- Copper(I)-Catalyzed Intramolecular Cyclization of o-Propargyloxy Diketopiperazines to Access Diverse Diazabicyclic and Spiro-Diketopiperazinochromanes
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In this report, two distinctive intramolecular cyclizations of o-propargyloxy diketopiperazines (achieved from a one-pot Ugi post-transformation) is achieved via a copper(I)-catalyzed intramolecular reaction of azomethine ylide and alkyne moiety. The presence of internal alkyne in the starting materials directed the reaction towards through [3+2]-cycloaddition, while terminal alkyne led to a spirocyclization reaction between azomethine ylide and terminal unsaturated C?C bond. This method offering an opportunity for the synthesis of challenging Diazabicyclics and Spiro-Diketopiperazinochromanes in high yields with exclusive diastereoselectivity. (Figure presented.).
- Armaghan, Mahsa,Balalaie, Saeed,Bijanzadeh, Hamid Reza,Frank, Walter,Manavi, Bita,Rominger, Frank,Tejeneki, Hossein Zahedian
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p. 4190 - 4196
(2021/08/06)
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- Iron-Catalyzed [2+2+2] Annulation of Aliphatic Bridged 1,n-Enynes with Aldehydes for the Synthesis of Fused Pyrans
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An iron-catalyzed [2+2+2] annulation of aliphatic bridged 1,n-enynes with aldehydes was developed. Aldehydes play a dual role as the precursors of acyl radicals to trigger the cascade cyclization but also as the radical acceptors to terminate the annulation. This two-in-one strategy overcomes the limitation in [2+2+m] cyclization that requires a rigid benzene skeleton as the essential linker, thus enabling the efficient synthesis of functionalized fused [5.6] and [6.6] pyran skeletons.
- Tian, Tian,Wang, Xin,Lv, Leiyang,Li, Zhiping
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p. 4425 - 4428
(2020/06/05)
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- Rhodium(i)-catalyzed Pauson-Khand-type reaction using formic acid as a CO surrogate: An alternative approach for indirect CO2 utilization
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Formic acid is found to be an ideal CO surrogate for the rhodium(i)-catalyzed Pauson-Khand-type (PK-type) reaction of various substituted 1,6-enynes to afford bicyclic cyclopentenones in moderate to good yields. High TON value of up to 263 and good results in the gram-scale experiment were also obtained, demonstrating the efficacy of this methodology. In addition, heterocyclic molecules of pharmaceutical importance were also furnished via inter- or intra-molecular hetero-PK-type reactions, further broadening the application of current strategy. In this protocol, formic acid was utilized as a bridging molecule for the conversion of CO2 to CO, since formic acid is manufactured via catalytic hydrogenation of CO2 and releases CO in the presence of acetic anhydride readily. Therefore, this methodology represents a green and indirect approach for chemical valorization of CO2 in the preparation of value-added compounds.
- Lang, Xian-Dong,You, Fei,He, Xing,Yu, Yi-Chen,He, Liang-Nian
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p. 509 - 514
(2019/02/14)
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- Iron-Catalyzed Coupling of Propargyl Bromides and Alkyl Grignard Reagents
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An iron-catalyzed Kumada-type cross-coupling reaction of propargyl halides with alkylmagnesium reagents is described. The reaction is fast, takes place in smooth conditions, tolerates several functional groups that would be able to react with the Grignard reagent, and may afford either allene or propargyl coupling derivatives. Factors involved in the observed regioselectivity have been studied.
- Domingo-Legarda, Pablo,Soler-Yanes, Rita,Quirós-López, M. Teresa,Bu?uel, Elena,Cárdenas, Diego J.
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supporting information
p. 4900 - 4904
(2018/09/10)
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- Design and synthesis of novel xanthine derivatives as potent and selective A2B adenosine receptor antagonists for the treatment of chronic inflammatory airway diseases
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Adenosine induces bronchial hyperresponsiveness and inflammation in asthmatics through activation of A2B adenosine receptor (A2BAdoR). Selective antagonists have been shown to attenuate airway reactivity and improve inflammatory cond
- Basu, Sujay,Barawkar, Dinesh A.,Ramdas, Vidya,Patel, Meena,Waman, Yogesh,Panmand, Anil,Kumar, Santosh,Thorat, Sachin,Naykodi, Minakshi,Goswami, Arnab,Reddy, B. Srinivasa,Prasad, Vandna,Chaturvedi, Sandhya,Quraishi, Azfar,Menon, Suraj,Paliwal, Shalini,Kulkarni, Abhay,Karande, Vikas,Ghosh, Indraneel,Mustafa, Syed,De, Siddhartha,Jain, Vaibhav,Banerjee, Ena Ray,Rouduri, Sreekanth R.,Palle, Venkata P.,Chugh, Anita,Mookhtiar, Kasim A.
