The complex H3(μ-η2-C6H4) (μ-η2-HC3NC6H5)Os3(CO)8 has been synthesized and characterized by IR, 1H NMR and X-ray crystal structure analyses. The compound contains a -benzyne ligand bridging one edge of a triangular cluster of osmium atoms and a -formimidoyl ligand bridging a different edge on the opposite face of the cluster from the benzyne ligand. 相似文献
Depending upon the experimental conditions, t-butyl (1,5,7,8)-1-ethoxycarbonyl-8-hydroxy-2-oxa-6-azabicyclo[3.2.0]octane-7-carboxylate (2a) reacts with methanesulphonyl chloride to give predominantly the -methanesulphonyl derivative (2b), the -methanesulphonyl derivative (3a), or the -(methanesulphonyl)methane-sulphonyl derivative (6a). 相似文献
Photoexcited 1, 4-dimethylcytosine (I) adds isopropanol to form 5,6-dihydro-1, 4-dimethyl-6-(2-hydroxy-2-propyl)cytosine (II) as the major product; a small amount of 5,6-dihydro-1-methyluracil (III) is formed as well. 相似文献
Transformation of 6- and 5,6-dialkyl-2-methoxy-4(3H)-pyrimidinones (1a and 1b) into 1--acylated-pyrimidine derivatives 3(-) under Friedel-Craft like conditions is presented. In different acylation conditions 4-O-acylated-pyrimidines (5a and 5b) are also obtained. Compounds (3c) and (3f) can be directly converted into 1--acyl-protected-isouridine analogues (8a and 8b). 相似文献
4-Dimethylamino--triphenylmethylpyridinium chloride () reacts with primary but not secondary alcohols to produce trityl ethers in good yield; in addition, amines may be selectively - tritylated witth in the presence of alcohols. 相似文献
The N-hydroxyazetidines and are prepared startinfrom 2,3-dihydroazete 1-oxides ( and 0 by reduction with sodium borohydride and by reaction with a nucleophile, respectively. The N-thydroxyazetidines and can be oxidized with mercury (II) oxide to the corresponding nitrones ; oxidation of the N-hydroxyazetidine (unsubstituted at C-4) with equivalent of lead tetraacetate tyields the N-tacetoxy β-lactam . 相似文献
N.m.r. parameters for nine (I-IX) -chloropolyfluorocyclohexa-2,5-dienylideneamines are reported and discussed; the magnitudes of the FF-coupling constants fall into the following ranges: 12 0-2.8; 13, 35 6.0-6.8; 14 <1; 15 0-2.6; 23, 34 25.5-27.2; 24 0-6.0; 25 0-1.2; 45 5.4-9.8 Hz (I) X = Y = Z = F; (II) X = OMe, Y = Z = F; (III) X - CF3, Y = Z = F; (IV) X = Ph, Y = Z = F; (V) X = Cl, Y = Z = F; (VI) X = Br, Y = Z = F; (VII) X = Y = F, Z = Cl; (VIII) X = Y = F, Z = Br; (IX) X = Z = F, Y = H. The spectra of -methyl-4-chloropentafluorocyclohexa-2,5-dienyldeneamine have also been analysed. All the imines examined are configurationally stable at the nitrogen atom. 相似文献
In contrast with the reaction of α-aminonitriles a, the corresponding -acylated α-aminonitriles b-f and oxalyl chloride do not yield pyrazinone derivatives, but 5-aminooxazoles - or 4(5)-imidazolones , the latter being converted in some cases into imidazo [2,1-]isoquinoline-2,5,6(3)-triones. Reactions of compounds b-f and ethyl chlorooxoacetate provide evidence for a 5(4)-iminooxazole intermediate , which aromatizes to yield 5-aminooxazoles -; however, unaromatizable īntermediates of type - isolable as 5(4)y-oxazolones after hydrolysis - undergo a catalyzed Dimroth-type rearrangement to give imidazolone derivatives . 相似文献
In strong base, e.g., sodium hydride in dimethylformamide, -(-azidobenzoyl)arylamines cyclise in high yield to 2-aryl-1,2-dihydro-3-indazolin-3-ones. 相似文献
Alkylation of lithiated -(benzyloxyacetyl)--2,5-bis(mehtoxyymethoxymethyl)- pyrrolidine proceeded with high stereoselectivity (≥96% de) and subsequent transformations of the alkylated products gave synthetically useful α-benzyloxy acids or α-hydroxy acids of high enantiomeric purity. 相似文献
Reaction of benzilmonohydrazone(1) with S4N4 gives the azine (6) and not the 2--imidazole (2); this invalidates the claim that (2) is not the intermediate in the formation of -benzoyltriphenylimidazole from benzil and ammonia. S4N4 converts diphenylketene into thiobenzophenone. 相似文献
