- Regiocontrolled and Stereoselective Syntheses of Tetrahydrophthalazine Derivatives using Radical Cyclizations
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Tetrahydrophthalazine derivatives have found important applications in pharmaceutical research, but existing synthetic methods are unable to access them regio- and stereoselectively. Here, a new approach is presented that addresses these challenges by utilizing a 6-endo-trig radical cyclization in the key step. The desired tetrahydrophthalazines can be accessed in high yields (55–98 %) and high diastereoselectivities for the trans-product (>95:5) starting either from readily accessible hydrazones, or from the corresponding aldehydes and substituted Boc-hydrazides in a one-pot process. The synthetic versatility of the tetrahydrophthalazine core was demonstrated by its straightforward conversion to dihydro-phthalazines, phthalazines, or pyrazolo dione derivatives. Furthermore, the N?N bond was reduced to afford a new route to 1,4-diamines.
- Zhang, Wei,Mo, Jia Yi,He, Weiying,Kennepohl, Pierre,Sammis, Glenn M.
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p. 976 - 980
(2019/01/04)
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- Preparation of 1,5-Dihydropyrazolo[3′,4′:5,6]pyrano[3,4- b]pyridines via a Microwave-Assisted, Palladium-Catalyzed Regioselective C-H Heteroarylation of Electron-Rich Pyrazoles
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Here we report the first synthesis of a family of novel heterocyclic compounds based on a 5-dihydropyrazolo[3′,4′:5,6]pyrano[3,4-b]pyridine core. In the course of our drug discovery programs, we had need to access the previously unknown 5-dihydropyrazolo[3′,4′:5,6]pyrano[3,4-b]pyridine core. Initial attempts required long reaction times, which led to degradation and side products. Reaction optimization identified a Pd-catalyzed, microwave-assisted C-H heteroarylation protocol for the rapid, general, and high yielding synthesis of this tricyclic core (as well as related analogs) suitable to drive optimization efforts.
- Garrison, Aaron T.,Childress, Elizabeth S.,Davis, Dexter C.,Lindsley, Craig W.
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p. 5855 - 5862
(2019/03/19)
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- Method for synthesizing alkyne through catalytic asymmetric cross coupling (by machine translation)
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The invention belongs to the field of, asymmetric synthesis, and discloses a method for catalyzing asymmetric cross- coupling to synthesize: an alkyne, and the L method comprises, the following steps, of A: preparing B a cuprous, salt and C a: ligand; preparing a catalyst; adding a base; reacting the compound with the compound with the compound; and reacting the compound with the compound. Of these, one of them, X is selected from the group consisting of, R halogens. 1 Optionally substituted heteroarylsulfonylcyanamide groups selected from the, group consisting, of optionally substituted, phenyl groups In-flight vehicle, R6 Trialkyl silyl groups or alkyl radicals, R2 Cycloalkyl radicals optionally substituted with an, optionally substituted alkyl, (CH radical2 )n R4 Multi,layer chain, n=0-10,R saw blade4 A group selected, from, the group consisting of phenyl, alkenyl, aralkynyls, noonyloxy,and, noonylsulfonylsulfonylsulfonylsulfonylsulfonylsulfonylsulfonylsulfonylsulfonylsulphonylsulphonylsulphonylsulphonylsulphonylsulphonylsulphonylsulphonylsulphonylsulphonylphenyl disiloxy-radicals. R3 A ligand, selected from hydrogen or any of the functional groups, is selected from the group consisting of, hydrogen and any L other functional group. The method, R disclosed by the, A invention has the, advantages of good catalytic, R ’ effect, wide application range. and high catalytic efficiency, and the, method disclosed by the, invention has the. advantages of good catalytic effect, wide application range and high catalytic efficiency. (by machine translation)
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Paragraph 0205-0212; 0267-0268
(2020/01/12)
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- Electrophile-Directed Diastereoselective Oxonitrile Alkylations
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Diastereoselective alkylation of prochiral oxonitrile dianions with secondary alkyl halides efficiently installs two contiguous stereogenic centers. The confluence of nucleophilic trajectory and the electrophile chirality causes distinct steric differences that allow efficient discrimination for one of the six possible conformers. Numerous oxonitrile-derived dianions efficiently displace secondary alkyl halides propagating the electrophile chirality to efficiently install two contiguous tertiary centers. The prevalence of chiral, secondary electrophiles makes the interdigitated alkylation of chiral electrophiles a particularly attractive route because the resulting oxonitriles are readily transformed into bioactive heterocycles.
- Chepyshev, Sergiy V.,Pitta, Bhaskar Reddy,Vangala, Saidi Reddy,Lujan-Montelongo, J. Armando,Steward, Omar W.,Fleming, Fraser F.
