User menu

Biologically active γ-lactams: synthesis and natural sources

Bibliographic reference Caruano, Joséphine ; Muccioli, Giulio ; Robiette, Raphaël. Biologically active γ-lactams: synthesis and natural sources. In: Organic & Biomolecular Chemistry, Vol. 14, no.43, p. 10134-10156 (2016)
Permanent URL
  1. Baldwin Jack E, Lowe Christopher, Schofield Christopher J, Lee Eun, A γ-lactam analogue of penems possessing antibacterial activity, 10.1016/s0040-4039(00)84822-4
  2. Boyd Donald B, Elzey Thomas K, Hatfield Lowell D, Kinnick Michael D, Morin John M, γ-Lactam analogues of the penems, 10.1016/s0040-4039(00)84820-0
  3. Boyd D.B, Foster B.J, Hatfield L.D, Hornback W.J, Jones N.D, Munroe J.E, Swartzendruber J.K, γ-Lactam analogues of carbapenems, 10.1016/s0040-4039(00)84821-2
  4. Wasserman Harry H., Precopio Frank M., Liu Tien-Chuan, Studies on the Mucohalic Acids. II. The Synthesis of Fused α-Lactam-thiazolidines Related to Penicillin1, 10.1021/ja01136a038
  5. V. Du Vignaud and H. F.Carpenter, in The Chemistry of Penicillin, Princeton University Press, Princeton, 1949, vol. XXVII, pp. 1004–1017
  6. Baldwin Jack E., Chan Ming Fai, Gallacher Gerard, Monk Peter, Prout Keith, γ-Lactam analogues of penicillanic and carbapenicillanic acids, 10.1039/c39830000250
  7. Baldwin Jack E., Chan Ming Fai, Gallacher Gerard, Otsuka Masami, Monk Peter, Prout Keith, γ-Lactam analogues of penicillanic and carbapenicillanic acids, 10.1016/s0040-4020(01)98828-3
  8. Baldwin Jack E., Adlington Robert M., Jones Richard H., Schofield Christopher J., Zarocostas Constantine, Greengrass Colin W., γ-Lactam analogues of carbapenicillanic acids, 10.1039/c39850000194
  9. Baldwin Jack E., Adlington Robert M., Jones Richard H., Schofield Christopher J., Zaracostas Constantine, Greengrass Colin W., γ-Lactam analogues of carbapenicillanic acids, 10.1016/s0040-4020(01)82070-6
  10. J. E. Baldwin , G. P.Lynch and J.Pitlik, in The Journal of Antibiotics, 1991, vol. 44, pp. 1–24
  11. Allen Norris E., Boyd Donald B., Campbell Jack B., Deeter Jack B., Elzey Thomas K., Foster Bennie J., Hatfield Lowell D., Hobbs Joseph N., Hornback William J., Hunden David C., Jones Noel D., Kinnick Michael D., Morin John M., Munroe John E., Swartzendruber John K., Vogt David G., Molecular modeling of γ-lactam analogues of β-lactam antibacterial agents: synthesis and biological evaluation of selected penem and carbapenem analoques, 10.1016/s0040-4020(01)80055-7
  12. M. B. Smith , in Three carbon-heteroatom bonds: Amides and derivatives; Peptides; Lactams, ed. G. T. Verlag, 2005, vol. 21, pp. 647–711
  13. Janecka, Drug Discovery Today, 17, 561 (2012)
  14. Albrecht Anna, Albrecht Łukasz, Janecki Tomasz, Recent Advances in the Synthesis of α-Alkylidene-Substituted δ-Lactones, γ-Lactams and δ-Lactams, 10.1002/ejoc.201001486
  15. Nay, Nat. Prod. Rep., 26, 1044 (2009)
  16. Royles, Chem. Rev., 95, 1981 (1995)
  17. Galeazzi, Targets Heterocycl. Syst., 1, 355 (1997)
  18. P.-Q. Huang , in New Methods for the Asymmetric Synthesis of Nitrogen Heterocycles, Research Signpost, Trivandrum, India, 2005, pp. 197–222
  19. Lebedev A., Preparation of chiral 4-substituted γ-lactams and the corresponding γ-aminobutyric acids. (Review), 10.1007/s10593-007-0110-1
  20. Feray, Targets Heterocycl. Syst., 12, 31 (2008)
  21. Ye, Org. Biomol. Chem., 12, 1833 (2014)
  22. Martelli Gianluca, Orena Mario, Rinaldi Samuele, Recent Advances in Chemistry of γ-Lactams: Part I. Synthesis Starting from Acyclic or Cyclic Precursors, 10.2174/1385272819666140407212959
  23. Martelli Gianluca, Monsignori Antonella, Orena Mario, Rinaldi Samuele, Recent Advances in Chemistry of γ-Lactams: Part II. Functionalization by C-C or CHeteroatom Bond Formation, 10.2174/1385272819666140407213209
  24. Akhilesh Kumar, Curr. Sci., 102, 288 (2012)
  25. IKOTA Nobuo, Stereoselective Synthesis of (+)-1,8-Di-epi- and (-)-1-epi-Swainsonine from an (S)-Pyroglutamic Acid Derivative., 10.1248/cpb.41.1717
  26. Nájera Carmen, Yus Miguel, Pyroglutamic acid: a versatile building block in asymmetric synthesis, 10.1016/s0957-4166(99)00213-x
  27. Machwate, Mol. Pharmacol., 60, 36 (2001)
  28. Riether Doris, Zindell Renee, Wu Lifen, Betageri Raj, Jenkins James E., Khor Someina, Berry Angela K., Hickey Eugene R., Ermann Monika, Albrecht Claudia, Ceci Angelo, Gemkow Mark J., Nagaraja Nelamangala V., Romig Helmut, Sauer Achim, Thomson David S., Selective CB2 receptor agonists. Part 2: Structure–activity relationship studies and optimization of proline-based compounds, 10.1016/j.bmcl.2014.12.019
  29. Giannini Giuseppe, Battistuzzi Gianfranco, Vignola Davide, Hydroxamic acid based histone deacetylase inhibitors with confirmed activity against the malaria parasite, 10.1016/j.bmcl.2014.12.051
