共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
A versatile and concise synthesis of N-alkylated 1,4-dideoxy-1,4-imino-D-arabinitol and 1,4-dideoxy-1,4-imino-L-xylitol derivatives is described. These were prepared using pseudohemiketal lactams as key intermediates, which in turn were obtained from sucrose. The key intermediates were prepared by a diastereospecific tandem reaction which facilitated the introduction of various substituents on the nitrogen atom of the iminosugars. 相似文献
3.
Cyclo-octa-1,4-diene and cyclohepta-1,4-diene give the bicyclic derivatives IIa–b and IVa–b on reaction with Br2-CCl4 or I2-AgClO4-MeOH respectively. Cyclo-octa-1,4-diene also undergoes homo-1,4-addition in the Prevost reaction with I2-AgOAc or I2-AgOCOPh in benzene. 相似文献
4.
5.
6.
L. M. Volkova I. M. Petrova N. V. Chizhova P. V. Petrovskii L. E. Vinogradova N. N. Makarova 《Russian Chemical Bulletin》1999,48(9):1712-1716
Transformations of HVinSiCl2, HVinSi(Me)Cl, HVinSi(Me)Ph, and HVinSi(Me)NEt2 in the presence of Pt catalyst were studied. In dilute solutions, the reaction gave a mixture of structural and stereoisomers
of five- and six-membered disilacyclanes, resulting from intramolecular cyclization of the initially formed linear dimer.
In the case of methyl(phenyl)disilacyclane, the structural isomers were separated andtrans-1,4-dimethyl-1,4-diphenyl-1,4-disilacyclohexane was isolated. The reaction of this product with HCl in the presence of AlCl3 followed by hydrolysis resulted in the synthesis oftrans-1,4-dichloro- andtrans-1,4-dihydroxy-1,4-dimethyl-1,4-disilacyclohexanes. The structures of the structural and stereoisomers synthesized were confirmed
by1H,13C, and29Si NMR and IR spectroscopies and mass spectrometry.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1734–1738, September, 1999. 相似文献
7.
An efficient, convenient synthesis of 1,4-benzoxazines, 1,4-benzothiazines, spiro-1,4-benzoxazines, and spiro-1,4-benzothiazines derivatives was accomplished in good yields via the novel intramolecular cyclization mediated by mild base K2CO3 in ethanol solvent. A variety of substrates can participate in the process with good yields, making this methodology have broad applicability. All the structures of synthesized compound have been confirmed by spectral analysis. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications ® to view the free supplemental file. 相似文献
8.
Electrochemical and theoretical investigations demonstrate through-bond interactions between two TTF moieties fused to a 1,4-dihydro-1,4-diphosphinine, for which the single crystal X-ray structure of the cis isomer is described together with that of a mixed-valent, charge-localized, radical cation salt with Mo6O19(2-), obtained upon electrocrystallization of the same cis isomer. 相似文献
9.
10.
S. Samaan 《Tetrahedron letters》1974,15(45):3927-3930
11.
12.
13.
14.
Catalytic hydrogenation of 1,4-phenylenediamine to 1,4-cyclohexanediamine using Ru/Al2O3 as a catalyst was carried out in water, and the results were compared with those in isopropanol and SC-CO2. 80% 1,4-phenylenediamine conversion with 87% selectivity to 1,4-cyclohexanediamine was achieved on 5% Ru/Al2O3 catalyst at 90°C and H2 pressure of 4 MPa. The hydrogenation of 1,4-phenylenediamine is influenced by the solvent. A systematic study of the hydrogenation of 1,4-phenylenediamine revealed that the reaction was consecutive. The longer the time, the lower was the CHDA selectivity. Also, the reaction temperature was an important parameter and played a vital role in preventing the formation of side products. 相似文献
15.
16.
Walter A. Szarek Dolatrai M. Vyas Barbara Achmatowicz 《Journal of heterocyclic chemistry》1975,12(1):123-127
The two regioisomers 6-chloro-9-(1, 4-oxathian-3-yl)-9H-purine ( 5 ) and 6-chloro-9-(1,4-oxathian-2-yl)-9H-purine ( 6 ) were obtained when 3-acetoxy-1,4-oxathiane ( 3 ) was subjected to the acid-catalyzed fusion procedure; compound 3 was prepared by a Pummerer reaction with 1,4-oxathiane 4-oxide ( 2 ). The nucleoside analog 6 could he converted into the adenine derivative 7 and 9-(1,4-oxathian-2-yl)-9H-purine-6(1H)thione ( 8 ). The following nucleoside analogs have also been synthesized: 6-chloro-9-(1,4-dithian-2-yl)-9H-purine ( 13 ), 9-(1,4-dithian-2-yl)adenine ( 14 ), 9-(1,4-dithian-2-yl)-9H-purine-6(1H)thione ( 15 ), and 6-chloro-9-(1,4-dioxan-2-yl)-9H-purine ( 18 ). 相似文献
17.
18.
Salvatore Cabiddu Costantino Floris Stefana Melis Francesca Sotgiu Giovanni Cerioni 《Journal of heterocyclic chemistry》1986,23(6):1815-1820
Benzocondensed six-membered heterocyclic rings containing two heteroatoms have been synthesized by a generally applicable method starting from disubstituted benzene compounds and methyl 4-chlorobutynoate ( 1 ) or methyl 4-bromobutenoate ( 2 ). The reactions with 1 yield a mixture of endo and exo (E or Z) isomers. The 13C nmr spectroscopy was used to assign the structure of the synthesized compounds. 相似文献
19.