Synlett 2008(19): 2989-2992  
DOI: 10.1055/s-0028-1087299
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Synthesis of 2,7-Naphthyridine-Containing Analogues of Luotonin A

Xiangqian Daia, Chen Chenga, Chunyong Dingb, Qizheng Yaob, Ao Zhang*a
a Synthetic Organic & Medicinal Chemistry Laboratory (SOMCL), Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, P. R. of China
Fax: +86(21)50806035; e-Mail: aozhang@mail.shcnc.ac.cn;
b School of Pharmacy, China Pharmaceutical University, Nanjing 210009, P. R. of China
Further Information

Publication History

Received 26 June 2008
Publication Date:
23 October 2008 (online)

Abstract

A series of luotonin A analogues 7a-d with the N-14 atom moved to position 18 was prepared using an intramolecular aza-hetero-Diels-Alder reaction.

    References and Notes

  • 1 Wall ME. Wani MC. Cook CE. Palmer KH. McPhail AT. Sim GA. J. Am. Chem. Soc.  1966,  88:  3888 
  • 2 Moertel CG. Schutt AJ. Reitemeier RJ. Hahn RG. Cancer Chemother. Rep.  1977,  56:  649 
  • 3 Li QY. Zu YG. Shi RZ. Yao LP. Curr. Med. Chem.  2006,  13:  202 
  • 4 Driver RW. Yang LX. Mini-Rev. Med. Chem.  2005,  5:  425 
  • 5 Du W. Tetrahedron  2003,  59:  8649 
  • 6 Kingsbury WD. Boehm JC. Jakas DR. J. Med. Chem.  1991,  34:  98 
  • 7 Graul AI. Prous JR. Drug News Perspect.  2005,  1:  21 
  • 8 Giovanella BC. Stehlin JS. Hinz HR. Kozielski AJ. Harris NJ. Vardeman DM. Int. J. Oncol.  2002,  20:  81 
  • 9 Eckhardt SG. Baker SD. Eckardt JR. Clin. Cancer Res.  1998,  4:  595 
  • 10 Minami H. Fujii H. Igarashi T. Itoh K. Tamanoi K. Oguma T. Sasaki Y. Clin. Cancer Res.  2001,  7:  3056 
  • 11 Ma Z.-Z. Hano Y. Nomura T. Chen Y.-J. Heterocycles  1997,  46:  541 
  • 12 Ma Z.-Z. Hano Y. Nomura T. Chen Y.-J. Bioorg. Med. Chem. Lett.  2004,  14:  1193 
  • 13 Ma Z.-Z. Hano Y. Nomura T. Heterocycles  2005,  65:  2203 
  • 14 Cagir A. Jones SH. Gao R. Eisenhauer BM. Hecht SM. J. Am. Chem. Soc.  2003,  125:  13628 
  • Most recent approaches:
  • 15a Bowman WR. Cloonan MO. Fletcher AJ. Stein T. Org. Biomol. Chem.  2005,  3:  1460 
  • 15b Lee ES. Park JG. Kim SI. Jahng Y. Heterocycles  2006,  68:  151 
  • 15c Mhaske SB. Argade NP. Tetrahedron  2006,  62:  9787 
  • 15d Servais M. Azzouz A. Lopes D. Courillon C. Malacria M. Angew. Chem. Int. Ed.  2007,  46:  576 
  • 15e Bowman WR. Elsegood MRJ. Stein T. Weaver GW. Org. Biomol. Chem.  2007,  5:  103 
  • 15f Mason JJ. Bergman J. Org. Biomol. Chem.  2007,  5:  2486 
  • 15g Nacro K. Zha C. Guzzo PR. Herr RJ. Peace D. Friedrich TD. Bioorg. Med. Chem. Lett.  2007,  15:  4237 
  • 16 Zhang A. Ding C. Cheng C. Yao Q. J. Comb. Chem.  2007,  9:  916 
  • 17 Gross H. Goeger DE. Hills P. Mooberry SL. Ballantine DL. Murray TF. Valeriote FA. Gerwick WH. J. Nat. Prod.  2006,  69:  640 
  • 18 Shamma M. Novak L. Tetrahedron  1969,  25:  2275 
  • 19 Wenkert E. Dave KG. Lewis RG. Sprague PW. J. Am. Chem. Soc.  1967,  89:  6741 
  • 20 Uehling DE. Nanthakumar SS. Croom D. Emerson DL. Leitner PP. Morton B. Profeta S. Vuong A. Besterman JM. J. Med. Chem.  1995,  38:  1106 
  • 21 Gaddam V. Nagarajan R. Tetrahedron Lett.  2007,  48:  7335 
  • 22a Fortunak JMD. Mastrocola AR. Mellinger M. Sisti NJ. Wood JL. Zhuang Z.-P. Tetrahedron Lett.  1996,  37:  5679 
  • 22b Twin H. Batey RA. Org. Lett.  2004,  6:  4913 
  • 23a Zhou H.-B. Liu G.-S. Yao Z.-J. J. Org. Chem.  2007,  72:  6270 
  • 23b Zhou H.-B. Liu G.-S. Yao Z.-J. Org. Lett.  2007,  9:  2003 
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General Procedure for the Intramolecular Aza-Diels-Alder Cyclization
To a solution of Ph3PO (837 mg, 2.98 mmol) in anhyd CH2Cl2 (20 mL) at 0 ˚C was added dropwise a solution of Tf2O (0.25 mL, 1.5 mmol) in CH2Cl2 (2 mL). After the mixture was stirred for 15 min at 0 ˚C, a solution of 2-allyl-1-oxo-N-aryl-2,7-naphthyridin-3-carboxamide (13, 1.0 mmol) or 2-propargyl-1-oxo-N-aryl-2,7-naphthyridin-3-carboxamide (16, 1.0 mmol) in CH2Cl2 (20 mL) was dropped slowly. The reaction mixture was stirred at 0 ˚C for 0.5 h, and then at r.t. for 1-5 h. The completion of the reaction was detected by disappearance of the carboxamide substrate 13. A solution of aq Na2CO3 (10%, 10 mL) was added to quench the reaction. The mixture was extracted with CHCl3 (3 × 30 mL). The organic phases were combined, washed with brine, and dried over anhyd Na2SO4. After filtration, the solvent was removed, and the residue was subjected to column chromatography (CH2Cl2-MeOH, 10:1). The cyclization products 7a-c were obtained.
Compound 7a (78%): white solid, mp >210 ˚C. MS (EI): m/z (%) =285(100) [M+]. ¹H NMR (300 MHz, CDCl3-CD3OD): δ = 5.17 (br s, 2 H), 7.47 (m, 3 H), 7.63 (m, 1 H), 7.75 (d, J = 8.4 Hz, 1 H), 7.99 (d, J = 8.7 Hz, 1 H), 8.27 (s, 1 H), 8.51 (d, J = 5.4 Hz, 1 H), 9.37 (s, 1 H). HRMS: m/z calcd for C18H11ON3: 285.0902; found: 285.0890.
Compound 7b (45%): slightly yellow solid, mp >200 ˚C. MS (EI): m/z (%) = 343(100) [M+]. ¹H NMR (300 MHz, CDCl3-CD3OD): δ = 3.81 (s, 3 H), 5.21 (br s, 2 H), 7.46 (s, 1 H), 7.52 (d, J = 5.4 Hz, 1 H), 8.03 (d, J = 9.0 Hz, 1 H), 8.16 (d, J = 8.4 Hz, 1H), 8.39 (s, 1 H), 8.48 (s, 1 H), 8.54 (d, J = 5.4 Hz, 1 H), 9.39 (s, 1 H). HRMS: m/z calcd for C20H13O3N3: 343.0957; found: 343.0959.
Compound 7c (64%): slightly yellow solid, mp >210 ˚C. MS (EI): m/z (%) = 315(100) [M+]. ¹H NMR (300 MHz, CDCl3-CD3OD): δ = 3.94 (s, 3 H), 5.31 (s, 2 H), 7.19 (s,
1 H), 7.45 (m, 1 H), 7.51 (s, 1 H), 7.58 (d, 1 H, J = 7.6 Hz), 8.06 (d, J = 12.4 Hz, 1 H), 8.25 (s, 1 H), 8.69 (s, 1 H), 9.60 (s, 1 H). HRMS: m/z calcd for C19H13O2N3: 315.1008; found: 315.1017.

