Neomacrophorin I, II, and III, novel drimenyl cyclohexanes with hydroxylated butanoates from Trichoderma sp. 1212-03

• DOI: 10.1016/j.tet.2013.12.087
• Publication Date: 2014-01-04T06:45:49Z
• Authors: Akane Hirose; Hayato Maeda; Akio Tonouchi; Tatsuo Nehira; Masaru Hashimoto
• Keywords: Diastereomer; Stereocenter; Moiety; Isocoumarins

Abstract Neomacrophorins I (1), II (2), and III (3) were isolated from the culture broth of Trichoderma sp. 1212-03, which was collected at Shirakami Mountainous area in Japan. Structural analyses disclosed that these resemble known macrophorins but possess axial-hydroxy group at C3 as well as different side chains at C7′. These are diastereomeric forms of macrophorins for 5′,6′-epoxide functionality. The NMR analyses suggested their relative configurational relationship between the C1–C15 drimene and C1′–C7′ epoxyquinone moieties. ECD spectral discussions verified them particularly for C5′,C6′-epoxyquinone (1), C5′,C6′-epoxysemiquinone (2 and 3), and 2″,3″-dihydroxybutanoate moiety in 1 and 2. The configuration of C3″-stereocenter of 3 was determined by chiral GC–MS after converting into methyl (S)-3″-hydroxybutanoate by basic of 3 methanolysis. Biological assays disclosed that 1 induces hyphal branching of Cochliobolus miyabeanus as well as cytotoxicity against human colorectal cancer COLO 201.