- Chiral exploration of 6,12-diphenyldibenzo[b,f][1,5]diazocine with stable conformation
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A first optical resolution of 6,12-diphenyldibenzo[b,f][1,5]diazocine with stable boat conformation was achieved by chiral supercritical fluid chromatography (SFC). The absolute configurations of enantiomers were first assigned and determined by X-ray cry
- Li, Zheng-Yi,Pan, Yong,Jin, Lin-Lin,Yin, Yue,Yang, Bao-Zhu,Sun, Xiao-Qiang
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- Facile synthesis of nitrogen-doped [(6.)M8]ncyclacene carbon nanobelts by a one-pot self-condensation reaction
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Synthesis of fully conjugated carbon nanobelts (CNBs) remains one of the biggest challenges in organic chemistry. Herein, we report a facile synthesis of four nitrogen-doped [(6.)m8]ncyclacene CNBs (m = 1-3; n = 3,4) with different sizes by a one-pot self-condensation reaction of three bis(o-aminobenzophenone) precursors. The belt-shaped structure was confirmed by X-ray crystallographic analysis. The existence of eight-membered [1,5]diazocine rings releases the strain while maintaining weak πconjugation throughout the belt backbone, which is supported by electronic absorption spectra and frontier molecular orbital analysis. NMR measurements and magnetic shielding calculations suggest an alternating aromatic-nonaromatic ring structure, with a slightly more shielded chemical environment in the cavity. Our method opens the opportunities to access more sophisticated πconjugated 2D/3D belt-/cage-like molecules in a simple way.
- Zhu, Jun,Han, Yi,Ni, Yong,Li, Guangwu,Wu, Jishan
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- Regioselective intramolecular annulations of ambident β-enamino esters: A diversity-oriented synthesis of nitrogen-containing privileged molecules
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Diversity-oriented, regioselective, intramolecular annulation of β-enamino esters is described under solvent-free, calcium-catalysis. 2-aminoaryl ketones and alkyl propiolates undergone a [4+2] annulation to yield substituted quinolines; with an excess of
- Yaragorla, Srinivasarao,Pareek, Abhishek
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supporting information
p. 909 - 913
(2018/02/12)
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- Indium-Catalyzed Annulation of o-Acylanilines with Alkoxyheteroarenes: Synthesis of Heteroaryl[b]quinolines and Subsequent Transformation to Cryptolepine Derivatives
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We disclose herein the first synthetic method that is capable of offering heteroaryl[b]quinolines (HA[b]Qs) with structural diversity, which include tricyclic and tetracyclic structures with (benzo)thienyl, (benzo)furanyl, and indolyl rings. The target HA[b]Q is addressed by the annulation of o-acylanilines and MeO-heteroarenes with the aid of an indium Lewis acid that effectively works to make two different types of the N-C and C-C bonds in one batch. A series of indolo[3, 2-b]quinolines prepared here can be subsequently transformed to structurally unprecedented cryptolepine derivatives. Mechanistic studies showed that the N-C bond formation is followed by the C-C bond formation. The indium-catalyzed annulation reaction thus starts with the nucleophilic attack of the NH2 group of o-acylanilines to the MeO-connected carbon atom of the heteroaryl ring in an SNAr fashion, and thereby the N-C bond is formed. The resulting intermediate then cyclizes to make the C-C bond through the nucleophilic attack of the heteroaryl-ring-based carbon atom to the carbonyl carbon atom, providing the HA[b]Q after aromatizing dehydration.
- Yonekura, Kyohei,Shinoda, Mika,Yonekura, Yuko,Tsuchimoto, Teruhisa
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- Quinolines formation by condensation of heteroaromatic ketones and 2-aminobenzophenones under MW irradiation
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Microwave (MW) irradiation facilitated synthesis provides fast, safe, simple, and green reaction conditions. MW irradiation of 2-aminobenzophenones with heteroaromatic ketones afforded quinolines via Friedlander condensation in high yields with intact hal
- Cho, Soo Kyung,Song, Ju Hyun,Lee, Eon Jin,Lee, Do-Hun,Hahn, Jung-Tai,Jung, Dai-Il
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supporting information
p. 2746 - 2749
(2015/11/17)
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- Palladium(ii)-catalysed regioselective synthesis of 3,4-disubstituted quinolines and 2,3,5-trisubstituted pyrroles from alkenes via anti-Markovnikov selectivity
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A novel strategy has been identified for the regioselective synthesis of 3,4-disubstituted quinolines and 2,3,5-trisubstituted pyrroles from simple alkenes via anti-Markovnikov selectivity under palladium catalysis. The salient features are synthesis of two different heterocycles, readily available starting materials, broad substrate scope, moderate to good yields and use of molecular oxygen as a terminal oxidant.