  30. Lunsford Carl D., Cale Albert D., Ward John W., Franko Bernard V., Jenkins Herndon, 4-(β-Substituted ethyl)-3,3-diphenyl-2-pyrrolidinones. A New Series of CNS Stimulants1, 10.1021/jm00333a012
  31. Yost C. Spencer, A New Look at the Respiratory Stimulant Doxapram, 10.1111/j.1527-3458.2006.00236.x
  32. Barrett Anthony G. M., Head John, Smith Marie L., Stock Nicholas S., White A. J. P., Williams D. J., Fleming−Tamao Oxidation and Masked Hydroxyl Functionality:  Total Synthesis of (+)-Pramanicin and Structural Elucidation of the Antifungal Natural Product (−)-Pramanicin, 10.1021/jo9905672
  33. Schwartz Robert E., Helms Gregory L., Bolessa Evon A., Wilson Kenneth E., Giacobbe Robert A., Tkacz Jan S., Bills Gerald F., Liesch Jerrold M., Zink Deborah L., Curotto James E., Pramanik Barnali, Onishi Janet C., Pramanicin, a novel antimicrobial agent from a fungal fermentation, 10.1016/s0040-4020(01)80843-7
  34. Andrés José M., de Elena Noemı́, Pedrosa Rafael, Pérez-Encabo Alfonso, Stereoselective synthesis of (5S,6S)- and (5S,6R)-aza-muricatacin from an l-glutamic acid derivative, 10.1016/s0957-4166(01)00251-8
  35. Rieser Matthew J., Kozlowski John F., Wood Karl V., McLaughlin Jerry L., Muricatacin: A simple biologically active acetogenin derivative from the seeds of annona muricata (annonaceae), 10.1016/s0040-4039(00)92027-6
  36. Shimamoto Keiko, Ishida Michiko, Shinozaki Haruhikio, Ohfune Yasufumi, Synthesis of four diastereomeric L-2-(carboxycyclopropyl)glycines. Conformationally constrained L-glutamate analogs, 10.1021/jo00013a018
  37. Robinson Ralph P., Laird Ellen R., Blake James F., Bordner Jon, Donahue Kathleen M., Lopresti-Morrow Lori L., Mitchell Peter G., Reese Matthew R., Reeves Lisa M., Stam Ethan J., Yocum Sue A., Structure-Based Design and Synthesis of a Potent Matrix Metalloproteinase-13 Inhibitor Based on a Pyrrolidinone Scaffold, 10.1021/jm0001368
  38. Krawczyk Henryk, Albrecht Łukasz, Wojciechowski Jakub, Wolf Wojciech M., Krajewska Urszula, Różalski Marek, A convenient synthesis and cytotoxic evaluation of N-unsubstituted α-methylene-γ-lactams, 10.1016/j.tet.2008.04.090
  39. Duan James J.-W., Chen Lihua, Wasserman Zelda R., Lu Zhonghui, Liu Rui-Qin, Covington Maryanne B., Qian Mingxin, Hardman Karl D., Magolda Ronald L., Newton Robert C., Christ David D., Wexler Ruth R., Decicco Carl P., Discovery of γ-Lactam Hydroxamic Acids as Selective Inhibitors of Tumor Necrosis Factor α Converting Enzyme:  Design, Synthesis, and Structure−Activity Relationships, 10.1021/jm0255670
  40. Barnes David M., Ji Jianguo, Fickes Michael G., Fitzgerald Michael A., King Steven A., Morton Howard E., Plagge Frederick A., Preskill Margo, Wagaw Seble H., Wittenberger Steven J., Zhang Ji, Development of a Catalytic Enantioselective Conjugate Addition of 1,3-Dicarbonyl Compounds to Nitroalkenes for the Synthesis of Endothelin-A AntagonistABT-546. Scope, Mechanism, and Further Application to the Synthesis of the Antidepressant Rolipram, 10.1021/ja026788y
  41. Baures Paul W., Eggleston Drake S., Erhard Karl F., Cieslinski Lenora B., Torphy Theodore J., Christensen Siegfried B., Crystal structure, absolute configuration, and phosphodiesterase inhibitory activity of (+)-1-(4-bromobenzyl)-4-[(3-cyclopentyloxy)-4-methoxyphenyl]-2-pyrrolidinone, 10.1021/jm00074a007
  42. Domingos Jorge L.O, Lima Evanoel C, Dias Ayres G, Costa Paulo R.R, Stereoselective preparation of pyrrolidin-2-ones from a Z-enoate derived from d-(+)-mannitol, 10.1016/j.tetasy.2004.06.013
  43. Nishiwaki, Yakuri to Chiryo, 20, 2847 (1992)
  44. Gouliaev Alex Haahr, Senning Alexander, Piracetam and other structurally related nootropics, 10.1016/0165-0173(94)90011-6
  45. Ikuta H., Shirota H., Kobayashi S., Yamagishi Y., Yamada K., Yamatsu I., Katayama K., Synthesis and antiinflammatory activities of 3-(3,5-di-tert-butyl-4-hydroxybenzylidene)pyrrolidin-2-ones, 10.1021/jm00394a011
  46. Kadow J.F., Vyas D.M., Doyle T.W., Synthesis of etoposide lactam via a mitsunobu reaction sequence, 10.1016/s0040-4039(00)99226-8
  47. Marchand-Brynaert Jacqueline, Couplet Blandine, Dive Georges, Ghosez Léon, New γ-lactam homologs of penems, 10.1016/s0960-894x(01)80944-6
  48. Zhang Y. Larry, Marepalli Hanumantha Rao, Lu Hui-fen, Becker Jeffrey M., Naider Fred, Synthesis, Biological Activity, and Conformational Analysis of Peptidomimetic Analogues of theSaccharomyces cerevisiaeα-Factor Tridecapeptide†, 10.1021/bi980787u
  49. Liu Di, Yu Xiaoming, Huang Liang, Novel Concise Synthesis of (−)-Clausenamide, 10.1002/cjoc.201201187
  50. Feng Zhiqiang, Li Xingzhou, Zheng Guojun, Huang Liang, Synthesis and activity in enhancing long-term potentiation (LTP) of clausenamide stereoisomers, 10.1016/j.bmcl.2009.03.018
