- Regioselective synthesis of substituted piperidine-2,4-diones and their derivatives via Dieckmann cyclisations
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Abstract A flexible route to piperidine-2,4-diones variously substituted at the 6-, 5,6- and 2,6-positions, both with and without 1-substitution, is described; no N-protective group is required. A related regioselective Dieckmann cyclisation is also described that uses Davies' α-methylbenzylamine auxiliary and affords 6-substituted piperidine-2,4-diones enantioselectively.
- Marson, Charles M.,Yau, Kin Cheung
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p. 7459 - 7469
(2015/08/24)
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- Design and synthesis of optically pure 3-aryl-6-methyl-2- thioxotetrahydropyrimidin-4(1H)-ones as anti-prostate cancer agents
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3-Aryl-6-methyl-2-thioxotetrahydropyrimidin-4(1H)-ones were proposed as a new class of anti-prostate cancer agents on the basis of molecular modeling studies. Stereoselective synthesis of 3-aryl-6-methyl-2- thioxotetrahydropyrimidin-4(1H)-one derivatives was achieved by chiral induction employing (R)/(S)-α-methyl benzylamine and subsequent debenzylation with HBr in AcOH afforded the desired enantiomers in good yields. The compounds were screened in vitro against prostate cancer cell lines, PC-3 and LNCaP and the most potent derivatives were identified. the Partner Organisations 2014.
- Kumar, Varun,Rachamalla, Mahesh,Nandekar, Prajwal,Khatik, Gopal L.,Sangamwar, Abhay T.,Tikoo, Kulbhushan,Nair, Vipin A.
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p. 37868 - 37877
(2014/11/07)
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- Design and synthesis of optically pure 3-aryl-6-methyl-2-thioxotetrahydropyrimidin-4(1H)-ones as anti-prostate cancer agents
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3-Aryl-6-methyl-2-thioxotetrahydropyrimidin-4(1H)-ones were proposed as a new class of anti-prostate cancer agents on the basis of molecular modeling studies. Stereoselective synthesis of 3-aryl-6-methyl-2-thioxotetrahydropyrimidin-4(1H)-one derivatives was achieved by chiral induction employing (R)/(S)-α-methyl benzylamine and subsequent debenzylation with HBr in AcOH afforded the desired enantiomers in good yields. The compounds were screened in vitro against prostate cancer cell lines, PC-3 and LNCaP and the most potent derivatives were identified. This journal is
- Kumar, Varun,Rachamalla, Mahesh,Nandekar, Prajwal,Khatik, Gopal L.,Sangamwar, Abhay T.,Tikoo, Kulbhushan,Nair, Vipin A.
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p. 37868 - 37877
(2014/12/11)
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- Michael additions of amines to methyl acrylates promoted by microwave irradiation
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A simple and efficient protocol has been developed for the Michael addition of amines to α,β-unsaturated esters under microwave irradiation. Under these conditions there was a significant decrease in the reaction time, increases in the yields and increased purity of the products.
- Escalante, Jaime,Carrillo-Morales, Manuel,Linzaga, Irma
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p. 340 - 347
(2008/09/17)
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- Lithium (α-Methylbenzyl)allylamide: A Differentially Protected Chiral Ammonia Equivalent for the Asymmetric Synthesis of β-Amino Acids and β-Lactams
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The addition products from the highly stereoselective conjugate additions of lithium (αS)-(α-methylbenzyl)allylamide to α,β-unsaturated tert-butyl esters are efficiently deallylated with tris(triphenylphosphine)rhodium(I) chloride and converted, after tra
- Davies, Stephen G.,Fenwick, David R.
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p. 1109 - 1110
(2007/10/02)
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- Enantioselective Synthesis of β-Amino Acids. 5. Stereoselective Reaction of Chiral Pyrimidinone Enolates with Aldehydes
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Hydro-pyrimidinones ((2S,6R)-3) and ((2S)-6) were prepared from methyl crotonate via 3-aminobutanoate, and their corresponding lithium enolate and dienolate derivatives were added to various aldehydes.The high regio- and stereoselectivities observed in these aldol reactions pave the road for the preparation of enantiomerically pure β-hydroxy-β'-amino acids.The structures of the products were confirmed by X-ray crystal structure analysis (eight examples).
- Murer, Peter,Rheiner, Beat,Juaristi, Eusebio,Seebach, Dieter
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p. 319 - 344
(2007/10/02)
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- 194. Diastereoselecktive Alkylation of 3-Aminobutanoic Acid in the 2-Position
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The enantiomerically pure 3-aminobutanoic acids (R)- and (S)-6 are readily available by preparative HPLC separation of the two diastereoisomers 5 obtained from addition of (S)-phenethylamine to methyl crotonate and subsequent hydrogenolysis (Scheme 2). (S)-methyl 3-(benzoylamino)butanoate ((S)-3) is also available by enzymatic kinetic resolution with pig-liver esterase.The N-benzoyl- and N-benzyloxycarbonyl derivatives rac-3, 8,and 9 of 3-aminobutanoates are doubly deprotonated with LDA and alkylated or aminated in high selectivity (17 examples, relative topicity like; see Tables 1 and 2).The configuration of three of the products is assigned (Schemes 4-6), and in four cases, the free α-substituted β-amino acid is prepared by acidic hydrolysis (see Table 3).It is shown that the doubly lithiated β-amino-acid derivative is solubilized, and its reactivity may be strongly influenced by the presence of 3 equiv. of LiCl.
- Estermann, Heinrich,Seebach, Dieter
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p. 1824 - 1840
(2007/10/02)
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- α-ALKYLATION OF β-AMINOBUTANOATES WITH lk-1,2-INDUCTION
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Dilithiated methyl- or ethyl-N-benzoyl-3-aminobutanoates are alkylated or added to benzaldehyde to give products of l- and u,u-configuration respectively.Several methods are presented by which enantiomerically pure 3-aminobutanoic derivatives can be prepared.
- Seebach, Dieter,Estermann, Heinrich
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p. 3103 - 3106
(2007/10/02)
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