- SYNTHESIS OF NATURAL AND UNNATURAL FRONTALIN
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(S)-(-)- and (R)-(+)-Frontalin were synthesized, respectively, in high enantiomer excess from β-methallyl alcohol (2) by three-step procedure; (i) asymmetric epoxidation of 2, (ii) the epoxide opening with homoallylmagnesium bromide, and (iii) Pd(II)-catalyzed intramolecular acetalization.
- Hosokawa, Takahiro,Makabe, Yoshiki,Shinohara, Toru,Murahashi, Shun-Ichi
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- Development of a scalable process for the synthesis of DNDI-VL-2098: A potential preclinical drug candidate for the treatment of visceral leishmaniasis
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A process suitable for kilogram-scale synthesis of (2R)-2-methyl-6-nitro-2-{[4-(trifluoromethoxy)phenoxy]- methyl}-2,3-dihydroimidazo[2,1-b][1,3]oxazole (DNDI-VL-2098, 2), a preclinical drug candidate for the treatment of visceral leishmaniasis, is described. The four-step synthesis of the target compound involves the Sharpless asymmetric epoxidation of 2- methyl-2-propen-1-ol, 8. Identification of a suitable synthetic route using retrosynthetic analysis and development of a scalable process to access several kilograms of 2 are illustrated. The process was simplified by employing in situ synthesis of some intermediates, reducing safety hazards, and eliminating the need for column chromatography. The improved reactions were carried out on the kilogram scale to produce 2 in good yield, high optical purity, and high quality.
- Satam, Vijay S.,Pedada, Srinivasa Rao,Kamaraj, Pasumpon,Antao, Nakita,Singh, Apoorva,Hindupur, Rama Mohan,Pati, Hari N.,Thompson, Andrew M.,Launay, Delphine,Martin, Denis
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Read Online
- Nitroimidazole compound as well as preparation method and application thereof
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The invention discloses a novel nitroimidazole compound as well as a preparation method and application thereof. The nitroimidazole compound has a general formula (I) shown in the specification.
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Paragraph 0112-0115; 0116-0117
(2021/02/10)
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- CARBAZOLE-CONTAINING AMIDES, CARBAMATES, AND UREAS AS CRYPTOCHROME MODULATORS
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The subject matter herein is directed to carbazole-containing amide, carbamate, and urea derivatives and pharmaceutically acceptable salts or hydrates thereof of structural formula I wherein the variable R1, R2, R3, R4, R5, R6, R7, A, D, E, G, J, L, M, Q, a, and b are accordingly described. Also provided are pharmaceutical compositions containing the compounds of formula I to treat a Cry-mediated disease or disorder, such as diabetes, complications associated with diabetes, Cushing's syndrome, NASH, NAFLD, asthma, and COPD.
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Paragraph 0350
(2015/10/28)
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- Novel pathway for the synthesis of arylpropionamide-derived selective androgen receptor modulator (SARM) metabolites of andarine and ostarine
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O-Dephenylandarine and O-dephenylostarine, two SARM metabolites relevant for doping control analysis, were synthesized in their endogenous (S)-forms as well as in terms of their racemates. The enantiopure (S)-metabolites were obtained after six steps in 20% and 23% overall yield, the slightly modified racemic route provided the compounds in 28% and 31% total yield, respectively.
- Schragl, Katharina M.,Forsdahl, Guro,Gmeiner, Guenter,Enev, Valentin S.,Gaertner, Peter
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supporting information
p. 2239 - 2242
(2013/05/09)
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- Asymmetric synthesis of α-Tocopherol
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α-Tocopherol was synthesized from a chiral intermediate α-hydroxy ester by means of two ring-closing methods to yield the chromanol in 94 % diastereomeric excess.
- Hengartner, Urs,Chougnet, Antoinette,Liu, Kegang,Woggon, Wolf-D.
