- Stereo-selective preparation of teneraic acid, trans-(2S,6S)-piperidine-2,6-dicarboxylic acid, via anodic oxidation and cobalt-catalyzed carbonylation
-
Teneraic acid (piperidine-2,6-dicarboxylic acid) is a naturally occurring imino acid that comprises three stereoisomers due to its two asymmetric centers at C2 and C6. The configuration of natural teneraic acid is reported to correspond to trans-(2S,6S).
- Amino, Yusuke,Nishi, Seiichi,Izawa, Kunisuke
-
p. 854 - 861
(2017/09/12)
-
- Design, synthesis, and biological activity of novel polycyclic aza-amide FKBP12 ligands
-
Since the discovery that FK-506 promotes neurite outgrowth, considerable attention has been focused on the development of potent nonimmunosuppressive ligands for FK-506 binding proteins (FKBPs). Such neuroimmunophilin agents have been reported to show neu
- Hudack Jr., Raymond A.,Barta, Nancy S.,Guo, Chuangxing,Deal, Judith,Dong, Liming,Fay, Lorraine K.,Caprathe, Bradley,Chatterjee, Arindam,Vanderpool, Darin,Bigge, Christopher,Showalter, Richard,Bender, Steve,Augelli-Szafran, Corinne E.,Lunney, Elizabeth,Hou, Xinjun
-
p. 1202 - 1206
(2007/10/03)
-
- Synthesis and evaluation of novel macrocyclic and acyclic ligands as contrast enhancement agents for magnetic resonance imaging
-
Novel chelates PIP-DTPA, AZEP-DTPA, NETA, NPTA, and PIP-DOTA were synthesized and evaluated as potential magnetic resonance imaging (MRI) contrast enhancement agents. The T1 and T2 relaxivities of their corresponding Gd(III) complexe
- Chong, Hyun-Soon,Garmestani, Kayhan,Bryant Jr., L. Henry,Milenic, Diane E.,Overstreet, Terrish,Birch, Noah,Le, Thien,Brady, Erik D.,Brechbiel, Martin W.
-
p. 2055 - 2062
(2007/10/03)
-
- Photocatalytic stereoselective N-cyclization of 2,6-diaminopimelic acid into piperidine-2,6-dicarboxylic acid by an aqueous suspension of activated cadmium(II) sulfide particles
-
Photoirradiation at a wavelength of >300 nm of a deaerated suspension of cadmium(II) sulfide (CdS) particles in an aqueous solution of a mixture of stereoisomers of 2,6-diaminopimelic acid (DAP; (S,S):(R,S):(R,R) = 1:2:1) produced piperidine-2,6-dicarboxylic acid (PDC) via a redox-combined mechanism including oxidation and reduction by positive holes and photoexcited electrons, respectively. Both the yield and trans:cis ratio of PDC markedly depended on the kinds of CdS photocatalysts, their pre-treatment, and the loading of fine platinum (or its oxide) particles. A CdS photocatalyst prepared by heat treatment of a commercial powder in hexagonal (wurtzite) structure at 1023 K in the presence of a small amount of air gave the highest yield and trans:cis ratio. Analyses of the activated CdS powder by powder X-ray diffraction (XRD), photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and BET surface area measurements revealed the formation of sulfur vacancies due to heat treatment, which promote the photoinduced cadmium metal (Cd0) deposition. The Cd0, deposited in situ on the CdS surface and detected by reduction of methylviologen, may act as a reduction site for photoexcited electrons toward a cyclic Schiff base intermediate produced by oxidation of DAP with positive holes followed by deamination and intramolecular condensation. Optically pure (R,R)- or (S,S)-PDCs were prepared successfully by photocatalytic reaction with the activated CdS particles using (R,R)- or (S,S)-DAPs, indicating that stereoselective conversion of organic compounds can be achieved via photocatalytic reaction under controlled conditions.
