ent-(8S,10R)-15,16-Epoxy-19-norcleroda-4,11,13(16),14-tetraene-18,6(R):20,12-diolactone (isocrotocaudin)

The title compound, C₁₉H₁₈O₅, is a diastereoisomer of crotocaudin, both being isolated from the plants of genus Croton. In isocrotocaudin, the furan moiety makes a dihedral angle with the adjacent lactone of 13.53 (17)°. The cyclo­hexyl ring of the diterpene moiety adopts a chair confirmation. The weak intermolecular C—H...O hydrogen bonds link the mol­ecules into linear chains along the c axis.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.056
• wR factor = 0.113
• Data-to-parameter ratio = 8.6

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          5

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           26.00
           From the CIF: _reflns_number_total               1866
           Count of symmetry unique reflns         1872
           Completeness (_total/calc)             99.68%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present           no

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL, PARST (Nardelli, 1995) and PLATON (Spek, 2003).

ent-(8S,10R)-15,16-epoxy-19-norcleroda-4,11,13 (16),14-tetraene- 18,6(R):20,12-diolactone

Crystal data

C19H18O5	Dx = 1.330 Mg m^−3
Mr = 326.33	Melting point = 485.5–486.8 K
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 743 reflections
a = 6.677 (2) Å	θ = 1.8–26.0°
b = 10.794 (3) Å	µ = 0.10 mm^−1
c = 22.608 (7) Å	T = 298 K
V = 1629.4 (8) Å^3	Slab, colourless
Z = 4	0.42 × 0.10 × 0.09 mm
F(000) = 688