  51. Turos Edward, Audia James E., Danishefsky Samuel J., Total synthesis of the Fusarium toxin equisetin: proof of the stereochemical relationship of the tetramate and terpenoid sectors, 10.1021/ja00203a026
  52. Corey E. J., Li Weidong, Nagamitsu Tohru, An Efficient and Concise Enantioselective Total Synthesis of Lactacystin, 10.1002/(sici)1521-3773(19980703)37:12<1676::aid-anie1676>;2-t
  53. Corey E. J., Reichard Gregory A., Total synthesis of lactacystin, 10.1021/ja00052a096
  54. Sunazuka Toshiaki, Hirose Tomoyasu, O̅mura Satoshi, Efficient Total Synthesis of Novel Bioactive Microbial Metabolites, 10.1021/ar6000044
  55. Sunazuka Toshiaki, Nagamitsu Tohru, Matsuzaki Keiichi, Tanaka Haruo, Omura Satoshi, Smith Amos B., Total synthesis of (+)-lactacystin, the first non-protein neurotrophic factor, 10.1021/ja00065a054
  56. NAITO Takeaki, HONDA Yuko, MIYATA Okiko, NINOMIYA Ichiya, Total syntheses of (.+-.)-anantine and (.+-.)-isoanantine via thiyl radical addition-cyclization reaction., 10.1248/cpb.41.217
  57. Janecka Anna, Wyrębska Anna, Gach Katarzyna, Fichna Jakub, Janecki Tomasz, Natural and synthetic α-methylenelactones and α-methylenelactams with anticancer potential, 10.1016/j.drudis.2012.01.013
  58. Qiao Lixin, Wang Shaomeng, George Clifford, Lewin Nancy E., Blumberg Peter M., Kozikowski Alan P., Structure-Based Design of a New Class of Protein Kinase C Modulators, 10.1021/ja980513u
  59. Snider Barry B., Gu Yonghong, Total Synthesis of (−)- and (+)-Dysibetaine, 10.1021/ol015954o
  60. Sakai Ryuichi, Oiwa Chie, Takaishi Kojiroh, Kamiya Hisao, Tagawa Michito, Dysibetaine: a new α,α-disubstituted α-amino acid derivative from the marine sponge Dysidea herbacea, 10.1016/s0040-4039(99)01356-8
  61. Ye Long-Wu, Shu Chao, Gagosz Fabien, Recent progress towards transition metal-catalyzed synthesis of γ-lactams, 10.1039/c3ob42181c
  62. Yoon Cheol Hwan, Nagle Advait, Chen Chiliu, Gandhi Drashti, Jung Kyung Woon, γ-Lactam Synthesis via C−H Insertion:  Elaboration ofN-Benzyl Protecting Groups for High Regioselectivity toward the Total Synthesis of Rolipram, 10.1021/ol0345834
  63. Meyers A. I., Snyder Lawrence, The synthesis of aracemic 4-substituted pyrrolidinones and 3-substituted pyrrolidines. An asymmetric synthesis of (-)-rolipram, 10.1021/jo00053a012
  64. Honda Toshio, Ishikawa Fumihiro, Kanai Kazuo, Sato Shigeki, Kato Daishiro, Tominaga Hideo, Chiral Synthesis of Phosphodiesterase Inhibitor, (R)-(-)-Rolipram, by Means of Enantioselective Deprotonation Strategy, 10.3987/com-95-s33
  65. Diaz Adolfo, Siro Jorge G., García-Navío José L., Vaquero Juan J., Alvarez-Builla Julio, A Stereoselective Synthesis of (R)-(-)-rolipram from L-Glutamic Acid, 10.1055/s-1997-3182
  66. Demnitz Joachim, LaVecchia Luigi, Bacher Edmond, Keller Thomas H., Müller Thomas, Schürch Friedrich, Weber Hans-Peter, Pombo-Villar Esteban, Enantiodivergent Synthesis of (R)- and (S)-Rolipram, 10.3390/30300107
  67. Becht, Synthesis, 2805 (2003)
  68. Hynes Peter S., Stupple Paul A., Dixon Darren J., Organocatalytic Asymmetric Total Synthesis of (R)-Rolipram and Formal Synthesis of (3S,4R)-Paroxetine, 10.1021/ol800108u
  69. Mulzer Johann, Asymmetric synthesis of the Novel Antidepressant Rolipram�, 10.1002/prac.19943360402
  70. Barluenga José, Fernández-Rodríguez Manuel A., Aguilar Enrique, Fernández-Marí Félix, Salinas Alejandro, Olano Bernardo, First Highly Regio- and Diastereoselective [3+2] Cycloaddition of Chiral Nonracemic Fischer Carbene Complexes with Azomethine Ylides: An Enantioselective Synthesis of (+)-Rolipram, 10.1002/1521-3765(20010817)7:16<3533::aid-chem3533>;2-e
  71. Lambert Tristan H., Danishefsky Samuel J., Total Synthesis of UCS1025A, 10.1021/ja0574567
  72. Agatsuma Tsutomu, Akama Tsutomu, Nara Shinji, Matsumiya Shigeki, Nakai Ryuichiro, Ogawa Harumi, Otaki Shizuo, Ikeda Shun-ichi, Saitoh Yutaka, Kanda Yutaka, UCS1025A and B, New Antitumor Antibiotics from the FungusAcremoniumSpecies, 10.1021/ol026923b
  73. Cook James H., Barzya Jeremy, Brennan Catherine, Lowe Derek, Wang Yamin, Redman Anikó, Scott William J., Wood Jill E., 4,5-Disubstituted cis-pyrrolidinones as inhibitors of 17β-hydroxysteroid dehydrogenase II. Part 1: Synthetic approach, 10.1016/j.tetlet.2005.01.003
  74. Hartwig Wolfgang, Born Liborius, Diastereoselective and enantioselective total synthesis of the hepatoprotective agent clausenamide, 10.1021/jo00228a037
  75. Gunn David, Akuche Christiana, Baryza Jeremy, Blue Marie-Louise, Brennan Catherine, Campbell Ann-Marie, Choi Soongyu, Cook James, Conrad Patricia, Dixon Brian, Dumas Jacques, Ehrlich Paul, Gane Todd, Joe Ted, Johnson Jeffrey, Jordan Jerold, Kramss Richard, Liu Peying, Levy Joan, Lowe Derek, McAlexander Ian, Natero Reina, Redman Anikó M., Scott William, Seng Thomas, Sibley Robert, Wang Ming, Wang Yamin, Wood Jill, Zhang Zhonghua, 4,5-Disubstituted cis-pyrrolidinones as inhibitors of type II 17β-hydroxysteroid dehydrogenase. Part 2. SAR, 10.1016/j.bmcl.2005.04.025