- Ohtani, Bunsho,Kusakabe, Satoshi,Okada, Katsumi,Tsuru, Shigeto,Nishimoto, Sei-Ichi,Amino, Yusuke,Izawa, Kunisuke,Nakato, Yoshihiro,Matsumura, Michio,Nakaoka, Yasuhiro,Nosaka, Yoshio
-
p. 201 - 209
(2007/10/03)
-
- Improvement of photocatalytic activity and product selectivity by cadmium metal deposited in situ on suspended cadmium(II) sulfide particles
-
Effect of annealing of commercial crystalline CdS powders on their photocatalytic activity and product selectivity was investigated for stereoselective diamino-N-cyclization of 2,6-diaminopimelic acid operated in deaerated aqueous solution.Surface analyses revealed the formation of sulfur vacancy, which promotes the photoinduced cadmium metal (Cd0) deposition.The Cd0, detected by reduction of methylviologen, may act as reduction site for photoexcited electrons.
- Ohtani, Bunsho,Kusakabe, Satoshi,Nishimoto, Sei-ichi,Matsumura, Michio,Nakato, Yoshihiro
-
p. 803 - 804
(2007/10/03)
-
- Stereoselective Synthesis of Piperidine-2,6-dicarboxylic Acids by Photocatalytic Reaction of Aqueous Cadmium(II) Sulfide Dispersion
-
Photoirradiation at wavelength > 300 nm onto a deareated aqueous suspension of cadmium(II) sulfide (CdS) particles in an aqueous solution of a mixture of stereo isomers of 2,6-diaminopimelic acid (DAP) produced piperidine-2,6-dicarboxylic acid (PDC).Both yield and trans/cis ratio of PDS markedly depend on the kind of CdS photocatalysts, its pre-treatment, and loading of fine platinum particles.A CdS photocatalyst prepared by heat-treatment at 1023 K in the presence of a small amount of air showed the highest yield and trans/cis ratio.
- Ohtani, Bunsho,Kusakabe, Satoshi,Okada, Katsumi,Tsuru, Shigeto,Izawa, Kunishuke,et al.
-
p. 3189 - 3192
(2007/10/02)
-
- Synthesis of a key intermediate in the diaminopimelate pathway to L-lysine: 2,3,4,5-tetrahydrodipicolinic acid
-
2,3,4,5-Tetrahydrodipicolinic acid (3) is a key intermediate in the diaminopimelate (DAP) pathway to L-lysine (7). It was synthesized as the stable racemic potassium salt (25) from dipicolinic acid (14) by esterification, hydrogenation to the cis-diester (17), followed by elimination of p-toluenesulfinic acid from the N-toluenesulfonyl derivative (24) of dimethyl cis-piperidine-2,6-dicarboxylate with concomitant cleavage of the esther groups. (±)-2,3,4,5-Tetrahydrodipicolinic acid is unstable in neutral or acidic solution, and in basic solution it exists in equilibrium with the corresponding enamine (27) and 2-oxo-6-aminoadipate (26).
- Chrystal, Ewan J. T.,Couper, Lynda,Robins, David J.
-
p. 10241 - 10252
(2007/10/02)
-
- Enzyme-Catalysed Hydrolysis of N-Benzyloxycarbonyl-cis-2,6-(acetoxymethyl)piperidine. A Facile Route to Optically Active Piperidines
-
We report the first enzymatic asymmetrization of a piperidine system.Hydrolysis of N-benzyloxycarbonyl-cis-2,6-(acetoxymethyl)piperidine in the presence of Aspergillus niger lipase gave the corresponding 2R, 6S mono-acetate in good chemical yield and very
- Chenevert, Robert,Dickman, Michael
-
p. 1021 - 1024
(2007/10/02)
-
- SYNTHESIS AND CONFIGURATION OF DIASTEREOMERIC 2,4-, 2,5-, AND 2,6-PIPERIDINEDICARBOXYLIC ACIDS AND THEIR DIMETHYL ESTERS
-
The reduction in an acidic medium over a platinum catalysts of 2,4-, 2,5-, and 2,6-pyridinedicarboxylic acids gave cis-2,4-, -2,5-, and -2,6-piperidinedicarboxylic acids, heating of which in an alkaline medium led to thermodynamically equilibrium mixtures of diastereomers.Individual trans-2,5-piperidinecarboxylic acid was isolated.The configurations of the 2,4-, 2,5-, and 2,6-piperidinedicarboxylic acids and their methyl esters were established by means of the PMR spectra.
- Mastafanova, L. I.,Turchin, K. F.,Evstratova, M. I.,Sheinker, Yu. N.,Yakhontov, L. N.
-
p. 305 - 309
(2007/10/02)
-