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Journal articles on the topic 'Oxazóis'

Author: Grafiati

Published: 4 June 2021

Last updated: 5 February 2022

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1

Pandit, Rameshwar Prasad, Jae-Jin Shim, Sung Hong Kim, and Yong Rok Lee. "Copper-catalyzed direct coupling of benzoxazin-2-ones with indoles for the synthesis of diverse 3-indolylbenzoxazin-2-ones: access to natural cephalandole A." RSC Advances 7, no. 87 (2017): 55288–95. http://dx.doi.org/10.1039/c7ra10634c.

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2

Yadav, Lal Dhar Singh, Ankita Rai, Vijai Kumar Rai, and Chhama Awasthi. "Cu(OTf)2-catalysed synthesis of structurally novel bicyclic 1,3-oxazines via condensation-dehydrazinative ring transformation cascades." Journal of Chemical Research 2009, no. 8 (2009): 520–26. http://dx.doi.org/10.3184/030823409x466753.

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The Cu(OTf)2-catalysed expeditious synthesis of 1,3-oxazin-2-ones(thiones) from unprotected D-glucose and D-xylose in excellent yields is reported. Cu(OTf)2 plays a dual role of a Lewis acid and an oxidant for dehydrazination, which is the cornerstone in the present investigation. The 1,3-oxazin-2-ones(thiones) serve as synthons for diversity oriented synthesis of structurally distinct bicyclic 1,3-oxazin-2-ones(thiones), when subjected to Malaprade reaction, followed by Cu(OTf)2-catalysed cyclisation with an appropriate traditional reagent such as phenylhydrazine, amidines, hydroxylamine, or

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3

Annor-Gyamfi, Joel K., and Richard A. Bunce. "4H-Benzo[d][1,3]oxazin-4-ones and Dihydro Analogs from Substituted Anthranilic Acids and Orthoesters." Molecules 24, no. 19 (2019): 3555. http://dx.doi.org/10.3390/molecules24193555.

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A one-pot route to 2-alkyl and 2-aryl-4H-benzo[d][1,3]oxazin-4-ones (also known as 4H-3,1-benzoxazin-4-ones) has been developed and studied. The method involves the reaction of aryl-substituted anthranilic acids with orthoesters in ethanol catalyzed by acetic acid. Additionally, we have also investigated the reaction under microwave conditions. Not all of the substrates were successful in yielding the target heterocycles as some of the reactions failed to undergo the final elimination. This process led to the isolation of (±)-2-alkyl/aryl-2-ethoxy-1,2-dihydro-4H-benzo[d][1,3]oxazin-4-ones. The

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4

El-Shahawi, Manal M., and Ahmed K. El-Ziaty. "Enaminonitrile as Building Block in Heterocyclic Synthesis: Synthesis of Novel 4H-Furo[2,3-d][1,3]oxazin-4-one and Furo[2,3-d]pyrimidin-4(3H)-one Derivatives." Journal of Chemistry 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/5610707.

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2-Amino-4,5-diphenylfuran-3-carbonitrile 1 was utilized as building block for the construction of new furo[2,3-d]pyrimidin-4(3H)-one derivative 2 and 4H-furo[2,3-d][1,3]oxazin-4-one derivative 3 via treatment with acetic anhydride and benzoyl chloride, respectively. The 4H-furo[2,3-d][1,3]oxazin-4-one derivative 3 was transformed into novel furo[2,3-d]pyrimidin-4(3H)-ones 4–8, tetrazolylfuran derivative 10, and furo[3,2-d]imadazolone derivative 11 via reaction with various nitrogen nucleophiles. The structure features of the synthesized compounds were established from their spectral and elemen

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5

Chovatiya, Pankaj, Charmy Mehta, Hardik Senjani, Anamik Shah, and Hitendra S. Joshi. "Synthesis and Characterization of some New Schiff Bases of 2-Oxonaphtho[2,1-b][1,4]Oxazine." International Letters of Chemistry, Physics and Astronomy 31 (March 2014): 26–30. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.31.26.

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The literature review reveal that [1,4]-oxazine derivatives represent one of the most active classes of compounds possessing wide spectrum of biodynamic activities and use as potent therapeutic agents. In the present work, a series of Schiff base of 2-(2,3-dihydro-2-oxonaphtho[2,1-b][1,4]oxazin-1-yl)acetohydrazide, 5a-5j has been synthesized using 1-aminonaphthalen-2-ol. Various aromatic aldehyde were react with carbohydrazide 4 in the presence of acid to produce the 2-oxonaphtho[2,1-b][1,4]oxazin Schiff base derivatives with good yields. All synthesized compounds were characterized by IR, NMR

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6

Singh, Shambhu Nath, Sarva Jayaprakash, K. Venkateshwara Reddy, Ali Nakhi, and Manojit Pal. "A metal catalyst-free and one-pot synthesis of (3,4-dihydro-2H-benzo[b][1,4]oxazin-2-yl)methanol derivatives in water." RSC Advances 5, no. 103 (2015): 84889–93. http://dx.doi.org/10.1039/c5ra14478g.