  76. Onyango Evans Otieno, Tsurumoto Joji, Imai Naoko, Takahashi Keisuke, Ishihara Jun, Hatakeyama Susumi, Total Synthesis of Neooxazolomycin, 10.1002/ange.200702229
  77. Kende Andrew S., Kawamura Kuniaki, DeVita Robert J., Enantioselective total synthesis of neooxazolomycin, 10.1021/ja00166a072
  78. Takahashi Kanji, Kawabata Michihiro, Uemura Daisuke, Iwadare Shuichi, Mitomo Ryuji, Nakano Fumio, Matsuzaki Akinori, Structure of neooxazolomycin, an antitumor antibiotic, 10.1016/s0040-4039(00)98516-2
  79. Gulder, Angew. Chem., Int. Ed., 49, 9346 (2010)
  80. Joazeiro Claudio A.P., Anderson Kenneth C., Hunter Tony, Proteasome Inhibitor Drugs on the Rise: Figure 1., 10.1158/0008-5472.can-06-2033
  81. Ma Gil, Nguyen Henry, Romo Daniel, Concise Total Synthesis of (±)-Salinosporamide A, (±)-Cinnabaramide A, and Derivatives via a Bis-cyclization Process:  Implications for a Biosynthetic Pathway?, 10.1021/ol070616u
  82. Reddy Leleti Rajender, Saravanan P., Corey E. J., A Simple Stereocontrolled Synthesis of Salinosporamide A, 10.1021/ja048613p
  83. Reddy Leleti Rajender, Fournier Jean-François, Subba Reddy B. V., Corey E. J., An Efficient, Stereocontrolled Synthesis of a Potent Omuralide−Salinosporin Hybrid for Selective Proteasome Inhibition, 10.1021/ja052376o
  84. Reddy Leleti Rajender, Fournier Jean-François, Reddy B. V. Subba, Corey E. J., New Synthetic Route for the Enantioselective Total Synthesis of Salinosporamide A and Biologically Active Analogues, 10.1021/ol0508734
  85. Kablaoui Natasha M., Buchwald Stephen L., Development of a Method for the Reductive Cyclization of Enones by a Titanium Catalyst, 10.1021/ja954192n
  86. Mandal Sunil K., Amin Sk. Rasidul, Crowe William E., γ-Butyrolactone Synthesis via Catalytic Asymmetric Cyclocarbonylation, 10.1021/ja005568m
  87. Crowe William E., Vu An T., Direct Synthesis of Fused, Bicyclic γ-Butyrolactones via Tandem Reductive Cyclization−Carbonylation of Tethered Enals and Enones, 10.1021/ja9535874
  88. Quan Long Guo, Cha Jin Kun, Reductive cyclization of enones by titanium(IV) aryloxide and a Grignard reagent, 10.1016/s0040-4039(01)01868-8
  89. Choi Eunhyun, Lee Chulho, Cho Misun, Seo Jeong Jea, Yang Jee Sun, Oh Soo Jin, Lee Kiho, Park Song-Kyu, Kim Hwan Mook, Kwon Ho Jeong, Han Gyoonhee, Property-Based Optimization of Hydroxamate-Based γ-Lactam HDAC Inhibitors to Improve Their Metabolic Stability and Pharmacokinetic Profiles, 10.1021/jm3009376
  90. Lee Chulho, Choi Eunhyun, Cho Misun, Lee Boah, Oh Soo Jin, Park Song-Kyu, Lee Kiho, Kim Hwan Mook, Han Gyoonhee, Structure and property based design, synthesis and biological evaluation of γ-lactam based HDAC inhibitors: Part II, 10.1016/j.bmcl.2012.04.045
  91. Carafa Vincenzo, Nebbioso Angela, Altucci Lucia, Histone Deacetylase Inhibitors: Recent Insights from Basic to Clinical Knowledge & Patenting of Anti-Cancer Actions, 10.2174/157489211793980088
  92. Pinza Mario, Farina Carlo, Cerri Alberto, Pfeiffer Ugo, Riccaboni Maria T., Banfi Silvano, Biagetti Raffaella, Pozzi Ottorino, Magnani Maurizio, Dorigotti Luciano, Synthesis and pharmacological activity of a series of dihydro-1H-pyrrolo[1,2-a]imidazole-2,5(3H,6H)-diones, a novel class of potent cognition enhancers, 10.1021/jm00078a011
  93. Ponzio F., Pozzi O., Banfi S., Dorigotti L., Brain Entry and Direct Central Pharmacological Effects of the Nootropic Drug Oxiracetam, 10.1055/s-2007-1014629
  94. Xi Ning, Arvedson Stephen, Eisenberg Shawn, Han Nianhe, Handley Michael, Huang Liang, Huang Qi, Kiselyov Alexander, Liu Qingyian, Lu Yuelie, Nunez Gladys, Osslund Timothy, Powers David, Tasker Andrew S., Wang Ling, Xiang Tingjian, Xu Shimin, Zhang Jiandong, Zhu Jiawang, Kendall Richard, Dominguez Celia, N-Aryl-γ-lactams as integrin αvβ3 antagonists, 10.1016/j.bmcl.2004.03.033
  95. Duong Le T., Rodan Gideon A., 10.1023/a:1010063225902
  96. Kanishchev Oleksandr S., Lavoignat Adeline, Picot Stéphane, Médebielle Maurice, Bouillon Jean-Philippe, New route to the 5-((arylthio- and heteroarylthio)methylene)-3-(2,2,2-trifluoroethyl)-furan-2(5H)-ones—Key intermediates in the synthesis of 4-aminoquinoline γ-lactams as potent antimalarial compounds, 10.1016/j.bmcl.2013.08.108
  97. Cornut Damien, Lemoine Hugues, Kanishchev Oleksandr, Okada Etsuji, Albrieux Florian, Beavogui Abdoul Habib, Bienvenu Anne-Lise, Picot Stéphane, Bouillon Jean-Philippe, Médebielle Maurice, Incorporation of a 3-(2,2,2-Trifluoroethyl)-γ-hydroxy-γ-lactam Motif in the Side Chain of 4-Aminoquinolines. Syntheses and Antimalarial Activities, 10.1021/jm301076q
