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排序方式: 共有152条查询结果,搜索用时 9 毫秒
1.
Max Robba Jean-Charles Lancelot Daniel Maume Alain Rabaron 《Journal of heterocyclic chemistry》1978,15(7):1159-1163
1,2,4-Triazino[4,5-b]indazol-1(2H)one and its derivatives were prepared by transposition of 3-[2-(-1,3,4-oxadiazolyl)]indazole or by ring closure of indazole ethoxymethylidenehydrazides. The synthesis of 1,2,3,4-tetrahydro-l,2,4-triazino[4,5-b]indazole-1,4-dione was achieved by cyclising the N-carbethoxyhydrazide of indazole-3-carboxylic acid and the synthesis of 1,2,4-triazino-[4,5-b]indazol-4(3H)one was made by cyclising the N-carbethoxy-hydrazone of indazole-3-carboxaldehyde. The Oxydation of 1,2,4-triazino[4,5-b]indazole-l(2H)thione gave 1,2,4-triazino-[4,5-b]indazoles. Nmr spectral data are reported. 相似文献
2.
Jean-Charles Boutonnet Francoise Rose-Munch Eric Rose Gilles Precigoux 《Journal of organometallic chemistry》1985,284(2):C25-C30
The complex CpV(CO)3THF has been prepared in THF solution (i) photochemically from CpV(CO)4, and (ii) from [CpV(H)(CO)3]?/[Ph3C]+ at low temperatures. THF is replaced by [CpV(H)(CO)3]? to form [{CpV(CO)3}2-μ-H]?, and by various ligands L with C, η2-CC, Sn, N, O, S, Se or Te functionality to yield CpV(CO)3L and cis-[CpV(CO)2LL] (LL = bipy, o-phen, tolane). The δ (51V) values range over ca. 1400 ppm and allow the assignment of distinct coordination modes for ambidentate ligands. The temperature gradient is ca. +1.2 ppm/deg. For [CpV(SnCl3)(CO)3]? (δ ?1340 ppm rel. to VOCl3), 1J(51V-117,119Sn) is 900 Hz. The isotope effect on introducing 12CO for 13CO in CpV(CO)4 is ?0.48(2) ppm; 1J(51V-13C) 107 Hz. 相似文献
3.
Lahboub Bouyazza Jean-Charles Lancelot Sylvain Rault Max Robba Marie Anne Quermonne 《Journal of heterocyclic chemistry》1991,28(2):373-377
Cyclization of 2-(1-pyrrolyl)piperonylcarboxamide derivatives gave iminium perchlorates which afforded 9-(N-substituted-imino) and 9-(N-substituted amino)-6,7-methylenedioxypyrrolo[1,2-a]indoles. 相似文献
4.
It is well known that in the computation of Gr?bner bases arbitrarily small perturbations in the coefficients of polynomials
may lead to a completely different staircase, even if the solutions of the polynomial system change continuously. This phenomenon
is called artificial discontinuity in Kondratyev’s Ph.D. thesis. We show how such phenomenon may be detected and even “repaired” by using a new variable to
rename the leading term each time we detect a “problem”. We call such strategy the TSV (Term Substitutions with Variables)
strategy. For a zero-dimensional polynomial ideal, any monomial basis (containing 1) of the quotient ring can be found with
the TSV strategy. Hence we can use TSV strategy to relax term order while keeping the framework of Gr?bner basis method so
that we can use existing efficient algorithms (for instance the F
5 algorithm) to compute an approximate Gr?bner basis. Our main algorithms, named TSVn and TSVh, can be used to repair artificial
e{\epsilon}-discontinuities. Experiments show that these algorithms are effective for some nontrivial problems. 相似文献
5.
Bureau R Daveu C Lancelot JC Rault S 《Journal of chemical information and computer sciences》2002,42(2):429-436
A first definition of a pharmacophore for the serotonin reuptake inhibitors was carried out by considering a three-dimensional model which correlates the chemical structures of series of reuptake inhibitors with their biological affinities. A molecular design was described by analyzing two different 3D serotonin pharmacophores. This successful approach enabled us to consider the design of new serotonin ligands by the same method. 相似文献
6.
