- Deracemization of acyclic α-hydroxy ketone derivatives by dynamic resolution using an optically active host compound
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The dynamic resolution of racemic acyclic α-hydroxy ketone derivatives is accomplished using an optically active host compound, TADDOL, under basic conditions to give the corresponding optically active ketones. Georg Thieme Verlag Stuttgart.
- Matsumoto, Kazutsugu,Otsuka, Keiko,Okamoto, Tomomi,Mogi, Hideto
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- A PROCESS FOR THE MANUFACTURE OF POSACONAZOLE
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The present invention discloses an improved process for the manufacture of Posaconazole, an anti-fungal agent belonging to the category of substituted Tetrahydrofuran Triazole compound. The present invention further describes preparation of formula A and formula B, the key intermediates in the preparation of Posaconazole. The invention also discloses novel intermediates that are useful in the synthesis of Posaconazole.
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Page/Page column 12; 17
(2019/05/10)
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- Toward Chromanes by de Novo Construction of the Benzene Ring
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The work describes three principal Diels-Alder cycloaddition approaches toward chromanes that are designed for the de novo construction of the benzene ring. This study specifically focuses on the potential exploitation in the total synthesis of chromane-bearing natural products such as cebulactam A.
- Geist, Egor,Berneaud-K?tz, Helge,Baikstis, Tomas,Dr?ger, Gerald,Kirschning, Andreas
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supporting information
p. 8930 - 8933
(2019/11/14)
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- Preparation method of posaconazole intermediate
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The invention discloses a preparation method of a key intermediate POB for preparing posaconazole. Firstly, BP004b04 and oxalic acid are salified to obtain POE; secondly, the POE reacts with di-tert-butyl dicarbonate in the presence of a base to obtain POP, and the POP is recrystallized; thirdly, the POP and POK react with each other in the presence of a base to obtain POR, and POS is obtained after a tert-butyl carbonate protecting group of the POR is removed; finally, the POS is subjected to ring closure to obtain the POB. By means of the method, in the obtained POB, the content of diastereomers is smaller than or equal to 0.01%, and the total yield of the entire route is high.
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Paragraph 0039; 0040; 0045; 0046; 0062; 0064
(2019/06/30)
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- Preparation method of high-purity posaconazole
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The invention discloses a preparation method of posaconazole, comprising: subjecting BP004b04 and oxalic acid to salt forming to obtain POE; subjecting POE and di-tert-butyl decarbonate to reaction inthe presence of a base to obtain POP, and recrystallizing POP; subjecting POP and POK o reaction in the presence of a base to obtain POR, and removing tert-butyl carbonate protecting group from POR to obtain POS; subjecting the POS to ring closing to obtain POB; subjecting the POB and POA to reaction to obtain posaconazole. Posaconazole prepared via the preparation method has the content of diastereoisomers being /=0.01%, and the overall route has high total yield.
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Paragraph 0043; 0044; 0049; 0050; 0072; 0074; 0079; 0080
(2019/06/27)
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- Intermediate for preparing posaconazole
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The invention discloses an intermediate POP for preparing posaconazole. A structure of the intermediate is as shown in the specification. By using the intermediate to prepare POB, the obtained POB hasa diastereomer content being smaller than or equal to 0.01%, and the total yield of the overall route is relatively high.
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Paragraph 0040-0041; 0046-0047; 0065; 0071-0072
(2019/07/04)
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- Total synthesis of (+)-herboxidiene/GEX 1A
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A total synthesis of (+)-herboxidiene/GEX 1A has been accomplished from (R)- and (S)-lactate esters in a highly efficient manner. Key steps of the synthesis involve substrate-controlled titanium-mediated aldol reactions from chiral lactate-derived ethyl ketones, an oxa-Michael cyclization, an Ireland-Claisen rearrangement, and a Suzuki coupling. Furthermore, computational studies of the oxa-Michael reaction have unveiled the dramatic influence of intramolecular hydrogen bonds on the stereochemical outcome of such cyclizations, whereas biological analyses have clearly proved the important cytoxicity of (+)-herboxidiene/GEX 1A.