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7

Walter, Magnus W., Neh Thaker, Jack E. Baldwin, Matthias Müller, and Christopher J. Schofield. "The reaction of Tms-Cf3 with Amino Acid Derived Ring-Templates: Studies with Oxazin-2-Ones and Oxazolidin-5-Ones." Journal of Chemical Research 2000, no. 7 (2000): 310–11. http://dx.doi.org/10.3184/030823400103167606.

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8

Shokol, Tetyana, Natalia Gorbulenko, and Volodymyr Khilya. "Synthesis of chromones, annulated with oxygen-containing heterocycles with two hetero atoms at C(7)-C(8) bond." French-Ukrainian Journal of Chemistry 7, no. 1 (2019): 121–39. http://dx.doi.org/10.17721/fujcv7i1p121-139.

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The present review represented the advanced synthetic strategies for chromones annulated at the C(7)-C(8) bond with five-membered, six-membered, and seven-membered oxygen-containing heterocycles with two heteroatoms, such as 6H-[1,3]dioxolo[4,5-h]chromen-6-one, 2,3-dihydro-7H-[1,4]dioxino[2,3-h]chromen-7-one, 3,4-dihydro-2H,8H-[1,4]dioxepino[2,3-h]chromen-8-one, 2,3-dihydro-1H,7H-chromeno[7,8-b][1,4]oxazin-7-one, 4H,12H-pyrano[2,3-a]phenoxazine-4-one and 9,10-dihydro-4H,8H-chromeno[8,7-e][1,3]oxazin-4-one. The biological activity of naturally occurring and modified synthetic fused hetarenochro

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9

Loakes, D., D. M. Brown, N. Mahmood, J. Balzarini, and E. De Clercq. "Antiviral Activity of Bicyclic Pyrimidine Nucleosides." Antiviral Chemistry and Chemotherapy 6, no. 6 (1995): 371–78. http://dx.doi.org/10.1177/095632029500600604.

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A number of pyrimidine nucleosides, which may show two hydrogen bonding modes, have been prepared and tested for antiviral activity against a series of viruses. Whilst none of the compounds described showed significant activity against human immunodeficiency virus (HIV), the bicyclic 2′-deoxynucleoside, [2], derived from the base 6H,8H-3,4-dihydropyrimido[4,5-c][1,2]oxazin-7-one, was shown to inhibit herpes simplex virus type 1 (HSV-1) at similar concentrations as BVDU1 and ACV. Compounds 13, 6-(2-deoxyribofuranosyl)-6H,8H-2-methyl-3,4-dihydropyrimido[4,5-c][1,2]oxazin-7-one, and 14, N4-hydrox

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10

Beyer, H., S. Melde, and K. Dittrich. "Hydrazine des Thiophens und Oxazols." Zeitschrift für Chemie 1, no. 6 (2010): 191. http://dx.doi.org/10.1002/zfch.19610010612.

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11

Yan, Shaoxi, Leping Ye, Miaochang Liu, et al. "Unexpected TFA-catalyzed tandem reaction of benzo[d]oxazoles with 2-oxo-2-arylacetic acids: synthesis of 3-aryl-2H-benzo[b][1,4]oxazin-2-ones and cephalandole A." RSC Adv. 4, no. 32 (2014): 16705–9. http://dx.doi.org/10.1039/c4ra01605j.

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12

Zhao, Hongyi, Wenting Zhao, Shihao Cheng, Haijia Lu, Dongfeng Zhang, and Haihong Huang. "Efficient and stereoselective one-pot synthesis of benzo[b]oxazolo[3,4-d][1,4]oxazin-1-ones." RSC Advances 10, no. 40 (2020): 24037–44. http://dx.doi.org/10.1039/d0ra04104a.

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13

Niu, Ben, Bo Jiang, Liu-Zhu Yu, and Min Shi. "Base-promoted [3 + 3] cyclization of cyclopropenones and cyclopropenethiones with amides for the synthesis of 6H-1,3-oxazin-6-ones and 6H-1,3-thiazin-6-ones." Organic Chemistry Frontiers 5, no. 8 (2018): 1267–71. http://dx.doi.org/10.1039/c8qo00091c.

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14

Xu, Yanli, Weigao Hu, Xiaodong Tang, Jinwu Zhao, Wanqing Wu, and Huanfeng Jiang. "Palladium-catalyzed Csp2–H carbonylation of aromatic oximes: selective access to benzo[d][1,2]oxazin-1-ones and 3-methyleneisoindolin-1-ones." Chemical Communications 51, no. 31 (2015): 6843–46. http://dx.doi.org/10.1039/c5cc01661d.

