N-(Fluoren-9-ylmethoxy-carbon-yl)-l-isoleucine.

In the crystal structure of the title compound [systematic name fluoren-9-ylmethyl N-(1-carb-oxy-2-methyl-butyl)carbamate], C(21)H(23)NO(4), the mol-ecular plane of the O=C-NH-C(α) unit is slightly pyramidalized. The N atom deviates from the basal plane by 0.2086 (12) Å. The O=C-N-C(α) torsion angle is -17.2 (2)°, and the C-N and O=C bond lengths are 1.3675 (17) and 1.2122 (17) Å, respectively. Apparently the character of the sp(2) hybrids of the mol-ecular plane is, to some extent, reduced. The crystal structure exhibits two inter-molecular hydrogen bonds (O-H⋯O and N-H⋯O), in which the hydr-oxy O atom acts as a donor to the carbonyl group and an acceptor of the amide group, respectively.

Related literature

For related literature on the crystal structures of N-α-fluoren-9-ylmethoxy­carbonyl-protected amino acids, see: Valle et al. (1984 ▶); Yamada, Hashizume & Shimizu (2008 ▶); Yamada, Hashizume, Shimizu et al. (2008 ▶).

Experimental

Crystal data

C21H23NO4

M = 353.40

Orthorhombic,

a = 5.3337 (2) Å

b = 13.6965 (4) Å

c = 25.2514 (9) Å

V = 1844.70 (11) Å3

Z = 4

Mo Kα radiation

μ = 0.09 mm−1

T = 90 K

0.77 × 0.06 × 0.04 mm

Data collection

Rigaku AFC-8 diffractometer with Saturn70 CCD

Absorption correction: none

19825 measured reflections

3351 independent reflections

2993 reflections with I > 2σ(I)

R int = 0.043

Refinement

R[F 2 > 2σ(F 2)] = 0.034

wR(F 2) = 0.084

S = 1.03

3351 reflections

327 parameters

All H-atom parameters refined

Δρmax = 0.23 e Å−3

Δρmin = −0.18 e Å−3

Data collection: CrystalClear (Rigaku/MSC, 2005 ▶); cell refinement: HKL-2000 (Otwinowski & Minor, 1997 ▶); data reduction: HKL-2000; program(s) used to solve structure: SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808021855/is2313sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808021855/is2313Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C21H23NO4	F000 = 752
Mr = 353.40	Dx = 1.272 Mg m−3
Orthorhombic, P212121	Mo Kα radiation λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 19896 reflections
a = 5.3337 (2) Å	θ = 1.6–31.0º
b = 13.6965 (4) Å	µ = 0.09 mm−1
c = 25.2514 (9) Å	T = 90 K
V = 1844.70 (11) Å3	Needle, colourless
Z = 4	0.77 × 0.06 × 0.04 mm

Rigaku AFC-8 with Saturn70 CCD diffractometer	3351 independent reflections
Radiation source: fine-focus rotating anode	2993 reflections with I > 2σ(I)
Monochromator: confocal	Rint = 0.043
Detector resolution: 28.5714 pixels mm-1	θmax = 31.0º
T = 90 K	θmin = 1.6º
ω scans	h = −7→7
Absorption correction: none	k = −13→19
19825 measured reflections	l = −36→36

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.034	All H-atom parameters refined
wR(F2) = 0.084	w = 1/[σ2(Fo2) + (0.0427P)2 + 0.2178P] where P = (Fo2 + 2Fc2)/3
S = 1.03	(Δ/σ)max < 0.001
3351 reflections	Δρmax = 0.23 e Å−3
327 parameters	Δρmin = −0.18 e Å−3
Primary atom site location: structure-invariant direct methods	Extinction correction: none

Experimental. All Friedel pairs were merged, and all f''s of containing atoms were set to zero.

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against all reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on all data will be even larger.

