- Efficient and practical synthesis of (R)-2-methylpyrrolidine
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An efficient, practical, and high yielding synthesis of (R)-2-methylpyrrolidine is described. The sequence allows for the scalable preparation of the target compound in just four synthetic steps and proceeds in 83% overall yield and >99% optical purity from readily available starting materials.
- Zhao, Dalian,Kuethe, Jeffrey T.,Journet, Michel,Peng, Zhihui,Humphrey, Guy R.
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- Synthesis and evaluation of in vivo anti-hypothermic effect of all stereoisomers of the thyrotropin-releasing hormone mimetic: Rovatirelin Hydrate
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We discovered the orally active thyrotropin-releasing hormone (TRH) mimetic: (4S,5S)-5-methyl-N-{(2S)-1-[(2R)-2-methylpyrrolidin-1-yl]-1-oxo-3-(1,3-thiazol-4-yl)propan-2-yl}-2-oxo-1,3-oxazolidine-4-carboxamide 1 (rovatirelin). The central nervous system (CNS) effect of rovatirelin after intravenous (iv) administration is 100-fold higher than that of TRH. As 1 has four asymmetric carbons in its molecule, there are 16 stereoisomers. We synthesized and evaluated the anti-hypothermic effect of all stereoisomers of 1, which has the (4S),(5S),(2S),(2R) configuration from the N-terminus to the C-terminus, in order to clarify the structure?activity relationship (SAR) of stereoisomers. The (4R),(5R),(2R),(2S)-isomer 16 did not show any anti-hypothermic effect. Only the (4S),(5S),(2S),(2S)-isomer 10, which has the (2S)-2-methylpyrrolidine moiety at the C-terminus showed the anti-hypothermic effect similar to 1. Stereoisomers, which have the (5R) configuration of the oxazolidinone at the N-terminus and the (2R) configuration at the middle-part, showed a much lower anti-hypothermic effect than that of 1. On the other hand, stereoisomers, which have the (4R) configuration of the oxazolidinone at the N-terminus or the (2S) configuration of the C-terminus, have little influence on the anti-hypothermic effect.
- Kobayashi, Naotake,Sato, Norihito,Sugita, Katsuji,Takahashi, Kouji,Sugawara, Tamio,Tada, Yukio,Yoshikawa, Takayoshi
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- Asymmetric lithiation trapping of N -boc heterocycles at temperatures above -78°C
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The asymmetric lithiation trapping of N-Boc heterocycles using s-BuLi/chiral diamines at temperatures up to -20°C is reported. Depending on the N-Boc heterocycle, lithiation is accomplished using s-BuLi and (-)-sparteine or the (+)-sparteine surrogate in the temperature range -50 to -20°C for short reaction times (2-20 min). Subsequent electrophilic trapping or transmetalation-Negishi coupling delivered functionalized N-Boc heterocycles in 47-95% yield and 77:23-93:7 er. With N-Boc pyrrolidine, trapped products can be generated in ~90:10 er even at -20°C.
- Gelardi, Giacomo,Barker, Graeme,O'Brien, Peter,Blakemore, David C.
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p. 5424 - 5427
(2013/11/19)
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- Asymmetric synthesis of chiral cyclic amine from cyclic imine by bacterial whole-cell catalyst of enantioselective imine reductase
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Streptomyces sp. GF3587 and 3546 were found to be imine-reducing strains with high R- and S-selectivity by screening using 2-methyl-1-pyrroline (2-MPN). Their whole-cell catalysts produced 91 mM R-2-methylpyrrolidine (R-2-MP) with 99.2%e.e. and 27.5 mM S-2-MP (92.3%e.e.) from 2-MPN at 91-92% conversion in the presence of glucose, respectively.
- Mitsukura, Koichi,Suzuki, Mai,Tada, Kazuhiro,Yoshida, Toyokazu,Nagasawa, Toru
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experimental part
p. 4533 - 4535
(2010/11/19)
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- MODULATORS OF THE HISTAMINE H3-RECEPTOR USEFUL FOR THE TREATMENT OF DISORDERS RELATED THERETO
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The present invention relates to certain biphenyl sulfonamide derivatives of Formula (Ia) and pharmaceutical compositions thereof that modulate the activity of the histamine H3-receptor. Compounds and pharmaceutical compositions thereof are directed to methods useful in the treatment of histamine H3-receptor associated disorders, such as, cognitive disorders, epilepsy, brain trauma, depression, obesity, disorders of sleep and wakefulness such as narcolepsy, hypersomnia, somnolence syndrome, jet lag, sleep apnea and the like, attention deficit hyperactivity disorder (ADHD), schizophrenia, allergies, allergic responses in the upper airway, allergic rhinitis, nasal congestion, dementia, Alzheimer's disease and the like.
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Page/Page column 79-80
(2008/06/13)
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- An efficient and convergent synthesis of the potent and selective H3 antagonist ABT-239
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An efficient and convergent process for the preparation of a potent and selective H3 receptor antagonist, ABT-239, 1A was accomplished with an overall yield of 64%. The key step in the synthesis is a Sonogashira coupling/cyclization reaction of 1-but-3-ynyl-2-(R)-methylpyrrolidine (9) with 4′-hydroxy-3′-iodo-biphenyl-4-carbonitrile (3). Additionally, the key amine component 2-(R)-methylpyrrolidine (7) was effectively synthesized from the readily available Boc-l-prolinol with a simple catalytical hydrogenolysis as the key step. This column chromatography-free process is highlighted by several simple work-up and purification procedures and is amendable to the large-scale preparation of 1A.