  98. Mylavarapu Ravikumar, Anand Ramasamy Vijaya, Kondaiah Golla China Mala, Reddy Lekkala Amarnath, Reddy Gade Srinivas, Roy Arnab, Bhattacharya Apurba, Mukkanti Kagga, Bandichhor Rakeshwar, An alternate synthesis of levetiracetam, 10.1080/17518251003716568
  99. Abou-Khalil Bassel, Levetiracetam in the treatment of epilepsy, 10.2147/ndt.s2937
  100. Kenda Benoit M., Matagne Alain C., Talaga Patrice E., Pasau Patrick M., Differding Edmond, Lallemand Bénédicte I., Frycia Anne M., Moureau Florence G., Klitgaard Henrik V., Gillard Michel R., Fuks Bruno, Michel Philippe, Discovery of 4-Substituted Pyrrolidone Butanamides as New Agents with Significant Antiepileptic Activity, 10.1021/jm030913e
  101. Gillard Michel, Fuks Bruno, Michel Philippe, Vertongen Pascale, Massingham Roy, Chatelain Pierre, Binding characteristics of [3H]ucb 30889 to levetiracetam binding sites in rat brain, 10.1016/j.ejphar.2003.08.032
  102. Ryvlin Philippe, Werhahn Konrad J., Blaszczyk Barbara, Johnson Martin E., Lu Sarah, Adjunctive brivaracetam in adults with uncontrolled focal epilepsy: Results from a double-blind, randomized, placebo-controlled trial, 10.1111/epi.12432
  103. Kwan Patrick, Trinka Eugen, Van Paesschen Wim, Rektor Ivan, Johnson Martin E., Lu Sarah, Adjunctive brivaracetam for uncontrolled focal and generalized epilepsies: Results of a phase III, double-blind, randomized, placebo-controlled, flexible-dose trial, 10.1111/epi.12391
  104. Bantreil, Synlett, 1441 (2009)
  105. Argade Anil, Bahekar Rajesh, Desai Jigar, Thombare Pravin, Shah Kiran, Gite Sanjay, Sunder Rajesh, Ranvir Ramchandra, Bandyopadhyay Debdutta, Chakrabarti Ganes, Joharapurkar Amit, Mahapatra Jogeswar, Chatterjee Abhijit, Patel Harilal, Shaikh Mubeen, Sairam Kalapatapu V. V. M., Jain Mukul, Patel Pankaj, Design, synthesis and biological evaluation of γ-lactam hydroxamate based TACE inhibitors, 10.1039/c0md00261e
  106. Musonda Chitalu C., Gut Jiri, Rosenthal Philip J., Yardley Vanessa, Carvalho de Souza Renata C., Chibale Kelly, Application of multicomponent reactions to antimalarial drug discovery. Part 2: New antiplasmodial and antitrypanosomal 4-aminoquinoline γ- and δ-lactams via a ‘catch and release’ protocol, 10.1016/j.bmc.2006.04.035
  107. Ley Steven V., Baxendale Ian R., Bream Robert N., Jackson Philip S., Leach Andrew G., Longbottom Deborah A., Nesi Marcella, Scott James S., Storer R. Ian, Taylor Stephen J., Multi-step organic synthesis using solid-supported reagents and scavengers: a new paradigm in chemical library generation, 10.1039/b006588i
  108. Aicher Thomas D., Balkan Bork, Bell Philip A., Brand Leonard J., Cheon S. H., Deems Rhonda O., Fell Jay B., Fillers William S., Fraser James D., Gao Jiaping, Knorr Douglas C., Kahle Gerald G., Leone Christina L., Nadelson Jeffrey, Simpson Ronald, Smith Howard C., Substituted Tetrahydropyrrolo[2,1-b]oxazol-5(6H)-ones and Tetrahydropyrrolo[2,1-b]thiazol-5(6H)-ones as Hypoglycemic Agents1, 10.1021/jm9803121
  109. Fishwick Colin W.G., Foster Richard J., Carr Robin E., A short dipolar cycloaddition approach to γ-lactam alkaloids from cynometra hankei, 10.1016/0040-4039(96)00688-0
  110. Waterman Peter G., Faulkner Dalton F., Imidazole alkaloids from Cynometra hankei, 10.1016/0031-9422(81)85283-1
  111. Gao Shuanhu, Tu Yong Qiang, Hu Xiangdong, Wang Shaohua, Hua Rongbao, Jiang Yijun, Zhao Yuming, Fan Xiaohui, Zhang Shuyu, General and Efficient Strategy for Erythrinan and Homoerythrinan Alkaloids:  Syntheses of (±)-3-Demethoxyerythratidinone and (±)-Erysotramidine, 10.1021/ol0607185
  112. Tanaka Hitoshi, Tanaka Toshihiro, Etoh Hideo, Goto Sachiko, Terada Yukimasa, Two New Erythrinan Alkaloids from Erythrina x bidwillii, 10.3987/com-99-8686
  113. Elford Tim G., Ulaczyk-Lesanko Agnieszka, De Pascale Gianfranco, Wright Gerard D., Hall Dennis G., Diversity-Oriented Synthesis and Preliminary Biological Screening of Highly Substituted Five-Membered Lactones and Lactams Originating From an Allyboration of Aldehydes and Imines, 10.1021/cc8001487
  114. Elford Tim G., Hall Dennis G., Imine allylation using 2-alkoxycarbonyl allylboronates as an expedient three-component reaction to polysubstituted α-exo-methylene-γ-lactams, 10.1016/j.tetlet.2008.09.112
  115. Enz Albert, Feuerbach Dominik, Frederiksen Mathias U., Gentsch Conrad, Hurth Konstanze, Müller Werner, Nozulak Joachim, Roy Bernard L., Gamma-lactams—A novel scaffold for highly potent and selective α7 nicotinic acetylcholine receptor agonists, 10.1016/j.bmcl.2009.01.073
  116. Zhuang Chunlin, Miao Zhenyuan, Zhu Lingjian, Dong Guoqiang, Guo Zizhao, Wang Shengzheng, Zhang Yongqiang, Wu Yuelin, Yao Jianzhong, Sheng Chunquan, Zhang Wannian, Discovery, Synthesis, and Biological Evaluation of Orally Active Pyrrolidone Derivatives as Novel Inhibitors of p53–MDM2 Protein–Protein Interaction, 10.1021/jm300969t
