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991.
Based on our synthetic strategy developed for the total synthesis of the macrocyclic salicylate natural product salicylihalamide, we describe herein the synthesis of a series of simplified salicylihalamide-based analogs. Alterations in the aromatic fragment, the macrolactone scaffold and side-chain were evaluated for in vitro inhibition of V-ATPase activity and human tumor cell growth. 相似文献
992.
993.
We report the practical synthesis of the new 5-azidopyrrolo[2,1-c][1,2,4]triazolo[4,3-a][1,4]benzo-diazepin-8-one and 11-alkylamino-2-azidopyrrolo[2,1-c][1,4]benzodiazepines via the corresponding hydroxy compounds. 相似文献
994.
A direct cross-coupling reaction of aromatic aldehydes with potassium trifluoro(organo)borates afforded ketones in high yields and under mild conditions in the presence of a rhodium catalyst and acetone. This new reaction, involving a formal aldehyde C-H bond activation, is believed to proceed via a Heck-type mechanism followed by hydride transfer to acetone. 相似文献
995.
Baudron SA Batail P Coulon C Clérac R Canadell E Laukhin V Melzi R Wzietek P Jérome D Auban-Senzier P Ravy S 《Journal of the American Chemical Society》2005,127(33):11785-11797
(EDT-TTF-CONH2)6[Re6Se8(CN)6], space group R, was prepared by electrocrystallization from the primary amide-functionalized ethylenedithiotetrathiafulvalene, EDT-TTF-CONH2 (E(1/2)1 = 0.49 V vs SCE in CH3CN), and the molecular cluster tetraanion, [Re6Se8(CN)6]4- (E(1/2) = 0.33 V vs SCE in CH3CN), equipped with hydrogen bond donor and hydrogen bond acceptor functionalities, respectively. Its Kagome topology is unprecedented for any TTF-based materials. The metallic state observed at room temperature has a strong two-dimensional character, in coherence with the Kagome lattice symmetry, and the presence of minute amounts of [Re6Se8(CN)6](3-)* identified by electron spin spectroscopy. A structural instability toward a distorted form of the Kagome topology of lesser symmetry is observed at ca. 180 K. The low-temperature structure is associated with a localized, electrically insulating electronic ground state and its magnetic susceptibility accounted for by a model of uniform chains of localized S = 1/2 spins in agreement with the 100 K triclinic crystal structure and band structure calculations. A sliding motion, within one out of the three (EDT-TTF-CONH2)2 dimers coupled to the [Re6Se8(CN6)(3-)*]/[Re6Se8(CN6)4-] proportion at any temperature, and the electronic ground state of the organic-inorganic hybrid material are analyzed on the basis of ESR, dc conductivity, 1H spin-lattice relaxation, and static susceptibility data which qualify a Mott localization in [EDT-TTF-CONH2]6[Re6Se8(CN)6]. The coupling between the metal-insulator transition and a structural transition allows for the lifting of a degeneracy due to the ternary axis in the high temperature, strongly correlated metallic phase which, in turn, leads to Heisenberg chains at low temperature. 相似文献
996.
Sylvain Rault Michel Cugnon De Svricourt Paulette Touzot Max Robba Hussein El-Kashef 《Journal of heterocyclic chemistry》1980,17(7):1399-1404
The nitration and bromination of both [1]benzothieno[3,2-d]pyrimidin-4(3H)one ( 1 ) and [1]benzothieno-[3,2-d]pyrimidine ( 2 ) has been studied. Nitration of 1 at ?30° afforded a mixture of 8-nitro[1]benzothieno-[3,2-d]pyrimidin-4(3H)one ( 7b ) (70%) and 6-nitro[1]benzothieno[3,2-d]pyrimidin-4(3H)one ( 7a ) (30%). However when the nitration was carried out at 60°, the 6,8-dinitro derivative 8 was the result. On the contrary, the nitration of 2 at ?30° gave a single nitration product, 8-nitro[1]benzothieno[3,2-d]pyrimidine ( 11 ). The bromination of both 1 and 2 gave the corresponding 8-bromo derivatives 10 and 13 . Assignment of structure of all the products was based on ir and nmr spectral studies and on unequivocal syntheses. 相似文献
997.