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experimental part
p. 1306 - 1311
(2010/06/12)
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- Development of a multikilogram synthesis of a chiral epoxide precursor to a CCR1 antagonist. Use of in situ monitoring for informed optimisation via fragile intermediates
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The optimisation and scale up of a manufacturing route to a key intermediate, acetic acid 4-acetylamino-3-(2-methyl-oxiranyl- methoxy)phenyl ester (2), utilising a SNAr coupling, the hydro- genation of a nitro moiety and the conversion of a chi
- Ange, Debra,Booker, James E. M.,Pedge, Nicholas,Sinclair, Rhona,Sleigh, Chris,Stefinovic, Marijan,Vaz, Luis-Manuel,Way, Edward
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scheme or table
p. 72 - 84
(2010/05/02)
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- Asymmetric synthesis of (+)-polyanthellin A
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(Chemical Equation Presented) A concise and convergent route to (+)-polyanthellin A is presented. This synthesis features a diastereoselective cyclopropane/aldehyde [3+2] cycloaddition to install the hydroisobenzofuran core. The use of MADNTf2
- Campbell, Matthew J.,Johnson, Jeffrey S.
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body text
p. 10370 - 10371
(2009/12/23)
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- Spongipyran synthetic studies. Evolution of a scalable total synthesis of (+)-spongistatin 1
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Three syntheses of the architecturally complex, cytotoxic marine macrolide (+)-spongistatin 1 (1) are reported. Highlights of the first-generation synthesis include: use of a dithiane multicomponent linchpin coupling tactic for construction of the AB and CD spiroketals, and their union via a highly selective Evans boron-mediated aldol reaction en route to an ABCD aldehyde; introduction of the C(44)-C(51) side chain via a Lewis acid-mediated ring opening of a glucal epoxide with an allylstannane to assemble the EF subunit; and final fragment union via Wittig coupling of the ABCD and EF subunits to form the C(28)-C(29) olefin, followed by regioselective Yamaguchi macrolactonization and global deprotection. The second- and third-generation syntheses, designed with the goal of accessing 1 g of (+)-spongistatin 1 (1), maintain both the first-generation strategy for the ABCD aldehyde and final fragment union, while incorporating two more efficient approaches for construction of the EF Wittig salt. The latter combine the original chelation-controlled dithiane union of the E- and F-ring progenitors with application of a highly efficient cyanohydrin alkylation to append the F-ring side chain, in conjunction with two independent tactics to access the F-ring pyran. The first F-ring synthesis showcases a Petasis-Ferrier union/rearrangement protocol to access tetrahydropyrans, permitting the preparation of 750 mg of the EF Wittig salt, which in turn was converted to 80 mg of (+)-spongistatin 1, while the second F-ring strategy, incorporates an organocatalytic aldol reaction as the key construct, permitting completion of 1.009 g of totally synthetic (+)-spongistatin 1 (1). A brief analysis of the three syntheses alongside our earlier synthesis of (+)-spongistatin 2 is also presented.
- Smith III, Amos B.,Sfouggatakis, Chris,Risatti, Christina A.,Sperry, Jeffrey B.,Zhu, Wenyu,Doughty, Victoria A.,Tomioka, Takashi,Gotchev, Dimitar B.,Bennett, Clay S.,Sakamoto, Satoshi,Atasoylu, Onur,Shirakami, Shohei,Bauer, David,Takeuchi, Makoto,Koyanagi, Jyunichi,Sakamoto, Yasuharu
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supporting information; scheme or table
p. 6489 - 6509
(2011/02/25)
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- Development and application of versatile bis-hydroxamic acids for catalytic asymmetric oxidation
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In this article, we describe the development and preliminary results of our new designed C2-symmetric bis-hydroxamic acid (BHA) ligands and the application of the new ligands for vanadium-catalyzed asymmetric epoxidation of allylic alcohols as well as homoallylic alcohols. From this success we demonstrate the versatile nature of BHA in the molybdenum catalyzed asymmetric oxidation of unfunctionalized olefins and sulfides.
- Barlan, Allan U.,Zhang, Wei,Yamamoto, Hisashi
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p. 6075 - 6087
(2008/02/03)
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- Enantioselective epoxidation of allylic alcohols by a chiral complex of vanadium: An effective controller system and a rational mechanistic model
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(Chemical Equation Presented) Bishydroxamic acid derivatives are used as ligands for a vanadium catalyst in the preparation of epoxy alcohols (see scheme). The methodology uses aqueous tert-butyl hydroperoxide (TBHP) as an achiral oxidant, low catalyst loading, low reaction temperatures (0°C to room temperature), and simple workup procedures. The reaction is applied to the kinetic resolution of a secondary allylic alcohol and the preparation of small epoxy alcohols. R1, R2, R3: alkyl, aryl, H.
