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1.
The thionation properties of 2,4-bismethylthio-1,3,2,4-dithiadiphosphetane 2,4-disulfide, , 2,4-bis(4-phen-oxyphenyl)-1,3,2,4-dithiaphosphetan is that , and thionate most amides and lactams In THF at room temperature (reaction time 5 min) to give the corresponding thionated compounds. Imides are easily thionated by , and In DME at 60 °C. The reactions of with amides, imides and most lactams are run at 60°C to give good yields of the corresponding thionated compounds. 相似文献
2.
The acid catalysed reaction of 4-oxa-homoadamantan-5-one () with benzene yielded a mixture of 4a-phenyladamantan-2-one (), the equatorial isomer' () and 2-phenyl-2,4-o- benzenoadamantane () A plausible reaction pathway for the occurrence of . is put forward. The structure of , was deduced from spectroscopic data and reaction of the proposed intermediate 2,4a-diphenyladamantan-2-ol () with acid. 2,4-o-Ben-zenoadamantane () is prepared likewise. 相似文献
3.
The synthesis of 2,4-dimethoxypyrrolo[3,2-]pyrimidine () is described. This facile, 3-step synthesis involves the bromination of 2,4-dimethoxy-6-methyl-5-nitropyrimidine (), and the subsequent conversion of compound into compound . 相似文献
4.
2,4-Di-t-butyl-cyclopentadiene-1-carbaldehyde () and 2,4-di-t-butyl-cyclopentadienone oxime () are easily converted into the title compounds and , respectively. The spectroscopic and chemical properties of the new heterocyclic 10π-electron systems are described. 相似文献
5.
The acetone-sensitized photocycloaddition of 6-chloro-1,3-dimethyluracil to alkenes affords directly 1,2-dihydrocyclobuta[]pyrimidine-4,6 (3H, 5H)-diones 1-chloro-2,4-dimethyl-2,4-diazabichyclo[4.2.0]octa-3,5-diones. 相似文献
6.
The 1H and 13C nmr spectra of , -9-oxobicyclo[3.3.1]nonane-2,4-dicarboxylic acid, 3, in DMSO-d6 or alkaline D2O, clearly show that it exists in a --conformation with carboxyl groups, thus being the first case of - preference of a bicyclo[3.3.1] nonan-9-one due to the presence of ,-2,4- substituents. 相似文献
7.
A synthesis of cyclopent[d][1,3]oxazines is reported involving the photochemically induced transformation of 2,4-cyclohexadienimines via dienylketenimine intermediates and the dihydroderivatives . 相似文献
8.
Masamichi Maruta Satoshi Kubota Narihiko Yoshimura Tomoya Kitazume Nobuo Ishikawa 《Journal of fluorine chemistry》1980,16(1):75-88
4-Fluoro-2-(-ethyl)-3-(-methyl)-1, 5-benzoxazepine was prepared by reaction of -2-methyl-2-pentene with 2-aminophenol in the presence of triethylamine in diethyl ether. The reaction of -2,4-dimethyl-3-heptene with 2-aminophenol in dimethylformamide gave 7-(-1-methylethyl)-8- (-ethyl)-9,14-benzoxazepino[4,3-b]1,6-benzoxazepine. Several ortho-bifunctional benzenes reacted similarly with -2-methyl-2-pentene and -2,4-dimethyl-3-heptene to give the corresponding seven-membered benzoheterocycles. 相似文献
9.
Boźenna Golankiewicz Piotr Januszczyk Maria Gdaniec Zofia Kosturkiewicz 《Tetrahedron》1985,41(24):5989-5994
2-Acylamino-2-cyanoacetic acid ethyl esters react with 2,4-bis (4-methoxyphenyl)-1, 3, 2, 4-dithiadiphosphetane 2,4-disulfide in refluxing benzene with formation of 2-alkyl(aryl)-5-aminothiazole-4-carboxylic acid ethyl esters . Structure was established by spectroscopic means and an X ray crystallographic investigation of . X-Ray analysis revealed that the thiazole ring, exocyclic nitrogen and carbonyl group forming a hydrogen-bonded cycle are nearly coplanar. A resonance interaction is manifested by distinctly shortened /1.447 (3)/ C(carbonyl)-C(thiazole) distance. 相似文献
10.
Base-catalyzed reaction of 5-acylmethyl-2,5-di--butyl-4-oxa-2-cyclopentenones selectively derived from 4-alkyl-2,6-di--butylphenols three steps involving oxygenation, acetylation, and acid-treatment gave 3-alkyl-2,5-di--butyl-2,4-cyclopentadienones in excellent yield. 相似文献
11.