- Ku, Yi-Yin,Pu, Yu-Ming,Grieme, Tim,Sharma, Padam,Bhatia, Ashok V.,Cowart, Marlon
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p. 4584 - 4589
(2007/10/03)
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- OXAZOLE DERIVATIVES AS HISTAMINE H3 RECEPTOR AGENTS, PREPARATION AND THERAPEUTIC USES
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The present invention discloses novel aryl oxazole compounds of Formula I (I), or pharmaceutically acceptable salts thereof, which have histamine-H3 receptor antagonist or inverse agonist activity, as well as methods for preparing and using such compounds. In another embodiment, the invention discloses pharmaceutical compositions comprising compounds of Formula I as well as methods of using these compositions to treat obesity, cognitive deficiencies, narcolepsy, and other histamine H3 receptor-related diseases. Formula I (I) or a pharmaceutically acceptable salt thereof, wherein: m is independenlly at each occurrence 1, 2, or 3, Z independently represents carbon (substituted with hydrogen or the optional substituents indicated herein) or nitrogen, provided that when Z is nitrogen then R6 is not attached to Z; R1 and R2 are independently -(C1-C7) alkyl(optionally substituted with one to three halogens), or R1 and R2 and the nitrogen to which they are attached form an azetidinyl ring, a pyrrolidinyl ring, or a piperidinyl ring, wherein further the azetidinyl, pyrrolidinyl, or piperidinyl ring so formed may be optionally substituted one to three times with R5; R6 is independently at each occurrence -H, -halogen, or -CH3.
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Page/Page column 44
(2008/06/13)
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- Process for preparing 2-methylpyrrolidine and specific enantiomers thereof
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The invention relates to a process for preparing 2-methylpyrrolidine and, more particularly, specific enantiomers of 2-methylpyrrolidine. Novel intermediates also are described.
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- Process for preparing 2-methylpyrrolidine and specific enantiomers thereof
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The invention relates to a process for preparing 2-methylpyrrolidine and, more particularly, specific enantiomers of 2-methylpyrrolidine. Novel intermediates also are described.
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- Complex-induced proximity effects: The effect of varying directing-group orientation on carbamate-directed lithiation reactions
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A series of selected bicyclic carbamates in which the range of accessible angles and distances between the carbonyl group and the proton removed in an α-lithiation reaction are structurally defined have been investigated. Oxazolidinones 7-10 undergo stereoselective lithiation-substitution reactions to provide cis-18-27 and cis-31-35 as the major diastereomers. Two series of competition experiments show that the conformationally restricted carbamates 7, 10, 11, and 15 undergo lithiation via complexes more efficiently than Boc amines 4-6. These results along with semiempirical calculations suggest that a small dihedral angle and a calculated distance of 2.78 A between the carbamate carbonyl oxygen and the proton to be removed are favorable for a carbamate-directed lithiation. A series of tin-lithium exchange experiments on cis- and trans-18 and (S)-39 indicate that the configurational stability of a carbamate-stabilized organolithium species may be enhanced by restrictive geometry.
- Bertini Gross,Beak
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p. 315 - 321
(2007/10/03)
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- Complex induced proximity effects: Enantioselective syntheses based on asymmetric deprotonations of N-Boc-pyrrolidines
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Lithiation of N-Boc-pyrrolidine (6) with sec-butyllithium (s-BuLi)/(-)-sparteine (14) effects an asymmetric deprotonation to give (S)-2-lithio-N-Boc-pyrrolidine ((S)-22), which reacts with electrophiles to provide the 2-substituted N-Boc-pyrrolidines 7-11 and 13 in enantiomeric excesses which generally are >90%. In the lithiation-silylation of 6 the chiral ligand 15 gives 7 with a lower enantiomeric excess and chiral ligands 16 and 17 give 7 with lower and opposite enantiomeric excesses than that obtained with 14. Diastereoselective amplification operates in a sequential lithiation-substitution sequence to provide the conversion of (S)-2-methyl-N-Boc-pyrrolidine ((S)-10) of 95% enantiomeric excess with s-BuLi/14 to (S,S)-2,5-dimethyl-N-Boc-pyrrolidine ((S,S)-19) with >99% enantiomeric excess. Synthetic preparations of a useful chiral ligand, (R)-α,α-diphenyl-2-pyrrolidine ((R)-20), and a useful chiral auxiliary, (S,S)-2,5-dimethylpyrrolidine hydrochloride ((S,S)-21), are reported. Reactions of racemic and enantioenriched 2-lithio-N-Boc-pyrrolidine and investigation of sequential lithiations-deuterations of 6 establish the reaction pathway to be asymmetric deprotonation rather than asymmetric substitution. A rationalization for the enantioselective deprotonation is provided.
- Beak, Peter,Kerrick, Shawn T.,Wu, Shengde,Chu, Jingxi
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p. 3231 - 3239
(2007/10/02)
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