A procedure is developed for the 'one-pot' acylation and methylation of isoxazolines at C(4). Thus the 5-substituted isoxazolines (8), (9), and (18) were converted into their -4-methoxycarbonyl--4-methyl derivatives (10), (11), and (19), by deprotonotion using lithium diisopropylamide, followed by the sequential addition of methyl chlorofonmate and methyl iodide. The reduction of these substituted isoxazolines was then investigated. -Methylation using Meerwein's salt, and reduction of the derived -methylisoxazolinium salt using sodium borohydride gave isoxazolidines (14) and (20), but only in modest yields. The analogous -methylation - reduction of the lactone-isoxazoline (12) was not stereoselective. The isoxazolidines (14) and (20) have the correct relative configurations at C(3) and C(4) for conversion into lankacidin analogues. 相似文献
6β(7β)-(-2,2,2-Trichloroethoxycarbonyl--trifluoromethanesulphonylamino) penicillins and cephalosporins have been converted into the corresponding 6α(7α)-formamido-6β(7β)-2,2,2-trichloroethoxycarbonylamino derivatives, by treatment with ,-bis(trimethylsilyl) formamide and triethylamine. 相似文献
- The corresponding - and -methyl- and -benzyl-5,6- and 4,5-tetramethylenetetrahydro-l,3-oxazines were synthesized from - and -methyl and-benzyl-2- aminomethyl-1-cyclohexanols , from - and -methyl- and benzyl -2-hydroxymethyl-1-cyclohexylamines by reaction with formaldehyde. The aminoalcohols and were prepared in considerably higher yields than in earlier procedures. NMR spectroscopy showed that the isomers of the synthesized oxazines were conformationally homogeneous in solution, and their preferred conformation (inside or outside) depended on the steric requirement of the groups attached to the anellation points, whereas a bulky C-2 substituent had no influence on the predominant conformation. The structure of -benzyl--4,5-tetramethylenetetrahydro-1,3-oxaziniumpicrate . determined by X-ray diffraction analysis, was in agreement with the predominant N-outside conformation of the corresponding base, established by means of NMR spectroscopy. 相似文献
In CFCl3, aziridines react with F2(6 %/N2, 20°C), COF2 (20 %/N2, 40°C) and CF3OF [1] (20 %/N2, 40°C).Substitution products are obtained : l-(aziridine)carbonyl fluorides and l-Fluoroaziridines In (Et)2O, aziridines react with COF2 (20 %/N2, 10°C) and we have the carbonyl fluorides . Products IV can be thermally decomposed into β fluoro isocyanates.In CFCl3, N substituted aziridines react with F2(6%/N2, 20°C) and with CF3OF [2] (20%/N2, 40°C). No reaction is observed with COF2in our conditions (5% to 25%/N2, 80°C to + 40°C).Addition products are obtained : N Fluoro amines β fluorinated , N Fluoro and NN difluoro amines β trifluoro methoxylated and .with R = SO2Ø, COØNO2, Cl. 相似文献
A quinolone quinone methide (; R=Me), prepared from 1,3-dimethyl-4- hydroxy-2-quinolone () and DDQ, reacted readily with -methylflindersine () to give a single cyclo-addition product (). 相似文献
Condensation of aldehydes with Zr enolate of chiral -propionyl--2,5-disubstituted pyrrolidine proceeded with high diastereo- and diastereoface-selection. Stereoselectivity in the reaction of the corresponding -acetyl compounds was also examined. 相似文献
tert-Butyl azidoformate () reacts with the conjugate bases of , , (R1 = R2 = CH3), and (R1 = CH3, R2 = H) to give products [, , , and , respectively] in addition to the expected N-(tert-butoxycarbonyl)indole derivatives. 相似文献
Microwave—optical double resonance signals have been detected in a mass-selected ion-beam spectrometer for 12C16O+. With the optical excitation of fluorescence from the R1 () line of the (0,0) band of the A2Π ← X2∑ transition of 20350.6 cm?1, the microwave resonances occurred at 118101.8 ± 0.2 MHz and at 117694 ± 2 MHz corresponding to the N= 1, J = ← N = 0, J = and the N = 1, J = ← N = 0, J = transitions. 相似文献