The readily-obtained carbohydrate α-enones , and are converted into the four diastereomeric 2,4-di-C-methyl glycopyranosides ,,, which are chiral synthons for the four multistriatins -. 相似文献
12.
The model tripeptide Boc-Gly-S-Ala-Aib-OMe () and the two monothiated analogues Boc-Gly(1ψ2CSNH)-S-Ala-Aib-OMe () and Boc-Gly-S-Ala(2ψ3 CSNH)-Aib-OMe () were synthesized. Peptide was obtained by thiation of using 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide, Lawesson's Reagent (LR), followed by deprotection of the Boc group and coupling with Boc-Gly-OH. Thiation of with LR regiospecifically transformed the protected tripeptide to the monothiated analogue . X-Ray diffraction analysis showed that the type-III β-turn formed by the reference peptide is preserved in the monothiated analogue ; conversely,the structure of the isomeric tripeptide is partially extended. 相似文献
13.
The preparation of phosphatidyl-β-glucosyl diglyceride is described. The synthesis of glycophospholipid was accomplished by using: (a) the levulinoyl group for the temporary protection of the glucose hydroxyl functions of , which could then be converted into the dioleoyl substituted derivative ; (b) the tetraisopropyldisiloxane-1,3-diyl (TIPS) group to protect the 3'- and 4'-hydroxyl groups of , in a two step procedure, to afford compound ; (c) a 2,4-dichlorophenyl protected phosphatidic acid derivative . Compound could be selectively coupled to the primary hydroxyl function of to afford the fully protected glycophospholipid . Finally, removal of the 2,4-dichlorophenyl and TIPS protecting groups from was performed with syn-4-nitrobenzaldoximate and fluoride ions, respectively, to afford glycophospholipid . 相似文献
14.
A series of phenoxathiins () were produced by the reaction between spiroepoxy-2,4-cyclohexadienones () and the pentachlorothiophenolate anion. The spiroepoxycyclohexadienones () may be regarded as polarity-reversed masked phenols in these reactions. 相似文献
15.
E.G. Frandsen 《Tetrahedron》1977,33(8):869-873
The reaction of 4- and 5-aryl-3-methylthio-1,2-dithiolylium iodides with 4-hydroxy-6-methyl-2-pyran-2-one and 4-hydroxycoumarin has been studied. 4-Substituted salts yielded 3-aryl-7-methyl-2-thioxo-2,5-pyrano [3,2-c]pyran-5-ones and 3-aryl-2-thioxo-2H,5H-pyrano[3,2-c]benzo[e]pyran-5-ones, respectively, whereas 5-substituted salts gave rise to 3-(5′-aryl-1′,2′-dithiol-3′-ylidene)-6-methyl-2-pyran-2,4-diones and 3-(5′-aryl-1′,2′-dithiol-3′-ylidene)-2-benzo [b]-pyran-2,4-diones. 相似文献
16.
Haru Ogawa Yoshinari Taketugu Taiji Imoto Yōichi Taniguchi Hidefumi Kato 《Tetrahedron letters》1979,20(36):3457-3460
Rearrangement of 2,4-di--pentadienals was described as a consequence of the successive alkyl substitutions on the C-2 and C-4 positions. 1H-FT nmr spectroscopy suggested that the reaction involves ketene as an intermediate. 相似文献
17.
Pummerer reaction intermediate of α-methylsulfinylacetate () has been found to react with 1-alkenes to afford ene adducts . E,E-2,4-decadienoic ester () was synthesized from the adduct (n=5). 相似文献
18.
Reaction of mucochloric and mucobromic acid with (ethoxycarbonylmethylene) triphenyl-phosphorane affords the ethyl ester of (2, 4 -4,5-dichloro- and (2, 4) -4, 5-dibromo-2,4-pentadienoic acid respectively; in the latter case ethyl (2 -5-bromo-2-penten-4-ynoate is formed concomittantly. 相似文献
19.
4-Acyl-2,6-di--butylphenols except 3,5-di--butyl-4-hydroxybenzaldehyde were oxygenated in the presence of Co(Salpr) exclusively at the ortho position to give the corresponding 3,5-di--butyl-6-hydroperoxy-2,4-cyclohexadienone derivatives in quantitative yield. 相似文献
20.
The 5-substituted 4-methoxycarbonyloxazole derived from L-serine derivative using diphenyl phosphorazidate (DPPA) has been converted to a 2,4-diaminosugar antibiotic, prumycin. 相似文献