Fast and highly regioselective allylation of indole and pyrrole compounds by allyl alcohols using Ru-sulfonate catalysts

New Ru-sulfonate catalysts have been synthesized and shown to very rapidly allylate indole and pyrrole compounds using allyl alcohols as substrates. The observed regioselectivity is exceptionally high (up to 100% of the branched isomer). Density functional theory calculations explain these results.     

Synthesis of heterocyclic analogs of prostaglandins from pyrrole and indole

Heterocyclic analogs of prostaglandin, dl-2-(trans-3-hydroxyocten-lyl)-N-(6-ethoxycarbonylhexyl)pyrrole and -indole were obtained by the condensation of 2-formylpyrrole and 2-formylindole with 2-oxoheptylidenetriphenylphosphorane, followed by alkylation with ethyl 7-iodoheptanoate and reduction of the keto group by sodium borohydride.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 40–43, January, 1986.     

Asymmetric substitutions of O-Boc-protected Morita-Baylis-Hillman adducts with pyrrole and indole derivatives

An efficient asymmetric substitution process of O-Boc-protected Morita-Baylis-Hillman adducts with various pyrrole and indole derivatives has been developed in the presence of (DHQD)(2)PYR in THF, affording the corresponding products in good to high yields (up to 99% yield) and moderate to high ee values (up to 92 and 96% ee) under mild conditions.     

Palladium-catalyzed indole, pyrrole, and furan arylation by aryl chlorides

The palladium-catalyzed direct arylation of indoles, pyrroles, and furans by aryl chlorides has been demonstrated. The method employs a palladium acetate catalyst, 2-(dicyclohexylphosphino)-biphenyl ligand, and an inorganic base. Electron-rich and electron-poor aryl chlorides as well as chloropyridine coupling partners can be used, and arylated heterocycles are obtained in moderate to good yields. Optimization of base, ligand, and solvent is required for achieving best results.     

Rearrangements of pyrrole and indole substituted enol esters of cyclohexane-1,3-dione

Enol esters 3a and 3b , from cyclohexane-1,3-dione and pyrrole-2-carbonyl chloride and indole-2-carbonyl chloride, respectively, rearranged in the presence of triethylamine to the enamino acids 7 and 12 . In the presence of cyanide, 3b , also underwent the expected rearrangement to 4b , whereas only 7 was formed from 3a . Treatment of 7 with mercuric acetate in hot acetic acid resulted in decarboxylation and aromatization to phenol 9 .     

Transesterification of palm oil using supercritical methanol with co-solvent HCFC-141b

The transesterification of palm oil in supercritical methanol has been investigated without using any catalyst. HCFC-141b was used as co-solvent to reduce the molar ratio of methanol to palm oil under the milder conditions. The reaction was carried out in a flow-type tubular reactor. The residence time was fixed at 40 min. When the molar ratio of methanol to palm oil was set to 20:1 at 325 °C and 35 MPa, the optimum molar ratio of methanol to co-solvent was found to be 20:1. Addition of HCFC-141b increased FAME production even at the lower molar ratio of methanol to palm oil. In addition, a similar FAME content was obtained under the milder conditions (5 MPa lower pressure) compared with conditions without co-solvent at higher pressure. The role of HCFC-141b in the transesterification reaction under supercritical conditions was investigated.     

Introduction of the pyrazolidine ring into the pyrrole ring of indole

The reaction of indoles with 1-acyl-5-hydroxypyrazolidines under heterogeneous catalysis conditions leads, depending on the structure of indole, to 2- and/or 3-(1-acyl-5-pyrazolidinyl)indoles. Thus, the formation of 2-pyrazolidinylindoles is the results of an unco-substitution at the 3-position of the indole, followed by migration of the pyrazolidine ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1207–1213, September, 1990.     

Synthesis of pyrrole and indole quinoxalinone and oxazinone derivatives by intramolecular copper-catalyzed reactions

Intramolecular N-arylation of pyrrole and indole carboxamides and carboxylates linked with a pendant haloarene by Cu-catalyzed reactions to synthesize pyrrole and indole quinoxalinone and oxazinone derivatives is reported. The ring closure reactions were carried out by conventional heating and MW irradiation. The use of conventional heating affords moderate to good yields of the quinoxalinone and oxazinone derivatives (34-72%), while by using MW heating the best results are obtained (41-99%).     