- Zhang, Wei,Basak, Arindrajit,Kosugi, Yuji,Hoshino, Yujiro,Yamamoto, Hisashi
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p. 4389 - 4391
(2007/10/03)
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- 1-SUBSTITUTED 4-NITROIMIDAZOLE COMPOUND AND PROCESS FOR PRODUCING THE SAME
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The present invention relates to a 1-substituted-4-nitroimidazole compound represented by the general formula (1) or a salt thereof, (wherein R is a hydrogen atom, a lower alkoxy group-substituted lower alkyl group, a phenyl-lower alkoxy group-substituted lower alkyl group, a cyano-substituted lower alkyl group, a phenyl-lower alkyl group which may have lower alkoxy groups as the substituents in the phenyl ring or a group of the formula -CH2RA; X is a halogen atom or a group of the formula -S(O)n-R1) and method for preparing the same. The compound of the formula (1) is a useful compound as an intermediate for synthesis of various pharmaceutical and agricultural chemicals, particularly, as intermediates for antitubercular agents.
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Page/Page column 47
(2010/02/12)
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- Spongistatin synthetic studies. An efficient, second-generation construction of an advanced ABCD intermediate
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(formula presented) A short, efficient, and stereocontrolled synthesis of (-)-4, an advanced ABCD subunit of the spongistatins, has been achieved. Central to the synthetic strategy is the multicomponent linchpin union of silyl dithianes with epoxides to access both the AB and CD fragments. Fragment coupling was then achieved via an efficient stereoselective aldol reaction. The linear sequence required 22 steps and proceeded in 4.0% overall yield.
- Smith III, Amos B.,Doughty, Victoria A.,Sfouggatakis, Chris,Bennett, Clay S.,Koyanagi, Jyunichi,Takeuchi, Makoto
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p. 783 - 786
(2007/10/03)
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- Mapping the substrate selectivity of new hydrolases using colorimetric screening: Lipases from Bacillus thermocatenulatus and Ophiostoma piliferum, esterases from Pseudomonas fluorescens and Streptomyces diastatochromogenes
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Recent advances in biochemistry and molecular biology have simplified the discovery and preparation of new hydrolases. Although these hydrolases might solve problems in organic synthesis, measuring their selectivity, especially enantioselectivity, remains tedious and time consuming. Recently, we developed a colorimetric screening method to measure the enantioselectivity of hydrolases. Here we apply this rapid screening method to map the substrate selectivity of four new hydrolases: lipases from the thermophilic Bacillus thermocatenulatus (DSM 730, BTL2) and a filamentous fungus Ophiostoma piliferum (NRRL 18917, OPL) and esterases from two bacteria, Pseudomonas fluorescens (SIK-W1, esterase I, PFE) and Streptomyces diastatochromogenes (Tue 20, SDE). We screened a general library of 29 substrates and a chiral library of 23 pairs of enantiomers. All four hydrolases catalysed the hydrolysis of unnatural substrates, but the two lipases accepted a broader range of substrates than the two esterases. As expected, the two lipases favoured more hydrophobic substrates, while the two esterases showed a preference for smaller substrates. Several moderately enantioselective reactions were identified for the solketal esters: BTL2, butyrate, E = 7.9 (R); octanoate, E = 4.9 (R) and 3-bromo-2-methyl propionate methyl esters, PFE, E = 12 (S); SDE, E = 5.6 (S). OPL showed low enantioselectivity toward all substrates tested. The current colorimetric screen could not measure the selectivity for several slow-reacting substrates. Traditional screening identified high enantioselectivity of BTL2 and PFE toward one of these slow substrates, 1-phenylethyl acetate (E>50).
