Synlett 2007(6): 0829-0850  
DOI: 10.1055/s-2007-973888
ACCOUNT
© Georg Thieme Verlag Stuttgart · New York

A Survey of Synthetic Routes towards the Pyranonaphthoquinone Antibiotic Pentalongin and Syntheses of the Corresponding Nitrogen Derivatives

Sven Claessens, Guido Verniest, Jan Jacobs, Eva Van Hende, Pascal Habonimana, Tuyen Nguyen Van, Luc Van Puyvelde, Norbert De Kimpe*
Department of Organic Chemistry, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
Fax: +32(9)2646243; e-Mail: norbert.dekimpe@UGent.be;
Further Information

Publication History

Received 16 April 2006
Publication Date:
26 March 2007 (online)

Abstract

A survey through the synthetic possibilities of pentalongin and its derivatives is presented. Pentalongin is the parent compound in the 3,4-dehydropyranonaphthoquinone series and is the active principle of the medicinal plant Pentas longiflora. Attention is paid to eight approaches towards these 3,4-dehydropyranonaphthoquinones. Synthetic methodologies for the corresponding nitrogen analogues are described, focusing on several natural products.

  • 1 Historical Background

  • 2 Isolation of Pyranonaphthoquinone Antibiotics

  • 2.1 Isolation of Pentalongin

  • 2.2 Isolation of Related Naphthoquinones

  • 2.3 Stability of Pentalongin

  • 3 Pyranonaphthoquinone Antibiotics

  • 4 Evaluation of Synthetic Strategies towards Pentalongin

  • 4.1 Retrosynthetic Analysis

  • 4.2 Base-Induced Intramolecular Cyclization (A)

  • 4.3 Acid-Induced Cyclization (B)

  • 4.4 Friedel-Crafts Cyclization (C)

  • 4.5 Lemieux-Johnson Oxidation of 2-Allyl-1,4-naphtho­quinone (D)

  • 4.6 Ring Closure via Lactonization (E)

  • 4.7 Ring Closure Using Grubbs’ Methodology (F)

  • 4.8 Heck Cyclization (G)

  • 4.9 Phthalide-Coupling Reaction (H)

  • 5 Nitrogen Analogues of Pentalongin

  • 5.1 Occurrence and Bioactivity

  • 5.2 Synthetic Approaches towards 2-Aza-anthraquinones

  • 6 Other Isolated Quinones and Syntheses Thereof

  • 6.1 Synthesis of Harounoside

  • 6.2 Synthesis of Isagarin

  • 6.3 Synthesis of 2-Alkoxymethyl-3-trifluoromethyl-1,4-naphthoquinones

  • 7 Concluding Remarks

1

Present adress: Institute of Chemistry, Vietnamese Academy for Sciences and Technology, 18 Hoang Quoc Viet Road, Cau Giay, Hanoi, Vietnam