- Gómez-Palomino, Alejandro,Pellicena, Miquel,Kr?mer, Katrina,Romea, Pedro,Urpí, Fèlix,Aullón, Gabriel,Padrón, José M.
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p. 1842 - 1862
(2017/03/09)
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- Method for preparing chiral hydrazine
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The invention discloses a method for preparing chiral hydrazine. The method comprises the following steps: (2S)-2-benzyloxy-1-(1-pyrrolidyl)-1-acetone is used as a starting material, a Grignard reaction is performed, carbonyl is reduced after ethyl is introduced, and hydroxyl is obtained; crystalizaiton for purification is performed after a reaction with a sulfonylation reagent, then a reaction with hydrazine hydrate is performed, salt formation is performed by adopting dibenzoyl-L-tartaric acid monohydrate, and a compound IV is obtained after free hydrazine is acylated, and is an important intermediate for preparing posaconazole. The method has the advantages that the operation is easy to perform, pollution to the environment is low, the product optical selectivity is high, the proportion of a (3S) isomer to a (3R) isomer reaches 94.6: 5.4 after the purification operation on a compound X, and the method is suitable for being applied to industrial production of posaconazole.
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Paragraph 0042; 0043; 0044
(2016/10/10)
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- (S) - 2-benzyloxy-3-pentanone method for the preparation of
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The invention discloses a preparation method of (S)-2- benzyloxy-3-pentanone. The preparation method comprises the steps as follows: (1), L-methyl lactate or L-ethyl lactate is taken as a raw material and compounded with N, O-dimethylhydroxylamine hydroch
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- Intermediate posaconazole (2S, 3R) - 2-benzyloxy-3-pentanol preparation method
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The invention relates to a method for preparing (2S, 3R)-2-benzyloxy-3-pentanol as an intermediate of posaconazole, The method comprises the following steps of directly protecting hydroxyl group of S-ethyl lactate with the benzyl chloride, carrying out a Grignard reaction to obtain (2S)-2-benzyloxy-3-pentanone and directly carrying out a chiral reduction with BH3 to obtain (2S, 3R)-2-benzyloxy-3-pentanol in the presence of a chiral catalyst, wherein the S-ethyl lactate, which is wide in source and low in cost, is used as a starting material. The method disclosed by the invention has the advantages of reduction in reaction steps, improved yield, effectively saved cost, low cost of raw materials, environmental protection, less pollution, wide source of S-ethyl lactate as the starting material, low price, relatively mild reaction conditions, high yield and greatly reduced cost. The products prepared by the method has high optical selectivity, ee values greater than 99%, purity greater than 99% and less impurities and can be used directly without purification.
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Paragraph 0032-0034
(2016/10/09)
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- Gold(III) complexes catalyze deoximations/transoximations at neutral pH
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Golden solution: A neutral solution of AuBr3, containing [AuBr2(OH)2]- in equilibrium with [AuBr 3(OH)]- and [AuBr4]-, promotes the chemoselective hydrolysis of robust oximes into carbonyl compounds without racemization (see scheme). The food additive diacetyl acts as a NH 2OH-trapping agent, thus avoiding the formation of gold nanoparticles and allows the reaction to run catalytically. Copyright
- Isart, Carles,Bastida, David,Bures, Jordi,Vilarrasa, Jaume
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experimental part
p. 3275 - 3279
(2011/05/12)
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- AuBr3-catalyzed thiooxime-to-carbonyl conversion: From chiral aliphatic nitro compounds to ketones without racemization
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A new variant of the NO2-to-CO transformation (the Nef reaction) that occurs at room temperature under neutral conditions is uncovered. After the conversion of secondary nitroalkanes to phenylsulfenylketlmines, these thlooximes are hydrolyzed quantitatively In situ, In THF-H2O at pH 7, by addition of AuBr3 (but not with other MXn!). Adducts arising from asymmetric nitro-Mlchael and nltro-aldol reactions afford 1,4-dlketones and a-alkoxy ketones, respectively, with full retention of the configuration of the stereocenters a to the CHNO2/C=N-SPh/C=o groups.
