Solvent-free tetrahydropyranylation (THP) of alcohols and phenols and their regeneration by catalytic aluminum chloride hexahydrate

Selective cleavage of acetal bonds in copolymers with polylactide block

“…4,6 The copolymer described in this article was subjected to methanolysis in conditions proposed by Namboodiri and Varma for the cleavage of acetal groups in case of simple organic alcohols. 14 A preliminary experiment of the methanolysis was carried out in perdeuterated methanol CD 3 OD, directly in an NMR tube. Full range 1 H NMR spectra were collected with at 5-min intervals.…”

A [2]Catenane and Pretzelane Based on Sn–Porphyrin and Crown Ether

“…Condensation of 10 with 11 followed by reduction gave bis(benzyl)amine 12; (Boc) 2 O-protected 12 reacted with TsCl to give bis(tosylate) 14 in 80 % yield. Compound 14 reacted with a monoprotected resorcinol derivative [15] in the presence of K 2 CO 3 followed by deprotection with ethanol/aqueous HCl at room temperature and removal of the Boc group with trifluoroacetic acid (TFA) to give free 15 in 85 % yield. Acidification with HCl followed by anion exchange with NH 4 PF 6 afforded the dialkylammonium salt 15-H·PF 6 .…”

Aluminium chloride hexahydrate: an efficient and versatile reagent in organic synthesis

“…Varma and Namboodiri 19 reported a AlCl 3 .6H 2 O catalyzed solvent free tetrahydropyranylation of alcohols and phenols by the reaction of aliphatic and aromatic alcohols 20 with 3,4-dihydro-2H-pyran (DHP) (21) (Scheme 6). A wide variety of alcohol and phenolic compounds (e.g., 3-hexanol, 4-butanediol, t-butanol, cyclohexanol, allyl alcohol, geraniol, 4-chlorobenzyl alcohol, phenol, 4-chlorophenol, 2-naphthol, benzhydrol etc.)…”