- Magnesium dicarboxylates promote the prenylation of phenolics that is extended to the total synthesis of icaritin
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The prenylation of phenolic substrates promoted by magnesium dicarboxylates was developed. An investigation of the scope demonstrated that substrates with electron-donating group(s) gave better yields than those with electron-withdrawing group(s). Althoug
- Fu, Xuewen,Lu, Xiaoxia,Wang, Chun,Wen, Yongju,Xiong, Wei,Zhang, Guolin,Zhang, Jichao
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supporting information
p. 1117 - 1124
(2022/02/16)
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- Candida antarctica lipase B-catalyzed regioselective deacylation of dihydroxybenzenes acylated at both phenolic hydroxy groups
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Candida antarctica lipase B proved to be highly active in the deacylation of substituted hydroquinones and resorcinols acylated at both phenolic hydroxy groups. The deacylation reactions were much faster than the corresponding direct acylations of these dihydroxybenzenes catalyzed by the same lipase. More importantly, they took place generally in a markedly regioselective manner: the acyloxy group remote from the substituent was preferentially cleaved. The main or exclusive products obtained were the regioisomers of those produced through the direct acylation of the dihydroxybenzenes. In the case of alkyl-substituted hydroquinone derivatives, the regioselectivity increased with an increase in the bulk of the substituent. In the case of 4-substituted diacylated resorcinols, the 3-O-monoacyl derivatives were obtained generally as the sole products. Quite interestingly, some secondary alcohols proved to act as better acyl acceptors than the corresponding primary alcohols in these enzymatic deacylations.
- Miyazawa, Toshifumi,Hamada, Manabu,Morimoto, Ryohei
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- Microwave-accelerated alkylation of arenes/heteroarenes with benzylic alcohols using antimony(III) chloride as catalyst: Synthesis of O-heterocycles
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An efficient protocol for alkylation of electron-rich arenes/heteroarenes with benzylic alcohols under microwave irradiation using antimony(III) chloride as catalyst has been developed. The mild reaction conditions, high yields, operational simplicity, and applicability to various substrates render the approach a useful route for the synthesis of diaryl/triarylalkane. In addition, a new route for the conversion of ortho-alkenylated phenols into functionalized O-heterocycles has been accomplished. Georg Thieme Verlag Stuttgart ? New York.
- Shukla, Prashant,Choudhary, Manoj K.,Nayak, Sandip K.
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supporting information; experimental part
p. 1585 - 1591
(2011/08/03)
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- Structure-based design, synthesis and preliminary anti-inflammatory activity of bolinaquinone analogues
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As a part of our drug discovery efforts we developed a series of simplified derivatives of bolinaquinone (BLQ), a hydroxyquinone marine metabolite, showing potent anti-inflammatory activity. Thirteen new hydroxyquinone derivatives closely related to BLQ were synthesized and tested on mouse macrophage-like RAW 264.7 cell line in order to investigate their ability to modulate the production of Prostaglandin E2 (PGE2). This optimization process led to the identification of three strictly correlated compounds with comparable and higher inhibitory potency than BLQ on PGE2 production. To evaluate the affinity of BLQ and its analogues for hsPLA2, surface plasmon resonance (SPR) experiments were performed.
- Petronzi, Carmen,Filosa, Rosanna,Peduto, Antonella,Monti, Maria Chiara,Margarucci, Luigi,Massa, Antonio,Ercolino, Simona Francesca,Bizzarro, Valentina,Parente, Luca,Riccio, Raffaele,De Caprariis, Paolo
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p. 488 - 496
(2011/03/19)
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- Acidic rearrangement of (benzyloxy)chalcones: A short synthesis of chamanetin
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Treatment of (benzyloxy)chalcones with trifluoroacetic acid in refluxing chloroform gave several new benzyl(hydroxy)flavanones in high yields and good regioselectivities. By using this procedure, we prepared the natural compound chamanetin in good yield from readily available reagents. Georg Thieme Verlag Stuttgart - New York.