- Bures, Jordi,Lsart, Carles,Vllarrasa, Jaume
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supporting information; experimental part
p. 4414 - 4417
(2009/12/24)
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- Optical resolution of acyclic α-hydroxy ketone derivatives by inclusion complexation
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A new method for the preparation of optically active acyclic α-hydroxy ketone derivatives by thermodynamic resolution using a chiral host compound is described. We examined the resolution of racemic 2-benzyloxy-3-pentanone with chiral host compounds in va
- Matsumoto, Kazutsugu,Okamoto, Tomomi,Otsuka, Keiko
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p. 2051 - 2056
(2007/10/03)
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- Simple and efficient preparation of enantiopure alkyl α-hydroxyalkyl ketones
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The acylation reaction of organolithium reagents with pyrrolidine-derived α-benzyloxy and α-silyloxy carboxamides provides a simple and high-yielding method for the preparation of enantiopure α-benzyloxy and α-silyloxy ketones.
- Ferrero,Galobardes,Martin,Montes,Romea,Rovira,Urpi,Vilarrasa
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p. 1608 - 1614
(2007/10/03)
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- A simple procedure for the preparation of enantiopure ethyl α-hydroxyalkyl ketones
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Amides derived from pyrrolidine and methyl (S)-lactate, methyl (S)-2-hydroxy-3-phenylpropanoate, or methyl (S)-2-hydroxy-3-methylbutanoate, after O-benzylation and O-silylation have been treated with EtLi or EtMgCl under suitable conditions, to give excellent overall yields of enantiopure ethyl ketones. The chelating ability of α-OBn amides (and even of α-O-TBS amides, which has been demonstrated by NMR to be better than that of N-OMe amides) accounts for the performance of the approach.
- Martin, Ricardo,Pascual, Oscar,Romea, Pedro,Rovira, Roser,Urpi, Felix,Vilarrasa, Jaume
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p. 1633 - 1636
(2007/10/03)
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- Simple and efficient preparation of ketones from morpholine amides
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Morpholine-derived amides react with RMgX to give the corresponding ketones in good yield. The mild conditions required and low cost of starting materials make this method very appealing for large scale preparations.
- Martín,Romea,Tey,Urpí,Vilarrasa
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p. 1414 - 1416
(2007/10/03)
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- Studies in polypropionate synthesis: High π-face selectivity in Syn and Anti aldol reactions of chiral boron enolates of lactate-derived ketones
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Use of (c)Hex2Bcl/Me2NEt in the aldol reactions of the α'-benzoyloxy ketone 7 with aldehydes leads to high stereoselectivity (97-95.5% ds) for the crystalline anti adducts 11. Under similar conditions, the corresponding benzyl ether 6 favours formation of the syn adducts 9.
- Paterson, Ian,Wallace, Debra J.,Velazquez, Silvia M.
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p. 9083 - 9086
(2007/10/02)
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- Preparation of Optically Active α-Hydroxy Ketone Derivatives by Enzyme-Mediated Hydrolysis of Enol Esters
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A new method of preparation of optically active α-hydroxy ketone derivatives has been developed.Incubation of (Z)-3-propionyloxy-4-benzyloxy-2-pentene (1a) with lipase OF gave optically pure (R)-enol propionate 1a, which in turn was converted without racemization to (R)-ketone 2a by the aid of LiAlH4.
- Matsumoto, Kazutsugu,Suzuki, Natsuko,Ohta, Hiromichi
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p. 7159 - 7162
(2007/10/02)
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