Structure of naematolin C and naematolin G, novel 4,8,11,11-tetramethyltricyclo[5.4.0.02,3]undecane sesquiterpenoids

Abstract

Naematolins C and G, metabolites of Naematoloma fasciculare, have the novel (1 S,2S,3S,4R,5S,6R,8R,9S)-6-acetoxy-2,3,5-tri hydroxy-4,8,11,11 -tetramethyltricyclo[5.4.0.0*r3]undecan-7-one (4) structure and its 6-epimer (7), respectively, as shown by a crystal structure determination of the chloroacetate (5). ~ ~~ Figure 1. ORTEP drawing of ( 5 ) .

Endophyte inspired chemical diversity from beta-caryophyllene

“…4a) revealed a 4/5/6 skeleton, the same as the core skeletons of naematolins C and G from the fungus Naematoloma fasciculare. 27 Its RC was deduced by NOESY correlations (Fig. 4b).…”

Lanostane Triterpenoids from the Mushroom Naematoloma fasciculare

“…10,16 Fasciculol K (2) was obtained as a colorless gum with a molecular formula of C 36 H 60 O 10 deduced by the molecular ion peak [M + Na] + at m/z 675.4082 (calcd for C 36 H 60 O 10 Na, 675.4084) in the HRESIMS. The 1 H and 13 C NMR spectra (Table 1) were quite similar to those of 1, the only difference being that a secondary methyl group [δ H 1.04 (d, J = 6.5 Hz); δ C 16.5] in 1 was replaced with an oxygenated methylene group [δ H 3.72 (dd, J = 11.0, 2.5 Hz) and 3.78 (dd, J = 11.0, 4.5 Hz); δ C 60.5] in 2. The location of this oxygenated methylene group was further confirmed to be C-21 by the HMBC correlations of H-21/C-17 (δ C 37.7), C-20 (δ C 42.8), and C-22 (δ C 27.4), suggesting that compound 2 was a C-21-hydroxylated product of 1.…”

“…The complete assignments of the 1 H and 13 C NMR data of 2 were determined by DEPT, HMQC, HMBC, and NOESY spectra. The relative configuration of 2 was established to be identical to 1 based on the coupling constants and a NOESY experiment and by comparison of the 1 H and 13 C NMR data with those of 1. The absolute configuration at C-3′ in 2 was determined using alkaline methanolysis of 2, which demonstrated the S-configuration for C-3′, the same as that of 1.…”

A Caryophyllene-Related Sesquiterpene and Two 6,7-Seco-caryophyllenes from Liquid Cultures of Hebeloma longicaudum

“…The assumption of a biosynthetic relationship between hebelophyllene D ( 1 ) and hebelophyllene C leads to the absolute configuration 1 S ,2 S ,3 S ,4 R ,5 R ,8 R ,9 S for 1 , as shown. The tricyclo[5.4.0.0 2,5 ]undecane skeleton of 1 has only two precedents, naematolins C and G, whose structures have been supported by X-ray analyses 1assignment a 1 b 2 c 3 c H-1 2.03 dd (8.2, 2.2) 2.08 ddt (13.5, 13.5, 2.5) 2.39 dddd (9.0, 8.8, 6.0, 2.7) H-2 3.99 br s 1.74 ddd (13.5, 6.2, 2.5, α) 1.30 ddd (14.1, 8.2, 6.0) 2.22 dd (13.5, 11.5, β) 1.67 ddd (14.1, 8.8, 5.4) H-3 4.13 dd (11.5, 6.2) 3.85 br dd (8.2, 5.4) H-4 2.37 dq (4.7, 7.2) H-5 3.99 ddd (5.5, 4.7, 2.0) 5.90 dd (17.2, 10.7) 3.32 br t (3.4) H-6 2.30 dd (14.5, 2.0, α) 5.39 dd (17.2, 1.1, a) 2.54 dd (5.9, 2.7, c) 3.06 dd (14.5, 5.5, β) 5.20 dd (10.7, 1.1, b) 2.87 dd (5.9, 4.1, d) H-8 2.81 dq (12.2, 6.5) H-9 3.41 ddd (9.5, 8.2, 7.8) 2.32 ddt (13.5, 12.2, 8.5) 3.55 dtt (9.5, 8.7, 1.3) H-10α 1.47 ddd (11.1, 9.5, 2.2) 1.87 ddd (11.3, 8.2, 2.5) 1.74 ddd (10.5, 8.3, 2.7) H-10β 2.28 dd (11.1, 7.8) 1.52 dd (11.3, 9.0) 1.92 br t (10.5) H-12 1.05 s 0.90 s 1.00 s H-13 1.22 s 1.17 s 1.26 s H-14 1.27 d (7.2) 1.38 s 5.02 t (1.1, a) 5.06 t (1.1, b) H-15 1.14 s 0.97 d (6.5) 5.60 t (1.3, e) 6.31 t (1.3, f) H-16 3.73 s a Assignments are based on coupling constants and 1 H− 1 H COSY spectra.…”