排序方式: 共有44条查询结果,搜索用时 8 毫秒
31.
Attanasi OA Favi G Filippone P Golobic A Stanovnik B Svete J 《The Journal of organic chemistry》2005,70(11):4307-4313
We observed a nucleophilic attack by the ene-amino carbon of 3-dimethylaminopropenoates at the terminal carbon of the azo-ene system of 1,2-diaza-1,3-butadienes. In tetrahydrofuran at 65 degrees C, this attack produced 1-aminopyrrolines with a high degree of cis-stereoselectivity by means of an unusual zwitterionic adduct intermediate followed by intramolecular ring closure. In toluene under reflux, 1-aminopyrrolines produced oxazoline-fused 1-aminopyrrolines. Oxazoline-fused 1-aminopyrrolines were directly obtained by reaction of 1,2-diaza-1,3-butadienes with 3-dimethylaminopropenoates in toluene under reflux. The ring opening of oxazoline-fused 1-aminopyrrolines in acidic or basic media provides highly substituted 1-aminopyrroles. 5-Unsubstituted 1-aminopyrrole derivatives were obtained from 1-aminopyrrolines under basic conditions by loss of dimethylamino and ester groups. We discuss the plausible mechanisms of the ring closure and opening. 相似文献
32.
Easily accessible cycloalkenyl-1-diazenes and β-dicarbonyl compounds are converted in one-pot into previously unknown functionalized fused cycloalkenyliden-pyrroles of different sizes. The domino reaction proceeds through a base-catalyzed conjugate addition/cyclization/elimination sequence. 相似文献
33.
Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
34.
D. Bevk M. Kmetic S. Recnik J. Svete L. Golic A. Golobic B. Stanovnik 《Chemistry of Heterocyclic Compounds》2001,37(12):1498-1510
Ethyl (Z)-2-(2,3-dihydro-1,3-dioxo-1H-isoindol-2-yl)-3-(dimethylamino)propenoate was prepared in one step from ethyl (2,3-dihydro-1,3-dioxo-1H-isoindol-2-yl)acetate and bis(dimethylamino)-tert-butoxymethane and treated with various amines and hydrazines to afford the corresponding amino substituted products. Reactions of the titled compound with N,N'-, C,N-, and C,O'-ambident nucleophiles in refluxing acetic acid furnished the corresponding fused pyrimidinones, quinolizinones, and pyranones. 相似文献
35.
Natasa Zabukovec Logar Gregor Mali Sanja Jevtic Amalija Golobic 《Journal of solid state chemistry》2010,183(5):1055-8710
A single-crystal X-ray diffraction analysis of an open-framework aluminophosphate ULM-3 Al prepared by 3-methylaminopropylamine (MAPA) as structure-directing agent revealed an orthorhombic Pcab symmetry (a=9.9949(4) Å, b=15.8229(7) Å, c=18.1963(5) Å, R=0.0648, Z=8, unit cell formula [Al24P24O96F16·C32H112N16]), which differs from the Pbc21 symmetry of the structural analogue prepared in the presence of 1,4-diaminobutane. The 27Al, 31P, 19F, 13C and 1H NMR investigations, which were performed to study in detail MAPA arrangement inside the framework as well as the interactions of MAPA with the aluminophosphate host, confirmed the crystal symmetry and the proposed hydrogen bonding scheme between the template and the framework. 相似文献
36.
Mateja Malei
Ale Krbav
i
Amalija Golobi
Ljubo Goli
Branko Stanovnik 《Journal of heterocyclic chemistry》1997,34(6):1757-1762
The synthesis of ethyl 2-(2-acetyl-2-benzoyl-1-ethenyl)amino-3-dimethylarninopropenoate ( 4 ) from benzoylacetone ( 1 ) via 3-dimethylarninomethylenebenzoylacetone ( 2 ) and ethyl N-(2-acetyl-2-benzoyl-1-ethenyl)glycinate ( 3 ) and its transformation into 4-benzoyl-2-ethoxycarbonyl-3-methylpyrrole ( 9 ) is described. Cyclization of 4 into 9 represents a new synthesis of polysubstituted pyrroles. 相似文献
37.
