Direct Aryloxylation/Alkyloxylation of Dialkyl Phosphonates for the Synthesis of Mixed Phosphonates
A strategy for the direct functionalization strategy of inertial dialkyl phosphonates with hydroxy compounds to afford diverse mixed phosphonates with good yields and functional-group tolerance has been developed. Mechanistic investigations involving both NMR studies and DFT studies suggest that an unprecedented highly reactive PV species (phosphoryl pyridin-1-ium salt), a key intermediate for this new synthetic transformation, is generated in situ from dialkyl phosphonate in the presence of Tf2O/pyridine.
Huang, Hai,Denne, Johanna,Yang, Chou-Hsun,Wang, Haobin,Kang, Jun Yong
supporting information
p. 6624 - 6628
(2018/05/14)
THE EFFECT OF CARBONYL CONTAINING SUBSTITUENTS IN THE TERMINAL CHAINS ON MESOMORPHIC PROPERTIES IN AROMATIC ESTERS AND THIOESTERS, 2. ACYLOXY GROUPS ON THE PHENOLIC END
The effect of replacing an alkoxy (Y=OR') with acyloxy (Y=OCOR') group on the phenolic end of the esters: on their mesomorphic properties has been studied.These esters were prepared by esterification of 4-acyloxyphenols with the appropriate acid chloride.The phenols were synthesized by acylation of 4-benzyloxyphenol with either an aliphatic acid or acid chloride followed by catalytic hydrogenolysis of the benzyl group.A comparison of the melting and clearing temperatures of these acyloxy esters with the corresponding known alkoxy ones showed small increases in both these temperatures for the acyloxy esters.The same types of mesophases (N, SA, SC, SB) were observed in both series, but the SB was more favored when Y=OCOR'.The SC phase was found to occur in the acyloxy series at chain lengths beyond which it disappeared in the alkoxy series.Comparisons were also made with the mesomorphic properties previously reported for the correponding alkyl and α-keto esters.Some correlation was observed between increasing dipole moments of these substituents and increasing transition temperatures but not in the types of mesophases observed.Fewer mesophases were found when the alkyl chain was attached to the benzene ring through a carbon atom than through an oxygen atom.
Neubert, Mary E.,Wildman, Patricia J.,Zawaski, Michael J.,Hanlon, Carol A.,Benyo, Theresa L.,Vries, Adriaan De
p. 111 - 158
(2007/10/02)
Topical skin depigmenting composition
A stable topical skin depigmenting composition having no irritant action to the skin which comprises an active ingredient a fatty acid ester of hydroquinone of the formula: STR1 wherein R1 and R2 are the same or different, each being hydrogen or a straight or branched, saturated or unsaturated aliphatic hydrocarbon radical having 1 to 20 carbon atoms, provided that at least one of R1 and R2 is the hydrocarbon radical and one or more conventional ingredients suitable for a topical preparation. A method of depigmentation of the skin using the ester of the formula [I] is also disclosed.
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(2008/06/13)
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