Ormula was determined as C13H18O4 by way of HRESIMS, establishing an index of hydrogen deficiency

Ormula was determined as C13H18O4 by way of HRESIMS, establishing an index of hydrogen deficiency of five. The NMR information recommended structural similarity with compound 1. Nevertheless, compound 2 lacked the olefinic proton at H six.90, which was replaced by 3 aliphatic protons (H 1.79, 2.43, and two.91). These information suggested a distinction among 1 and two of a double bond, as supported by a two amu distinction inside the HRMS data. The 1H NMR data of 2 revealed the presence of 4 olefinic protons, corresponding to two trans-disubstituted olefins (H 5.52, ddq, J = 15.5, eight.0, 1.7; five.55, ddq, J = 15.five, 5.two, 1.7; 5.91, dqd, J = 15.5, six.9, 1.7; and 5.99, dq, J = 15.five, six.9, for H-1, H-1, H-2, and H-2, respectively), four oxymethines (H three.48, dd, J = 12.0, eight.six; 3.84, bq, J = two.9; 4.03, ddd, J = 5.two, two.9, 1.7; and 4.67, dd, J = eight.6, eight.0, for H-7a, H-3, H-2, and H-7, respectively), one methine (H 2.91, ddd, J = 12.six, 12.0, 3.four, for H-4a), a single methylene (H 1.79, ddd, J = 13.two, 12.six, two.9; and two.43, ddd, J = 13.two, three.four, 2.9, for H-4 and H-4, respectively), two equivalent methyls (H 1.77, dd, J = 6.9, 1.7, for H-3 and H-3), and a single exchangeable proton (H 1.84, for 3-OH). The 13C NMR information revealed 13 carbons, constant with the HRMS information and indicative of 1 carbonyl (C 173.5 for C-5), four olefinic carbons (C 125.7, 126.four, 130.six, and 134.3, for C-1, C-1, C-2, and C-2, respectively), five methines (C 39.0, 66.3, 81.two, 82.1, and 82.four for C-4a, C-3, C-2, C-7a, and C-7, respectively), a single methylene (C 30.0 for C-4), and two methyls (C 18.1 and 18.two for C-3 and C-3, respectively) (see Supplementary Figures S3 and S4 for the 1H and 13C NMR spectra and Table S1). The two double bonds along with the carbonyl group accounted for three degrees of unsaturations, leaving the remaining two accommodated by the bicyclic ring program. COSY information identified one spin program as H3-3/H-2/H-1/H-2/ H-3/H2-4/H-4a/H-7a/H-7/H-1/H-2/H3-3 (NF-κB supplier Figure 2a). The following crucial HMBC correlations have been observed: H3-3C-1, H3-3C-1, H-2C-2, H-7C-2, H-3C-4a, H-7aC-4, H-4aC-7, and H-4aC-5 (Figure 2a). NOESY correlations from H-1 to H-7a, from H-7a to H-2, and from H-2 to H-3 and H-2 indicated that H-1, H-7a, H-2, H-3, and H-2 had been all around the identical face. Alternatively, NOESY correlations observed from H-4a to H-7 indicated that these two protons were around the same side of the molecule but opposite for the earlier set (Figure 2b). Comparing all of those information with these for 1 yielded the structure of two (Figure 1), which was ascribed the trivial name transdihydrowaol A. The Thyroid Hormone Receptor Source absolute configuration of 2 was assigned through a modified Mosher’s ester system,17 establishing the configuration as 2R, 3R, 4aR, 7S, and 7aR (Figure 3).18 Compound 3 (1.45 mg) was obtained as a colorless oil.19 The molecular formula was determined as C13H18O4 by means of HRESIMS, and was the same as compound 2. The NMR information (Table S1 and Figures S5 and S6) suggested structural similarity with two. Important variations have been a coupling continual of 0.six Hz among H-4a (H two.58, ddd, J = 7.five, 2.three, 0.6) and H-7a (H 4.17, dd, J = 4.6, 0.six) in three vs 12 Hz in 2, along with a NOESY correlation from H-4a to H-7a in 3 vs H-4a to H-7 in two (Figure 2d). These information implied a pseudoaxial/pseudoequatorial cis orientation of H-4a/H-7a. NOESY correlations were also observed from H-2 to H-7a and H-4a, and from H-4a to H-3, indicating that those protons were on the identical face (FigureTetrahedron Lett. Author manuscript; offered in PMC 2014 August 07.NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-P.