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15

Journal, Baghdad Science. "Synthesis and Characterization of Some New Azo Dyes Derivatives Via Chalcone and Study Some of Their Biological Activity." Baghdad Science Journal 13, no. 1 (2016): 122–32. http://dx.doi.org/10.21123/bsj.13.1.122-132.

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This work includes synthesis of new six membered heterocyclic rings with effective amino group using the reaction of benzylideneacetophenone (chalcone) (1) with thiourea or urea in alcoholic basic medium to form: 1,3-thiazen-2-amine (2), and 1,3-oxazin-2-amine (8) respectively. The diazotization reaction was carried out with sodium nitrite in presence of hydrochloric acid to form diazonium salts which suffered coupling reaction with naphthols and phenols in the presence of sodium hydroxide to form colored azo dyes (4-7, and 10-13). o-methylation reaction of compounds (7) and (10) yielded : 1,3

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16

Su, Shikuan, Jie Hu, Yongmei Cui, Chongrong Tang, Yali Chen, and Jian Li. "A formal (5+1) annulation reaction from heterodimerization of two different isocyanides: stereoselective synthesis of 2H-benzo[b][1,4]oxazin-2-one." Chemical Communications 55, no. 81 (2019): 12243–46. http://dx.doi.org/10.1039/c9cc06678k.

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A novel (5+1) annulation reaction of functionalized 2-isocyanophenyloxyacrylate and aromatic, aliphatic isocyanides has been disclosed. This strategy allows for a quick access to many 2H-benzo[b][1,4]oxazin-2-one derivatives.

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17

Pandey, Garima, and Sanjay Batra. "Microwave-assisted palladium-catalysed isonitrile insertion in 2-bromophenylureas for efficient synthesis of 4-substituted imino 4H-benzo[d][1,3]oxazin-2-amines." RSC Advances 5, no. 37 (2015): 28875–78. http://dx.doi.org/10.1039/c5ra03062e.

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The palladium-catalysed isonitrile insertion in 2-bromophenylureas leads to the formation of 4-substituted imino 4H-benzo[d][1,3]oxazin-2-amines via C–O cross coupling reaction of the intermediate imidoylpalladium species.

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18

Chen, Ziyi, Xuguang Yin, Xiu-Qin Dong, and Xumu Zhang. "Efficient access to chiral dihydrobenzoxazinones via Rh-catalyzed hydrogenation." RSC Advances 9, no. 27 (2019): 15466–69. http://dx.doi.org/10.1039/c9ra02694k.

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Rh/(S)-DTBM-SegPhos-catalyzed asymmetric hydrogenation of prochiral (Z)-2-(2-oxo-2H-benzo[b][1,4]oxazin-3(4H)-ylidene)acetate esters was successfully developed to prepare various chiral dihydrobenzoxazinones with good to excellent results.

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19

Pandey, Garima, and Sanjay Batra. "Correction: Microwave-assisted palladium-catalysed isonitrile insertion in 2-bromophenylureas for efficient synthesis of 4-substituted imino 4H-benzo[d][1,3]oxazin-2-amines." RSC Advances 5, no. 38 (2015): 30022. http://dx.doi.org/10.1039/c5ra90031j.

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Correction for ‘Microwave-assisted palladium-catalysed isonitrile insertion in 2-bromophenylureas for efficient synthesis of 4-substituted imino 4H-benzo[d][1,3]oxazin-2-amines’ by Garima Pandey et al., RSC Adv., 2015, 5, 28875–28878.

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20

Thorimbert, Serge, Candice Botuha, and Kevin Passador. "‘Heteroaromatic Rings of the Future’: Exploration of Unconquered Chemical Space." Synthesis 51, no. 02 (2018): 384–98. http://dx.doi.org/10.1055/s-0037-1611279.

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William Pitt and co-workers have created a virtual exploratory heterocyclic library ‘VEHICLe’ containing over 200 unconquered bicyclic heteroaromatic rings, synthetically feasible with potential medicinal interest. Since the publication of the 22 ‘heteroaromatic rings of the future’ by Pitt in 2009, 15 of them have been successfully synthesized as bicyclic or polycyclic forms and evaluated for applications in both biology and material science. This short review presents the critical synthesis associated with innovative synthetic methodologies of the synthetically conquered ring scaffolds from

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21

Alcaide, Benito, Pedro Almendros, M. Teresa Quirós, and Israel Fernández. "Gold-catalyzed oxycyclization of allenic carbamates: expeditious synthesis of 1,3-oxazin-2-ones." Beilstein Journal of Organic Chemistry 9 (April 26, 2013): 818–26. http://dx.doi.org/10.3762/bjoc.9.93.