  117. Gein V. L., Kasimova N. N., Potemkin K. D., 10.1023/a:1020783623210
  118. Shenvi Ryan A., Corey E. J., A Short and Efficient Synthesis of (−)-7-Methylomuralide, a Potent Proteasome Inhibitor, 10.1021/ja901400q
  119. Satoh Nobuhiro, Yokoshima Satoshi, Fukuyama Tohru, Total Synthesis of (−)-Salinosporamide A, 10.1021/ol200886j
  120. Mori Tatsuya, Takahashi Kanji, Kashiwabara Masato, Uemura Daisuke, Katayama Chuji, Iwadare Shuichi, Shizuri Yoshikazu, Mitomo Ryuji, Nakano Fumio, Matsuzaki Akinori, Structure of oxazolomycin, a novel β-lactone antibiotic, 10.1016/s0040-4039(00)98515-0
  121. Donohoe Timothy J., Chiu Jessica Y. K., Thomas Rhian E., Synthesis of the Pyrrolidinone Core of KSM-2690 B, 10.1021/ol062705x
  122. OTANI TOSHIO, YOSHIDA KEN-ICHIRO, KUBOTA HIROMI, KAWAI SHUJI, ITO SUSUMU, HORI HIROSHI, ISHIYAMA TADAYUKI, OKI TOSHIKAZU, Novel Triene-.BETA.-lactone Antibiotics, Oxazolomycin Derivative and Its Isomer, Produced by Streptomyces sp. KSM-2690., 10.7164/antibiotics.53.1397
  123. Berini Christophe, Pelloux-Léon Nadia, Minassian Frédéric, Denis Jean-Noël, From N-triisopropylsilylpyrrole to an optically active C-4 substituted pyroglutamic acid: total synthesis of penmacric acid, 10.1039/b911217k
  124. Isichei M.O., Achinewhu S.C., The nutritive value of African oil bean seeds (itPentaclethra macrophylla), 10.1016/0308-8146(88)90146-x
  125. Akah Peter A., Nwambie Alphonsus I., Evaluation of Nigerian traditional medicines: 1. Plants used for rheumatic (inflammatory) disorders, 10.1016/0378-8741(94)90083-3
  126. Kang Sung Ho, Jun Hyuk-Sang, An enantiocontrolled synthesis of a key intermediate to (+)-lactacystin, 10.1039/a804954h
  127. Ooi Hidenori, Ishibashi Norihisa, Iwabuchi Yoshiharu, Ishihara Jun, Hatakeyama Susumi, A Concise Route to (+)-Lactacystin, 10.1021/jo048817o
  128. OMURA SATOSHI, FUJIMOTO TOMOKO, OTOGURO KAZUHIKO, MATSUZAKI KEIICHI, MORIGUCHI RYOZO, TANAKA HARUO, SASAKI YASUHARU, Lactacystin, a novel microbial metabolite, induces neuritogenesis of neuroblastoma cells., 10.7164/antibiotics.44.113
  129. Khim Seock-Kyu, Schultz Arthur G., Synthesis of (−)-9,10-epi-Stemoamide, 10.1021/jo049083i
  130. Bogliotti, Synlett, 349 (2005)
  131. Lin Wen-Han, Ye Yang, Xu Ren-Sheng, Chemical Studies on New Stemona Alkaloids, IV. Studies on New Alkaloids from Stemona tuberosa, 10.1021/np50083a003
  132. Wang Yan, Zhu Lili, Zhang Yuying, Hong Ran, Bioinspired and Concise Synthesis of (±)-Stemoamide, 10.1002/anie.201005833
  133. Zheng Xiao, Dai Xi-Jie, Yuan Hong-Qiu, Ye Chen-Xi, Ma Jie, Huang Pei-Qiang, Umpolung of Hemiaminals: Titanocene-Catalyzed Dehydroxylative Radical Coupling Reactions with Activated Alkenes, 10.1002/anie.201210088
  134. Bates Roderick, Sridhar S., A Synthesis of (±)-Stemoamide Using the Intramolecular Propargylic Barbier Reaction, 10.1055/s-0029-1217540
  135. Yamashita Sho, Mase Nobuyuki, Takabe Kunihiko, Chemoenzymatic total synthesis and determination of the absolute configuration of (S)-nebracetam, 10.1016/j.tetasy.2008.09.004
  136. Shorvon Simon, Pyrrolidone derivatives, 10.1016/s0140-6736(01)06890-8
  137. Maiya Shubha, Grundmann Alexander, Li Xiang, Li Shu-Ming, Turner Geoffrey, Identification of a Hybrid PKS/NRPS Required for Pseurotin A Biosynthesis in the Human PathogenAspergillus fumigatus, 10.1002/cbic.200700202
  138. Kumar, Curr. Sci., 102, 288 (2012)
  139. Hamed Refaat B., Gomez-Castellanos J. Ruben, Henry Luc, Ducho Christian, McDonough Michael A., Schofield Christopher J., The enzymes of β-lactam biosynthesis, 10.1039/c2np20065a
  141. Nay Bastien, Riache Nassima, Evanno Laurent, Chemistry and biology of non-tetramic γ-hydroxy-γ-lactams and γ-alkylidene-γ-lactams from natural sources, 10.1039/b903905h
  142. Royles Brodyck J. L., Naturally Occurring Tetramic Acids: Structure, Isolation, and Synthesis, 10.1021/cr00038a009
  143. Osterhage Claudia, Kaminsky Ronald, König Gabriele M., Wright Anthony D., Ascosalipyrrolidinone A, an Antimicrobial Alkaloid, from the Obligate Marine FungusAscochytasalicorniae, 10.1021/jo000307g
  144. Kontnik Renee, Clardy Jon, Codinaeopsin, an Antimalarial Fungal Polyketide, 10.1021/ol801726k
  145. Singh Sheo B., Goetz Michael A., Jones E. Tracy, Bills Gerald F., Giacobbe Robert A., Herranz Lucia, Stevens-Miles Siobhan, Williams David L., Oteromycin: A Novel Antagonist of Endothelin Receptor, 10.1021/jo00126a071
  146. Singh Sheo B., Zink Deborah L., Goetz Michael A., Dombrowski Anne W., Polishook Jon D., Hazuda Daria J., Equisetin and a novel opposite stereochemical homolog phomasetin, two fungal metabolites as inhibitors of HIV-1 integrase, 10.1016/s0040-4039(98)00269-x