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p. 218 - 229
(2017/04/19)
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- Synthesis of 3-benzylisoquinolines by domino imination/cycloisomerisation of 2-propargylbenzaldehydes
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An easy entry to uncommon 2-propargylbenzaldehydes was developed. 2-Propargylbenzaldehydes demonstrated to be suitable building blocks for the synthesis of 3-benzyl isoquinolines by microwave promoted domino imination/cycloisomerisation in the presence of
- Dell'Acqua, Monica,Pirovano, Valentina,Confalonieri, Giorgio,Arcadi, Antonio,Rossi, Elisabetta,Abbiati, Giorgio
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p. 8019 - 8030
(2015/01/08)
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- Room temperature syntheses of entirely diverse substituted β-fluorofurans
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Synthesis of highly substituted 3-fluorofurans is reported. The sequence began with preparation of tert-butyldimethylsilyl alk-1-en-3-yn-1-yl ethers from 1,4-disubstituted alk-3-yn-1-ones. Subsequent fluorination of alkenynyl silyl ethers with Selectfluor
- Li, Yan,Wheeler, Kraig A.,Dembinski, Roman
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p. 2395 - 2408
(2012/04/10)
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- Lactone radical cyclizations and cyclization cascades mediated by SmI 2-H2O
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Unsaturated lactones undergo reductive radical cyclizations upon treatment with SmI2-H2O to give decorated cycloheptanes in a single highly selective operation during which up to three contiguous stereocenters are generated. Furthermore, cascade processes involving lactones bearing two alkenes, an alkene and an alkyne, or an allene and an alkene allow "one-pot" access to biologically significant molecular scaffolds with the construction of up to four contiguous stereocenters. The cyclizations proceed by the trapping of radical anions formed by electron transfer reduction of the lactone carbonyl.
- Parmar, Dixit,Matsubara, Hiroshi,Price, Kieran,Spain, Malcolm,Procter, David J.
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p. 12751 - 12757
(2012/09/05)
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- Selectivity in Garratt-Braverman cyclization: An experimental and computational study
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Bispropargyl sulfones equipped with aromatic rings of dissimilar nature were synthesized. Under basic conditions, these sulfones isomerized to the bisallenic sulfones, creating a competitive scenario between two alternate Garratt-Braverman (GB) cyclizatio
- Maji, Manasi,Mallick, Dibyendu,Mondal, Sayantan,Anoop, Anakuthil,Bag, Subhendu Sekhar,Basak, Amit,Jemmis, Eluvathingal D.
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p. 888 - 891
(2011/04/27)
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- Iodocyclization of hydroxylamine derivatives based on the control of oxidative aromatization leading to 2,5-dihydroisoxazoles and isoxazoles
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An efficient method for the synthesis of 2,5-dihydroisoxazoles and isoxazoles using iodocyclization of N-alkoxycarbonyl O-propargylic hydroxylamines has been developed. 2,5-Dihydro-4-iodoisoxazole underwent the cross-coupling reactions without aromatization to afford polyfunctionalized 2,5-dihydroisoxazoles. This process was applied to the preparation of valdecoxib and its 2,5-dihydro-derivative.
- Okitsu, Takashi,Sato, Kana,Potewar, Taterao M.,Wada, Akimori
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experimental part
p. 3438 - 3449
(2011/06/26)
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- Synthesis of carbazoles by gold(I)-catalyzed carbocyclization of 2-(enynyl)indoles
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A new synthetic protocol for carbazoles through gold(I)-catalyzed intramolecular hydroarylation of (Z)-2-(enynyl)indoles was achieved in good yields. The requisite (Z)-2-(enynyl)indoles were synthesized stereoselectively by trimethylgallium-promoted, Z-selective Wittig olefination of N-alkylindole-2-carboxaldehydes with propargyl ylides. Substrates possessing both alkyl as well as aromatic groups are well tolerated under these reaction conditions. Georg Thieme Verlag Stuttgart.
- Praveen, Chandrasekaran,Perumal, Paramasivan Thirumalai
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scheme or table
p. 521 - 524
(2011/04/17)
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- Gold(I)-catalyzed enantioselective ring expansion of allenylcyclopropanols
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(Chemical Equation Presented) The asymmetric gold(I)-catalyzed ring expansion of 1-allenylcyclopropanols is described. The method provides synthetically valuable cyclobutanones with a vinyl-substituted quaternary stereogenic center in high enantioselectivities and yields. The method shows a broad substrate scope, tolerating protected alcohols and amines, alkenes, unsaturated esters, and acetals. The reaction is easily adjustable to large-scale synthesis, leading to product formation without significant loss of selectivity or yield with only 0.5 mol% catalyst loading.