	x	y	z	Uiso*/Ueq
O1	−0.0029 (2)	0.12876 (8)	0.48657 (4)	0.0236 (2)
H1H	−0.038 (4)	0.1865 (16)	0.5004 (8)	0.040 (6)*
O2	0.3719 (2)	0.19896 (8)	0.47355 (4)	0.0287 (2)
O3	0.4252 (2)	0.06814 (8)	0.34059 (4)	0.0254 (2)
O4	0.83023 (19)	0.09577 (8)	0.36430 (4)	0.0219 (2)
N1	0.5644 (2)	0.03926 (9)	0.42480 (4)	0.0201 (2)
H1N	0.683 (4)	0.0588 (14)	0.4465 (7)	0.028 (5)*
C1	0.3145 (3)	0.03122 (10)	0.44681 (5)	0.0198 (3)
H1	0.201 (4)	0.0187 (13)	0.4152 (7)	0.029 (5)*
C2	0.2942 (3)	−0.05077 (10)	0.48868 (5)	0.0221 (3)
H2	0.124 (4)	−0.0497 (14)	0.5026 (7)	0.025 (5)*
C3	0.4615 (4)	−0.03098 (13)	0.53677 (6)	0.0322 (4)
H3A	0.641 (5)	−0.0353 (16)	0.5239 (9)	0.045 (6)*
H3B	0.433 (4)	0.0382 (16)	0.5491 (8)	0.043 (6)*
C4	0.4141 (5)	−0.10079 (16)	0.58280 (7)	0.0429 (5)
H4A	0.524 (5)	−0.0821 (19)	0.6146 (10)	0.063 (7)*
H4B	0.449 (5)	−0.1707 (17)	0.5734 (9)	0.050 (6)*
H4C	0.237 (6)	−0.1000 (19)	0.5925 (10)	0.067 (8)*
C5	0.3466 (4)	−0.14964 (12)	0.46325 (7)	0.0321 (4)
H5A	0.235 (4)	−0.1587 (15)	0.4308 (9)	0.043 (6)*
H5B	0.302 (4)	−0.2030 (14)	0.4887 (8)	0.034 (5)*
H5C	0.526 (5)	−0.1554 (16)	0.4525 (8)	0.040 (6)*
C6	0.2335 (3)	0.12921 (10)	0.47018 (5)	0.0209 (3)
C7	0.5913 (3)	0.06860 (10)	0.37335 (5)	0.0195 (3)
C8	0.8909 (3)	0.12808 (11)	0.31097 (5)	0.0214 (3)
H8A	1.018 (4)	0.0822 (13)	0.2966 (7)	0.023 (4)*
H8B	0.746 (3)	0.1242 (12)	0.2898 (6)	0.016 (4)*
C9	0.9917 (3)	0.23248 (10)	0.31308 (5)	0.0218 (3)
H9	1.136 (4)	0.2340 (14)	0.3393 (7)	0.033 (5)*
C10	0.7894 (3)	0.30772 (10)	0.32413 (5)	0.0227 (3)
C11	0.6461 (3)	0.32177 (11)	0.36923 (6)	0.0273 (3)
H11	0.678 (4)	0.2802 (14)	0.4013 (7)	0.032 (5)*
C12	0.4624 (3)	0.39449 (12)	0.36893 (6)	0.0307 (3)
H12	0.365 (4)	0.4056 (14)	0.4011 (8)	0.037 (5)*
C13	0.4225 (3)	0.45181 (12)	0.32390 (7)	0.0307 (3)
H13	0.289 (4)	0.5019 (16)	0.3241 (8)	0.038 (5)*
C14	0.5681 (3)	0.43873 (11)	0.27881 (6)	0.0272 (3)
H14	0.540 (4)	0.4779 (14)	0.2461 (8)	0.033 (5)*
C15	0.7524 (3)	0.36682 (10)	0.27912 (5)	0.0222 (3)
C16	0.9326 (3)	0.33767 (10)	0.23824 (5)	0.0218 (3)
C17	0.9758 (3)	0.37521 (11)	0.18767 (5)	0.0251 (3)
H17	0.877 (4)	0.4283 (15)	0.1741 (7)	0.033 (5)*
C18	1.1730 (3)	0.33647 (11)	0.15819 (6)	0.0271 (3)
H18	1.201 (4)	0.3628 (13)	0.1225 (7)	0.027 (4)*
C19	1.3197 (3)	0.26081 (11)	0.17784 (6)	0.0270 (3)
H19	1.452 (4)	0.2330 (14)	0.1573 (7)	0.030 (5)*
C20	1.2715 (3)	0.22127 (11)	0.22789 (6)	0.0248 (3)
H20	1.374 (4)	0.1663 (14)	0.2398 (7)	0.029 (5)*
C21	1.0792 (3)	0.26106 (10)	0.25795 (5)	0.0219 (3)