25

The cycloadducts 7a-c showed extremely poor solubility in regular deuterated solvents (CDCl3, CD3OD, CD3SOCD3, D2O). Their purity (>95%) was further confirmed by HPLC analysis on an Agilent 1100 series LC system (Agilent ChemStation Rev.A.10.02; ZORBAX Eclipse XDB-C8,
4.8 mm × 150 mm, 5 µM, 1.0 mL/min, UV: λ = 254 nm, r.t.) with two solvent systems (MeCN-H2O, and MeOH-H2O).

26

Compound 7d (30%): yellow solid, mp 202-204 ˚C. MS (EI): m/z = 341 [M+]. ¹H NMR (300 MHz, CDCl3-CD3OD): δ = 4.90 (d, J = 6.0 Hz, 1 H), 5.35 (s, 2 H), 5.36 (d, J = 6.6 Hz, 1 H), 5.50 (dd, J = 1.2, 17.1 Hz, 1 H), 6.37 (m, 1 H), 7.62 (t, J = 7.2 Hz, 1 H), 7.78 (t, J = 7.2 Hz, 1 H), 7.86 (m, 2 H), 8.23 (d, J = 8.7 Hz, 1 H), 8.28 (s, 1 H), 8.85 (d, J = 5.7 Hz, 1 H), 9.68 (s, 1 H). ¹³C NMR (75 MHz, CDCl3-CD3OD):
δ = 49.7, 76.0, 115.4, 118.9, 119.6, 127.0, 127.6, 127.8, 128.4, 129.8, 130.2, 133.3, 134.2, 134.9, 140.7, 148.8, 150.4, 150.5, 151.7, 158.6. HRMS: m/z calcd for C21H15O2N3: 341.1164; found: 341.1160.