• Bulletin of the Korean Chemical Society
• /
• v.25 no.10
• /
• pp.1447-1448
• /
• 2004

• Bulletin of the Korean Chemical Society
• /
• v.21 no.9
• /
• pp.901-904
• /
• 2000

The mechanism for the photo-Fries rearrangement of phenyl acetate andbiphenylyl acetates were reinvestigat-ed in phenol (or phenol derivatives) containing media. The results showed that the phenol (or phenol deriva-tives) which is the most common by-product of Fries reaction reacts with acyl radical togive Fries-product. These phenol (or phenol derivatives) contributions to the Fries-products were suggested as the Trivial mecha-nism for the photo-Fries reaction.

• Bulletin of the Korean Chemical Society
• /
• v.7 no.6
• /
• pp.442-444
• /
• 1986

Starting with the readily available p-tert-butyl-calix[4]arene 2, tert-butyl groups are removed by $AlCl_3$-catalyzed de-alkylation reaction, and the calix[4]arene 3 formed is converted to the tetraacetate 4. This compound undergoes Fries rearrangement to yield p-acetylcalix[4]arene 6, which seems to be an attractive starting material for the introduction of functional groups. As a preliminary experiment p-(1-hydroxyethyl)calix[4]arene 7 is prepared by LiAlH$_4$ reduction of 6.

• YAKHAK HOEJI
• /
• v.53 no.6
• /
• pp.377-381
• /
• 2009

Isowogonin, 5,8-dihydroxy-7-methoxyflavone, is a flavonoid isolated from the root of Scutellaria baicalensis Georgi, a medicinal plant traditionally used since the ancient time. It was thought to possess a variety of biological activities, such as antioxidation, anti-inflammation and hepatoprotective effect. But a quantity of isowogonin obtained from Scutellaria baicalensis Georgi is not that enough for in vivo test. There have been no appropriate approaches available for a facile synthesis of isowogonin. So we describe a concise and efficient scheme for synthesis of isowogonin from a commercial available 2,4,6-trimethoxyphenol, which includes the Fries rearrangement and selective demethylation as key steps.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.1
• /
• pp.65-70
• /
• 2011

Coumarins are ubiquitous in plant kingdom and have been used as antitumor, antifungals, anticoagulants, insecticides. Chalcones are also widespread in plant kingdom and have been known to possess diverse biological activities; antibacterial, antifungal, antitumor and anti-inflammatory, etc. As they are considered as important natural products, numerous synthetic approaches have been reported up to the present. We devise a new selective method of preparing dihydrocoumarins and chalcones from aryl cinnamates by the selection of reagents. Dihydrocoumarin derivatives were prepared selectively by using intramolecular cyclization catalyzed by p-toluene sulfonic acid. Also, chalcones were prepared by Fries-rearrangement catalyzed by $TiCl_4$. This method can be used for preparing various coumarin & chalcone compounds.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.6
• /
• pp.1939-1944
• /
• 2012

Benzoyloxy benzophenone derivatives were prepared in 3 steps including DCC coupling, Fries rearrangement and esterification from benzoic acids in 24-89% total yields. Among the prepared 12 benzophenone analogues 1a-1l, the compound 1b having three chloro groups at the para position showed maximum inhibitory effects of ICAM-1 expression but, 1a which have no substituents at all showed no inhibitory activity. This study provides the evidences that benzoyloxy benzophenone derivative, 1b may exert its anti-inflammatory activity by suppressing IFN-${\gamma}$-induced ICAM-1 expression.

• Bulletin of the Korean Chemical Society
• /
• v.13 no.6
• /
• pp.689-695
• /
• 1992

Methods for the selective functionalization of calix[4]arene at the upper rim are described. The diametrically substituted calix[4]arene dimethyl ether 2, obtained from the treatment of calix[4]arene 1 with methyl iodide in the presence of $K_2CO_3$, is converted to the two isomeric p-diacetylcalix[4]arene dimethyl ether 3 and 6 by direct substitution and by Fries rearrangement of corresponding diacetyloxycalix[4]arene dimethyl ether 5 respectively. Diametrically substituted p-diacetylcalix[4]arene 8 was also prepared by Fries rearrangement of calix[4]arene tetraacetate 7 using a limited amount of $AlCl_3$.

• Bulletin of the Korean Chemical Society
• /
• v.20 no.5
• /
• pp.547-550
• /
• 1999

Irradiation of 1-(o-acetoxyphenyl)-2-pentamethyldisilanyl ethyne 2 in benzene yields the photo-Fries rearrangement products 5 and 6 and a photoproduct 4 via silacyclopropene intermediate.

• Bulletin of the Korean Chemical Society
• /
• v.11 no.1
• /
• pp.58-59
• /
• 1990

A method is described for the selective functionalization of calix[4]arene at the para positions of the phenyl rings. The diametrically substituted calix[4]arene dimethyl ether 3, obtained from the treatment of calix[4]arene 2 with methyl iodide in the presence of $K_2CO_3$, is converted to the diacetyloxy calix[4]arene dimethyl ether 4. This compound undergoes Fries rearrangement to yield the diametrically p-diacetylcalix[4]arene dimethyl ether 5 in 68% yield.

• Bulletin of the Korean Chemical Society
• /
• v.16 no.11
• /
• pp.1122-1125
• /
• 1995

Three inherently chiral calix[4]arenes 3-5 were synthesized as racemate starting from the ethylation at 1.3-distal hydroxy groups of calix[4]arene 2 which has two phenyl groups at upper rim in AABB fashion, and then two remaining hydroxy groups were acetylated by treatment with acetyl chloride in the presence of NaH to produce calix[4]arene 4. Treatment of 4 with AlCl3 under Fries rearrangement conditions, only one acetyl group was rearranged to the para-position to afford calix[4]arene 5 with AABC substitution pattern at the upper rim of calix. The structure of chiral calix[4]arenes were confirmed based on NMR and massspectra.