Data collection

Bruker SMART APEX CCD area-detector diffractometer	1866 independent reflections
Radiation source: fine-focus sealed tube	1583 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.035
Detector resolution: 83.66 pixels mm^-1	θmax = 26.0°, θmin = 1.8°
ω scans	h = −8→8
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −13→13
Tmin = 0.960, Tmax = 0.991	l = −18→27
8831 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.056	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.113	H-atom parameters constrained
S = 1.18	w = 1/[σ^2(Fo^2) + (0.0462P)^2 + 0.3404P] where P = (Fo^2 + 2Fc^2)/3
1866 reflections	(Δ/σ)max < 0.001
217 parameters	Δρmax = 0.16 e Å^−3
0 restraints	Δρmin = −0.13 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	1.1679 (6)	0.3232 (3)	0.44225 (11)	0.0774 (9)
O2	0.8829 (4)	0.3716 (2)	0.27849 (9)	0.0481 (6)
O3	0.6987 (4)	0.4292 (2)	0.20096 (10)	0.0521 (6)
O4	0.6785 (4)	0.2900 (3)	0.01985 (10)	0.0605 (7)
O5	0.7258 (5)	0.4628 (3)	−0.03299 (12)	0.0869 (10)
C1	1.1822 (5)	0.4127 (3)	0.15144 (14)	0.0475 (9)
H1A	1.0990	0.4719	0.1724	0.057*
H1B	1.2949	0.3921	0.1767	0.057*
C2	1.2589 (6)	0.4714 (4)	0.09482 (16)	0.0605 (11)
H2A	1.3413	0.4120	0.0738	0.073*
H2B	1.3421	0.5421	0.1046	0.073*
C3	1.0880 (6)	0.5137 (3)	0.05458 (16)	0.0573 (10)
H3A	1.0265	0.5879	0.0705	0.069*
H3B	1.1393	0.5325	0.0155	0.069*
C4	0.9381 (5)	0.4130 (3)	0.05087 (13)	0.0418 (8)
C5	0.9356 (5)	0.3159 (3)	0.08600 (13)	0.0352 (7)
C6	0.7800 (5)	0.2275 (3)	0.06742 (14)	0.0457 (8)
H6A	0.8441	0.1524	0.0521	0.055*
C7	0.6461 (5)	0.1936 (3)	0.11863 (15)	0.0512 (9)
H7A	0.5567	0.1270	0.1070	0.061*
H7B	0.5652	0.2645	0.1297	0.061*
C8	0.7728 (5)	0.1523 (3)	0.17134 (15)	0.0451 (8)
H8A	0.8488	0.0793	0.1587	0.054*
C9	0.9281 (5)	0.2511 (3)	0.19197 (12)	0.0351 (7)
C10	1.0609 (5)	0.2958 (3)	0.13902 (12)	0.0343 (7)
H10A	1.1558	0.2292	0.1298	0.041*
C11	1.0549 (5)	0.2085 (3)	0.24245 (13)	0.0399 (8)
H11A	1.1413	0.1410	0.2411	0.048*
C12	1.0280 (5)	0.2792 (3)	0.28895 (13)	0.0406 (8)
C13	1.1131 (6)	0.2818 (3)	0.34758 (14)	0.0461 (9)
C14	1.2892 (7)	0.2164 (4)	0.36677 (16)	0.0648 (11)
H14A	1.3705	0.1651	0.3440	0.078*
C15	1.3119 (8)	0.2442 (5)	0.42338 (18)	0.0803 (14)
H15A	1.4139	0.2134	0.4472	0.096*
C16	1.0483 (7)	0.3431 (3)	0.39508 (15)	0.0578 (10)
H16A	0.9351	0.3933	0.3956	0.069*
C17	0.6363 (6)	0.1112 (4)	0.22187 (18)	0.0735 (13)
H17A	0.5439	0.0499	0.2077	0.110*
H17B	0.5632	0.1814	0.2366	0.110*
H17C	0.7158	0.0766	0.2531	0.110*
C18	0.7761 (6)	0.3981 (4)	0.00767 (15)	0.0551 (10)
C20	0.8209 (5)	0.3598 (3)	0.22091 (14)	0.0396 (8)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.103 (2)	0.0812 (19)	0.0479 (15)	0.003 (2)	−0.0166 (17)	−0.0192 (15)
O2	0.0579 (15)	0.0499 (13)	0.0366 (12)	0.0154 (12)	0.0067 (12)	−0.0020 (10)
O3	0.0464 (15)	0.0536 (14)	0.0562 (14)	0.0220 (13)	0.0030 (12)	0.0064 (12)
O4	0.0562 (16)	0.0787 (18)	0.0465 (14)	−0.0022 (15)	−0.0208 (13)	−0.0024 (13)
O5	0.091 (2)	0.109 (2)	0.0610 (17)	0.011 (2)	−0.0216 (18)	0.0279 (17)
C1	0.037 (2)	0.057 (2)	0.0481 (19)	−0.0058 (18)	−0.0007 (17)	−0.0065 (17)
C2	0.049 (2)	0.071 (2)	0.062 (2)	−0.019 (2)	0.009 (2)	0.0009 (19)
C3	0.065 (3)	0.053 (2)	0.054 (2)	−0.006 (2)	0.011 (2)	0.0079 (18)
C4	0.0427 (19)	0.0497 (19)	0.0329 (16)	0.0080 (18)	0.0041 (16)	−0.0027 (15)
C5	0.0274 (17)	0.0431 (17)	0.0350 (16)	0.0041 (15)	0.0031 (14)	−0.0062 (14)
C6	0.043 (2)	0.0515 (19)	0.0426 (19)	0.0014 (17)	−0.0080 (16)	−0.0078 (15)
C7	0.037 (2)	0.056 (2)	0.061 (2)	−0.0103 (18)	−0.0071 (18)	−0.0017 (18)
C8	0.040 (2)	0.0392 (17)	0.056 (2)	−0.0004 (16)	0.0006 (17)	0.0049 (16)
C9	0.0342 (17)	0.0372 (15)	0.0338 (16)	0.0073 (15)	0.0007 (14)	−0.0011 (13)
C10	0.0283 (16)	0.0393 (16)	0.0352 (16)	0.0036 (15)	−0.0006 (13)	−0.0050 (13)
C11	0.0379 (19)	0.0416 (16)	0.0403 (18)	0.0101 (16)	0.0005 (15)	0.0011 (15)
C12	0.0426 (19)	0.0402 (17)	0.0390 (18)	0.0041 (16)	0.0081 (16)	0.0036 (14)
C13	0.059 (2)	0.0472 (19)	0.0317 (17)	−0.0014 (18)	−0.0026 (17)	−0.0016 (15)
C14	0.060 (3)	0.082 (3)	0.052 (2)	0.011 (2)	−0.012 (2)	−0.007 (2)
C15	0.078 (3)	0.104 (3)	0.059 (3)	0.007 (3)	−0.026 (3)	−0.008 (3)
C16	0.076 (3)	0.053 (2)	0.045 (2)	0.000 (2)	−0.008 (2)	−0.0016 (18)
C17	0.054 (2)	0.085 (3)	0.081 (3)	−0.019 (2)	−0.002 (2)	0.037 (2)
C18	0.058 (2)	0.069 (3)	0.038 (2)	0.014 (2)	−0.0016 (19)	−0.0009 (18)
C20	0.0375 (18)	0.0431 (17)	0.0383 (17)	0.0029 (16)	0.0114 (16)	0.0049 (14)