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A combined experimental and computational study on regioselective gold-catalyzed synthetic routes to 1,3-oxazinan-2-ones (kinetically controlled products) and 1,3-oxazin-2-one derivatives (thermodynamically favored) from easily accessible allenic carbamates has been carried out.

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22

Naidu, Shivaji, and Sabbasani Rajasekhara Reddy. "Copper-catalyzed tandem reaction in ionic liquid: an efficient reusable catalyst and solvent media for the synthesis of fused poly hetero cyclic compounds." RSC Advances 6, no. 67 (2016): 62742–46. http://dx.doi.org/10.1039/c6ra13712a.

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Herein we report a copper catalyzed tandem reaction for the therapeutically important pyrrolo-/pyrido[2,1-b] benzo[d][1,3]oxazin-1-ones using 2-aminobezyl alcohols, green solvent medium, alkynoic acids, under ligand and base free conditions.

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23

Lauro, Figueroa-Valverde, Díaz-Cedillo Francisco, Rosas-Nexticapa Marcela, et al. "Design and Synthesis of Two Oxazine Derivatives Using Several Strategies." Journal of Chemistry 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/757953.

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Several oxazine derivatives have been synthesized; nevertheless, expensive reagents and special conditions are required. Therefore, in this study, two oxazine derivatives (2-chloro-3-{{2-[-(3-chloro-2-oxo-cyclobutyl)-(2,3-dimethoxy-9,10-dihydrostrychnid-10-yl)-amino]-ethyl}-[1,5-dimethyl-4-(1H-naphtho[1,2-e][1,3-oxazin-2-yl)-2-phenyl-2,3-dihydro-1H-pyrazol-3-yl]-amino}-cyclobutanone and 2-chloro-3-{{2-[(3-chloro-2-oxo-cyclobutyl)-(1,7,7-trimethyl-bicyclo[2.2.1]hept-2-yl)-amino]-ethyl}-[1,5-dimethyl-4-(1H-naphtho[1,2-e][1,3]oxazin-2-yl)-2-phenyl-2,3-dihydro-1H-pyrazol-3-yl]-amino}-cyclobutanone

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24

Yang, Zhanhui, Siqi Li, Zhong Zhang, and Jiaxi Xu. "Base-switched annuloselectivity in the reactions of ethyl malonyl chloride and imines." Org. Biomol. Chem. 12, no. 48 (2014): 9822–30. http://dx.doi.org/10.1039/c4ob01454e.

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The [2 + 2] and [2 + 2 + 2] annuloselectivity in the reactions of ethyl malonyl chloride with imines was controlled by different bases, providing a simple synthesis of β-lactam-3-carboxylates and 2,3-dihydro-1,3-oxazin-4-ones.

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25

Lin, Ching Hsuan, Yu-Chun Chou, Meng Wei Wang, and Ru Jong Jeng. "A study on the co-reaction of benzoxazine and triazine through a triazine-containing benzoxazine." RSC Advances 6, no. 21 (2016): 17539–45. http://dx.doi.org/10.1039/c5ra23760b.

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To study the co-reaction of benzoxazine and triazine, a triazine-containing benzoxazine (P-tta) was prepared through nucleophilic substitution of 4-(2H-benzo[e][1,3]oxazin-3(4H)-yl)phenol (P-ap) with 2,4,6-trichloro-1,3,5-triazine.

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26

Kumar, Sumit, and Naseem Ahmed. "A facile approach for the synthesis of novel 1-oxa- and 1-aza-flavonyl-4-methyl-1H-benzo[d][1,3]oxazin-2(4H)-ones by microwave enhanced Suzuki–Miyaura coupling using bidentate chromen-4-one-based Pd(ii)–diimine complex as catalyst." RSC Advances 5, no. 94 (2015): 77075–87. http://dx.doi.org/10.1039/c5ra15274g.

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A facile access to novel 1-oxa- and 1-aza-flavonyl-4-methyl-1H-benzo[d][1,3]oxazin-2(4H)-ones using microwave assisted Suzuki coupling of bromo flavones with boronic acids using a novel catalytic system (C) under aerobic condition is reported.

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27

Singh, Ambrish, K. R. Ansari, M. A. Quraishi, Savas Kaya, and Priyabrata Banerjee. "The effect of an N-heterocyclic compound on corrosion inhibition of J55 steel in sweet corrosive medium." New Journal of Chemistry 43, no. 16 (2019): 6303–13. http://dx.doi.org/10.1039/c9nj00356h.

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The corrosion inhibition behavior of a naphthoxazinone derivative 1-phenyl-1,2-dihydronaphtho[1,2-e][1,3]oxazin-3-one (PNO) on J55 steel in 3.5 wt% NaCl solution saturated with carbon dioxide was evaluated using weight loss, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization.