- Kleinbeck, Florian,Toste, F. Dean
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supporting information; experimental part
p. 9178 - 9179
(2009/12/06)
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- Enantioselective syntheses of various chiral multicyclic compounds with quaternary carbon stereocenters by catalytic intramolecular cycloaddition
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The intramolecular cycloaddition of 1,n-diene-ynes (n = 4-6), where alkyne and alkene moieties are connected by a 1,1-disubstituted alkene, was examined using a chiral rhodium catalyst, and various types of cycloadducts with quaternary carbon stereocenter
- Shibata, Takanori,Tahara, Yu-Ki,Tamura, Kohei,Endo, Kohei
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p. 3451 - 3457
(2008/10/09)
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- 5,5-Diaryl-2-amino-4-pentenoates as novel, potent, and selective glycine transporter type-2 reuptake inhibitors
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A novel series of 5,5-diaryl-2-amino-4-pentenoates was synthesized and found to be potent and selective glycine transporter type-2 reuptake inhibitors.
- Isaac, Methvin,Slassi, Abdelmalik,Silva, Kathleen Da,Arora, Jalaj,MacLean, Neil,Hung, Bill,McCallum, Kirk
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p. 1371 - 1373
(2007/10/03)
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- Novel 5-(3-aryl-2-propynyl)-5-(arylsulfonyl)thiazolidine-2,4-diones as antihyperglycemic agents
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Novel 5-(3-aryl-2-propynyl)-5-(arylsulfonyl)thiazolidine-2,4-diones and 5-(3-aryl-2-propynyl)5-(arylsulfanyl)thiazolidine-2,4-diones were prepared and evaluated as oral antihyperglycemic agents in the obese, insulin resistant db/db mouse model at 100 mg/kg and, if the analogue had sufficient potency, 20 mg/kg. The sulfonylthiazolidinediones, 2, were more potent than the corresponding sulfanylthiazolidinedione congeners, 1. With regard to substituent effects on the 3-propynyl phenyl ring (Ar') of 2, 4-halogen substitution generally resulted in the more potent analogues. Substituent effects on the phenylsulfonyl moiety (Ar) of 2 were less clear, although para-halogen substitution on Ar generally was preferable. 2-Pyridinesulfonyl derivatives (Ar = 2-pyridine in 2) also had good potency. Several compounds from series 2 were effective at lowering glucose and insulin in the obese, insulin resistant ob/ob mouse at the 50 mg/kg oral dose. Compound 20 significantly improved the glucose tolerance of obese, insulin resistant Zucker rats at the 20 mg/kg dose level and had no effect on plasma glucose or on glucose tolerance in normal rats fasted for 18 h at the 100 mg/kg level.
- Wrobel, Jay,Li, Zenan,Dietrich, Arlene,McCaleb, Michael,Mihan, Brenda,Sredy, Janet,Sullivan, Donald
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p. 1084 - 1091
(2007/10/03)
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- (Methoxyalkyl)thiazoles: A new series of potent, selective, and orally active 5-lipoxygenase inhibitors displaying high enantioselectivity
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(Methoxyalkyl)thiazoles are novel 5-lipoxygenase (5-LPO) inhibitors that are neither redox agents nor iron chelators. Consideration of a hypothetical model of the enzyme active site led to this series which is exemplified by 1-[3(naphth-2-ylmethoxy)phenyl]-1-(thiazol-2-yl)propyl methyl ether (2d, ICI211965). 2d inhibits cell-free guinea pig 5-LPO activity, LTC4 synthesis in plasma free mouse macrophages, and LTB4 synthesis in rat and human blood (IC50s 0.1 μM, 8nM, 0.5 μM, and 0.4 μM, respectively) but does not inhibit the synthesis of cyclooxygenase products at concentrations up to 50 μM in macrophages and 100 μM in blood. 2d is orally active in rat (ex vivo ED50 10 mg/kg in blood taken in 1h after dosing). SAR studies show that high in vitro potency requires methoxy, thiazolyl, and naphthyl groups and depends critically on the substitution pattern. (Methoxyalkyl)thiazoles are chiral. Resolution of 1-methoxy-6-(naphth-2-ylmethoxy)-1-(thiazol-2-yl)indan (2j, ICl216800) shows that (+)-2j is 50-150-fold more potent than (-)-2j in in vitro assays. Thus, (methoxyalkyl)thiazoles are a new series of orally active, selective 5-LPO inhibitors and represent the first class of inhibitors in which inhibition is mediated by specific, enantioselective interactions with the enzyme.
- Bird,Bruneau,Crawley,Edwards,Foster,Girodeau,Kingston,McMillan
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p. 2176 - 2186
(2007/10/02)
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