Cvetka Turk Jurij Svete Branko Stanovnik Ljubo Goli
Simona Goli
‐Grdadolnik Amalija Golobi
Lovro Seli
《Helvetica chimica acta》2001,84(1):146-156
The 5,5‐dimethylpyrazolidin‐3‐one ( 4 ), prepared from ethyl 3‐methylbut‐2‐enoate ( 3 ) and hydrazine hydrate, was treated with various substituted benzaldehydes 5a – i to give the corresponding (1Z)‐1‐(arylmethylidene)‐5,5‐dimethyl‐3‐oxopyrazolidin‐1‐ium‐2‐ide azomethine imines 6a – i . The 1,3‐dipolar cycloaddition reactions of azomethine imines 6a – h with dimethyl acetylenedicarboxylate (=dimethyl but‐2‐ynedioate; 7 ) afforded the corresponding dimethyl pyrazolo[1,2‐a]pyrazoledicarboxylates 8a – h , while by cycloaddition of 6 with methyl propiolate (=methyl prop‐2‐ynoate; 9 ), regioisomeric methyl pyrazolo[1,2‐a]pyrazolemonocarboxylates 10 and 11 were obtained. The regioselectivity of cycloadditions of azomethine imines 6a – i with methyl propiolate ( 9 ) was influenced by the substituents on the aryl residue. Thus, azomethine imines 6a – e derived from benzaldehydes 5a – e with a single substituent or without a substituent at the ortho‐positions in the aryl residue, led to mixtures of regioisomers 10a – e and 11a – e . Azomethine imines 6f – i derived from 2,6‐disubstituted benzaldehydes 5f – i gave single regioisomers 10f – i . 相似文献
38.
I. Golobic J. Petkovsek M. Baselj A. Papez D. B. R. Kenning 《Heat and Mass Transfer》2009,45(7):857-866
Experiments were performed to study the spatio-temporal temperature variation underneath growing bubbles on a thin platinum
heating foil in saturated and subcooled nucleate pool boiling of water at atmospheric pressure. The transient wall temperature
distributions were recorded with spatial resolution of 40 μm by a high-speed infrared camera at intervals of 1 ms, synchronised
with a high-speed video camera to record bubble motion. Examples are presented of the transient distributions of wall temperature,
heat flux and heat transfer coefficient underneath bubbles growing with the fast and slow bubble detachment mechanisms in
saturated and subcooled pool boiling. Comments are made on the evidence for and against particular mechanisms of heat transfer. 相似文献
39.
Methyl and ethyl 3-dimethylamino-2-(indol-3-yl)propenoate were prepared from alkyl 3-indoleacetates and tert-butoxy-bis(dimethylamino)methane. Upon treatment of these two N,N-dimethylenaminones with α-heteroarylamines as N,N-1,3-dinucleophiles, condensed indolylpyrimidones as meridianine analogues were obtained in poor to moderate yields, while intramolecular condensations with C,O-1,3-dinucleophiles furnished condensed indolylpyranones. Similarly, reaction with hydrazinium chloride led to indolylpyrazolol, while with 3-chloro-6-hydrazinopyridazine only the dimethylamine substitution took place to give the corresponding hydrazone. 相似文献
40.
Samo Pirc David Bevk Amalija Golobi
Branko Stanovnik Jurij Svete 《Helvetica chimica acta》2006,89(1):30-44
N‐Protected L ‐phenylalanines 1a,b were transformed, via the corresponding Weinreb amides 2 and ethynyl ketones 3 , into chiral enamino ketones 4 (Scheme 1). Similarly, L ‐threonine 6 was transformed in four steps into the enamino ketone 10 . Cyclocondensations of 4 and 10 with pyrazolamines 11 , benzenecarboximidamide ( 12 ), and hydrazine derivatives 18 afforded N‐protected 1‐heteroaryl‐2‐phenylethanamines 15a – e, 16, 17 , and 21a – k and 1‐heteroaryl‐1‐aminopropan‐2‐ols 23a,b in good yields (Schemes 2 and 3). Finally, deprotection by catalytic hydrogenation furnished free amines 22a – g and 24a,b (Scheme 3). 相似文献