- Photocatalyzed Generation of Nitrosocarbonyl Intermediates Under Solar Light Irradiation
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Tetrabutylammonium decatungstate (TBADT) has emerged as a valuable photocatalyst for sunlight-induced organic reactions. In this communication we wish to present its use for the photocatalytic oxidation of hydroxamic acids to generate fleeting nitrosocarb
- Basile, Teresa,Capaldo, Luca,Ravelli, Davide,Quadrelli, Paolo
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p. 1443 - 1447
(2019/06/08)
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- A new synthetic route to acylnitroso intermediates and their applications in HDA and ene reactions
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Background: Acylnitroso intermediates are considered as highly reactive and useful transient that have been used to synthesize a broad class of biological active compounds and synthetic drugs. Although there are some reported methods for the generation of these intermediates, but still challenge for mild and environmental benign protocol. Herein, we report the facile in situ synthesis of acylnitroso intermediates and their efficient hetero Diels-Alder (HDA) and ene reactions. Methods: Acylnitroso intermediates were readily obtained by hydrogen peroxide oxidation of hydroxamic acids catalyzed by Cu(I)-, Ir(I)- or Ru(II)-complexes and easily reacted with symmetric and asymmetric conjugated dienes beside their reaction with different alkenes which converted to biological active products. Results: The resulted acylnitroso intermediates were efficiently afforded the hetero Diels-Alder cycloadducts in the presence of cyclopentadiene, cyclohexadiene or α-terpinene in high yields along with good regioselectivity for the later. In case of N-dienyl lactams, the cycloadducts were formed in the yield up to 89% with complete regioselectivity. In the presence of optically active N-dienyl pyroglutamates, diastereoisomers were formed in high yields with up to 72 de. In addition, the transient acylnitroso species were trapped with alkene to form the ene product in yield up to 95 %. As an interesting transformation, the halocyclization of the ene products gave substituted oxazolidone in 77% yield which considered as one of the effective antimicrobial and antibiotic compounds. Conclusion: In a brief, we introduce a mild and effective route to deliver acylnitroso intermediates in situ by using environmentally benign, cost effective, and non-toxic hydrogen peroxide oxidant catalyzed by Cu(I)-, Ir(I)- or Ru(II)-complexes. Good to excellent yields, regio- and diastereoselectivity were obtained by trapping these intermediates in symmetric and asymmetric HDA and ene reactions. Interestingly, the ene products easily transformed to potent drugs.
- Fakhruddin, Ahmad,Abu-Elfotoh, Abdel-Moneim,Shibatomi, Kazutaka,Iwasa, Seiji
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supporting information
p. 196 - 205
(2018/03/09)
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- Hetero Diels–Alder Reaction and Ene Reaction of Acylnitroso Species in situ Generated by Hypoiodite Catalysis
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As a first non-metal-catalyzed oxidation for the in situ generation of acylnitroso species, we describe the hypoiodite catalysis using tetra-n-butylammonium iodide as precatalyst with tert-butyl hydroperoxide or hydrogen peroxide as a terminal oxidant. Th
- Uraoka, Saki,Shinohara, Ikumi,Shimizu, Hisato,Noguchi, Keiichi,Yoshimura, Akira,Zhdankin, Viktor V.,Saito, Akio
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supporting information
p. 6199 - 6203
(2018/11/10)
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- Oxidative cycloaddition of hydroxamic acids with dienes or guaiacols mediated by iodine(III) reagents
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[Bis(trifluoroacetoxy)iodo]benzene (BTI) and (diacetoxyiodo)benzene (DIB) efficiently promote the formation of acylnitroso species from hydroxamic acids in the presence of various dienes to give the corresponding hetero-Diels-Alder (HDA) adducts in moderate to high yields. The present method could be applied to the HDA reactions of acylnitroso species with o-benzoquinones generated by the oxidative dearomatization of guaiacols.