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p. 2850 - 2853
(2018/02/09)
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- Visible-light-mediated benzylic sp3 C-H bond functionalization to C-Br or C-N bond
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A visible-light-promoted functionalization of unactivated benzylic sp3 C-H bonds was developed. Ethylbenzene derivatives were converted to the corresponding benzyl bromides or afforded benzylamine derivatives in a one-pot manner under visible light photoredox conditions.
- Hou, Tianyuan,Lu, Ping,Li, Pixu
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supporting information
p. 2273 - 2276
(2016/05/10)
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- Thioacids and thioacid salts for determining the enantiomeric excess of chiral compounds containing an electrophilic carbon center
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The invention provides novel chiral compounds including 2-methoxy-2-trifluoromethylphenylacetic thioacid useful to react with and analyze other chiral compounds that have an electrophilic chiral carbon center.
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Page/Page column 19
(2010/07/02)
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- Salts of Mosher's thioacid: agents for determining the enantiomer excess of SN2 substrates
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The racemic and the (S)-enantiomer of Mosher's thioacid, 2-methoxy-2-trifluoromethylphenylacetic thioacid, form air-stable salts with Proton Sponge [1,8-bis(dimethylamino)naphthalene]. These salts are powerful nucleophiles that react cleanly (SN2 inversion) in CDCl3 with optically active alkyl halides ranging in reactivities from unactivated alkyl bromides and iodides to benzylic bromides. The diastereomeric excess (de) of the thioester products indicates the enantiomeric excess (ee) of the starting alkyl halides.
- Richman, Jack E.
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supporting information; experimental part
p. 2793 - 2796
(2010/07/06)
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- POTASSIUM CHANNEL INHIBITORS
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The present invention relates to pyridin-3-yl pyridin-3-amine compounds and derivatives thereof having the structure formula (I) useful as potassium channel inhibitors to treat cardiac arrhythmias, and the like.
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Page/Page column 34
(2010/11/28)
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- HALOGEN SUBSTITUTED METALLOCENE COMPOUNDS FOR OLEFIN POLYMERIZATION
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A metallocene compound is represented by the formula (1): wherein: M is a Group 3, 4, 5 or 6 transition metal atom, or a lanthanide metal atom, or actinide metal atom, preferably a Group 4 transition metal atom selected from titanium, zirconium or hafnium; E is a substituted or unsubstituted monocyclic or polycyclic arenyl ligand pi-bonded to M; A is a substituted or unsubstituted polycyclic arenyl ligand that is pi-bonded to M and has a different ring structure than the E ligand; at least one of the A and E ligands includes at least one halogen substituent directly bonded to an sp2 carbon at a bondable ring position; Y is a bridging group containing at least one Group 13, 14, 15, or 16 element and any single position of the ring structure of A and to any single position of the ring structure of E; and y is zero or 1, indicating the absence (y = 0) or presence (y =1) of Y; and each X is a univalent anionic ligand, or two X are joined and bound to the metal atom to form a metallocycle ring, or two X are joined to form a chelating ligand, a diene ligand, or an alkylidene ligand; provided that when E is an unsubstituted cyclopentadienyl ligand, either y is one or A is not 2-bromofluorenyl or 2,7-dibromofluorenyl.
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Page/Page column 136
(2010/11/27)
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- Halogen substituted metallocene compounds for olefin polymerization
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A metallocene compound is represented by the formula (1): wherein: M is a Group 3, 4, 5 or 6 transition metal atom, or a lanthanide metal atom, or actinide metal atom, preferably a Group 4 transition metal atom selected from titanium, zirconium or hafnium; E is a substituted or unsubstituted monocyclic or polycyclic arenyl ligand pi-bonded to M; A is a substituted or unsubstituted polycyclic arenyl ligand that is pi-bonded to M and has a different ring structure than the E ligand; at least one of the A and E ligands includes at least one halogen substituent directly bonded to an sp2 carbon at a bondable ring position; Y is a bridging group containing at least one Group 13, 14, 15, or 16 element and any single position of the ring structure of A and to any single position of the ring structure of E; and y is zero or 1, indicating the absence (y=0) or presence (y=1) of Y; and each X is a univalent anionic ligand, or two X are joined and bound to the metal atom to form a metallocycle ring, or two X are joined to form a chelating ligand, a diene ligand, or an alkylidene ligand; provided that when E is an unsubstituted cyclopentadienyl ligand, either y is one or A is not 2-bromofluorenyl or 2,7-dibromofluorenyl.
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- 1,2,4,5-Tetrahydro-3H-2-benzazepin-3-ones
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New physiologically active 1,2,4,5-tetrahydro-3H-2-benzazepin-3-ones having the general formula STR1 wherein R1 is hydrogen or phenyl, R2 is hydrogen, alkyl, C3 -C6 -alkenyl, C1 -C4 -acyl,
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