- Liu, Andrew Man Fai,Somers, Neil A.,Kazlauskas, Romas J.,Brush, Terry S.,Zocher, Frank,Enzelberger, Markus M.,Bornscheuer, Uwe T.,Horsman, Geoff P.,Mezzetti, Alessandra,Schmidt-Dannert, Claudia,Schmid, Rolf D.
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p. 545 - 556
(2007/10/03)
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- Total synthesis of (+)-conagenin
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The first total synthesis of (+)-conagenin, a novel immunomodulator produced by Streptomyces roseosporus, has been achieved in highly stereo- and enantioselective manner. The carboxylic acid moiety was synthesized starting with asymmetric aldor reaction of propiophenone with acetaldehyde followed by in situ syn-selective NaBH4 reduction. The amin acid moiety was synthesized based upon Et2AlCl catalyzed cyclization of the epoxy trichloroacetimidate prepared from (S)-methylglycidol. Condensation of both moieties and alkaline hydrolysis led to (+)-conagenin.
- Hatakeyama, Susumi,Fukuyama, Hiroko,Mukugi, Yasuko,Irie, Hiroshi
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p. 4047 - 4050
(2007/10/03)
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- Facile Chemoenzymatic Preparation of Enantiomerically Pure 2-Methylglycerol Derivatives as Versatile Trifunctional C4-Synthons
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Both enantiomers of a series of synthetically valuable 2-methylglycerol derivatives have been prepared with >99percent ee using a chemoenzymatic reaction sequence.The introduction of chirality was achieved by enantioselective esterification of 1,2-O-protected 2-methylglycerol 3 or enantioselective hydrolysis of its butyryl ester 4.The enzymatic reaction proceeded with unusually high selectivity and velocity for a primary alcohol (ester) substrate.
- Wirz, Beat,Barner, Richard,Huebscher, Joseph
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p. 3980 - 3984
(2007/10/02)
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- A direct HPLC method for the determination of enantiomeric excess of some highly enantiomerically enriched derivatives of chiral glycidols
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A newly developed HPLC method which requires no derivatization is used to determine accurately the enantiomeric purity of some glycidol-based derivatives that have been enantiomerically enriched by recrystallization or lipase-catalyzed kinetic resolution after the Sharpless Asymmetric Epoxidation.
- Chen, Jian
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p. 7663 - 7666
(2007/10/02)
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- Preparation of C-4 alkylated dideoxyribosides: Potential precursors to a novel series of nucleosides
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Methallyl alcohol can be converted in five simple operations (alkylation, epoxidation, alkynyl-coupling, hydroboration/oxidation, cyclization) to C-5 protected, chiral, non-racemic dideoxyribosides containing an alkyl appendage at the C-4 site.
- Lipshurtz,Sharma,Dimock,Behling
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p. 191 - 195
(2007/10/02)
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- A convenient gas chromatographic method for the optical purity determination of chiral epoxy alcohols
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Short-chain aliphatic epoxy alcohols can be readily resolved without derivatization on a capillary gc column coated with permethylated hydroxypropyl derivative of α-cyclodextrin.
- Dougherty,Liotta,Mondimore,Shum
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p. 4389 - 4390
(2007/10/02)
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- ASYMMETRIC SYNTHESIS OF (R)-(+)- AND (S)-(-)-2,2,4-TRIMETHYL-4-(HYDROXYMETHYL)-1,3-DIOXOLANE OF HIGH ENANTIOMERIC PURITY
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The title compounds, 1 and 1', are readily available in four steps from 2-benzyloxymethyl-2-propen-1-ol, the key step being Sharpless asymmetric epoxidation to give the chiral epoxides 5 or 5'.The total chemical yield of 1 or 1' is 50percent, the final pr
- Tanner, David,Somfai, Peter
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p. 5985 - 5990
(2007/10/02)
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- Synthesis of (1S)-(-)-Frontalin
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The aggregation pheromone 1 of the southern pine beetle Dendroctonus frontalis has been synthesized in high optical yield starting from (2R)-2-methyl-2-epoxy-1-propanol (4) which is obtained from methallyl alcohol (3) via enantioselective epoxidation according to Sharpless.
- Meister, Christoph,Scharf, Hans-Dieter
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p. 913 - 921
(2007/10/02)
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