- Design of oxa-spirocyclic PHOX ligands for the asymmetric synthesis of lorcaserin: Via iridium-catalyzed asymmetric hydrogenation
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Phosphine-oxazoline (PHOX) ligands are a very important class of privileged ligands in asymmetric catalysis. A series of highly rigid oxa-spiro phosphine-oxazoline (O-SIPHOX) ligands based on O-SPINOL was synthesized efficiently, and their iridium complexes were synthesized by coordination of the O-SIPHOX ligands to [Ir(cod)Cl]2 in the presence of sodium tetrakis-3,5-bis(trifluoromethyl)phenylborate (NaBArF). The cationic iridium complexes showed high reactivity and excellent enantioselectivity in the asymmetric hydrogenation of 1-methylene-tetrahydro-benzo[d]azepin-2-ones (up to 99% yield and up to 99% ee). A key intermediate of the anti-obesity drug lorcaserin could be efficiently synthesized using this protocol.
- Ye, Xiang-Yu,Liang, Zhi-Qin,Jin, Cong,Lang, Qi-Wei,Chen, Gen-Qiang,Zhang, Xumu
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supporting information
p. 195 - 198
(2021/01/14)
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- Remodeling and Enhancing Schmidt Reaction Pathways in Hexafluoroisopropanol
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The effect of carrying out two variations of the Schmidt reaction with ketone electrophiles in hexafluoroisopropanol (HFIP) solvent has been studied. When TMSN3 is reacted with ketones in the presence of triflic acid (TfOH) promoter, tetrazoles are obtained as the major products. This observation is in contrast to established methods, which usually lead to amides or lactams arising from formal NH insertion as the major products. The full product profiles of several examples of this reaction are also reported and found to include mechanistically interesting products (e.g., double ring expansion). Application of TfOH promoter in HFIP was also found to promote the reaction of a hydroxyalkyl azide with a ketone, which affords lactams following nucleophilic opening of initially formed iminium ether more efficiently than previously reported methods. (Chemical Equation Presented).
- Motiwala, Hashim F.,Charaschanya, Manwika,Day, Victor W.,Aubé, Jeffrey
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p. 1593 - 1609
(2016/03/01)
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- 7-Sulfonamido-3-benzazepines as potent and selective 5-HT2C receptor agonists: Hit-to-lead optimization
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New 7-sulfonamido-3-benzazepines 3 are disclosed as 5-HT2C receptor agonists. Appropriate substitution of the amino group (R1R2N-) gave compounds that were potent 5-HT2C agonists with minimal activation of the 5-HT2A and 5-HT2B receptors. Furthermore, representative examples had excellent in vitro ADME properties and good selectivity over ion channel activity.
- Fish, Paul V.,Brown, Alan D.,Evrard, Edel,Roberts, Lee R.
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scheme or table
p. 1871 - 1875
(2009/12/03)
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- Azido-Schmidt reaction for the formation of amides, imides and lactams from ketones in the presence of FeCl3
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Ketones undergo smooth rearrangement with TMSN3 in the presence of FeCl3 under extremely mild conditions to provide the corresponding amides, imides and lactams in good yields with high selectivity. This method is very useful for the preparation of a wide range of amides, imides and lactams from ketones. The use of FeCl3 makes this method simple, convenient and cost-effective.
- Yadav,Reddy, B.V. Subba,Reddy, U.V. Subba,Praneeth
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p. 4742 - 4745
(2008/12/21)
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- Further studies on a samarium diiodide-promoted reductive carbon-nitrogen bond cleavage rection: Synthesis of (+)-aphanorphine
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Samarium diiodide-promoted carbon-nitrogen bond cleavage reaction was applied to the 1,2,3,4-tetrahydroisoquinoline derivatives bearing an ester group at the 1- or 3-position to give the corresponding benzazepinones. Synthesis of (+)-aphanorphine was esta
- Katoh, Miho,Inoue, Hiroshi,Honda, Toshio
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p. 497 - 516
(2008/03/12)
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- Effects of remote N-(tert-butoxycarbonyl) groups on heteroatom directed lithiation at benzylic positions
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Lithiation of N-BOC-2-methylphenethylamine (6) occurs exclusively at the methyl group whereas lithiation of the phenylpropyl congener (11) is less regioselective. N-BOC-phenylpropylamine (17) is efficiently lithiated at the benzylic position while N-BOC-2
- Clark, Robin D.,Jahangir
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p. 1351 - 1356
(2007/10/02)
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- Benzazepine derivatives, their pharmaceutical compositions and method of use
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Compounds of the formula STR1 wherein A is --CH2 --CH2 --, --CH=CH--, --NH--CO--, --CH2 --CO-- or STR2 where R7 is alkyl of 1 to 3 carbon atoms, and B is methylene, carbonyl or thiocarbonyl, or A is --CO--CO--, --N=CH--, STR3 where R8 is hydrogen or alkyl of 1 to 3 carbon atoms substituted by a phenyl, methoxyphenyl or dimethoxyphenyl, and B is methylene; E is n-alkylene of 2 to 4 carbon atoms optionally substituted by an alkyl of 1 to 3 carbon atoms, 2-hydroxy-n-propylene, 2-hydroxy-n-butylene or 3-hydroxy-n-butylene; G is n-alkylene of 1 to 5 carbon atoms optionally substituted by an alkyl of 1 to 3 carbon atoms, wherein one methylene group of an n-alkylene of 2 to 5 carbon atoms can be replaced by a carbonyl group, with the proviso that B represents a methylene or carbonyl group, or methylene-n-hydroxy-alkylene of 1 to 4 carbon atoms, where the methylene group is attached to the nitrogen atom; and R1 to R5 are simple substituents of various types; and non-toxic, pharmacologically acceptable acid addition salts thereof. The compounds as well as their salts are useful as bradycardiacs.
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