- Efficient Stereoselective Synthesis of a Key Chiral Aldehyde Intermediate in the Synthesis of Picolinamide Fungicides
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A highly stereoselective and efficient synthesis of (4S,5S,6S)-6-(benzyloxy)-5-phenoxy-4-propoxyheptanal, a key intermediate for syntheses of picolinamide fungicides, is described in this report. The synthesis features a scalable allylpropyl ether preparation, an efficient synthesis of the C1-C3 anti,syn-(S,S,S) stereotriad via a highly diastereoselective allylboration, and Cu-catalyzed phenylation of a sterically hindered secondary alcohol with BiPh3(OAc)2 followed by highly regioselective hydroformylation with the formation of a linear aldehyde. Excellent overall route efficiency was achieved (six steps and 39% yield) starting from readily available and inexpensive (S)-ethyl lactate.
- Li, Fangzheng,Good, Steffen,Tulchinsky, Michael L.,Whiteker, Gregory T.
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p. 2253 - 2260
(2019/10/16)
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- Mechanistic Studies of Bismuth(V)-Mediated Thioglycoside Activation Reveal Differential Reactivity of Anomers
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The mechanism of bismuth(V)-mediated thioglycoside activation was examined using reaction kinetics and quantum chemical reaction models. NMR experiments show an unusual nonlinear growth/decay curve for the glycosylation reaction. Further studies suggest an anomeric inversion of the β-glycoside donor to the α-donor during its activation, even in the presence of a neighboring 2-position acetate. Interestingly, in situ anomerization was not observed in the activation of an α-glycoside donor, and this anomer also showed faster reaction times and higher product diastereoselectivites. Density functional theory calculations identify the structure of the promoter triphenyl bismuth ditriflate, [Ph3Bi(OTf)2, 1], in solution and map out the energetics of its interactions with the two thioglycoside anomers. These calculations suggest that 1 must bind the thiopropyl arm to induce triflate loss. The computational analyses also show that, unlike most O-glycosides, the β- and α-donor S-glycosides are similar in energy. One energetically reasonable anomerization pathway of the donors is an SN1-like mechanism promoted by forming a bismuth-sulfonium adduct with the Lewis acidic Bi(V) for the formation of an oxacarbenium intermediate. Finally, the computed energy compensations needed to form these α vs β Bi adducts is a possible explanation for the differential reactivity of these donors.
- Goswami, Manibarsha,Ashley, Daniel C.,Baik, Mu-Hyun,Pohl, Nicola L. B.
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p. 5949 - 5962
(2016/07/23)
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- Facile one-pot synthesis of triphenylbismuth(V) bis(carboxylate) complexes
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Triphenylbismuth(V) bis(carboxylates), Ph3Bi(O 2CR)2 (R = 5-Br-2-OH-C6H3 (1), 2-OH-C6H4 (2), 2,6-(OH)2-C6H 3 (3), 3-Me-2-NH2-C6H3 (4), Ph (5), Me (6)), were obtained from the reaction of triphenylbismuth with hydrogen peroxide and excess carboxylic acid in wet 2-propanol. The synthesis avoids the use of halogens as oxidants, and the products crystallize directly from the solution as pure compounds. They crystallize from solution without further need for purification. The structures of 1-5 were confirmed by single-crystal X-ray diffraction. Compounds 2 and 5 exhibit a polymorph different from that previously reported in the literature. While all of the Bi(V) compounds adopt a trans-axial trigonal-bipyramidal configuration with the carboxylates in axial positions, there is considerable variation in the coordination of the carboxylate that ranges from simple η1 to a mixture of mono- and bidentate chelating bonding modes.
- Kumar, Ish,Bhattacharya, Prateek,Whitmire, Kenton H.
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p. 2906 - 2909
(2014/06/24)
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- Bismuth(V)-mediated thioglycoside activation
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A straightforward method utilizing a bismuth(V) compound was developed for the activation of thiopropylglycosides for coupling to various acceptors; good to excellent yields were obtained without applying additional additives/co-promoters. The method does
- Goswami, Manibarsha,Ellern, Arkady,Pohl, Nicola L. B.
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supporting information
p. 8441 - 8445
(2013/09/02)
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- 3-SUBSTITUTED QUINOLINIUM AND 7H-INDOLO[2,3-c]QUINOLINIUM SALTS AS NEW ANTIINFECTIVES
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The present invention relates to quinolinium antiinfective agents in which the qunolinium nucleus is fused to an indole ring or the qunolinium nucleus is linked to a cyclic structure through an opened indole or a benzothiophene or benzofuran ring. The compound is further substituted with various substituent groups. The compounds are represented by formula (I), (II) and (III): Pharmaceutical compositions and methods of use are also included.