- Senadi, Gopal Chandru,Hu, Wan-Ping,Garkhedkar, Amol Milind,Boominathan, Siva Senthil Kumar,Wang, Jeh-Jeng
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supporting information
p. 13795 - 13798
(2015/09/07)
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- Mechanistic study of a complementary reaction system that easily affords quinazoline and perimidine derivatives
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A new reaction between 2-aminobenzophenone and thiourea in dimethyl sulfoxide (DMSO) has been developed that primarily affords 4-phenylquinazoline as a single product. This reaction is also applicable, in general, to the reactions between thiourea and conformation-restricted β-amino ketones, such as 1-aminoanthracene-9,10-dione and 1-amino-9H-fluoren-9-one, to prepare perimidine derivatives. Experimental data is consistent with our computational study on the thermal decomposition of thiourea to form hydrogen sulfide and carbodiimide. This reaction involves a coupling between 2-aminobenzophenone and carbodiimide generated in situ from thiourea to form 4-phenylquinazolin-2(1H)-imine intermediate, and the generation of sulfur-containing reducing agent from hydrogen sulfide and DMSO, which reduces 4-phenylquinazolin-2(1H)-imine to 4-phenyl-1,2-dihydroquinazolin-2-amine. Elimination of ammonia from the latter yields 4-phenylquinazoline.
- Wang, Zerong Daniel,Eilander, Joshua,Yoshida, Motoko,Wang, Tianzhi
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supporting information
p. 7664 - 7674
(2015/04/22)
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- Steric factors in the single-electron transfer carbolithiation and transannular reduction of 6,12-diphenyldibenzo[b,f][1,5]diazocine by organolithium reagents
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The puckered tricyclic heterocycle 6,12-diphenyldibenzo-[b,f][1,5] diazocine, a novel probe for revealing single-electron transfer (SET) reactions, is here employed as a model substrate for investigating the carbolithiation of imines and the stereochemistry, the regiochemistry, and the electronic nature (polar or SET) of such R-Li additions. The chemical behavior of the following organolithium reagents (mainly in THF) toward the diazocine was studied: benzyl-, methyl-, phenyl-, n-butyl-, and phenylethynyllithiums, as well as the reactive allylmagnesium chloride and the typical tert-butylmagnesium chloride. The only reagent that failed to carbometalate or to reduce the diazocine transannularly was phenylethynyllithium. The tert-butyl Grignard reagent could not carbometalate but did reduce the diazocine with photocatalysis. The other five organometallics yielded both carbometalation of the diazocine and, upon hydrolysis, transannular SET reduction to 4b,9b-diphenyl-4b,5,9b,10- tetrahydroindolo[3,2-b]indole ( indoloindole ) in varying pro- portions. Three types of carbometalation products were observed in such hydrolyzed reactions: (1) exo-1,2-addition to a C=N bond by C6H 5CH2Li, H2C=CHCH2MgCl, and CH 3Li, as established by spectral and XRD data; (2) 1,4-addition to the ortho-phenyl carbon Co=C-C=N linkage by phenyllithium with the subsequent elimination of LiH; and (3) 1,4-addition, as in type 2, by n-butyllithium but without the elimination of LiH. The foregoing modes of reactivity, the concomitant formation of the telltale SET reduction product, indoloindole , and the failure of PhC≡CLi to react at all with the diazocine are marshaled to support the conclusion that the organometallics reacting with the diazocine, by carbometalation and by transannular reduction, do so by SET processes and not by straightforward nucleophilic attack. The relative stabilities of sp3-, sp2-, and sp-hybridized carbon radicals possibly involved were assessed in concluding that PhC≡CLi is incapable of reacting through any SET pathway.
