- Nanomole-scale assignment of configuration for primary amines using a kinetic resolution strategy
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The absolute configurations of primary amines were assigned using a kinetic resolution strategy with Mioskowski's enantioselective 1-(R,R) and 2-(S,S) acylating agents. A simple mnemonic was developed to determine the configuration. A pseudoenantiomeric pair of reagents, 1-(R,R) and 2-(S,S)-d 3, was prepared and used to assay primary amines on a micromolar scale. The ESI-MS readout of the resulting acetamide products reproduced the selectivity factors from kinetic experiments. The method can be used on mixtures of amines and was validated with amine samples as small as 50 nmol.
- Miller, Shawn M.,Samame, Renzo A.,Rychnovsky, Scott D.
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supporting information
p. 20318 - 20321
(2013/02/23)
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- An annulation reaction for the synthesis of morpholines, thiomorpholines, and piperazines from β-heteroatom amino compounds and vinyl sulfonium salts
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(Chemical Equation Presented) Heterocycling: Diphenyl vinyl sulfonium salt 1 acts first as an electrophile, then a base, and then again as an electrophile in this operationally simple, high yielding, one-pot synthesis of pharmacologically important morpholines, thiomorpholines, and piperazines. Compound 1 is an excellent synthon for the 1,2-ethane dication.
- Yar, Muhammad,McGarrigle, Eoghan M.,Aggarwal, Varinder K.
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p. 3784 - 3786
(2008/12/23)
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- From the production of amphetamine phenylpropanolamine
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A process for making compound of formula Ifrom a phenylpropanolamine salt of formula IIwherein:R1 is hydrogen or a lower alkyl group;each R2 is independently a hydrogen, halogen, lower alkyl group, lower alkoxy groups, lower alkyl group substituted with 1 to 5 halogens, lower alkoxy groups substituted with 1 to 5 halogens, or both R2 together when on adjacent carbons constitute a -O(CH2)xO- where x is 1 to 4, thereby forming a ring structure fused with the phenyl group;R3 is a C1-C8-alkyl group, a C1-C12-aralkyl group, C1-C12-alkaryl group, or a phenyl group, each optionally substituted by 1 to 5 substituents selected from halogen, hydroxy, or C1-C6-alkyl; andHX is an equivalent of an organic or inorganic acid,the process comprising:(a) acylating the phenylpropanolamine salt of formula II with an acylating agent in a solvent at elevated temperature to make a reaction mixture containing an O-acylated phenylpropanolamine salt of formula III which can be isolated by the addition of a crystallization solvent, or optionally this mixture can be used in the next step; and(b) hydrogenating the O-acylated phenylpropanolamine salt to make the compound of formula I in the presence of a catalyst.
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Page/Page column 17-18
(2008/06/13)
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- Aeruginoguanidines 98-A-98-C: Cytotoxic unusual peptides from the cyanobacterium Microcystis aeruginosa
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Aeruginoguanidines 98-A-98-C (1-3) were isolated from the cyanobacterium Microcystis aeruginosa (NIES-98). The structures of aeruginoguanidines 98-A-98-C (1-3) were determined by two-dimensional 1H-1H and 1H-13C NMR correlation experiments and confirmed by mass spectral analysis. The absolute stereochemistry of 1, consisting of Hphpa trisulfate (1-(4-hydroxy-3-hydroxymethyl)phenyl-1-hydroxy-2-propylamine 4′,3′,1-tri-O-sulfate), MpArg (Nα-methyl-Nω-prenylarginine) and MgArg ((Z)-Nα-methyl-Nω-geranylarginine), was determined by the NMR analyses of phenylglycine methyl ester (PGME) or Boc phenylglycine (BPG) derivatives of acid hydrolysates. These compounds showed moderate cytotoxicity against the P388 murine leukemia cells.
- Ishida, Keishi,Matsuda, Hisashi,Okita, Yuji,Murakami, Masahiro
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p. 7645 - 7652
(2007/10/03)
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- The synthesis and biological characterization of a ceramide library
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A facile synthesis of a combinatorial ceramide library and their activities in the NF-κB pathway and in apoptosis induction/prevention were demonstrated. A novel NF-κB activating molecule was discovered among ceramide containing β-galactose, and the structural requirements of ceramides for apoptosis induction was elucidated. Copyright
- Chang, Young-Tae,Choi, Jaehwa,Ding, Sheng,Prieschl, Eva E.,Baumruker, Thomas,Lee, Jae-Mok,Chung, Sung-Kee,Schultz, Peter G.