- Shimizu, Hisato,Yoshimura, Akira,Noguchi, Keiichi,Nemykin, Victor N.,Zhdankin, Viktor V.,Saito, Akio
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supporting information
p. 531 - 536
(2018/03/21)
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- Probing competitive and co-operative hydroxyl and ammonium hydrogen-bonding directed epoxidations
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The diastereoselectivities and rates of epoxidation (upon treatment with Cl3CCO2H then m-CPBA) of a range of cis- and trans-4- aminocycloalk-2-en-1-ol derivatives (containing five-, six-, and seven-membered rings) have been investigated. In all cases where the two potential directing groups can promote epoxidation on opposite faces of the ring scaffold, evidence of competitive epoxidation pathways, promoted by hydrogen-bonding to either the in situ formed ammonium moiety or the hydroxyl group, was observed. In contrast to the relative directing group abilities already established for the sixmembered ring system (NHBn ? OH > NBn2), an N,N-dibenzylammonium moiety appeared more proficient than a hydroxyl group at directing the stereochemical course of the epoxidation reaction in a five- or seven-membered system. In the former case, this was rationalized by the drive to minimize torsional strain in the transition state being coupled with assistance from hydrogenbonding to the ammonium moiety. In the latter case, this was ascribed to the steric bulk of the ammonium moiety disfavoring conformations in which hydrogen-bonding to the hydroxyl group results in direction of the epoxidation to the syn face. In cases where the two potential directing groups can promote epoxidation on the same face of the ring scaffold, an enhancement of epoxidation diastereoselectivity was not observed, while introduction of a second, allylic heteroatom to the substrate results in diminishment of the rate of epoxidation in all cases. Presumably, reduction of the nucleophilicity of the olefin by the second, inductively electron-withdrawing heteroatom is the dominant factor, and any assistance to the epoxidation reaction by the potential to form hydrogen-bonds to two directing groups rather than one is clearly unable to overwhelm it.
- Brambilla, Marta,Brennan, Méabh B.,Csatayová, Kristína,Davies, Stephen G.,Fletcher, Ai M.,Kennett, Alice M.R.,Lee, James A.,Roberts, Paul M.,Russell, Angela J.,Thomson, James E.
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p. 10297 - 10309
(2018/05/31)
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- Solid-phase supported nitrosocarbonyl intermediates: Old scope and new limitations in the organic synthesis
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Nitrosocarbonyl intermediates on solid polystyrenic support are generated at room temperature by the mild oxidation of resin-bound stable nitrile oxides. They undergo one-pot ene reactions with tetramethyl- and trimethyl-ethylene and other highly substitu
- Joshi, Bhupendra Prasad,Memeo, Misal Giuseppe,Quadrelli, Paolo
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p. 3271 - 3275
(2017/07/27)
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- Straightforward hetero Diels-Alder reactions of nitroso dienophiles by microreactor technology
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The hetero Diels-Alder reactions of 2-nitrosotoluene and some representative acylnitrosodienophiles with a selected set of 1,3-dienes were studied under microflow conditions. The main assets of the technology, that is, an accurate control of the reaction
- Monbaliu, Jean-Christophe M.R.,Cukalovic, Ana,Marchand-Brynaert, Jacqueline,Stevens, Christian V.
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experimental part
p. 5830 - 5833
(2010/12/20)
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- Conversion of a nitrosocarbonyl hetero Diels-Alder cycloadduct to useful isoxazoline-carbocyclic aminols
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A new approach to useful precursors for the synthesis of isoxazoline-carbocyclic nucleosides is detailed, starting from the readily available N-benzoyl-2,3-oxazanorborn-5-ene and introducing more polar and hydrophilic functionalities through 1,3-dipolar cycloaddition of carbethoxyformonitrile oxide, generated either from the corresponding hydroximoyl chloride or, more conveniently, by catalyzed condensation with ethyl nitroacetate.