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Page/Page column 12
(2012/07/13)
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- Antifungal and antiparasitic indoloquinoline derivates
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A compound having the formula: wherein: R is an electron withdrawing or electron donating moiety; R5 and R10 may be the same or different and are a straight or branched 1-5 carbon or heteroatom chain substituted terminally by a cycloalkyl or aromatic ring, or other structural isomer or complex thereof; n is the position of substitution of R; Z is N—R10, O, S, S═O, CH2 or C═O; y is 1-5 and Q is Z or NH, with the proviso that, where Z is NH, N—CH3, S or O and Rn is H, R5 may not be CH3; as well as quaternary ammonium salts thereof and their use as pharmacological compositions and for methods of treatment.
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Page/Page column 7
(2008/06/13)
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- 4-ARYLMORPHOLIN-3-ONE DERIVATIVES, THEIR PREPARATION AND THERAPEUTIC USE THEREOF
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The invention relates to compounds corresponding to formula (I): in which: Ar represents a mono- or disubstituted phenyl; R1 represents an unsubstituted or substituted phenyl; R2 represents: a pyridyl; an unsubstituted or substituted phenyl; a benzyl that is unsubstituted or substituted on the phenyl; R2 may moreover represent: a heterocyclic radical; R3 represents various values. The invention also comprises methods for the compounds preparation, formulations comprising them and therapeutic applications thereof.
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Page/Page column 12
(2008/06/13)
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- Study of homo- and cross-coupling competition in the reaction of triarylbismuth(V) dicarboxylates with methyl acrylate in the presence of a palladium catalyst
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Triarylbismuth(V) derivatives Ar3Bi(O2CR)2 (Ar = Ph, m-Tol, p-Tol; R = H, Me, Et, n-Bu, t-Bu, n-C5H 11, CF3, CH2Cl, CCl3, Ph) were prepared in good to excellent yields by reaction of Ar3Bi with equimolar amounts of t-BuOOH in the presence of an acid. These compounds were tested in the C-arylation reaction of methyl acrylate, as a model substrate, in the presence of palladium catalyst (4 mol%). It was found that triphenylbismuth dicarboxylates are very active phenylating agents under mild conditions (20 °C). The effect of the carboxylic group, the effect of the nature of the palladium catalyst and the effect of oxygen on the reactivity of the organobismuth compounds and on the selectivity of the C-arylation reaction were studied. Methyl cinnamate, the C-phenylation product, and biphenyl, the homo-coupling by-product, were obtained in all cases. Triphenylbismuth divalerate Ph3Bi(O2CBu)2 is the most reactive compound among the triphenylbismuth dicarboxylates studied.
- Moiseev, Dmitry V.,Malysheva, Yulia B.,Shavyrin, Andrey S.,Kurskii, Yury A.,Gushchin, Aleksey V.
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p. 3652 - 3663
(2007/10/03)
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- Reactions of triarylbismuth bis(arenesulfonates)
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Reactions of triphenylbismuth with sodium salts, acids, alkalies, and zinc are studied. In the first three cases Bi-O bond cleavage takes place, while zinc reduces the starting bismuth compounds to triphenylbismuth.
- Sharutin,Sharutina,Egorova,Ettenko
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p. 1236 - 1237
(2007/10/03)
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- Unexpected Formation of Triarylbismuth Diformates in the Oxidation of Triarylbismuthines with Ozone at Low Temperatures
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Oxidation of triphenylbismuthine 1 with ozone in toluene at -78 deg C gave, unexpectedly, a high yield of triphenylbismuth diformate 3, which was also obtainable as a minor product by a similar oxidation in ethyl acetate and acetone.An X-ray crystallographic study revealed that compound 3 has C2 symmetry, the geometry around the bismuth atom being best described as a distorted trigonal bipyramid as a result of strong intramolecular interaction between the bismuth and carbonyl oxygen atoms.Treatment of compound 3 with aqueous sodium acetate or halides readily converted it into the corresponding triphenylbismuth diacetate 5 or dihalides 7 - 9.
- Suzuki, Hitomi,Ikegami, Tohru,Matano, Yoshihiro,Azuma, Nagao
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p. 2411 - 2416
(2007/10/02)
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