at d 1.03 and a three-proton double

at d 1.03 and a three-proton doublet at d 1.33, indicating the presence
of a trisubstituted double bond and two methyl groups, one bonded
to a quaternary carbon and another to a methine, respectively. The
spectroscopic data of 1 proved to be very similar to that reported for
the aglycone of amaloside C, a steroidal secondary metabolite with an
extra hydroxyl group at C8, isolated from Amalocalyx yunnanensis
(Apocynaceae) (Shen et al., 1993). The C-14 location of the tertiary
hydroxyl group in the structure of 1 was established by comparing
the chemical shift (85.3 ppm) of the quaternary oxygenated carbon in
the 13C NMR spectrum of 1, with those reported for the oxygenated
carbons C8 (76.1 ppm) and C14 (86.4 ppm) in amalosideC and similar
pregnanes (Shen et al., 1993; Hu et al., 1992). Alternatively, a 3J
correlation observed in the HMBC experiment between the protons of
the C-19 methyl group at d 1.03 and the olefinic quaternary carbon at
139.8 ppm confirmed the C5 location of the double bond; similarly,
the 3J correlation observed between the protons of the C-21 methyl
group at d 1.33 and the methine carbon at 56.2 ppm, and the 2J
correlation between the same protons and the oxygenated methine
carbon at 83.3 ppm, confirmed C21 being a secondary methyl group.
Both the structure and relative stereochemistry of 1 were confirmed
unambiguously by a single-crystal X-ray diffraction experiment
(Fig. 1). The spectroscopic data of 1 proved to be identical to
that reported for 3b,14b,20-trihydroxypregn-5-ene-18-oic-(18-20)-
lactone, a secondary metabolite previously isolated from Ecdysanthera
rosea Hook et Arn. (Apocynaceae) (Luger et al., 1998) and
recently reported as the hydrolysis product of the novel saponins
ecdysantherosides A and B (Zhu et al., 2011).

ผลลัพธ์ (อังกฤษ) 1:

at d 1.03 and a three-proton doublet at d 1.33, indicating the presence
of a trisubstituted double bond and two methyl groups, one bonded
to a quaternary carbon and another to a methine, respectively. the
spectroscopic data of 1 proved to be very similar to that reported for
the aglycone of amaloside c, a steroidal secondary metabolite with an
extra hydroxyl group at c8,.isolated from amalocalyx yunnanensis
(apocynaceae) (shen et al., 1993). the c-14 location of the tertiary
hydroxyl group in the structure of 1 was established by comparing
the chemical shift (85.3 ppm) of the quaternary oxygenated carbon in
the 13c nmr spectrum of 1, with those reported for the oxygenated
carbons. c8 (76.1 ppm) and c14 (86.4 ppm) in amalosidec and similar
pregnanes (shen et al.,.1993; hu et al., 1992). alternatively, a 3j
correlation observed in the hmbc experiment between the protons of
the c-19 methyl group at d 1.03 and the olefinic quaternary carbon at
139.8 ppm confirmed the c5 location of the double bond; similarly,
the 3j correlation observed. between the protons of the c-21 methyl
group at d 1.33 and the methine carbon at 56.2 ppm, and the 2j
.correlation between the same protons and the oxygenated methine
carbon at 83.3 ppm, confirmed c21 being a secondary methyl group.
both the structure and relative stereochemistry of 1 were confirmed
unambiguously by a single-crystal x-ray diffraction experiment
(fig. first). the spectroscopic data of 1 proved to be identical to
that reported for 3b, 14b ,20-trihydroxypregn-5-ene-18-oic-(18-20) -
lactone,.a secondary metabolite previously isolated from ecdysanthera
rosea hook et arn. (Apocynaceae) (luger et al., 1998) and
recently reported as the hydrolysis product of the novel saponins
ecdysantherosides a and b (zhu et al., 2011).

ผลลัพธ์ (อังกฤษ) 3:

At D 1.03 and a three-proton doublet at D 1.33, indicating the presence of a
trisubstituted double bond and two methyl groups, one
bonded to a quaternary carbon and another to a methine, respectively. The
spectroscopic data of 1 proved to be very similar to that reported for the aglycone of
amaloside C, a steroidal secondary metabolite with an extra hydroxyl group at C
8,isolated from Amalocalyx
yunnanensis (Apocynaceae (Shen et al ., 1993 ). The C - 14
location of the tertiary hydroxyl group in the structure of 1 was established by comparing the
chemical shift (85.3 ppm) of the oxygenated quaternary carbon in the
13 C NMR spectrum of 1, with those reported for the oxygenated carbons C
8 (76.1 ppm) and 14 C (86.4 ppm) and similar in amalosideC
pregnanes (Shen et al.,1993 ; Hu et al ., 1992 ). Alternatively, a 3
J HMBC correlation observed in the experiment between the protons of the
C - 19 methyl group at D 1.03 and the olefinic quaternary carbon at 139.8 ppm
C 5 confirmed the location of the double bond; similarly, the
3 J correlation observed between the protons of the C - 21
methyl group at D 1.33 and the methine carbon at 56.2 ppm, and the 2 J
correlation between the same and the oxygenated methine protons
carbon at 83.3 ppm, confirmed C 21 being a secondary methyl Group.
Both structure and the relative stereochemistry of 1
were confirmed unambiguously by a single-crystal X-ray diffraction experiment
(Fig. 1) .The spectroscopic data of 1
proved to be identical to that reported for 3B, 14B, 20-trihydroxypregn - 5 - ene - 18 - oic- (18 - 20) -
lactone,a secondary metabolite isolated from previously Ecdysanthera
rosea Hook et Arn (Apocynaceae (Luger et al ., 1998 ), and
recently reported as the hydrolysis product of the novel saponins
ecdysantherosides A and B (Zhu et al ., 2011 ).