Comparison of the 1H and 13C NMR
data (Table 1) derived from this moiety with the reference data3
suggested that it was a brevifolincarboxylate, which was verified
by the observation of HMBC correlations from H-2 to C-1 and
C-6, from H-3 to C-4 and C-6, and from H-3′ to C-2′, C-5′, and
C-7′ as shown in Figure 1