity of supported reagents has been demonstrated during the past ten years. As a result many reactions can be now carried out cleanly and rapidly under mild condit ions by using reagents which have been previously adsorbed on inorganic supports . Si lica gel has been one of the most used inorganic supports in organic synthesis' 2. In this paper we present the protection of hydroxy compounds as THP ethers and removal of the protective group over sulphuric ac id adsorbed on silica gel in aprotic (CH2Cb) and protic (MeOH) solvents, respectively. ROH • RoD
File Format	PDF HTM / HTML
DOI	10.1002/chin.200014061
Volume Number	31
Alternate Webpage(s)	http://nopr.niscair.res.in/bitstream/123456789/16653/1/IJCB%2038B(11)%201285-1286.pdf
Alternate Webpage(s)	https://doi.org/10.1002/chin.200014061
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article