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28

Wang, Yu-Chao, Keke Huang, Xiaojing Lai, Zhongning Shi, Jin-Biao Liu, and Guanyinsheng Qiu. "Radical bromination-induced ipso cyclization–ortho cyclization sequence of N-hydroxylethyl-N-arylpropiolamides." Organic & Biomolecular Chemistry 19, no. 9 (2021): 1940–44. http://dx.doi.org/10.1039/d1ob00010a.

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A facile procedure is reported for the synthesis of various 2-bromo-1-phenyl-5,6-dihydro-3H,7aH-benzo[b]pyrrolo[2,1-c][1,4]oxazin-3-ones via a brominative spiro-tricyclization of N-arylpropiolamides in the presence of TBAB and oxone.

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29

Mukerjee, Arya K., Gangadhar J. Sanjayan, and Krishnan Ravikumar. "Reaction of methylphthalimidoketene with benzylidene- and cinnamylideneanilines: structure and configuration of the products." Canadian Journal of Chemistry 73, no. 4 (1995): 614–17. http://dx.doi.org/10.1139/v95-079.

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Methylphthalimidoketene reacts with cinnamylideneanilines to give tetrahydrooxazin-6-ones exclusively, whereas with benzylideneaniline it also forms β-lactam. Configurations are based on X-ray studies. Keywords: β-lactam, tetrahydro-1,3-oxazin-5-ones, ketene–imine reactions, cycloaddition of methylphthalimidoketene, 3-phthaloylamino-3-methylazetidin-2-one.

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30

Ravikumar, Krishnan, Balasubramanian Sridhar, Jagadeesh Babu Nanubolu, Venkatasubramanian Hariharakrishnan, and Awadesh Narain Singh. "Structures of benzoxazine-fused triazoles as potential diuretic agents." Acta Crystallographica Section C Crystal Structure Communications 68, no. 8 (2012): o302—o307. http://dx.doi.org/10.1107/s0108270112029800.

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6,8-Dinitro-2,4-dihydro-1H-benzo[b][1,2,4]triazolo[4,3-d][1,4]oxazin-1-one, C9H5N5O6, (I), a potential diuretic, and its acetylacetone derivative (E)-2-(2-hydroxy-4-oxopent-2-en-3-yl)-6,8-dinitro-2,4-dihydro-1H-benzo[b][1,2,4]triazolo[4,3-d][1,4]oxazin-1-one, C14H11N5O8, (II), both crystallize from methanol but in centrosymmetric and noncentrosymmetric space groups, respectively. To the best of our knowledge, this is the first report of crystal structures of benzoxazine–triazole fused systems. The acetylacetone group in (II) exists as the keto–enol tautomer and is oriented perpendicular to the

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31

Xie, Yuanyuan, and Suping Wang. "PhI(OAc)2-Mediated One-Pot Synthesis of Benzoxazinones from Anthranilic Acids and Aromatic Aldehydes." Journal of Chemical Research 36, no. 3 (2012): 123–26. http://dx.doi.org/10.3184/174751912x13285455672357.

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A novel way to synthesise 2-aryl-4H-benzo[d][1,3]oxazin-4-ones has been developed by the cyclisation of Schiff bases with (diacetoxyiodo)benzene. The salient features of this new protocol which starts from an anthranilic acid and an aromatic aldehyde, are short reaction time, mild reaction conditions and good yields.

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32

Taskaya, Sultan, Nurettin Menges, and Metin Balci. "Gold-catalyzed formation of pyrrolo- and indolo-oxazin-1-one derivatives: The key structure of some marine natural products." Beilstein Journal of Organic Chemistry 11 (May 28, 2015): 897–905. http://dx.doi.org/10.3762/bjoc.11.101.

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Various N-propargylpyrrole and indolecarboxylic acids were efficiently converted into 3,4-dihydropyrrolo- and indolo-oxazin-1-one derivatives by a gold(III)-catalyzed cyclization reaction. Some of the products underwent TFA-catalyzed double bond isomerization and some did not. Cyclization reactions in the presence of alcohol catalyzed by Au(I) resulted in the formation of hemiacetals after cascade reactions.

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33

Sruthi, V., M. Visalakshi, T. Rambabu, et al. "Greener One-pot Synthesis of Chromeno Oxazin and Oxazin Quinoline Derivatives and their Antibacterial Activity." International Journal of Advanced Engineering Research and Science 4, no. 5 (2017): 147–51. http://dx.doi.org/10.22161/ijaers.4.5.23.

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34

Best, WM, RFC Brown, PD Tiso, and KG Watson. "The Synthesis of Cyclohexane-1,3-diones Bearing an Isoxazoline or a Dihydro-1,2-oxazine Ring at C2." Australian Journal of Chemistry 43, no. 2 (1990): 427. http://dx.doi.org/10.1071/ch9900427.