- Quadrelli, Paolo,Bovio, Bruna,Piccinini, Achille,Caramella, Pierluigi,De Sarlo, Francesco,Machetti, Fabrizio
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experimental part
p. 10679 - 10684
(2010/02/28)
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- IMPROVEMENTS IN PHARMACEUTICALLY USEFUL COMPOUNDS
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A compound of formula (I) or (II): wherein A is hydrogen or CR1R2; Y and Z are each, independently, hydrogen or a halogen;X is -NR4R5, or R7; R1 is hydrogen, or a substituted or unsubstituted alkyl or alkenyl group containing 1-4 carbon atoms; when X is -NR4R5, R2 is a substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, aralkyl aralkenyl, or aralkynyl group, that optionally includes at least one heteroatom in its carbon skeleton and contains 1-12 carbon atoms; when X is R7, R2 is an unsubstituted alkyl, alkenyl or alkynyl group, or a substituted or unsubstituted aryl, aralkyl aralkenyl, or aralkynyl group, that optionally includes at least one heteroatom in its carbon skeleton and contains 1-12 carbon atoms; R3 is a substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, aralkyl aralkenyl, or aralkynyl group, that optionally includes at least one heteroatom in its carbon skeleton and contains 1-12 carbon atoms; R4 is hydrogen, a substituted or unsubstituted alkyl, alkenyl, alkynyl, aryl, aralkyl aralkenyl, or aralkynyl group, that optionally includes at least one heteroatom in its carbon skeleton and contains 1-12 carbon atoms, -COOR8, or -COR8; R5 is hydrogen, or a substituted or unsubstituted alkyl or alkenyl group containing 1-5 carbon atoms; R7 is an unsubstituted alkyl, alkenyl, or alkynyl group, that contains 1-4 carbon atoms; and, R8 is an unsubstituted or halo-substituted alkyl, aryl, or aralkyl group, that contains 1-12 carbon atoms.
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- Iridium(I)-catalyzed hydrogen peroxide oxidation of hydroxamic acids and hetero Diels-Alder reaction of the acyl nitroso intermediates with cyclopentadiene
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[Ir(I)(coe)2Cl]2 (2 mol%)-catalyzed hydrogen peroxide oxidation of hydroxamic acids in the presence of cyclopentadiene gave the corresponding cycloadducts up to 97% yield. With a catalyst loading of 0.05 mol%, a maximum TON was attai
- Iwasa, Seiji,Fakhruddin, Ahmad,Tsukamoto, Yasuyuki,Kameyama, Masayuki,Nishiyama, Hisao
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p. 6159 - 6161
(2007/10/03)
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- A mild oxidation method of hydroxamic acids: Efficient trapping of acyl nitroso intermediates
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Ruthenium(II)-pyridine-2,6-dicarboxylate (pydic) of 2,6-bis(oxazolinyl)pyridine (pybox-dh) complex catalyzed the hydrogen peroxide oxidation of hydroxamic acid in the presence of cyclopentadiene to give acyl nitroso cycloadducts in 74-99% yield.
- Iwasa, Seiji,Tajima, Kentaro,Tsushima, Shinji,Nishiyama, Hisao
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p. 5897 - 5899
(2007/10/03)
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- Generation of acyl nitroso compounds by the oxidation of N-acyl hydroxylamines with the Dess-Martin periodinane
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The oxidation of hydroxamic acids, N-hydroxyureas and N- hydroxycarbamates with the Dess-Martin periodinane generates the corresponding acyl nitroso compounds that react with conjugated dienes to produce the corresponding cycloadducts.
- Jenkins, Neil E.,Ware Jr., Roy W.,Atkinson, Robert N.,King, S. Bruce
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p. 947 - 953
(2007/10/03)
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- Cycloadditions of nitrile oxides to the highly reactive N-acyl-2-oxa-3- azanorborn-5-enes afford versatile cycloadducts and a convenient entry to highly functionalized derivatives
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N-Acyl-2-oxa-3-azanorborn-5-enes are highly reactive dipolarophiles in cycloadditions with nitrile oxides. The cycloadducts can be easily elaborated to various functionalized structures that are not directly accessible by 1,3- dipolar cycloadditions.