Ferid Abidi Nayssene Aissaoui Jean-Charles Gaudin Jean-Marc Chobert Thomas Haertlé Mohamed Nejib Marzouki 《Applied biochemistry and biotechnology》2013,170(2):231-247
Prot-2 protease previously purified to homogeneity from Botrytis cinerea showed potentiality to be used in detergency and for production of bioactive peptides. To extend the characterization of Prot-2 protease, antifungal and antibacterial assays were performed in vitro using protein hydrolysates prepared from muscle of mackerel (Scomber scomborus) treated with this enzyme. The most active hydrolysate (degree of hydrolysis of 8 %) exhibited inhibition effect towards bacteria and phytopathogenic fungi, demonstrating that Prot-2 proteolysis generated bioactive peptides. Biochemical and molecular characterization of the purified Prot-2, by SDS-PAGE/Tryptic in gel-digestion and LC-MS/MS analysis, was investigated. The peptide amino acid sequence alignment search in database revealed a moderate homology between the determined amino acid sequence of Prot-2 protease and the known fungal trypsin/chymotrypsin in particular from Glomerella, Metarhizium and Streptomyces. From peptide sequence data obtained by mass spectrometry and sequences homologies, primers were defined and a cDNA fragment of 786 bp was amplified by RT-PCR. The cDNA nucleotide sequence analysis revealed an open reading frame coding for 262 amino acid residues. The deduced amino acid sequence of Prot-2 showed moderate identity with trypsin of Glomerella graminicola (74 %) and with chymotrypsin from Metarhizium anisopliae (71 %). Prot-2 exhibited a Ser protease homology and showed in addition the specific His motif of trypsin/chymotrypsin family. 相似文献
7.
Saturnino C Buonerba M Boatto G Pascale M Moltedo O de Napoli L Montesarchio D Lancelot JC de Caprariis P 《Chemical & pharmaceutical bulletin》2003,51(8):971-974
The therapy of human cancer is one of the more pursued goals by medicinal chemistry research. Most of the compounds clinically used as a treatment owe their efficacy to their cytotoxic interaction (direct or indirect) with nuclear DNA. This interaction results in the inhibition of DNA synthesis and the degradation of nucleic strands. Ellipticine is a naturally occurring 6H-pyrido[4,3-b]carbazole alkaloid endowed with antitumor activity, and several ellipticine derivatives have been used in clinical trials. We previously reported some 1,4-dimethyl-9H-carbazole derivatives structurally related to ellipticine. The purpose of our research was to transform the pyridocarbazole in a prodrug so that it would have more penetration in the tumor cells and block their replication. Our prodrug is slowly hydrolyzed in human plasma in the corresponding acid. From these preliminary results, we deduce that our compound can block cellular replication. Our hypothesis is that the antitumoral activity is probably related to the induction of damage to DNA, without cellular lysis in the short term. 相似文献
8.
The chemoselective and stereoselective synthesis of gem-difluoro-β-aminoesters or gem-difluoro-β-lactams was investigated from ethylbromodifluoroacetate and imines during Reformatsky reaction. Influence of various reaction parameters, such as nature of the amine part, nature of the chiral auxiliary, was evaluated. High levels of stereoselectivity (up to 98%) were obtained for gem-difluoro-β-aminoesters and gem-difluoro-β-lactams using either (R)-phenylglycinol or (R)-methoxyphenylglycinol. 相似文献
9.
Yamien Effi Jean-Charles Lancelot Sylvain Rault Max Robba 《Journal of heterocyclic chemistry》1986,23(1):17-23
The reactivity of pyrrolo[1,2-a]thieno[2,3-e]pyrazine towards quaternisation, bromination, nitration, Friedel-Crafts, Vilsmeier-Haack and Reissert reactions was studied. Assignment of structures to the product is based upon ir, nmr and mass spectral studies. 相似文献
10.
The synthesis of aza-2 pyrrolo[1,2-a]indole derivatives was achieved by a 1,3-dipolar cycloaddition reaction of dimethylacetylenedicarboxylate with a mesoionic ion. 相似文献