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81.
Chiral fluorous imidazolidinone catalyst 2 provides consistently high enantioselectivities in Diels–Alder reactions of dienes and ,β-unsaturated aldehydes. The catalyst can be readily separated from the reaction products by fluorous solid-phase extraction, and recovered in excellent purity for direct reuse. 相似文献
82.
Shih-I Chu 《Chemical physics letters》1978,54(2):367-372
A practical non-perturbative approach is presented for multiphoton ionization of atoms induced by circularly polarized radiation. By use of co-ordinate rotation transformation and L2-discretization of the atomic continuum, the complex energy spectrum of a stationary quesienergy operator can be located and multiphoton ionization rates determined as a function of time and arbitrary photon intensity. The theory is applied to the two-photon ionization of the H atom in intense fields. 相似文献
83.
An unprecedented N-transacylation reaction on 2-acetamido-2-deoxy-α-d-glucopyranosides was disclosed in the presence of acyl chloride and DMAP under reflux in pyridine. 相似文献
84.
Gao Ping Li Zhen-Jia Chu Hai-Bo Huang Fen-Rei 《Journal of Radioanalytical and Nuclear Chemistry》1996,206(2):233-237
In this article, postsplenectomy changes of serum tuftsin level were studied on both human subjects and rabbits by using a self-established radioimmunoassay protocol. Antituftsin antibodies were raised in rabbits and roosters.125I-tuftsin was prepared through an Iodogen method. The characteristics of the RIA were satisfactory with a detecting range of 0.5–100 ug/ml and the lowest detection limit of 400ng/ml. Serum tuftsin levels of splenectomized subjects were measured and compared with control groups. The serum tuftsin level from 30 postsplenectomy human beings was 406±179 ng/ml (
± s) while that from a control group of 40 healthy blood donors was 557±256 ng/ml; the serum tuftsin level of 10 postsplenectomy rabbits was found to be 206±75 ng/ml while that of a control group of 10 normal rabbits was 318±96 ng/ml. The results showed that serum tuftsin level decreased markedly after splenectomy. 相似文献
85.
用TRP技术研究了以全硅MCM-41(Si-MCM-41)和HNO3交换的全硅MCM-41(H-MCM-41)为载体制备的Ni-Mo、Co-Mo和Ni-W加氢脱硫(HDS)催化剂的还原性能,并以0.8(wt)%二苯并噻吩(DBT)的十氢萘溶液为模型化合物,在高压固定床反应器上考察了上述催化剂的加氢脱硫(HDS)反应性能。结果表明,Si-MCM-41经稀HNO3交换后,所担载的Ni-Mo和Ni-W催化剂还原性能、HDS活性和加氢活性有显著变化,但对Co-Mo催化剂影响不大。这说明在Ni-Mo/H-MCM-41和Ni-W/H-MCM-41中可能存在氢溢流现象,DBT的HDS活性与载体表面酸性和氢溢流有关。 相似文献
86.
Design, synthesis, and binding affinities of pyrrolinone-based somatostatin mimetics 总被引:1,自引:0,他引:1
Smith AB Charnley AK Mesaros EF Kikuchi O Wang W Benowitz A Chu CL Feng JJ Chen KH Lin A Cheng FC Taylor L Hirschmann R 《Organic letters》2005,7(3):399-402
[structure: see text] Tetrapyrrolinone somatostatin (SRIF) mimetics (cf. 1), based on a heterochiral (D,L-mixed) pyrrolinone scaffold, were designed, synthesized, and evaluated for biological activity. The iterative synthetic sequence, incorporating the requisite functionalized coded and noncoded amino acid side chains, comprised a longest linear synthetic sequence of 23 steps. Binding affinities at two somatostatin receptor subtypes (hsst 4 and 5) reveal micromolar activity, demonstrating that the d,l-mixed pyrrolinone scaffold can be employed to generate functional mimetics of peptide beta-turns. 相似文献
87.
EPR study showed that the semi-quinone radical anion of chloranil (TCQ) was formed in a charge-transfer process between ground state chloranil as acceptor and each one of the following ground state donors,i.e.,N,N'-diethyl aniline (DEA),phenothiazine (PTZ),carbazole (CBZ),pyrene (PY),ferrocene (FRO),triphenylphosphine (TPP),triethylamine (TEA),anthracene (AN) and N,N-diethyl-3-aminophenyl ester of palmitic acid (DPP).Our results indicate that there is a tunneling effect for the ground-state charge-transfer process between chloranil and the donor. 相似文献
88.
Blinov BB Chu CM Courant ED Crandell DA Kaufman WA Krisch A Nurushev TS Phelps RA Raczkowski DB Ratner LG Wong VK Caussyn DD Derbenev YS Ellison TJ Lee SY Rinckel T Schwandt P Sperisen F Stephenson EJ von Przewoski B Baiod R Minty MG Ohmori C Wienands U 《Physical review letters》1994,73(12):1621-1623
89.
90.