Synthesis of functionalized pyrrole and indole derivatives through carbometallation of lithiated double bonds

Bis(2-lithioallyl)amines derived from bis(2-bromoallyl)amines undergo intramolecular carbometallation of a lithiated double bond, giving dilithiated dihydropyrroles. The cyclizations are promoted by N,N,N',N'-tetramethylethylenediamine (TMEDA). Reaction of these intermediates with electrophiles allows the preparation of some new fused and nonfused five-membered functionalized heterocycles. Although 2-lithioallylamines do not suffer intermolecular carbometallation, dimerization products are obtained with their copper or zirconium derivatives. Finally, the application of this new reaction to 2-lithio-N-(2-lithioallyl)anilines leads to 3-lithiomethylindole derivatives, which are transformed to functionalized indole derivatives by reaction with electrophiles.     

N-Amination of pyrrole and indole heterocycles with monochloramine (NH2Cl)

A survey of several electrophilic ammonia reagents for the N-amination of indole- and pyrrole-containing heterocycles revealed that monochloramine (NH(2)Cl) is an excellent reagent for this transformation. Pyrroles and indoles containing a variety of substitution were aminated on nitrogen with isolated yields ranging from 45% to 97%.     

I2-catalyzed Michael addition of indole and pyrrole to nitroolefins

An easy and efficient method to generate indolyl nitroalkane 5 and pyrrolyl nitroalkane 7 in high yields using β-nitrostyrene and indole/pyrrole at room temperature in the presence of catalytic amount of iodine is reported. The short reaction times and high yields of product are noteworthy. Molecular iodine promoted Michael addition is operationally simple and efficient method compared to the known Lewis acids or rare earth metal catalysts to generate different indolyl/pyrrolyl nitroalkanes in high yield.     

脂肪酸在超临界甲醇中的酯化反应研究

超临界甲醇中的酯化和酯交换反应是利用植物油、动物油或废油脂制备生物柴油的新工艺.它的最大特点是不需要添加催化剂,超临界甲醇既是反应媒介,又是反应物.     

Study of H-bond characteristics in sub- and supercritical methanol

Classical molecular dynamics simulations of various methanol phase lines near the saturation curve and the critical point have been performed to study the changes in H-bonded clusters structure at transition of methanol to supercritical state. Analysis of H-bonds statistics with combined distance-energy H-bond criterion showed that the correlations between topological characteristics of H-bonds and the mole fraction of H-bonded molecules have unique functional representation despite the phase path applied. In the present study, an attempt has been also made to evaluate the degree of hydrogen bonding by combining the DFT computations on classical MD configurations with the natural bond orbital analysis of the waves functions obtained.     

Mechanism of migration of an acyl group in the pyrrole ring of indole

The isomerization of deuterium-labeled (in position 3) 2-acylindoles in polyphosphoric and trifluoroacetic acids was studied. It is shown that migration of the acyl group from position 2 to position 3 is accompanied by an intramolecular hydride shift.Deceased.Translated from Khimiya Geterotsoklicheskikh Soedinenii, No. 9, pp. 1235–1238, September, 1980.     

Regioselective synthesis of pentathiepines fused with pyrrole, thiophene, or indole rings

Pentathiepines fused with pyrrole, thiophene, or indole rings were obtained by reactions of the corresponding heterocycles or their tetrahydro derivatives with a prepared mixture of sulfur monochloride and DABCO. Dedicated to Academician O. M. Nefedov on the occasion of his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2002–2005, November, 2006.     

Thermolysis and analysis of TDI char by supercritical methanol using TGA,DSC, IR and SEM

Journal of Thermal Analysis and Calorimetry - TDI's synthetic plant generates about 5 mass % of tar by phosgenation process, which has been currently a bottleneck needed to be broken through...     

Novel synthesis of bicycles with fused pyrrole, indole, oxazole, and imidazole rings

Reactions of benzotriazol-1-yl(1H-pyrrol-2-yl)methanone 10 and benzotriazol-1-yl(1H-indol-2-yl)methanone 11 with diverse ketones, isocyanates, and isothiocyanates in the presence of base afforded pyrrolo[1,2-c]oxazol-1-ones 1, oxazolo[3,4-a]indol-1-ones 2, pyrrolo[1,2-c]imidazoles 3, and imidazo[1,5-a]indoles 4 by a simple one-step procedure.