共查询到20条相似文献,搜索用时 15 毫秒
1.
Danilo Annibali Gerhard Ecker Wilhelm Fleischhacker Thomas Helml Wolfgang Holzer Christian R. Noe 《Monatshefte für Chemie / Chemical Monthly》2000,131(4):375-382
Summary. The synthesis of 2,3-disubstituted 2,3-dihydrobenzofuran diastereomers is described. The key step in the reaction sequence
is the chemoselective reduction of a tert. alcohole with tert.-butylamine-borane/AlCl3. The relative configuration of the substituents on the dihydrofurane moiety was assigned via NMR spectroscopy.
Received September 7, 1999. Accepted November 9, 1999 相似文献
2.
The terahertz spectrum of the crystalline explosive taggant 2,3-dimethyl-2,3-dinitrobutane (C(6)H(12)N(2)O(4)) has been investigated as an alternative means of detecting solid-state explosives. The room-temperature spectrum exhibits two broad absorption features centered at 38.3 and 49.2 cm(-1). Once the sample is cooled to liquid-nitrogen temperatures, the resolution of three additional peaks occurs, with absorption maxima now appearing at 40.1, 47.5, 56.6, 63.9, and 73.6 cm(-1). Solid-state density functional theory simulations, both with and without London force dispersion corrections, have been used for the assignment of the experimental cryogenic THz spectrum to specific molecular motions in the crystalline solid. The B3LYP hybrid density functional paired with the 6-311G(2d,2p) basis set provides an excellent reproduction of the experimental data revealing that the THz spectrum arises from a mixture of intramolecular torsional vibrations localized primarily in the nitro groups and intermolecular lattice vibrations composed of rigid molecular rotations. 相似文献
3.
4.
5.
6.
7.
Anodic oxidation of 2-nitropropane in a methanol solution of sodium iodide and hydroxide is found to produce 2,3-dimethyl-2,3-dinitrobutane
with a yield of 65-70% under optimum conditions.
Deceased. 相似文献
8.
O. A. Sof''ina N. M. Igidov E. N. Koz''minykh N. N. Trapeznikova Yu. S. Kasatkina V. O. Koz''minykh 《Russian Journal of Organic Chemistry》2001,37(7):1017-1025
Acylpyruvic acids readily react with 2,3-diaminopyridine to form (Z)-3-acylmethylene-1H-3,4-di- hydropyrido[2,3-b]pyrazin-2-ones. 5-Aryl-2,3-dihydrofuran-2,3-diones which can be regarded as lactones derived from -enolized aroylpyruvic acids react with 2,3-diaminopyridine under mild conditions, yielding regioisomeric (Z)-2-aroylmethylene-4H-1,2-dihydropyrido[2,3-b]pyrazin-3-ones. The structure of the products and reaction chemoselectivity are discussed. 相似文献
9.
10.
Makoto Fukudome 《Tetrahedron letters》2005,46(7):1115-1118
3A-Azido-3A-deoxy-altro-β-cyclodextrin, although having as many as 20 different hydroxyl groups, was selectively sulfonylated at the 2A-OH of the altrose residue by 2-mesitylenesulfonyl chloride to give 3A-azido-3A-deoxy-2A-O-mesitylenesulfonyl-altro-β-cyclodextrin. A one-pot reduction-intramolecular substitution of the latter afforded the title compound as a promising intermediate for the introduction of two different functional groups to two different positions of one sugar unit, which has not been succeeded hitherto. 相似文献
11.
12.
13.
14.
15.
16.
2,3-Diaryl-1,4-diazolyl-2,3-epoxybutanes have been prepared from dimethylstilbenes. An efficient although neglected synthesis of the required olefins has been recovered from the literature. The target compounds show moderate antifungal activity. 相似文献
17.
18.
3,5-dihydro-3,5-dialkyl-3,5-diaryl-4H-pyrazol-4-ones stimulate interest as potential precursors for 2,3-diarylcyclopropanones. Photoreactions of trans-3,5-dihydro-3,5-dimethyl-3,5-diphenyl-4H-pyrazol-4-one were studied by continuous-wave (CW) and pulsed laser UV photolysis revealing an intermediate that undergoes rearrangement to form cis- and trans-1,3-dimethyl-1-phenyl-2-indanones with the yield of ca. 60%. Steady-state photolysis (254 and 350 nm excitation) in different solvents produced an intermediate cyclohexadiene as evidenced by UV/vis, IR, and 1H NMR spectra. In contrast, the nanosecond laser pulsed photolysis at 355 nm produced 2,3-dimethyl-2,3-diphenylcyclopropanone along with two products of retro-1,3-dipolar addition phenylmethylketene and 1-phenyldiazoethane. These can be observed by time-resolved IR (TRIR) spectroscopy as characteristic absorption bands at 1814, 2101, and 2038 cm-1, respectively. Similar retro-1,3-dipolar addition showed 1-phenyldiazoethane formed following flash photolysis of 1-pyrazoline (trans-4,5-dihydro-3,5-dimethyl-3,5-diphenyl-3H-pyrazol-4-ol). The formation of the corresponding cyclopropanone as well the products of retro-1,3-dipolar addition during photoreaction of starting pyrazol-4-one is directly confirmed by the nanosecond TRIR spectroscopy for the first time. On the basis of the CW and pulsed laser UV photolysis, a dynamic equilibrium between cyclopropanone and intermediate 2,4-diphenyl-3-pentanone-2,4-diyl (dimethyldiphenyloxyallyl) was proposed. 相似文献
19.
2,3-Benzodiazepine-1-thione in the synthesis of substituted and hetero-annelated 2,3-benzodiazepines
A series of S-substituted and 1,2-annelated derivatives of 2,3-benzodiazepine has been obtained on the basis of 2,3-benzodiazepine-1-thione.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, 594-601, April, 2009. 相似文献