- Synthesis of 2-Methoxy- and 4-Methoxy-Estrogens with Halogen-Methoxy Exchange Reaction
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Synthesis of 2-methoxy- and 4-methoxy-estrone (6) and (9), 2-methoxy- and 4-methoxy-estradiol (15) and (18), and 2-methoxy- and 4-methoxy-estratriol (24) and (27) are described.Catalytic hydrogenation over Pd/C of 2,4-dibromo or 2,4-diiodo estrogens gave regioselectively the corresponding 4-halogeno derivatives in excellent yields.Reaction of 2-iodo or 4-iodo estradiol and 2-iodo or 4-iodo estriol with NaOCH3 in MeOH and dimethylformamide (DMF) in the presence of CuCl2 gave in an excellent yield and in a good yield, while (6) and (9) were also similarly obtained by the reaction with pyridine instead of DMF.
- Numazawa, Mitsuteri,Ogura, Yuko,Kimura, Katsuhiko,Nagaoka, Masao
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p. 3701 - 3715
(2007/10/02)
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- Methylation of catechol estrogen with diazomethane
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Dynamic aspects of methylation of catechol estrogen with diazomethane were investigated by means of thin-layer chromatography. The methylation rate of the hydroxyl group at the C-3 position was almost the same as that of the C-2 hydroxyl group in the reaction of 2-hydroxyestrogen, and 2-3 times that of the C-4 hydroxyl group in the reaction of 4-hydroxyestrogen. In these experiments, the maximum yields of 2-methoxyestrone, 2-hydroxyestrone 3-methyl ether, 4-methoxyesterone and 4-hydroxyesterone 3-methyl ether were 32, 39, 13, and 70%, respectively. In addition, demethylation of catechol estrogen dimethyl ethers with boron tribromide and synthesis of 4-hydroxyestrone monomethyl ethers are described.
- Teranishi,Fujii,Yamazaki,Miyabo
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p. 3309 - 3314
(2007/10/02)
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- Efficient Synthesis of 2-Methoxy- and 4-Methoxy-estrogens
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2-Methoxy- and 4-methoxy-estrogens are easily prepared from the corresponding 2-iodo or 4-bromo derivatives in high yields by a halogen-methoxy group exchange reaction using sodium methoxide-copper(II) chloride.
- Numazawa, Mitsuteru,Ogura, Yuko
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p. 533 - 534
(2007/10/02)
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