  147. WEST ROBERT R., NESS JEFFREY VAN, VARMING ANNE-MARIE, RASSING BIRGITTE, BIGGS SHAULA, GASPER SHIRLEY, MCKERNAN PATRICIA A., PIGGOTT JIM, ZG-1494.ALPHA., a Novel Platelet-activating Factor Acetyltransferase Inhibitor from Penicilium rubrum, Isolation, Structure Elucidation and Biological Activity., 10.7164/antibiotics.49.967
  148. Suzuki Shohei, Hosoe Tomoo, Nozawa Koohei, Kawai Ken-ichi, Yaguchi Takashi, Udagawa Shun-ichi, Antifungal Substances Against Pathogenic Fungi, Talaroconvolutins, fromTalaromyces convolutus, 10.1021/np990371x
  149. Li J. Y., Strobel Gary, Harper James, Lobkovsky Emil, Clardy Jon, Cryptocin, a Potent Tetramic Acid Antimycotic from the Endophytic FungusCryptosporiopsis cf.quercina, 10.1021/ol000008d
  150. VESONDER RONALD F., TJARKS LARRY W., ROHWEDDER WILLIAM K., BURMEISTER HARLAND R., LAUGAL JAMES A., Equisetin, an antibiotic from Fusarium equiseti NRRL 5537, identified as a derivative of N-methyl-2,4-pyrollidone., 10.7164/antibiotics.32.759
  151. Phillips N. J., Goodwin J. T., Fraiman A., Cole R. J., Lynn D. G., Characterization of the Fusarium toxin equisetin: the use of phenylboronates in structure assignment, 10.1021/ja00203a025
  152. Whitt James, Shipley Suzanne M., Newman David J., Zuck Karina M., Tetramic Acid Analogues Produced by Coculture ofSaccharopolyspora erythraeawithFusarium pallidoroseum, 10.1021/np400761g
  153. Wheeler M.H., Stipanovic R.D., Puckhaber L.S., Phytotoxicity of equisetin and epi-equisetin isolated from Fusarium equiseti and F. pallidoroseum, 10.1017/s0953756298008119
  154. Gelderblom Wentzel C. A., Marasas Walter F. O., Steyn Pieter S., Thiel Pieter G., van der Merwe Kirsten J., van Rooyen Petrus H., Vleggaar Robert, Wessels Philippus L., Structure elucidation of fusarin C, a mutagen produced by Fusarium moniliforme , 10.1039/c39840000122
  155. Gelderblom, Appl. Environ. Microbiol., 54, 1806 (1988)
  156. Sondergaard T.E., Hansen F.T., Purup S., Nielsen A.K., Bonefeld-Jørgensen E.C., Giese H., Sørensen J.L., Fusarin C acts like an estrogenic agonist and stimulates breast cancer cells in vitro, 10.1016/j.toxlet.2011.05.1029
  157. Bohnert Markus, Dahse Hans-Martin, Gibson Donna M., Krasnoff Stuart B., Hoffmeister Dirk, The fusarin analog NG-391 impairs nucleic acid formation in K-562 leukemia cells, 10.1016/j.phytol.2013.01.001
  158. KAKEYA HIDEAKI, TAKAHASHI ISAMU, OKADA GEN, ISONO KIYOSHI, OSADA HIROYUKI, Epolactaene, a Novel Neuritogenic Compound in Human Neuroblastoma Cells, Produced by a Marine Fungus., 10.7164/antibiotics.48.733
  159. NAGUMO Yoko, KAKEYA Hideaki, SHOJI Mitsuru, HAYASHI Yujiro, DOHMAE Naoshi, OSADA Hiroyuki, Epolactaene binds human Hsp60 Cys442resulting in the inhibition of chaperone activity, 10.1042/bj20041355
  160. Hayashi Yujiro, Kanayama Jun, Yamaguchi Junichiro, Shoji Mitsuru, Diastereoselective Total Synthesis of Both Enantiomers of Epolactaene, 10.1021/jo025641m
  161. Kuramochi Kouji, Sunoki Takashi, Tsubaki Kazunori, Mizushina Yoshiyuki, Sakaguchi Kengo, Sugawara Fumio, Ikekita Masahiko, Kobayashi Susumu, Transformation of thiols to disulfides by epolactaene and its derivatives, 10.1016/j.bmc.2011.06.015
  162. Hayashi Yujiro, Shoji Mitsuru, Yamaguchi Junichiro, Sato Kenji, Yamaguchi Shinpei, Mukaiyama Takasuke, Sakai Ken, Asami Yukihiro, Kakeya Hideaki, Osada Hiroyuki, Asymmetric Total Synthesis of (−)-Azaspirene, a Novel Angiogenesis Inhibitor, 10.1021/ja0276826
  163. Asami Yukihiro, Kakeya Hideaki, Onose Rie, Yoshida Arika, Matsuzaki Hiroshi, Osada Hiroyuki, Azaspirene:  A Novel Angiogenesis Inhibitor Containing a 1-Oxa-7-azaspiro[4.4]non-2-ene-4,6-dione Skeleton Produced by the FungusNeosartoryasp., 10.1021/ol020104+
  164. Ishikawa Minoru, Ninomiya Tomohisa, Akabane Hirotomo, Kushida Nobuaki, Tsujiuchi Go, Ohyama Makoto, Gomi Shuichi, Shito Keiko, Murata Takashi, Pseurotin A and its analogues as inhibitors of immunoglobuline E production, 10.1016/j.bmcl.2009.01.029
  165. Hayashi Yujiro, Shoji Mitsuru, Mukaiyama Takasuke, Gotoh Hiroaki, Yamaguchi Shinpei, Nakata Munetaka, Kakeya Hideaki, Osada Hiroyuki, First Asymmetric Total Synthesis of Synerazol, an Antifungal Antibiotic, and Determination of Its Absolute Stereochemistry, 10.1021/jo050664x
  166. He Haiyin, Yang Hui Y., Bigelis Ramunas, Solum Eric H., Greenstein Michael, Carter Guy T., Pyrrocidines A and B, new antibiotics produced by a filamentous fungus, 10.1016/s0040-4039(02)00099-0
  167. Wicklow Donald T., Poling Stephen M., Antimicrobial Activity of Pyrrocidines fromAcremonium zeaeAgainst Endophytes and Pathogens of Maize, 10.1094/phyto-99-1-0109
  168. Kawashima, Chemical Abstract, 113, 113856 (1990)
  169. Shiraki Ryota, Sumino Akihiko, Tadano Kin-ichi, Ogawa Seiichiro, Total Synthesis of Natural PI-091, a New Platelet Aggregation Inhibitor of Microbial Origin, 10.1021/jo951897z
