84740-98-7Relevant academic research and scientific papers
Structural and mechanistic studies of the base-induced Sommelet-Hauser rearrangement of: N -α-branched benzylic azetidine-2-carboxylic acid-derived ammonium salts
Tayama, Eiji,Watanabe, Kazutoshi,Sotome, Sho
, p. 6668 - 6678 (2017/08/16)
The base-induced Sommelet-Hauser rearrangement of N-α-branched benzylic azetidine-2-carboxylic acid ester-derived ammonium salts to obtain α-arylazetidine-2-carboxylic acid esters was investigated. The substrates, two diastereomeric salts (1S,2S,1′S)- and (1R,2R,1′S)-2, showed different reactivities. The rearrangement of (1S,2S,1′S)-2a proceeded with a perfect N-to-C chirality transfer to provide (R)-3a in 74% yield with 99% ee. However, the rearrangement of (1R,2R,1′S)-2a under the same conditions afforded (S)-3a in only 15% yield with a lower 66% ee, along with the competitive [1,2] Stevens rearrangement product 4a. Structural and mechanistic studies of this rearrangement were carried out to clarify the exact reason. Our results define the scope and limitations of the Sommelet-Hauser rearrangement and provide unique synthetic access to α-aryl amino acid derivatives.
Controlled light-mediated preparation of gold nanoparticles by a Norrish type i reaction of photoactive polymers
M?sing, Florian,Mardyukov, Artur,Doerenkamp, Carsten,Eckert, Hellmut,Malkus, Ursula,Nüsse, Harald,Klingauf, Jürgen,Studer, Armido
supporting information, p. 12612 - 12617 (2015/10/28)
Gold nanoparticles (AuNPs) are subjects of broad interest in scientific community due to their promising physicochemical properties. Herein we report the facile and controlled light-mediated preparation of gold nanoparticles through a Norrish type I reaction of photoactive polymers. These carefully designed polymers act as reagents for the photochemical reduction of gold ions, as well as stabilizers for the in situ generated AuNPs. Manipulating the length and composition of the photoactive polymers allows for control of AuNP size. Nanoparticle diameter can be controlled from 1.5 nm to 9.6 nm. Instant preparation of Au nanoparticles! Mixing a photoactive polymer with HAuCl4 and NaOH in DMF/H2O and irradiating with light for a few minutes provides stable, spherical, polymer-coated Au nanoparticles with defined diameter. The diameter can be adjusted from 1.5 to 9.6 nm by varying the length and composition of the photoactive polymer.
Precision polyelectrolytes
Srichan, Sansanee,Oswald, Laurence,Zamfir, Mirela,Lutz, Jean-Franois
supporting information; scheme or table, p. 1517 - 1519 (2012/03/26)
Charged macromolecules with controlled microstructures were prepared. Well-defined non-ionic precursors were first synthesized by sequence-controlled radical polymerization of tert-butyl 4-vinyl benzoate with various N-substituted maleimides. Afterwards, these macromolecules were hydrolyzed into polyanions.
Photoinduced nitric oxide release from a nitrobenzene derivative in mitochondria
Horinouchi, Taeko,Nakagawa, Hidehiko,Suzuki, Takayoshi,Fukuhara, Kiyoshi,Miyata, Naoki
experimental part, p. 4809 - 4813 (2011/06/26)
We report a novel NO donor (RpNO), containing a 2,6-dimethylnitrobenzene moiety for photocontrollable NO release and a rhodamine moiety for targeting to mitochondria. Photorelease of NO from RpNO in aqueous solution was confirmed by means of ESR analysis. Cellular release of NO from RpNO was confirmed with the aid of DAF-FMDA, an NO-specific fluorescence probe. RpNO was colocalized with MitoTracker GreenFM, a mitochondrial stain, in HCT116 colon cancer cells and exhibited photodependent cytotoxicity. Our results indicate that RpNO is an effective NO donor for time-controlled, mitochondria-specific NO treatment. NO entry! A novel NO donor (RpNO) containing a 2,6-dimethylnitrobenzene moiety for photocontrollable NO release and a rhodamine moiety for targeting to mitochondria was synthesized (see graphic). It was confirmed that RpNO became localized in the mitochondria of HCT116 colon cancer cells, and showed photodependent cytotoxicity. This is the first example of a photocontrollable, mitochondria-localizing NO donor. Copyright
Vinylation of aromatic halides using inexpensive organosilicon reagents. Illustration of design of experiment protocols
Denmark, Scott E.,Butler, Christopher R.