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Dimedone (6) was C-acylated with 4-(1′-methylethylideneaminooxy) butanoic acid (7), and the product (8) was hydrolysed to give 2-(5′,6′-dihydro-4′H-1′,2′-oxazin-3′-yl)- 5,5-dimethylcyclohexane-1,3-dione (3). The 2-(4′,5′-dihydroisoxazol-3′-yl) 1,3-dione (4) was obtained in <2% yield from dimedone anion and 3-nitro-2-isoxazoline (11).

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35

Enders, Dieter, Qiang Liu, Xiang-Yu Chen, Sun Li, Fabrizio Vetica та Gerhard Raabe. "Two-Step Synthesis of α,β-Unsaturated γ-Amino Acid Esters via N-Heterocyclic Carbene Catalyzed [4+2] Cycloaddition of Enals and Nitroso Compounds". Synthesis 50, № 01 (2017): 127–33. http://dx.doi.org/10.1055/s-0036-1590901.

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An efficient strategy for the synthesis of various of α,β-unsaturated γ-amino acid esters has been established employing N-heterocyclic carbene catalyzed [4+2] cycloadditions of β-methyl enals and aromatic nitroso compounds to afford 1,2-oxazin-6-ones in good yields. A subsequent acid-catalyzed esterification under ring opening yields the γ-amino enoates in good yields.

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36

Osarumwense, Peter O. "Analgesic activity of newly synthesized 7-chloro–2–methyl-4H–benzo[d] [1,3]–oxazin–4–one and 3–amino-7-chloro-2–methyl-quinazolin-4(3H)–one." Ovidius University Annals of Chemistry 29, no. 1 (2018): 25–28. http://dx.doi.org/10.2478/auoc-2018-0003.

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Abstract The current study is aimed at the analgesic evaluation of quinazolinone derivatives. The quinazolinone derivatives 7-chloro-2-methyl-4H-benzo[d][1,3]-oxazin-4-one and 3-amino-7-chloro-2-methyl-quinazolin-4(3H)-one were evaluated pharmacologically for their in vivo analgesic activities by acetic acid induced writhing in mice. The compounds exhibited significant analgesic activity in the range of 74.67 - 83.80% in comparison to control.

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37

Nikitin, Kirill V., та Nonna P. Andryukhova. "Cyclization of 2-(2-bromoethoxy)-acetophenones and 5-(ω-haloalkoxy)-1,5-dihydro-2H-pyrrol-2-ones Formation of five- to eight-membered oxygen-containing heterocycles via intramolecular alkylation". Canadian Journal of Chemistry 82, № 5 (2004): 571–78. http://dx.doi.org/10.1139/v04-011.

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Under basic conditions (lithium diisopropylamide or sodium hydride in THF) 2-(2-bromoethoxy)-acetophenones were transformed to 3,4-dihydro[1]benzoxepin-5(2H)-ones (homochromanones) in high yields. The preparation of novel tetrahydropyrano[2,3-b]pyrrol-6(2H)-ones and 3,4-dihydro-2H-pyrrolo[2,1-b][1,3]oxazin-6(8aH)-ones and spiro compounds was performed using similar cyclization in moderate to good yields.Key words: cyclization, lithiation, spiro heterocycles.

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38

Żesławska, Ewa, Anna Jakubowska, and Wojciech Nitek. "Conformational study of the 3,6-dihydro-2H-1,4-oxazin-2-one fragment in 8-tert-butyl-7-methoxy-8-methyl-9-oxa-6-azaspiro[4.5]decane-2,10-dione stereoisomers." Acta Crystallographica Section C Structural Chemistry 73, no. 7 (2017): 556–62. http://dx.doi.org/10.1107/s2053229617009068.

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Unnatural cyclic α-amino acids play an important role in the search for biologically active compounds and macromolecules. Enantiomers of natural amino acids with a D configuration are not naturally encoded, but can be chemically synthesized. The crystal structures of two enantiomers obtained by a method of stereoselective synthesis, namely (5R,8S)-8-tert-butyl-7-methoxy-8-methyl-9-oxa-6-azaspiro[4.5]decane-2,10-dione, (1), and (5S,8R)-8-tert-butyl-7-methoxy-8-methyl-9-oxa-6-azaspiro[4.5]decane-2,10-dione, (2), both C14H21NO4, were determined by X-ray diffraction. Both enantiomers crystallize i

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39

Mahmoud, Naglaa F. H., Eman A. El-Bordany, and Galal A. Elsayed. "Synthesis and Pharmacological Activities of Pyrano[2,3-d]pyrimidine and Pyrano[2,3-d]pyrimidine-5-one Derivatives as New Fused Heterocyclic Systems." Journal of Chemistry 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/5373049.