Geometric parameters (Å, º)

O1—C16	1.350 (5)	C6—H6A	0.9800
O1—C15	1.354 (5)	C7—C8	1.528 (5)
O2—C20	1.372 (4)	C7—H7A	0.9700
O2—C12	1.411 (4)	C7—H7B	0.9700
O3—C20	1.196 (4)	C8—C17	1.527 (5)
O4—C18	1.365 (5)	C8—C9	1.559 (4)
O4—C6	1.439 (4)	C8—H8A	0.9800
O5—C18	1.202 (4)	C9—C11	1.494 (4)
C1—C2	1.517 (5)	C9—C20	1.522 (4)
C1—C10	1.526 (4)	C9—C10	1.566 (4)
C1—H1A	0.9700	C10—H10A	0.9800
C1—H1B	0.9700	C11—C12	1.312 (4)
C2—C3	1.529 (5)	C11—H11A	0.9300
C2—H2A	0.9700	C12—C13	1.442 (4)
C2—H2B	0.9700	C13—C16	1.334 (5)
C3—C4	1.480 (5)	C13—C14	1.439 (6)
C3—H3A	0.9700	C14—C15	1.323 (5)
C3—H3B	0.9700	C14—H14A	0.9300
C4—C5	1.316 (4)	C15—H15A	0.9300
C4—C18	1.466 (5)	C16—H16A	0.9300
C5—C6	1.471 (4)	C17—H17A	0.9600
C5—C10	1.478 (4)	C17—H17B	0.9600
C6—C7	1.508 (5)	C17—H17C	0.9600
C16—O1—C15	105.8 (3)	C9—C8—H8A	107.1
C20—O2—C12	107.5 (2)	C11—C9—C20	100.1 (2)
C18—O4—C6	109.1 (3)	C11—C9—C8	113.3 (2)
C2—C1—C10	111.7 (3)	C20—C9—C8	110.1 (3)
C2—C1—H1A	109.3	C11—C9—C10	111.0 (3)
C10—C1—H1A	109.3	C20—C9—C10	110.9 (2)
C2—C1—H1B	109.3	C8—C9—C10	111.0 (2)
C10—C1—H1B	109.3	C5—C10—C1	109.2 (2)
H1A—C1—H1B	107.9	C5—C10—C9	110.1 (3)
C1—C2—C3	112.0 (3)	C1—C10—C9	114.5 (2)
C1—C2—H2A	109.2	C5—C10—H10A	107.6
C3—C2—H2A	109.2	C1—C10—H10A	107.6
C1—C2—H2B	109.2	C9—C10—H10A	107.6
C3—C2—H2B	109.2	C12—C11—C9	110.8 (3)
H2A—C2—H2B	107.9	C12—C11—H11A	124.6
C4—C3—C2	108.6 (3)	C9—C11—H11A	124.6
C4—C3—H3A	110.0	C11—C12—O2	111.8 (3)
C2—C3—H3A	110.0	C11—C12—C13	134.0 (3)
C4—C3—H3B	110.0	O2—C12—C13	114.3 (3)
C2—C3—H3B	110.0	C16—C13—C14	105.4 (3)
H3A—C3—H3B	108.3	C16—C13—C12	128.5 (4)
C5—C4—C18	107.8 (3)	C14—C13—C12	126.1 (3)
C5—C4—C3	124.0 (3)	C15—C14—C13	105.9 (4)
C18—C4—C3	128.1 (3)	C15—C14—H14A	127.1
C4—C5—C6	110.7 (3)	C13—C14—H14A	127.1
C4—C5—C10	126.8 (3)	C14—C15—O1	111.5 (4)
C6—C5—C10	122.4 (3)	C14—C15—H15A	124.3
O4—C6—C5	104.0 (3)	O1—C15—H15A	124.3
O4—C6—C7	114.1 (3)	C13—C16—O1	111.4 (4)
C5—C6—C7	110.9 (3)	C13—C16—H16A	124.3
O4—C6—H6A	109.2	O1—C16—H16A	124.3
C5—C6—H6A	109.2	C8—C17—H17A	109.5
C7—C6—H6A	109.2	C8—C17—H17B	109.5
C6—C7—C8	110.0 (3)	H17A—C17—H17B	109.5
C6—C7—H7A	109.7	C8—C17—H17C	109.5