- Quadrelli, Paolo,Mella, Mariella,Paganoni, Pierangela,Caramella, Pierluigi
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p. 2613 - 2620
(2007/10/03)
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- The mild oxidation of nitrile oxides affords a convenient entry to nitrosocarbonyl intermediates, versatile tools in organic syntheses
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Nitrile oxides are oxidized by tertiary amine N-oxides in different solvents at room temperature to afford in the presence of dienes nitrosocarbonyl adducts in fair yields. The mild conditions used in oxidizing a variety of nitrile oxides promise a wide application of this method in synthetic processes.
- Quadrelli,Mella,Gamba Invernizzi,Caramella
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p. 10497 - 10510
(2007/10/03)
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- A mild oxidation of nitrile oxides: A new synthetic route to nitroso carbonyl intermediates
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Addition of N-methyl morpholine N-oxide (NMO) to a nitrile oxide solution in dichloromethane at room temperature in the presence of a diene affords nitroso carbonyl adducts in fair yields.
- Quadrelli,Gamba Invernizzi,Caramella
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p. 1909 - 1912
(2007/10/03)
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- Reactive Intermediates from the Solvolysis of Mutagenic O-Alkyl N-Acetoxybenzohydroxamates
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Mutagenic O-(para-substituted benzyl) N-acetoxybenzohydroxamates undergo acid-catalysed solvolysis in aqueous acetonitrile but three is a change in mechanism from AA11 to E1 on going from para electron-withdrawing substituents to para +M electron-donating groups.The former permit the formation of a discrete nitrenium ion intermediate whereas the latter promote a concerted elimination of a resonance stabilized benzyl carbocation.
- Bonin, Antonio M.,Glover, Stephen A.,Hammond, Gerard P.
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p. 1173 - 1180
(2007/10/02)
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- REACTIONS OF TRANSIENT C-NITROSOCARBONYL COMPOUNDS WITH DIENES, MONOOLEFINS, AND NUCLEOPHILES
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Nitrosocarbonylbenzene and nitrosocarbonylmethane, formed as transient intermediates by oxidation of benzo- and aceto-hydroxamic acid, respectively, with tetraethylammonium periodate, are trapped by cyclopentadiene to give the corresponding cycloadducts (5).The adduct (5; R=Ph) dissociates in solution at 80 deg C to reform nitrosocarbonylbenzene, which reacts with thebaine (1) to give (4; R=Ph) and with triphenylphosphine to give phenyl isocyanate.Cycloadducts of nitrosocarbonylbenzene with cyclohexa-1,3-diene (6) and with cyclo-octatetraene (7) have also been prepared.The adduct (3; R=Ph) of nitrosocarbonylbenzene and 9,10-dimethylanthracene, when heated with 1-allyl-3,4-methylenedioxybenzene, oct-1-ene, or 2,5-dimethylhexa-2,4-diene, gives the corresponding 'ene' reaction products of the olefins and nitrosocarbonylbenzene.When heated alone, the adduct (3; R=Ph) gives 9,10-dimethylanthracene, benzoic anhydride, and nitrous oxide.Oxidation of 2,4,6-trimethylbenzohydroxamic acid in the presence of thebaine gives the adduct (4; R=2,4,6-trimethylphenyl).However, 2,4,6-trimethylnitrosocarbonylbenzene is insufficiently stable to be isolated; in the absence of a diene it decomposes to give 2,4,6-trimethylbenzoic anhydride as the major product.
- Corrie, John E.T.,Kirby, Gordon W.,Mackinnon, John W.M.
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p. 883 - 886
(2007/10/02)
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- THE PREPARATION AND TRANSFORMATIONS OF 2-AZA-3-OXABICYCLO HEPTENE HYDROCHLORIDE
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Reaction of 1-chloro 1-nitroso cyclohexane with excess freshly prepared cyclopentadiene in ether: ethanol gives the crystalline 2-aza 3-oxabicyclo(2.2.1)heptene hydrochloride (1) in 89percent yields. 2-Aza 3-oxabicyclo(2.2.1)heptene (2), generated in situ
- Ranganathan, D.,Ranganathan, S.,Rao, C. B.,Raman, K.
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p. 629 - 635
(2007/10/02)
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