- Enantioselective Synthesis of Cyclic Nitrones by Chemoselective Intramolecular Allylic Alkylation of Oximes
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The enantio- and chemoselective iridium-catalyzed N-allylation of oximes is described for the first time. Intramolecular kinetic resolution provides access to cyclic nitrones and enantioenriched aliphatic allylic alcohols. Salient features of this transformation are its ability to employ E/Z-isomeric mixtures of oxime starting materials convergently and high functional group tolerance. The implementation of N-allylation/1,3-dipolar cycloaddition reaction sequences furnishes tricyclic isoxazolidines in highly enantio- and diastereoselective fashion. The synthetic utility of the approach is demonstrated by the efficient, formal synthesis of the marine natural product (+)-halichlorine.
- Sandmeier, Tobias,Carreira, Erick M.
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supporting information
p. 9913 - 9918
(2021/03/29)
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- METHODS FOR PREPARING TYROSINE RECEPTOR KINASE INHIBITORS
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The present disclosure relates to pyrazolo[1,5-α]pyrimidine compounds useful as TRK inhibitors and compounds useful in preparing pyrazolo[1,5-α]pyrimidine compounds, and methods of making and using same. This abstract is intended as a scanning tool for pu
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Paragraph 00460-00461
(2021/10/22)
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- DIAZASPIRODECANE OREXIN RECEPTOR ANTAGONISTS
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The present invention is directed to diazaspirodecane compounds which are antagonists of orexin receptors, and which are useful in the treatment or prevention of neurological and psychiatric disorders and diseases in which orexin receptors are involved. The invention is also directed to pharmaceutical compositions comprising these compounds and the use of these compounds and compositions in the prevention or treatment of such diseases in which orexin receptors are involved.
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Page/Page column 27-28
(2008/06/13)
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- Electroactive and luminescent polymers: New fluorene-heterocycle-based hybrids
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The synthesis, characterization, and electrochromic properties of copolymers derived from 9,9-dialkyl-2,7-dibromofluorene (18a, alkyl = C10H21; 24, alkyl = Et) and pyrrole, thiophene, 3,4- ethylenedioxythiophene, and furan are described. Two synthetic routes to 9,9- diethyl-2,7-bis(pyrrol-2-yl)fluorene (30) afford product in 30% and 20% yields, respectively. Monomer 30 undergoes electropolymerization to yield electroactive polymer films. The lowest monomer oxidation potential (E(p,m) = 0.4 V vs. Ag/Ag+) is found in tetraethylammonium tosylate (TEATOS)-CH3CN, but film formation is slow. Spectroelectrochemical analysis of poly(30) reveals a band gap at 2.4 eV and upon polymer oxidation, two low energy absorptions peaking at 1.2 and 2.2 eV appear. This phenomenon is attributed to formation of bipolaron bands between the valence and conduction bands. Soluble fluorene-heterocycle polymers 34a-d have been synthesized by the Stille coupling reaction of 18a and 2,5-bis(trimethylstannyl)thiophene (21a), 5,5'-bis(trimethylstannyl)-2,2'-bithiophene (21b), 2,5- bis(trimethylstannyl)-3,4-ethylenedioxythiophene (21c), and 2,5- bis(trimethylstannyl)furan (22), respectively, in high yields. The NMR spectra are consistent with the proposed structures of the polymers 34a-d, and no evidence of ring opening of the furyl unit in 34d is seen in the NMR and IR spectra. The molecular weights of 34a-d are in the range of 8000 g mol-1 with polydispersity indices (PDI) of 2. Polymers 34a-c have band gaps measured at 2.4 eV, while polymer 34d has its gap at 2.6 eV. Polymers 34a-c undergo solution doping with SbCl5 to form new low energy bipolaron bands at the expense of the absorption in the UV-VIS. However, polymer 34d does not oxidatively dope with SbCl5.
- Tsuie, Barbara,Reddinger, Jerry L.,Sotzing, Gregory A.,Soloducho, Jadwiga,Katritzky, Alan R.,Reynolds, John R.
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p. 2189 - 2200
(2007/10/03)
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