Guillemot G Solari E Rizzoli C Floriani C 《Chemistry (Weinheim an der Bergstrasse, Germany)》2002,8(9):2072-2080
This is the first coherent report on the metalation of calix[4]arene by alkali and alkaline-earth metals, thus providing a high-yield production of appropriate synthons for the synthesis of transition metal calix[4]arenes. In addition, various facets of the coordination chemistry by calix[4]arene anions of alkali and alkaline-earth metal ions have been singled out. Among them: 1) the exo and endo coordination of metal ions by the calix[4]arene skeleton; 2) the pi solvation of the ions by the phenyl rings; 3) the ion-carrier properties of metallacalix[4]arenes; 4) the simulation of the kinetically labile coordination sphere of alkali and alkaline-earth metal ions by a polyoxo rigid skeleton. The peculiarities of the complexation of alkali and alkaline-earth metal ions by calix[4]arenes outlined are deduced from the synthesis and the structural characterization both in solution ((1)H NMR) and in the solid state (X-ray structure analysis) of the following classes of compounds: 1) [p-tBu-calix[4](OMS(n))(4)](2) (M=Li, Na, K); 2) [p-tBu-calix[4](OR)(2)(O)(2)ML] (M=Mg, L=THF, R=C(5)H(9); M=Ca, L=TMEDA (tetramethylethylenediamine), R=C(5)H(9); M=Ca, L=DME (dimethoxyethane), R=C(5)H(9); M=Ba, L=TMEDA, R=C(5)H(9); M=Ba, L=none, R=C(5)H(9)); 3) [p-tBu-calix[4](OC(5)H(9))(2)(O)(2)Ca(2)I(2)(MeCN)(2)]; 4) [(p-tBu-calix[4](OR)(2)(O)(2))(2)BaNa(2)]. 相似文献
998.
Xiao Feng Jean-Charles Lancelot Alain-Claude Gillard Henriette Landelle Sylvain Rault 《Journal of heterocyclic chemistry》1998,35(6):1313-1316
The synthetic pathway leading to 5,6-dihydro-4H-furo[3,2-f]pyrrolo[1,2-a][1,4]diazepines is described in four steps starting from α-bromophenones via 2-amino-3-furonitriles. 相似文献
999.
Yamien Effi Jean-Charles Lancelot Sylvain Rault Max Robba 《Journal of heterocyclic chemistry》1983,20(4):913-918
The 4,5-dihydropyrrolo[1,2-e]pyrazin-5-one (1) exhibits lactam-lactim tautomerism. N-Electrophilic substitutions could be achieved via the intermediate of the substitutions could be achieved via the intermediate of the sodium salt la. The 5-chloropyrazine 11 obtained by chlorodehydroxylation of pyrazinone 1 allowed nucleophilic substitution. Thionation of the pyrazinone 1 afforded the thioxopyrazine 27 wich gave studied and the tautomerism of the hydrazinopyrazine 14 and its derivatives are discussed in terms of hydrazone and azine structures 相似文献
1000.
Sylvain Valère T. Sob Pierre Tane Bonaventure T. Ngadjui Joseph D. Connolly 《Tetrahedron》2007,63(36):8993-8998
Two novel labdane type diterpenoids, 8β(17)-epoxy-14,15,16-trihydroxylabd-12(E)-ene (aulacocarpin C) and 15,16-epoxy-14ξ,16ξ-dimethoxylabda-8(17),12-(E)-diene (aulacocarpin D) together with the known aulacocarpin A and B; 14,15-epoxy-8(17),12(E)-labdadien-16-al, coronarin E, and 15,16-epoxy-12β-hydroxy-labda-8(17)-13(16),14-triene were isolated from the seeds of Aframomum aulacocarpos. To the best of our knowledge, the last compound was isolated from a natural source for the first time. Acid hydrolysis of aulacocarpin D led to another new labdane type diterpenoid, 15,16-epoxy-12β-methoxylabda-8(17)-13(16),14-triene. The structures of all compounds were established on the basis of their spectroscopic data. These new compounds exhibit moderate trypanocidal activity. 相似文献