- Eisch, John J.,Yu, Kun,Rheingold, Arnold L.
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p. 818 - 832
(2014/03/21)
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- Synthetic studies towards 1,5-benzodiazocines
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Anthranilonitrile reacted with phenylmagnesium bromide to yield a dianion, which when heated (~120 °C) yielded the condensation product 2-(2-aminophenyl)-2,4-diphenyl-1,2-dihydroquinazoline 8. This heterocycle, when treated with palladium acetate, was converted into 6,12-diphenyldibenzo[b,f][1, 5]diazocine 9. Methylmagnesium bromide and anthranilonitrile, under similar conditions directly gave a nitrogen-bridged diazocine, whose structure was determined by X-ray crystallography and also proven to be an analogue of Tro?ger's base. Acid-induced condensation of 2-amino-3-methoxybenzaldehyde gave the trimeric product 45 rather than a dibenzo[b,f][1,5]diazocine.
- Pettersson, Birgitta,Bergman, Jan,Svensson, Per H.
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p. 2647 - 2654
(2013/03/28)
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- Trifluoroacetic acid catalyzed dibenzodiazocine synthesis: Optimization and mechanism study
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Dibenzo[b,f][1,5]diazocines, a class of potential building blocks for novel electrochemical actuators, were synthesized via a novel, efficient acid-catalyzed reaction of 2-acylbenzoisocyanate at room temperature. Real-time NMR analysis and the captured intermediate showed the mechanism was an unprecedented cyclization of the isocyanate with the neighboring acyl group, followed by the dimerization.
- Zhao, Na,Qiu, Li,Wang, Xiao,Li, Jianzhong,Jiang, Yi,Wan, Xiaobo
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p. 9665 - 9671,7
(2020/08/20)
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- InCl3-driven regioselective synthesis of functionalized/ annulated quinolines: Scope and limitations
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The efficient, regioselective synthesis of functionalized/annulated quinolines was achieved by the coupling of 2-aminoaryl ketones with alkynes/active methylenes/α-oxoketene dithioacetals promoted by InCl 3 in refluxing acetonitrile as well as under solvent-free conditions in excellent yields. This transformation presumably proceeded through the hydroamination-hydroarylation of alkynes, and the Friedlaender annulation of active methylene compounds and α-oxoketene dithioacetals with 2-aminoarylketones. In addition, simple reductive and oxidative cyclization of 2-nitrobenzaldehyde and 2-aminobenzylalcohol, respectively, afforded substituted quinolines. Systematic optimization of the reaction parameters allowed us to identify two-component coupling (2CC) conditions that were tolerant of a wide range of functional groups, thereby providing densely functionalized/annulated quinolines. This approach tolerates the synthesis of various bioactive quinoline frameworks from the same 2-aminoarylketones under mild conditions, thus making this strategy highly useful in diversity-oriented synthesis (DOS). The scope and limitations of the alkyne-, activated methylene-, and α-oxoketene dithioacetal components on the reaction were also investigated.
- Chanda, Tanmoy,Verma, Rajiv Kumar,Singh, Maya Shankar
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supporting information; experimental part
p. 778 - 787
(2012/06/29)
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- A rapid and efficient access to diaryldibenzo[b,f][1,5]diazocines
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2-Benzoylbenzoyl azides undergo facile cyclization under acidic conditions to give substituted dibenzo[b,f][1,5]-diazocines in good yields. This approach shortens the synthetic steps toward these compounds as compared with conventional methods. The mechanism of the diazocine synthesis is assumed to proceed by an unprecedented intermolecular [2 + 2] cyclization.
