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31.
Two diamines were synthesized as new aromatic monomers. A series of novel aromatic polyamides (aramids) were also synthesized by direct and indirect polycondensation of these diamines with various aromatic dicarboxylic acids. These aramids have inherent viscosities of 0.43-0.84 dl/g and were obtained in quantitative yield. 相似文献
32.
Zita Zalán 《Tetrahedron》2005,61(22):5287-5295
By condensation of 1-(2′-aminoethyl)-1,2,3,4-tetrahydroisoquinoline derivatives with substituted benzaldehydes, 1,6-unsubstituted and diastereomers of 1-methyl- or 6-methyl-substituted 4-aryl-9,10-dimethoxy-1,3,4,6,7,11b-hexahydro-2H-pyrimido[6,1-a]isoquinolines were prepared. The ring-chain tautomeric equilibria of most of these compounds in CDCl3 at 300 K were found to be shifted nearly totally towards either the cyclic or the open tautomeric forms, while the (6R*,11bR*)-6-methyl substituted compounds proved to be three-component tautomeric mixtures, the equilibria of which could be characterized by a Hammett-type equation. The conformational equilibria of the cyclic forms turned out to be strongly influenced by the 1- and 6-methyl substituents and the configurations of the substituted carbons (C-1 or C-6 and C-4) relative to C-11b. 相似文献
33.
Agnieszka Hryniewicka Zenon Łotowski Barbara Seroka Stanisław Witkowski Jacek W. Morzycki 《Tetrahedron》2018,74(38):5392-5398
A new steroidal-platinum(II) hybrid compound was synthesized using a simple and efficient methodology. The synthesis was performed by a convergent approach with cross metathesis (CM) as a key step. An olefin derived from lithocholic acid and a vinyl substituted ethylenediamine derived from l-serine were used as chiral building blocks, which were combined in the CM step. The most important advantage of this method was the utilization of l-serine as a cheap, stereoisomerically pure substrate. A steroid with a diamino system in the side chain was subjected to reaction with potassium tetrachloroplatinate to obtain the target platinum(II) complex. Attempts to synthesize similar diamine systems using the asymmetric Strecker reaction were unsuccessful. 相似文献
34.
Activated nitrocompounds, in the presence of dipolarophiles and a tertiary diamine (e.g., DABCO), undergo dehydration to afford directly isoxazoline derivatives, formal cycloadducts of nitrile oxides; this mild procedure is very efficient for the synthesis of the reported isoxazolines. 相似文献
35.
Kamal M. El‐Shaieb 《中国化学会会志》2008,55(5):1150-1155
1‐(Dicyanomethylene)acenaphthene‐2‐one ( 1 ) reacts with 1,8‐diaminonaphthalene ( 2 ) to yield two products, identified as acenaphtho[1,2‐b]naphtho[1,8‐ef][1,4]diazepine ( 3 ) and (Z)‐2‐(8‐aminonaphthalen‐1‐ylamino)‐2‐(2‐oxoacenaphthylen‐1(2H)‐ylidene)acetonitrile ( 4 ). On the other hand, (2Z,2′Z)‐2,2′‐(hydrazine‐1,2‐diylidene)diacenaphthylen‐1(2H)‐one ( 6 ) was obtained during the condensation process of 1 with hydrazine hydrate ( 5 ). Reaction of 1 with 3,4‐diaminotoluene ( 8b ) produces 9‐methylacenaphtho[1,2‐b]quinoxaline ( 9b ) and (Z)‐2‐(2‐amino‐5‐methylphenyl‐amino)‐2‐(2‐oxoacenaphthylen‐1(2H)‐ylidene)acetonitrile ( 10b ). However, treatment of 5,6‐diamino‐pyrimidine‐2,4‐diol hemisulphate ( 11 ) with 1 affords acenaphtho[1,2‐g]pteridine‐9,11‐diol ( 12 ). 相似文献
36.
The vapor pressures of (1,3-pentanediamine + water), or (1,5-diamino-2-methylpentane + water) binary mixtures, and of pure 1,3-pentanediamine or 1,5-diamino-2-methylpentane components were measured by means of a static device at temperatures between (273 and 363) K. The data were correlated with the Antoine equation. From these data excess Gibbs functions (GE) were calculated for several constant temperatures and fitted to a three order Redlich–Kister equation using the Barker’s method. The (1,3-pentanediamine + water) or (1,5-diamino-2-methylpentane + water) binary systems exhibit negative deviations in GE for all investigated temperatures over the whole composition. Additionally, the NRTL UNIQUAC and Modified UNIFAC (Do) models have been used for the correlation or prediction of the total pressure. 相似文献
37.
Denis Lucet Thierry Le Gall Charles Mioskowski 《Angewandte Chemie (International ed. in English)》1998,37(19):2580-2627
Especially in the field of enantioselective synthesis , vicinal diamines (1,2-diamines) 1 and compounds easily prepared from them—such as 1,2-bisimines, 1,2-diamides, or imidazolidin-2-ones—are widely used by organic chemists. Various strategies have been developed to produce these compounds selectively. Many natural products and medicinal agents also contain a 1,2-diamino unit. 相似文献
38.
An efficient one‐pot synthesis of pyrido[1,2‐a]‐fused 1,3‐diazaheterocyclic compounds by three‐component reaction of diamine, nitroketene dithioacetal (=1,1‐bis(methylsulfanyl)‐2‐nitroethene), and electron‐poor itaconic anhydride (=2‐methylidenesuccinic anhydride=2‐methylidenebutanedioic anhydride) in aqueous EtOH is reported. This protocol has the advantages of easiness, higher yields, and shorter reaction times. The structures were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS) and by elemental analyses. A plausible mechanism for this type of cyclization is proposed (Scheme 2). 相似文献
39.
40.
By means of convenient domino ring closure reactions of 1-(2-aminoethyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline 2 and γ-oxo-acids, 14-substituted 8,13-diazaoestrone derivatives (5 and 6) were formed with ∼100% diastereoselectivity. 相似文献