, p. 3690 - 3704 (2008/10/09)
The preparation of styrenes by palladium-catalyzed cross-coupling of aromatic iodides and bromides with divinyltetramethyldisiloxane (DVDS) in the presence of inexpensive silanolate activators has been developed. To facilitate the discovery of optimal reaction conditions, Design of Experiment (DoE) protocols were used. By the guided selection of reagents, stoichiometries, temperatures, and solvents, the vinylation reaction was rapidly optimized with three stages consisting of ca. 175 experiments (of a possible 1440 combinations). A variety of aromatic iodides undergo cross-coupling at room temperature in the presence of potassium trimethylsilanoate using Pd(dba) 2 in DMF in good yields. Triphenylphosphine oxide is needed to extend catalyst lifetime. Application of these conditions to aryl bromides was accomplished by the development of two complementary protocols. First, the direct implementation of the successful reaction conditions using aryl iodides at elevated temperature in THF provided the corresponding styrenes in good to excellent yields. Alternatively, the use of potassium triethylsilanolate and a bulky "Buchwald-type" ligand allows for the vinylation reactions to occur at or just above room temperature. A wide range of bromides underwent coupling in good yields for each of the protocols described.
Chemo- and stereoselectivity in titanium-mediated regioselective ring-opening reaction of epoxides at the more substituted carbon
Tanaka, Tetsuaki,Hiramatsu, Kei,Kobayashi, Yasutaka,Ohno, Hiroaki
, p. 6726 - 6742 (2007/10/03)
Chemo- and stereoselectivity in the ring-opening reaction of epoxides with a reagent prepared from allylmagnesium halide and chlorotitanium triphenoxide is described. It has been proven that the allylating reagent can also be used for the reaction of epoxides bearing a tert-butyl ester, amide, or acetal moiety, and that the epoxide cleavage regioselectively takes place at the more substituted carbon in all cases. Interestingly, while the reaction of acyclic 2,2,3-trialkyl epoxides or 3,3-disubstituted 2,3-epoxy alcohol derivatives with the allyltitanium reagent yielded the allylated products as an almost 1:1 diastereomixture, the ring-opening reaction of 2-substituted 2,3-epoxy alcohol derivatives stereospecifically proceeded through the anti pathway. The latter reaction is extremely useful for asymmetric construction of quaternary carbon centers.
A convenient synthesis of cis and trans 4-tert-butoxycarbonyl-substituted cyclohexylglycine
Venkatraman, Srikanth,Njoroge, F. George,Girijavallabhan, Viyyoor,McPhail, Andrew T.
, p. 2686 - 2688 (2007/10/03)
A novel synthesis of cis and trans substituted 4-tert-butoxycarbonyl cyclohexylglycines via asymmetric aminohydroxylation of vinyl styrene followed by reduction of the aromatic ring and subsequent oxidation is reported.
Condensed pyrimidine derivative
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, (2008/06/13)
A novel pyrimidine derivative having an excellent antitumor activity, which is represented by the following general formula (I) or a pharmacologically acceptable salt thereof: STR1 wherein R1 represents a hydroxyl or amino group; R2 represents a phenylene, pyridinediyl, thiendiyl, furandiyl or thiazoldiyl group, --CO2 R5 and --CO2 R6 may be the same or different from each other and each represents a carboxyl group or a carboxylic acid ester, the part STR2 A represents an oxygen atom, a group represented by the formula: STR3 (wherein R3 and R4 may be the same or different from each other and each represents a hydrogen or halogen atom or a hydrocarbon group which may be substituted, or alternatively R3 and R4 may be united to form an alkylidene group which may be substituted) or a group represented by the formula: STR4 (wherein R70 represents a hydrogen atom or a hydrocarbon group), and n is an integer of 1 to 3, provided that the compound in which R1 represents oxygen, and hydrogen is attached to nitrogen at 3-position is included in the above shown definition, a process for preparation the same, and an antitumor drug containing the same.
Pyrrolopyrimidine Folate Analogues: "Inverted" Analogues of the Cytotoxic Agent LY231514
Taylor, Edward C.,Young, Wendy B.
, p. 7947 - 7952 (2007/10/03)
N-pyrimidin-5-yl)ethyl>benzoyl>-L-glutamic acid (3a) and N-pyrimidin-5-yl)propyl>benzoyl>-L-glutamic acid (3b) were synthesized as potential anticancer agents.
Synthesis and antitumor activities of novel 6-5 fused ring heterocycle antifolates: N-[4-[ω-(2-amino-4-substituted-6,7- dihydrocyclopenta[d]pyrimidin-5-yl)alkyl]benzoyl]-L-glutamic acids
Kotake,Iijima,Yoshimatsu,Tamai,Ozawa,Koyanagi,Kitoh,Nomura
, p. 1616 - 1624 (2007/10/02)
Novel antifolates with a 6-5 fused ring system, 6,7- dihydrocyclopenta[d]pyrimidine, (3a,b and 4a,b) were synthesized on the basis of combined modification of the heterocycle and bridge regions of the folate molecule. The synthetic method involves (1) syn
