Note on the Preparation of Trialkyl Phosphates and their Use as Alkylating Agents

Abstract

On cooling, needle crystals separated which, after recrystallization from alcohol, gave 0.5 g. of light cream-colored needles which melted at 223°. The analytical data were satisfactory for the monofurfuryl ether of the diol.

Methylation of Polyols with Trimethylphosphate in the Presence of a Lewis or Brønsted Acid Catalyst

“…[6] The use of less toxic reagents,s uch as dimethylcarbonate [10] or dimethylsulfite, [11] has also been explored. [16][17][18] To our knowledge,o nly two reports have described the methylationo fa liphatic alcohols with trimethylphosphate. More precisely,a th igh temperatures (above160 8C) the alkylation of glycerol is in competition with the formation of acrolein.…”

“…From monopentyl dimethyl tartrate, the reactionwas heated at 150 8C, leading to the formation of compound 12 after 48 h. This could be attributed to steric hindrance limiting the access to the alcoholic hydroxy groups to methylate. Under similar conditions at 100 8C during 20 hi nt he presenceo fF e(OTf) 2 ,1 -ethoxyoctane (16), 1-isopropoxyoctane (17), and 1-butoxyoctane (18)w ere prepared from 1-octanol. Finally,weevaluated the methylation of phenol under the developed conditions, which was previously previously reported to have been carriedo utwith a base.…”

“…Methylation and alkylation (using trialkylphosphate) of phenolica lcohols were realized by using aL ewis acid or ab ase, respectively. [16][17][18] To our knowledge,o nly two reports have described the methylationo fa liphatic alcohols with trimethylphosphate. In 1944, To yd escribed the methylation of alcohols in moderate yield by heatingb oth reagents at reflux.…”

“…Finally,weevaluated the methylation of phenol under the developed conditions, which was previously previously reported to have been carriedo utwith a base. [17] From catechol, the rate of reactionw as very slow; after 40 ho nly 55 %y ield of guaiacol (14)w as detecteda longside 25 %ofthe monomethylated product. One limitation of this reaction concerns the methylation of carbohydrates.…”

“…The alkylation of alcohols with other alkylphosphates was then considered (Table4). Under similar conditions at 100 8C during 20 hi nt he presenceo fF e(OTf) 2 ,1 -ethoxyoctane (16), 1-isopropoxyoctane (17), and 1-butoxyoctane (18)w ere prepared from 1-octanol. The measured conversionso ft he octanol into the desired ethersw ere, respectively 70, 72, and 90 %.…”