Improved Procedure for the Bimolecular Oxidative Amidation of Phenols
摘要:
Trifluoroacetic acid (TFA) is an effective promoter of the bimolecular Ritter-like oxidative amidation of 4-substituted phenols induced by PhI(OAc)(2) in MeCN. This suppresses the need for fluoroalcohol cosolvents, increases the yields, and facilitates isolation/purification procedures.
A compound having ferroelectric liquid crystal properties of the formula: ##STR1## wherein A is the residue of a liquid crystal material or a liquid crystal compatible material; X is O or S; n is 0 or 1; Y is any inert group which does not cause the melting point of the compound of Formula I to exceed 200.degree. C.; R.sup.1 is selected from H, C.sub.1-4 -alkyl and halogen; and R.sup.2 is C.sub.1-4 -alkyl or halogen; provided that R.sup.1 and R.sup.2 are different. In a suitable environment the compound is capable of alignment in two metastable states and is therefore suitable for use in multiplex-addressed, liquid crystal devices, such as flat bed large area screens and displays.
Improved Procedure for the Bimolecular Oxidative Amidation of Phenols
作者:Huan Liang、Marco A. Ciufolini
DOI:10.1021/jo800267q
日期:2008.6.1
Trifluoroacetic acid (TFA) is an effective promoter of the bimolecular Ritter-like oxidative amidation of 4-substituted phenols induced by PhI(OAc)(2) in MeCN. This suppresses the need for fluoroalcohol cosolvents, increases the yields, and facilitates isolation/purification procedures.
Uncatalyzed Reaction of Silyl Ketene Acetals with Oxalyl Chloride: A Straightforward Preparation of Symmetrical Pulvinic Acids
作者:Benoît Heurtaux、Claude Lion、Thierry Le Gall、Charles Mioskowski
DOI:10.1021/jo048403v
日期:2005.2.1
natural pulvinicacids were synthesized. Silyl ketene acetals derived from methyl arylacetates (4 equiv) reacted with oxalyl chloride at −78 °C, without the need of adding a catalyst. After treatment of the crude diketones with DBU and acidification with hydrochloric acid, symmetrical pulvinicacids methyl esters were obtained. Saponification of the methyl esters afforded the corresponding pulvinic acids