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111.
112.
A practical synthesis of (R)-homopipecolinic acid methyl ester 1 and (R)-homoproline methyl ester 2 was performed utilizing (i) a direct intramolecular cyclization of ω-chloro-β-enamino esters 11 and 12, which were prepared from available (S)-1-phenylethylamine or (S)-1-(1-naphthyl)ethylamine and ω-chloro-β-keto esters 5 and 10, respectively and (ii) a highly diastereoselective NaBH4 reduction followed by hydrogenolysis. The present method is a short-step process using inexpensive and readily available substrates and reagents with fewer wasted materials. 相似文献
113.
We describe InBr3-catalyzed cyclization of 2-alkynylaniline derivatives having a variety of functional groups producing polysubstituted indoles. This methodology could be applied to the one-pot synthesis of an amino acid precursor by the addition of a catalytic amount of the indium salt, an imine, and TMSCl. 相似文献
114.
Norio Sakai 《Tetrahedron letters》2006,47(8):1261-1265
A catalytic amount of ytterbium triflate (Yb(OTf)3) promotes the cyclization of an N-silylenamine with in situ generated 2-methylene-1,3-cyclohexanedione and 2-methylenecyclohexanone to produce the corresponding 2,3-disubstituted 7,8-dihydroquinolin-5-one and 5,6,7,8-tetrahydroquinolin-5-one in moderate to good yields. A one-pot conversion of 7,8-dihydroquinolin-5-one to the quinoline derivative also proceeded in good yield. 相似文献
115.
Sasada T Aoki Y Ikeda R Sakai N Konakahara T 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(34):9385-9394
The [5+1] annulation of enamidines, which were prepared from functionalized silanes, organolithium compounds and two nitriles, with N,N-dimethylformamide dialkyl acetals as the C1 unit is described, leading to the synthesis of tri- and tetrasubstituted pyrimidine derivatives under catalyst- and solvent-free reaction conditions. Furthermore, the [5+1] annulation of enamidines by using orthoesters as the C1 unit is described, in which catalytic amounts of ZnBr(2) catalyze the annulation to produce polysubstituted pyrimidines under toluene or xylene reflux conditions. Moreover, the combination of a reductive ring-opening reaction with [Mo(CO)(6)] and a subsequent intramolecular cyclization with tBuOK effectively causes a skeletal transformation from the pyrimidines containing an isoxazolyl and an ethoxy substituent to form pyrido[2,3-d]pyrimidin-5-one frameworks in excellent yield. 相似文献
116.
Polycyclic aromatic compounds can be synthesized from 2-benzylic- or 2-allylbenzaldehydes using a catalytic amount of In(III) or Re(I) complexes. By using this method, polycyclic aza-aromatic compounds can also be prepared efficiently. In these reactions, only water is formed as a side product. 相似文献
117.
A convenient synthesis of indole triflones is reported. N-Alkyl, aryl and N-H indole triflones were obtained in 82-96% yields by the Tf(2)O/TTBP System. Biindolyl triflones were accessed in 51-81% yields for the first time by simple treatment of the resulting indole triflones with a base and without any use of organometallic chemistry. An environmentally friendly solvent, Solkane 365/227, can be substituted for this process without any loss of efficiency. 相似文献
118.
119.
Miura S Nishizawa S Suzuki A Fujimoto Y Ono K Gao Q Teramae N 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(50):14104-14110
A surface plasmon resonance (SPR) biosensor that carries DNA-binding small ligands has been developed for the detection of single-nucleotide polymorphisms (SNPs). 3,5-Diaminopyrazine derivatives, with a hydrogen-bonding profile fully complementary to the thymine base, were utilized as recognition elements on the sensor surface, and a target single-stranded DNA sequence was hybridized with a DNA probe containing an abasic site to place this site opposite a nucleobase to be detected. In a continuous flow of sample solutions buffered to pH 6.4 (0.25 M NaCl), the 3,5-diaminopyrazine-based SPR sensor can detect an orphan nucleobase in the duplex with a clear selectivity for thymine over cytosine, guanine, and adenine (5'-GTT GGA GCT GXG GGC GTA GGC-3'/3'-CAA CCT CGA CNC CCG CAT CCG-5'; X=abasic site, N=target nucleobase G, C, A, or T). The SPR response was linear in the concentration range 10-100 nM. Allele discrimination is possible based on the combination of different binding surfaces in a flow cell of the SPR system, which is demonstrated for the analysis of the thymine/cytosine mutation present in 63-meric polymerase chain reaction (PCR) amplification products (Ha-ras gene, codon 12, antisense strand). Comparison with a bulk assay based on 3,5-diaminopyrazine/DNA binding shows that the immobilization of 3,5-diaminopyrazine derivatives on the SPR sensor allows more sensitive detection of the target DNA sequence, and binding selectivity can be tuned by controlling the salt concentration of sample solutions. These features of the DNA-binding small-molecule-immobilized SPR sensor are discussed as a basis for the design of SPR biosensors for SNP genotyping. 相似文献
120.
Norio Sakai Ken NagasawaReiko Ikeda Yumi NakaikeTakeo Konakahara 《Tetrahedron letters》2011,52(24):3133-3136
An InBr3-Et3SiH reducing system was developed to selectively convert aliphatic ketones to a variety of secondary alcohols in moderate to good yields. An initial mixing of InBr3 and PhSiH3 was followed by the addition of aliphatic ketones and a solvent to afford the symmetrical ether derivatives. 相似文献