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991.
992.
A series of phenylated dihydrophthalimides has been synthesized by the Diels-Alder reaction of tetraphenylcyclopentadienone with maleimide, N-phenylmaleimide, and N,N'-o-, -m-, and -p-phenylenedimaleimide. Subsequent dehydrogenation of these compounds yielded the corresponding phenylated phthalimides. These phthalimides were also obtained in one step when the initial reactions were carried out in refluxing nitrobenzene.  相似文献   
993.
Two new compounds containing molybdenum thiocyanide cluster anions, K6[Mo4S4(CN)12]·10H2O (1) and (18-crown-6K)8[Mo6S6(CN)16]·17.5H2O (2), were synthesized and investigated by X-ray structure analysis. Crystal data: a=11.8430(17), b=11.8430(17), c=35.170(7) , V=4932.8(14) 3, space group I41/a, Z=4, dcalc=1.563 g/cm3 for 1; a=28.7513(5), b=18.4190(3), c=20.7586(4) , =118.5982(7)°, V=9651.9(3) 3, space group C2/m, Z=4, dcalc =1.563 g/cm3 for 2. The [Mo4S4(CN)12]6- cluster anion in 1 has an ordinary structure typical of cubane transition metal complexes. In the structure of the [Mo6S6(CN)16]8- anion of 2, two crystallographically independent molybdenum atoms form a Mo6 metallocluster, represented as two edge-sharing tetrahedra.  相似文献   
994.
The crystal structure of Ru2Si3 has been refined by leastsquares using three-dimensional X-ray data from a twinned crystal (1355 reflections,R=5.8%). Ru2Si3 is isostructural with Ru2Ge3 and like this compound a member of the Mn11Si19 structure family. The lattice parameters of the orthorhombic unit cell (Pnca—D 14 2h ) are:a=5.530 (1),b=11.060 (2) andc=8.952 (2) Å.

Mit 1 Abbildung  相似文献   
995.
The preparation of 5-phenyl-1H-thieno[3.2-e]1.4-diazepin-2(3H)-one, its alkylation in position 1 and its N-oxide formation (in position 4) are described.

Diese Abhandlung hätte sinngemäß unmittelbar vor der Arbeit auf S. 1105 stehen müssen, ist aber infolge eines red. Versehens erst jetzt gedruckt worden. Das Zitat2 auf S. 1108 ist zwangsläufig zu ändern auf Mh. Chem.104, 1343 (1973).  相似文献   
996.
A Lagrange multipliers method is shown to be a convenient way of applying constraints to a Newton-Raphson minimization algorithm in a conformational analysis program. To illustrate this method two applications are dealt with in some detail. The Eckart conditions are used as a set of constraints to avoid mathematical difficulties associated with the empirical valence-force potential in a conformational analysis problem. For the molecules considered the use of constraints speeds up the Convergence. The second application illustrates how the method can be used to study selected sections through potential energy surfaces.  相似文献   
997.
It is well known that in the ergot alkaloids of the peptide type the proline appears in thel-configuration. Different methods of acid hydrolysis may lead to various cleavage products; hydrolysis by HCl yieldsd-proline, on the other hand hydrolytic cleavage by means of strongly acid cation exchange resin preserved the orginall-configuration.

Teilveröffentlichung der Dissertation vonH. Kolassa, Univ. Wien, 1973.  相似文献   
998.
A method is described for the analysis of fecal neutral steriods with a dual-column gas-liquid chromatography (GLC) system. After saponification of the fecal slurry, the neutral steroids were extracted with hexane. The GLC separation of the compounds and quantitation were achieved by simultaneous injection of the derivatized and derivatized aliquots of the extract onto dual colmuns under identical conditions. The neutral steroids of interest were than identified by matching the retention times with those of known standards, and identification was confirmed by use of an interfaced GLC high-resolution mass spectrometry system. The detection limit was 0.003 mg of steroid/g of fecal slurry. The pricision of the method is illustrated by a relative standard diviation of 2-10% and a recovery of neutral steroids from 73-96%. The method was applied to the determination of fecal neutral steroids in a "High protein diet in colon cancer study". A considerably larger level of coprostanone than of coprostanol was observed. Data on neutral steroids in fecal samples from subjects on different diets are the subject of a separate publication.  相似文献   
999.
A method was developed for the preparation of 4-chloro-5-formylimidazolones, Δ4-thiazolinones, and 4-chloro-5-formyluracils by reaction of 4-azolidones or barbituric acids with dimethylformamide and phosphorus oxychloride.  相似文献   
1000.
Summary Polarographic studies have been made of the reaction between Cerium(IV) and potassium thiocyanate in acidic medium. CeIVin the concentration range 2 · 10–4 M to 5 · 10–3 M was found to be reduced to CeIII by thiocyanate ion. One equivalent of thiocyanate reduced 4–6 equivalents of CeIV in the concentration range studied.
Zusammenfassung Die Reaktion zwischen CerIV und Kaliumthiocyanat wurde in saurem Medium polarographisch untersucht. CerIII wurde im Bereich von 2 · 10–4 m bis 5 · 10–3 m von Thiocyanat zu CerIII reduziert. In diesem Konzentrationsbereich entsprachen einem Äquivalent Thiocyanat 4–6 Äquivalente CerIV.
  相似文献   
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