C8—C7—H7A	109.7	H17A—C17—H17C	109.5
C6—C7—H7B	109.7	H17B—C17—H17C	109.5
C8—C7—H7B	109.7	O5—C18—O4	121.2 (4)
H7A—C7—H7B	108.2	O5—C18—C4	130.7 (4)
C17—C8—C7	109.7 (3)	O4—C18—C4	108.2 (3)
C17—C8—C9	111.8 (3)	O3—C20—O2	120.4 (3)
C7—C8—C9	113.7 (3)	O3—C20—C9	129.9 (3)
C17—C8—H8A	107.1	O2—C20—C9	109.7 (3)
C7—C8—H8A	107.1
C10—C1—C2—C3	62.5 (4)	C20—C9—C10—C1	43.6 (4)
C1—C2—C3—C4	−46.3 (4)	C8—C9—C10—C1	166.3 (3)
C2—C3—C4—C5	12.6 (5)	C20—C9—C11—C12	−1.1 (4)
C2—C3—C4—C18	−164.1 (3)	C8—C9—C11—C12	−118.3 (3)
C18—C4—C5—C6	2.6 (4)	C10—C9—C11—C12	116.1 (3)
C3—C4—C5—C6	−174.7 (3)	C9—C11—C12—O2	2.1 (4)
C18—C4—C5—C10	−174.7 (3)	C9—C11—C12—C13	−178.4 (4)
C3—C4—C5—C10	8.1 (5)	C20—O2—C12—C11	−2.2 (3)
C18—O4—C6—C5	5.5 (3)	C20—O2—C12—C13	178.2 (3)
C18—O4—C6—C7	126.5 (3)	C11—C12—C13—C16	−166.0 (4)
C4—C5—C6—O4	−5.0 (4)	O2—C12—C13—C16	13.5 (5)
C10—C5—C6—O4	172.4 (3)	C11—C12—C13—C14	13.7 (7)
C4—C5—C6—C7	−128.1 (3)	O2—C12—C13—C14	−166.8 (3)
C10—C5—C6—C7	49.3 (4)	C16—C13—C14—C15	0.3 (5)
O4—C6—C7—C8	−168.6 (3)	C12—C13—C14—C15	−179.5 (4)
C5—C6—C7—C8	−51.5 (4)	C13—C14—C15—O1	−0.9 (5)
C6—C7—C8—C17	−176.9 (3)	C16—O1—C15—C14	1.2 (5)
C6—C7—C8—C9	57.0 (4)	C14—C13—C16—O1	0.4 (4)
C17—C8—C9—C11	56.6 (4)	C12—C13—C16—O1	−179.8 (4)
C7—C8—C9—C11	−178.4 (3)	C15—O1—C16—C13	−1.0 (5)
C17—C8—C9—C20	−54.5 (4)	C6—O4—C18—O5	175.4 (4)
C7—C8—C9—C20	70.4 (3)	C6—O4—C18—C4	−4.2 (4)
C17—C8—C9—C10	−177.8 (3)	C5—C4—C18—O5	−178.5 (4)
C7—C8—C9—C10	−52.8 (3)	C3—C4—C18—O5	−1.4 (6)
C4—C5—C10—C1	6.0 (4)	C5—C4—C18—O4	1.0 (4)
C6—C5—C10—C1	−171.0 (3)	C3—C4—C18—O4	178.1 (3)
C4—C5—C10—C9	132.5 (3)	C12—O2—C20—O3	−179.1 (3)
C6—C5—C10—C9	−44.4 (4)	C12—O2—C20—C9	1.4 (3)
C2—C1—C10—C5	−39.7 (4)	C11—C9—C20—O3	−179.7 (3)
C2—C1—C10—C9	−163.7 (3)	C8—C9—C20—O3	−60.2 (4)
C11—C9—C10—C5	169.8 (2)	C10—C9—C20—O3	63.1 (4)
C20—C9—C10—C5	−79.9 (3)	C11—C9—C20—O2	−0.3 (3)
C8—C9—C10—C5	42.9 (3)	C8—C9—C20—O2	119.3 (3)
C11—C9—C10—C1	−66.8 (3)	C10—C9—C20—O2	−117.5 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C7—H7B···O3	0.97	2.56	3.172 (4)	121
C16—H16A···O5^i	0.93	2.49	3.223 (4)	136

Symmetry code: (i) −x+3/2, −y+1, z+1/2.