- Wang, Xiao,Li, Jianzhong,Zhao, Na,Wan, Xiaobo
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supporting information; experimental part
p. 709 - 711
(2011/04/24)
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- Simple synthesis of quinolines and dibenzo[b,f][1,5]diazocines under microwave irradiation
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Quinolines 3a-f, 5a-f, and dibenzo[b,f][1,5]diazocines 4, 6 were synthesized in the presence of 0.5 equiv. of diphenyl phosphate (DPP) under microwave irradiation. The obtained yield of 6,12-diphenyl-dibenzo[b,f][1,5]diazocine 4 was higher when using anhy
- Jung, Dai-Il,Song, Ju-Hyun,Lee, Eon-Jin,Kim, Yun-Young,Lee, Do-Hun,Lee, Yong-Gyun,Hahn, Jung-Tai
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experimental part
p. 5805 - 5807
(2009/12/26)
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- Friedel-Crafts Acylation with 2-Isocyanatobenzoyl Chlorides: The Structure of the Intermediate Complex
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The intermediate complex obtained in the Friedel-Crafts acylation of benzene with 2-isocyanatobenzoyl chloride (1a) reacts with methanol or ethanol in the presence of ether affording 4-alkoxy-4-phenyl-1,4-dihydro-3,1-benzoxazin-2(1H)-ones, whereas with anilines, the corresponding anils of 2-aminobenzophenone are obtained.In the presence of triethylamine, the complex reacts with aniline and 2-aminobenzophenone affording 4-hydroxy-4-phenyl-3-substituted 3,4-dihydroquinazolin-2(1H)-ones whereas, with alkyl anthranilates, the new 11b-phenyl-7,11b-dihydroquinazolinobenzoxazine-6,13-diones are obtained.Similar products are also obtained from 5-chloro-2-isocyanatobenzoyl chloride.The intermediate complex has been shown to exist exclusively in the cyclic form in both acidic and basic media.
- Acharya, Baman Prasad,Rao, Y. Ramachandra
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p. 1001 - 1035
(2007/10/02)
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- Mass Spectral and Pyrolitic Studies of Some 4,4-Disubstituted 1,4-Dihydro-2H-3,1-benzoxazin-2-ones
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Pyrolysis of 4,4-diaryl-1,4-dihydro-2H-3,1-benzoxazin-2-ones at 230-240 deg C gives 9-arylacridines and (2-aminophenyl)diarylmethanes.Their formation correlates well with the mass fragmentation of the respective parent compounds.
- Acharya, Baman Prasad,Misra, Bijaya Kumar,Rao, Yerramalli Ramachandra
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p. 4417 - 4420
(2007/10/02)
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- Synthesis of Unsymmetrically Substituted 6,12-Diaryldibenzodiazocines and Their Precursor Schiff Bases
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A new route for the preparation of some unsymmetrically substituted 6,12-diaryldibenzodiazocines 5 and their precursor Schiff bases 4 from 2-isocyanatobenzoyl chloride and its 5-chloro derivative are described.
- Acharya, Baman P.,Ramachandra Rao, Y.
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p. 324 - 326
(2007/10/02)
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- Friedel-Crafts Acylation of Some Aromatic Compounds with 2-Isocyanatobenzoyl Chloride
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Friedel-Crafts acylation of benzene, toluene, anisole and chlorobenzene with 2-isocyanatobenzoyl chloride (1) afford either 2-aminobenzophenones (2) or 4,4-diaryl-1,2-dihydro-3,1-benzoxazin-2(4H)-ones (3) as major products depending on reaction temperature and/or substrate reactivity.Other minor products isolated are 3-aryl-1,2,3,4-tetrahydroquinazoline-2,4-diones (4), 6,12-diaryldibenzodiazocines (6) and 2-aminophenyl-α,α-diarylmethanols (7).The formation of 2 and 3 has been shown to take place via a common intermediate complex to which the cyclic 4-aryl-3,1-benzoxazinonium ion structure (12) has been assigned on the basis of its rection with methanol and 2-aminobenzophenone.While the formation of 6 occurs through the intermediate complex (12), 4-aryliminoquinazolin-2-ones (5) are formed most probably from the 1-AlCl3 complex.
- Misra, B. K.,Rao, Y. R.,Mahapatra, S. N.
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p. 1132 - 1138
(2007/10/02)
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- Studies in Large Ring Compounds: Part V - Synthesis of 6,12-Diphenyldibenzodiazocines
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Polyphosphate ester (PPE) has been found to be an elegant reagent for the synthesis of 6,12-diphenyldibenzodiazocines (IIa-e) from (2-aminophenyl)(aryl)methanones (Ia-e).
- Wakankar, D. M.,Hosangadi, B. D.
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p. 703 - 704
(2007/10/02)
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