- PROCESSES FOR THE PREPARATION OF APREMILAST AND INTERMEDIATES THEREOF
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Disclosed are processes for the preparation of Apremilast and intermediates for its preparation.
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Paragraph 0078
(2017/07/29)
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- Rh/DuanPhos-Catalyzed Asymmetric Hydrogenation of β-Acetylamino Vinylsulfides: An Approach to Chiral β-Acetylamino Sulfides
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Rh/DuanPhos-catalyzed asymmetric hydrogenation of challenging β-acetylamino vinylsulfides has been developed, affording chiral β-acetylamino sulfides with high yields and excellent ee's (up to 99% ee). This novel methodology provides an efficient and concise synthetic route to chiral β-acetylamino sulfides. The potential utility of this protocol in the synthesis of Apremilast has also been disclosed.
- Gao, Wenchao,Lv, Hui,Zhang, Xumu
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supporting information
p. 2877 - 2880
(2017/06/07)
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- Preparation method of Apremilast and intermediate
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The invention provides a preparation method of Apremilast and its intermediate. The invention provides an Apremilast intermediate as shown in the formula III. According to the preparation method, the compound as shown in the formula III reacts with methanesulfinate to obtain a compound as shown in the formula IV; the compound as shown in the formula IV undergoes reductive amination to obtain a compound as shown in the formula V; the compound as shown in the formula V and asymmetry acid undergo salifying to obtain a compound as shown in the formula VI; and the compound as shown in the formula VI reacts with 3-acetamido-phthalic anhydride to obtain Apremilast. By the method for synthesizing Apremilast, usage of an n-butyllithium hexane solution can be avoided. Production cost is reduced, and operation process is convenient. In addition, safety in the industrial production is raised to a great extent, and the preparation method is more suitable for industrial continuous production. According to the preparation method of 3-acetamido-phthalic anhydride, yield is raised to 81%. As the yield is high, the method provided by the invention is extremely suitable for industrial production of Apremilast.
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Paragraph 0044; 0045; 0046; 0047
(2016/10/07)
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- Novel 3-Thia-10-Aza-Phenanthrene Derivatives
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The compounds of formula I in which A, R1, R2 and R3 have the meanings as given in the description, are novel effective PDE4 inhibitors.
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Page/Page column 18-19
(2008/06/13)
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- BENZOQUINAZOLINE DERIVATIVES AND THEIR USE IN TREATING BONE DISORDERS
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A compound of formula (I) or a pharmaceutically acceptable salt or prodrug ester thereof, wherein the groups R2, R3, R4, Q, X and Y are as defined in the specification, is useful in the treatment of bone conditions related to increased calcium depletion or resorption.
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Page/Page column 44
(2008/06/13)
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- Novel 3-Oxa-10-Aza-Phenanthrenes
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The compounds of formula I in which R1, R2 and R3 have the meanings as given in the description, are novel effective PDE4 inhibitors.
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Page/Page column 16
(2010/11/28)
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- Synthesis of tetrahydropyran-4-ones and thiopyran-4-ones from donor-substituted α-bromostyrene derivatives
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Tetrahydropyran-4-one and tetrahydrothiopyran-4-one derivatives with a 3-aryl substituent were synthesized by double-conjugate addition of water or H2S to divinyl ketones. These starting materials were prepared in two steps by conversion of lit
- Rosiak, Anna,Frey, Wolfgang,Christoffers, Jens
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p. 4044 - 4054
(2007/10/03)
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- Acetylation of aromatic ethers using acetic anhydride over solid acid catalysts in a solvent-free system. Scope of the reaction for substituted ethers
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The acetylation of aryl ethers using acetic anhydride in the presence of zeolites under modest conditions in a solvent-free system gave the corresponding para-acetylated products in high yields. The zeolite can be recovered, regenerated and reused to give almost the same yields as that given when fresh zeolite is used.
- Smith, Keith,El-Hiti, Gamal A.,Jayne, Anthony J.,Butters, Michael
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p. 1560 - 1564
(2007/10/03)
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- An Unambiguous Synthesis of Melannein
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Melannein (6-hydroxy-7-methoxy-4-(3'-hydroxy-4'-methoxyphenyl)coumarin, I) and its O,O-diethyl ether (II) have been synthesised.The steps involved in the synthesis of I and II are the respective condensation of o-methoxyhydroquinone with ethyl m-benzyloxy-p-methoxybenzoylacetate (XI) and ethyl m-ethoxy-p-methoxybenzoylacetate (III) in absolute ethyl alcohol in the presence of dry hydrogen chloride gas.The isomeric O,O-diethyl ether of melannein, viz. 6-ethoxy-7-methoxy-4(4'-ethoxy-3'-methoxyphenyl)coumarin (VI) has also been prepared by the condensation of o-methoxyhydroquinone with ethyl p-ethoxy-m-methoxybenzoylacetate (VII).The esters (III), (VII) and (XI) have been prepared by the reaction of the appropriate acetophenone derivatives with diethyl carbonate in the presence of sodium hydride.
- Ahluwalia, V. K.,Kapur, Kanchan,Manchanda, Saroj
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p. 186 - 188
(2007/10/02)
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- Cleavage of the Methylenedioxy Ring. III. Cleavage with Sodium Benzyloxide in Dimethyl Sulfoxide
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Cleavage of the methylenedioxy ring in aromatic formyl (1-3), nitro (4 and 5), and acetyl (30) compounds with N-sodium benzyloxide-benzyl alcohol in dimethyl sulfoxide gave 3-hydroxybenzene derivatives (19, 22-24, 26, 27, and 33).In the case of the acetyl compound 30, the 4-hydroxybenzene derivative (34) was also obtained as a minor product.Regioselective cleavage of the ring in aromatic compounds having electronwithdrawing groups with nucleophilic oxide anions is discussed.Cleavage of the ring in 1-5 and 30 with 2 N sodium methoxide in dimethyl sulfoxide-dimethylformamide was found to be useful for the practical preparation of 3-hydroxybenzene derivatives (6-10 and 31).Keywords - Cleavage of methylenedioxy ring; regioselectivity; piperonals; 3,4-methylenedioxy-nitrobenzene; 3,4-methylenedioxy-acetophenone; sodium methoxide; sodium phenoxide; sodium benzyloxide; dimethyl sulfoxide; dimethylformamide
- Kobayashi, Shigeru,Okimoto, Kazuto,Imakura, Yasuhiro
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p. 1567 - 1573
(2007/10/02)
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