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Various fused oxazine such as 4-(4-methoxyphenyl)-3,7-dimethyl-1,4-dihydro-5H-pyrazolo [4′,3′:5,6]pyrano[2,3-d][1,3]oxazin-5-one2has been prepared and utilized as a starting material for novel pyrazolopyranopyrimidinones3,5,6, and7a–cand pyrazolopyranopyrimidines4,9,10, and11which are expected to possess considerable chemical and pharmacological activities. The structures of the new compounds have been elucidated by spectroscopic data and elemental analysis. The antioxidant and anticancer activities of synthesized products have been evaluated.

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40

Matsuo, Jun-ichi, Yusuke Shima, Emiko Igarashi, and Tomoyuki Yoshimura. "Reactions of Nitrosobenzenes with Cyclobutanones by Activation with a Lewis Acid." Synlett 29, no. 06 (2017): 723–26. http://dx.doi.org/10.1055/s-0036-1588469.

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Formal [4+2] cycloaddition between 3-ethoxy-2-alkylcyclobutanones and nitrosobenzene proceeded by activation with Me3SiOTf to afford 6-alkyl-2-phenyl-2H-1,2-oxazin-5(6H)-one by regioselective cleavage of the more substituted C2–C3 bond of the cyclobutanone ring. On the other hand, reactions of 3-phenylcyclobutanones and 2-benzyloxycyclobutanone with nitrosobenzene gave γ,δ-unsaturated and cyclic hydroxamic acid derivatives, respectively, by cleavage of a cyclobutanone C1–C2 bond.

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41

Reinus, Brandon, and Sean Kerwin. "A Copper-Catalyzed N-Alkynylation Route to 2-Substituted N-Alkynyl Pyrroles and Their Cyclization into Pyrrolo[2,1-c]oxazin-1-ones: A Formal Total Synthesis of Peramine." Synthesis 49, no. 11 (2017): 2544–54. http://dx.doi.org/10.1055/s-0036-1588736.

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Screening of a variety of ligands and reaction conditions for the copper-catalyzed cross-coupling of alkynyl bromides with pyrroles, reveals that the use of the phenanthroline ligand 4,7-dimethoxy-1,10-phenanthroline affords a range of ynpyrroles in good to moderate yields. Furthermore, the utility of these ynpyrroles is demonstrated in the preparation of a series of pyrrolo[2,1-c][1,4]oxazin-1-ones and a formal total synthesis of the pyrrole natural product peramine.

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42

Guo, Yong En, Xiao Guang Niu, Cai Ju Zhou, Jie Chu, Wei Wei Xu, and Guo Zhen Fang. "Design and Preparation of 1H-3, 4-Dihydropyrrolo[1,2-a] Pyrazin-1-One via 1H-3,4-Dihydropyrrolo[1,2-C] [1,4] Oxazin-1-One Route." Advanced Materials Research 343-344 (September 2011): 1242–47. http://dx.doi.org/10.4028/www.scientific.net/amr.343-344.1242.

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With 2-pyrrolyltrichloroacetone as major starting material, unreported 1H-3,4-dihydropyrrolo- [1,2-a]pyrazin-1-one was prepared successively by its monoesterification with ethylene glycol, bromine displacement of hydroxy group, cyclization to lactone and its amidation. Unreported 7-aroyl-1H-3,4-dihydropyrrolo[1,2-c][1,4]oxazin-1-one compounds were also synthesized in turn by 2-pyrrolyl-trichloroacetone’s Friedel-Crafts acylation and cyclization. Their structures were characterized by IR, 1H NMR, 13C NMR, MS, HRMS, etc.

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43

Oleshchuk, Alena L., Zarina T. Shulgau, Tulegen M. Seilkhanov, Alexey S. Vasilchenko, Samat A. Talipov, and Ivan V. Kulakov. "Synthesis and Biological Activity of 4-(Pyridin-3-yl)-2-hydroxy-4-oxobut-2-enoic Acid Derivatives." Synlett 31, no. 02 (2019): 165–70. http://dx.doi.org/10.1055/s-0037-1610738.

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Claisen condensation reaction of diethyl oxalate with 1-[4-(furan-2-yl)-2-methyl-5-nitro-6-phenylpyridin-3-yl]ethan-1-one afforded (Z)-4-[4-(furan-2-yl)-2-methyl-5-nitro-6-phenylpyridin-3-yl]-2-hydroxy-4-oxobut-2-enoic acid. The latter reacted with various binucleophiles to form the corresponding 3,4-dihydroquinoxaline-2(1H)-one, 3,4-dihydro-2H-benzo[b][1,4]oxazin-2-one, and 1H-pyrazole derivatives. Biological screening of the obtained compounds revealed analgesic and antibacterial activity.

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44

Patel, Harun, Rahul Pawara, and Sanjay Surana. "Resolving the Mystery of Ring Opening in the Synthesis of Benzo[d][1, 3]oxazin-4-one and Quinazolin-4(3H)-one." Letters in Organic Chemistry 16, no. 11 (2019): 898–905. http://dx.doi.org/10.2174/1570178616666181217114030.