  170. Ning Na, Hu Jin-Feng, Sun Jian-Dong, Han Ning, Zhang Jun-Tian, Chen Nai-Hong, (−)Clausenamide facilitates synaptic transmission at hippocampal Schaffer collateral-CA1 synapses, 10.1016/j.ejphar.2012.02.004
  171. Zhu Xing Zu, Li Xiao-Yu, Liu Jin, Recent pharmacological studies on natural products in China, 10.1016/j.ejphar.2004.07.027
  172. Chu Shifeng, Liu Shaolin, Duan Wenzhen, Cheng Yong, Jiang Xueying, Zhu Chuanjiang, Tang Kang, Wang Runsheng, Xu Lin, Wang Xiaoying, Yu Xiaoming, Wu Kemei, Wang Yan, Wang Muzou, Huang Huiyong, Zhang Juntian, The anti-dementia drug candidate, (−)-clausenamide, improves memory impairment through its multi-target effect, 10.1016/j.pharmthera.2016.01.002
  173. Tchissambou L., Benechie M., Khuong-Huu F., Alcaloides imidazoliques—VI, 10.1016/0040-4020(82)80023-9
  174. A. Bouquet , Féticheurs et médecines traditionnelles du Congo (Brazzaville), Orstom Editions, Paris, 1969
  175. Jang Dae Sik, Lee Ga Young, Lee Yun Mi, Kim Young Sook, Sun Hang, Kim Dong-Hee, Kim Jin Sook, Flavan-3-ols Having a γ-Lactam from the Roots of Actinidia arguta Inhibit the Formation of Advanced Glycation End Products in Vitro, 10.1248/cpb.57.397
  176. Wink M., Evolution of secondary metabolites in legumes (Fabaceae), 10.1016/j.sajb.2013.06.006
  177. Welter Andre, Jadot Joseph, Dardenne Gaston, Marlier Michel, Casimir Jean, Acide 3(R)[1′(S)-aminocarboxymethyl]2-pyrrolidone-5(S)-carboxylique dans les graines de Pentaclethra macrophylla, 10.1016/s0031-9422(00)98623-0
  178. Mbadiwe Eddie I., A new dicarboxylic amino acid from seeds of Pentaclethra macrophylla, 10.1016/s0031-9422(00)98624-2
  179. Singh, Int. J. Conserv. Sci., 3, 319 (2012)
  180. Pilli Ronaldo Aloise, Rosso Giovanni Bernardi, de Oliveira Maria da Conceição Ferreira, The chemistry of Stemona alkaloids: An update, 10.1039/c005018k
  181. Pilli Ronaldo Aloise, Ferreira de Oliveira Maria da Conceição, Recent progress in the chemistry of the Stemona alkaloids, 10.1039/a902437i
  182. D. S. Bhakuni and D. S.Rawat, Bioactive Marine Natural Products, Springer, 2005
  183. Manam Rama Rao, Teisan Sy, White Donald J., Nicholson Benjamin, Grodberg Jennifer, Neuteboom Saskia T. C., Lam Kin S., Mosca Deborah A., Lloyd G. Kenneth, Potts Barbara C. M., Lajollamycin, a Nitro-tetraene Spiro-β-lactone-γ-lactam Antibiotic from the Marine ActinomyceteStreptomycesnodosus, 10.1021/np049725x
  184. Feling Robert H., Buchanan Greg O., Mincer Tracy J., Kauffman Christopher A., Jensen Paul R., Fenical William, Salinosporamide A: A Highly Cytotoxic Proteasome Inhibitor from a Novel Microbial Source, a Marine Bacterium of the New Genus Salinospora, 10.1002/anie.200390115
  185. Fenical William, Jensen Paul R., Palladino Michael A., Lam Kin S., Lloyd G. Kenneth, Potts Barbara C., Discovery and development of the anticancer agent salinosporamide A (NPI-0052), 10.1016/j.bmc.2008.10.075
  186. Gulder Tobias A. M., Moore Bradley S., Salinosporamide Natural Products: Potent 20 S Proteasome Inhibitors as Promising Cancer Chemotherapeutics, 10.1002/anie.201000728
  187. Takahashi Keisuske, Midori Michiko, Kawano Kei, Ishihara Jun, Hatakeyama Susumi, Entry to Heterocycles Based on Indium-Catalyzed Conia-Ene Reactions: Asymmetric Synthesis of (−)-Salinosporamide A, 10.1002/anie.200801967
  188. Macherla Venkat R., Mitchell Scott S., Manam Rama Rao, Reed Katherine A., Chao Ta-Hsiang, Nicholson Benjamin, Deyanat-Yazdi Gordafaried, Mai Bao, Jensen Paul R., Fenical William F., Neuteboom Saskia T. C., Lam Kin S., Palladino Michael A., Potts Barbara C. M., Structure−Activity Relationship Studies of Salinosporamide A (NPI-0052), a Novel Marine Derived Proteasome Inhibitor, 10.1021/jm048995+
  189. Stadler Marc, Bitzer Jens, Mayer-Bartschmid Anke, Müller Hartwig, Benet-Buchholz Jordi, Gantner Florian, Tichy Hans-Volker, Reinemer Peter, Bacon Kevin B., Cinnabaramides A−G:  Analogues of Lactacystin and Salinosporamide from a Terrestrial Streptomycete, 10.1021/np060162u
  190. COREY E. J., LI Wei-Dong Z., Total Synthesis and Biological Activity of Lactacystin, Omuralide and Analogs., 10.1248/cpb.47.1
  191. Dick Lawrence R., Cruikshank Amy A., Grenier Louis, Melandri Francesco D., Nunes Sandra L., Stein Ross L., Mechanistic Studies on the Inactivation of the Proteasome by Lactacystin : A CENTRAL ROLE FORclasto-LACTACYSTIN β-LACTONE, 10.1074/jbc.271.13.7273
  192. Tonew, Acta Virol., 36, 166 (1992)
  193. Kawazu Kazuyoshi, Kanzaki Hiroshi, Kawabata Goro, Kawai Satoru, Kobayashi Akio, Oxazolomycin Esters, Specific Inhibitors of Plant Transformation, 10.1271/bbb.56.1382
  194. Bennett Nicholas J., Prodger Jeremy C., Pattenden Gerald, A synthesis of a common intermediate to the lactone–pyrrolidinone ring systems in oxazolomycin A and neooxazolomycin, 10.1016/j.tet.2007.03.043