- Sagrera, Gabriel,Seoane, Gustavo
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scheme or table
p. 4190 - 4202
(2011/03/20)
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- ISOXAZOLE COMPOUNDS AS INHIBITORS OF HEAT SHOCK PROTEINS
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Isoxazoles of formula (A) or (B) are inhibitors of HSP90 activity, and useful for treatment of, for example cancers: (A), (B) wherein R1, is a group of formula (IA): -Ar1-(Alk1)p-(Z)r-(Alk2)S-Q, wherein in any compatible combination Ar1 is an optionally substituted aryl or heteroaryl radical, Alk1and Alk2 are optionally substituted divalent Cl-C6 alkylene or C2-C6 alkenylene radicals, p, r and s are independently 0 or 1, Z is -0-, -S-, -(C=O)-, -(C=S)-, -SO2-, -C(=O)O-, -C(=O)NRA-, -C(=S)NRA-, - SO2NRA-, -NRAC(=O)-, -NRASO2- or -NRA- wherein RA is hydrogen or Cl-C6 alkyl, and Q is hydrogen or an optionally substituted carbocyclic or heterocyclic radical; R2 is (i) a group of formula (IA) above or (ii) a carboxamide radical; or (iii) a non aromatic carbocyclic or heterocyclic ring wherein a ring carbon is optionally substituted, and/or a ring nitrogen is optionally substituted by a group of formula -(Alk1)p-(Z)r-(Alk2)s-Q wherein Q, Alk1, Alk2, Z, p, r and s are as defined above in relation to group (IA); and R3 is hydrogen, optionally substituted cycloalkyl, cycloalkenyl, C1-C6 alkyl, C1-C6 alkenyl, or C1-C6 alkynyl; or a carboxyl, carboxamide, or carboxyl ester group.
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- Inhibition of tyrosinase by flavonoids, stilbenes and related 4- substituted resorcinols: Structure-activity investigations
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Several flavonoids, stilbenes and related 4-substituted resorcinols, obtained from Artocarpus incisus and other plants or synthesized, were tested for their inhibitory activity against tyrosinase. The structure-activity relationships suggested that specific natural or synthesized compounds having the 4-substituted resorcinol skeleton have potent tyrosinase inhibitory ability. Kinetic studies have indicated that specific compounds having the 4- substituted resorcinol skeleton exhibit competitive inhibition of the oxidation of DL-β-(3,4-dihydroxyphenyl)alanine (DL-DOPA) by mushroom tyrosinase. These findings could lead to the design and discovery of new tyrosinase inhibitors.
- Shimizu, Kuniyoshi,Kondo, Ryuichiro,Sakai, Kokki
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- Antioxidant activities of dihydric phenol derivatives for the autoxidation of tetralin
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The antioxidant activities of dihydric phenols, such as catechol, resorcinol, and hydroquinone, and their twenty-three alkyl and benzyl substituted derivatives were evaluated by means of an oxygen-absorption method at 60°C for determining the oxidation of tetralin. Catechols exhibited a much higher stoichiometric factor (2.0-2.3) compared with those of other compounds. The stoichiometric factors of hydroquinones (0.6-1.1) are almost half those of catechols, and are lower for the resorcinols (0.3-0.6). In addition, the rates of oxidation during the induction period (R(inh)) were 1.1-1.6 x 10-6, 3.0-3.8 x 10-6, and 13.3-18.4 x 10-6 M min-1 for catechols, hydroquinones, and resorcinols, respectively. According to these results, catechols and hydroquinones are efficient antioxidants, and their activities may be dependent on the stability of phenoxyl radicals as oxidation products due to the formation of the quinone structure. Furthermore, the stability of phenoxyl radicals derived from catechols is higher than that of those from hydroquinones. In spite of having two OH substituents, resorcinols behave as monohydric phenols in the reaction with peroxyl radicals.
- Yamamura,Nishiwaki,Tanigaki,Terauchi,Tomiyama,Nishiyama
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p. 2955 - 2960
(2007/10/03)
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- ALKYLATION OF ACTIVE HYDROGEN COMPOUNDS WITH ALLYLIC AND BENZYLIC ALCOHOLS UNDER CoCl2 CATALYSIS. A USEFUL SYNTHESIS OF GRIFOLIN
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CoCl2 is a useful catalyst for the condensation of allylic and benzylic alcohols with active hydrogen compounds.Under these neutral conditions orcinol and farnesol react to afford the antibiotic grifolin.
- Marquet, J.,Moreno-Manas, M.
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p. 173 - 176
(2007/10/02)
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