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Quinazoline is the six-membered heterocyclic ring system reported for its versatile biological activities. This characteristic feature of quinazoline makes it a good template for a lead generation library. Ring opening is one of the major concerns in the synthesis of quinazolin-4(3H)-one that results in diamide formation. Here, alternative fusion strategy is reported, which is a time-saving and costeffective method to overcome the ring opening problem associated with the synthesis of benzo[ d][1,3]oxazin-4-one and quinazolin-4(3H)-one.

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45

Dyall, LK. "Mass-Spectra of Annelated 4H-3,1-Oxazin-4-ones." Australian Journal of Chemistry 42, no. 10 (1989): 1813. http://dx.doi.org/10.1071/ch9891813.

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Electron-impact fragmentation of 2-R-4H-3,1-benzoxazin-4-ones involves primary losses of CO2 and R; there is also loss of ketene when R is methyl. The ion RCO+ is a major daughter. Successive losses of CO2and RCN yield an ion m/z 76 formulated as dehydrobenzene radical cation. In the case of 2-methyl-4H-3,1-naphth[2,3-d]oxazin-4-one, the 2,3-dehydronaphthalene ion is produced efficiently, and linked scans (B/E) were used to demonstrate that it loses C4H2 ( diacetylene ) in a retro Diels-Alder reaction.

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46

Monnier, Karin, Gérard Schmitt, Bernard Laude, Marie-France Mercier, Marek M. Kubicki, and Michel Jannin. "Étude de la stéréochimie de la réaction de cycloaddition dipolaire-1,3 de quelques 5-phényl-3,6-dihydro-2H-1,4-oxazin-2-ones avec les N-méthyl et N-phénylmaléimides." Canadian Journal of Chemistry 73, no. 2 (1995): 181–90. http://dx.doi.org/10.1139/v95-027.

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Six derivatives of 5-phenyl-3,4-dihydro-2H-1,4-oxazin-2-ones 1 were synthetized from α-amino acids. These compounds are precursors of six-membered cyclic azomethine ylids involving one stereocenter. The 1,3-dipolar species react with N-methyl and N-phenylmaleimides, leading diastereospecifically to cycloadducts where the approach of the dipolarophile occurs from the less hindered side of the 1,3-dipole and with the maleimido moiety in an exo position. Unfortunately, racemization was observed during the cycloaddition reaction, presumably owing to reversible imine–enamine transformation. Keyword

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47

Beccalli, Egle M., Tiziana Benincori, and Alessandro Marchesini. "1,3-Oxazin-6-ones from 5(2H)-Isoxazolones." Synthesis 1988, no. 08 (1988): 630–31. http://dx.doi.org/10.1055/s-1988-27660.

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48

Nizovtsev, Alexey V., and Mikhail S. Baranov. "Synthesis of 6H-1,2-oxazin-6-ones (microreview)." Chemistry of Heterocyclic Compounds 56, no. 10 (2020): 1280–82. http://dx.doi.org/10.1007/s10593-020-02811-4.

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49

Shustov, Gennady V., Melanie K. Chandler, and Saul Wolfe. "Stereoselective synthesis of multiply substituted [1,2]oxazinan-3-ones via ring-closing metathesis." Canadian Journal of Chemistry 83, no. 2 (2005): 93–103. http://dx.doi.org/10.1139/v04-174.

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The title compounds are α-amino acids whose nitrogen atoms are enclosed within 4,5-disubstituted, six-membered cyclic hydroxamates and they are of interest as potential β-lactam surrogates. The compounds have been synthesized in the present work by functionalization of the double bonds of N-substituted 6H-[1,2]oxazin-3-ones, which are obtained upon successive reaction of the triflates of S-α-hydroxy esters with O-allylhydroxylamine and acryloyl chloride, followed by cyclization of the resulting R-α-N-acryloyl-N-allyloxyamino esters in the presence of the ring-closing metathesis (RCM) catalyst

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50

da Silva, Amanda, Alessandra Fernandes, Samuel Thurow, Mateus Stivanin, and Igor Jurberg. "Isoxazol-5-ones as Strategic Building Blocks in Organic Synthesis." Synthesis 50, no. 13 (2018): 2473–89. http://dx.doi.org/10.1055/s-0036-1589534.

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Isoxazol-5-one rings have been identified as relevant motifs in drug candidates, agrochemicals, and materials. Furthermore, this heterocycle has been also applied as a versatile building block for the preparation of a variety of densely functionalized molecules. This short review will present the most representative applications of isoxazol-5-ones in organic synthesis while discussing their properties and reactivity.1 Introduction1.1 General Aspects1.1.1 Tautomerism1.1.2 Importance: Natural Products Isolation, Biological Activity, and Materials1.1.3 Preparation Methods2 Isoxazol-5-ones in Orga

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