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p. 1856 - 1857
(2007/10/03)
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- Protease-mediated fragmentation of p-amidobenzyl ethers: A new strategy for the activation of anticancer prodrugs
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A new anticancer prodrug activation strategy based on the 1,6-elimination reaction of p-aminobenzyl ethers is described. Model studies were undertaken with the N-protected peptide benzyloxycarbonylvaline-citrulline (Z-val-cit), which was attached to the amino groups of p-aminobenzyl ether derivatives of 1-naphthol and N-acetylnorephedrine. The amide bond that formed was designed for hydrolysis by cathepsin B, a protease associated with rapidly growing and metastatic carcinomas. Upon treatment with the enzyme, the Z-val-cit-p-amidobenzyl ether of 1-naphthol (2) underwent peptide bond hydrolysis with the rapid release of 1-naphthol. The aliphatic Z-val-cit-p-amidobenzyl ether of N-acetylnorephedrine (5) also underwent amide bond hydrolysis, but without the ensuing elimination of N-acetylnorephedrine. On the basis of these results, the phenolic anticancer drugs etoposide (6) and combretastatin A-4 (7) were attached to the Z-val-cit-p-amidobenzyl alcohol through ether linkages, forming the peptide-drug derivatives 8 and 9, respectively. Both compounds were stable in aqueous buffers and serum and underwent ether fragmentation upon treatment with cathepsin B, resulting in the release of the parent drugs in chemically unmodified forms. The released drugs were 13-50 times more potent than were the prodrug precursors on a panel of cancer cell lines. In contrast, the corresponding carbonate derivative of combretastatin A-4 (13) was unstable in aqueous environments and was as cytotoxic as combretastatin A-4. This result extends the use of the self-immolative p-aminobenzyl group for the fragmentation of aromatic ethers and provides a new strategy for anticancer prodrug development.
- Toki, Brian E.,Cerveny, Charles G.,Wahl, Alan F.,Senter, Peter D.
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p. 1866 - 1872
(2007/10/03)
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- Preparation of secondary and tertiary amides under neutral conditions by photochemical acylation of amines
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The smooth and neutral acylation of amines to form amides by photoactivation of N-acyl-5,7-dinitroindolines is described. An improved acylation of nitroindolines allows the convenient preparation of N-acylnitroindolines. This reaction makes possible the recycling of the nitroindoline released during the photoactivation.
- Helgen,Bochet
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p. 1968 - 1970
(2007/10/03)
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- MISE EN EVIDENCE PAR RMN-(1)H ET -(13)C D'ISOMERISME Z/E ET D'EQUILIBRE CONFORMATIONNEL SUR UNE SERIE DE DERIVES MONO- ET DIACETYLES DE 2-ALKYLAMINO-1-PHENYLPROPAN-1-OLS
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(1)H- and (13)C NMR studies of mono- and diacetylated-erythro- and threo-2-alkylamino-1-phenylpropan-1-ols, C6H5CHOHCHNHRCH3 (R = H, CH3, C2H5 AND i-C3H7) show that the series exhibit Z/E isomerism about the C-N amide bond.The Z/E ratio increases in the monoacetylated series CH3 1-C2 and N-C2 bonds.In the Z configuration, the conformer Z-s-syn where the proton H-2 is syn with the N-alkyl substituent predominates.
- Tytgat, D.,Gelbcke, M.
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p. 479 - 490
(2007/10/02)
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- Polymer-bound N-Alkylnorephedrines as Efficient Chiral Catalysts for the Enantioselective Addition of Dialkylzincs to both Aromatic and Aliphatic Aldehydes
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Polymer-bound N-alkylnorephedrines are recyclable catalysts of the enantioselective addition of dialkylzincs to both aromatic and aliphatic aldehydes.Optically active aromatic and aliphatic secondary alcohols are obtained in high enantiomeric excess.The c
- Soai, Kenso,Niwa, Seiji,Watanabe, Masami
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p. 109 - 113
(2007/10/02)
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