	U11	U22	U33	U12	U13	U23
O1	0.0187 (5)	0.0237 (5)	0.0284 (5)	0.0005 (4)	0.0011 (4)	−0.0042 (4)
O2	0.0264 (6)	0.0232 (5)	0.0365 (5)	−0.0060 (5)	0.0050 (5)	−0.0056 (4)
O3	0.0191 (5)	0.0341 (5)	0.0231 (4)	−0.0028 (5)	−0.0025 (4)	0.0014 (4)
O4	0.0169 (5)	0.0277 (5)	0.0210 (4)	−0.0022 (4)	−0.0003 (4)	0.0047 (4)
N1	0.0162 (5)	0.0243 (5)	0.0199 (5)	−0.0010 (5)	−0.0006 (4)	0.0006 (4)
C1	0.0166 (6)	0.0209 (6)	0.0219 (6)	−0.0012 (5)	0.0009 (5)	−0.0011 (5)
C2	0.0196 (6)	0.0214 (6)	0.0254 (6)	−0.0013 (5)	0.0031 (5)	0.0008 (5)
C3	0.0373 (10)	0.0340 (8)	0.0253 (7)	−0.0043 (7)	−0.0023 (6)	0.0050 (6)
C4	0.0577 (13)	0.0424 (10)	0.0287 (8)	−0.0021 (10)	−0.0003 (8)	0.0117 (7)
C5	0.0400 (10)	0.0229 (7)	0.0334 (7)	0.0015 (7)	0.0038 (7)	0.0012 (6)
C6	0.0197 (7)	0.0229 (6)	0.0203 (5)	−0.0006 (6)	−0.0005 (5)	−0.0009 (5)
C7	0.0177 (6)	0.0186 (6)	0.0222 (6)	−0.0001 (5)	0.0011 (5)	−0.0005 (4)
C8	0.0203 (7)	0.0250 (6)	0.0189 (5)	−0.0008 (6)	0.0003 (5)	0.0040 (5)
C9	0.0197 (6)	0.0244 (6)	0.0214 (6)	−0.0024 (5)	−0.0004 (5)	0.0024 (5)
C10	0.0221 (7)	0.0228 (6)	0.0233 (6)	−0.0024 (6)	−0.0008 (5)	−0.0009 (5)
C11	0.0298 (8)	0.0280 (7)	0.0239 (6)	−0.0033 (6)	0.0026 (6)	−0.0008 (5)
C12	0.0306 (8)	0.0310 (8)	0.0306 (7)	−0.0015 (7)	0.0065 (6)	−0.0053 (6)
C13	0.0287 (8)	0.0268 (7)	0.0367 (7)	0.0032 (7)	0.0011 (6)	−0.0055 (6)
C14	0.0292 (8)	0.0239 (7)	0.0287 (7)	0.0014 (6)	−0.0022 (6)	−0.0001 (5)
C15	0.0217 (7)	0.0215 (6)	0.0234 (6)	−0.0035 (6)	−0.0012 (5)	−0.0013 (5)
C16	0.0206 (7)	0.0215 (6)	0.0234 (6)	−0.0034 (5)	−0.0004 (5)	−0.0001 (5)
C17	0.0295 (8)	0.0228 (6)	0.0230 (6)	−0.0015 (6)	−0.0005 (6)	0.0018 (5)
C18	0.0322 (9)	0.0267 (7)	0.0224 (6)	−0.0064 (6)	0.0031 (6)	0.0012 (5)
C19	0.0245 (8)	0.0290 (7)	0.0274 (6)	−0.0037 (6)	0.0040 (6)	−0.0027 (5)
C20	0.0209 (7)	0.0257 (7)	0.0277 (6)	−0.0028 (6)	0.0008 (6)	0.0007 (5)
C21	0.0192 (7)	0.0233 (6)	0.0230 (6)	−0.0039 (6)	−0.0005 (5)	0.0012 (5)

O1—C6	1.3270 (18)	C8—H8B	0.942 (17)
O1—H1H	0.88 (2)	C9—C10	1.518 (2)
O2—C6	1.2102 (18)	C9—C21	1.5196 (18)
O3—C7	1.2122 (17)	C9—H9	1.01 (2)
O4—C7	1.3471 (17)	C10—C11	1.385 (2)
O4—C8	1.4541 (16)	C10—C15	1.4092 (19)
N1—C7	1.3675 (17)	C11—C12	1.397 (2)
N1—C1	1.4484 (18)	C11—H11	1.005 (19)
N1—H1N	0.88 (2)	C12—C13	1.398 (2)
C1—C6	1.5284 (19)	C12—H12	0.98 (2)
C1—C2	1.5462 (19)	C13—C14	1.390 (2)
C1—H1	1.015 (19)	C13—H13	0.99 (2)
C2—C5	1.525 (2)	C14—C15	1.392 (2)
C2—C3	1.531 (2)	C14—H14	1.00 (2)
C2—H2	0.975 (19)	C15—C16	1.466 (2)
C3—C4	1.526 (2)	C16—C17	1.3957 (19)
C3—H3A	1.01 (2)	C16—C21	1.400 (2)
C3—H3B	1.01 (2)	C17—C18	1.393 (2)
C4—H4A	1.03 (3)	C17—H17	0.96 (2)
C4—H4B	1.00 (2)	C18—C19	1.390 (2)
C4—H4C	0.98 (3)	C18—H18	0.983 (18)
C5—H5A	1.02 (2)	C19—C20	1.399 (2)
C5—H5B	1.00 (2)	C19—H19	0.96 (2)
C5—H5C	1.00 (2)	C20—C21	1.387 (2)
C8—C9	1.529 (2)	C20—H20	0.98 (2)
C8—H8A	0.993 (19)
C6—O1—H1H	108.7 (15)	C9—C8—H8B	111.2 (10)
C7—O4—C8	116.86 (11)	H8A—C8—H8B	108.6 (14)
C7—N1—C1	118.91 (12)	C10—C9—C21	102.23 (11)
C7—N1—H1N	115.3 (12)	C10—C9—C8	113.04 (12)
C1—N1—H1N	116.5 (12)	C21—C9—C8	108.49 (11)
N1—C1—C6	109.97 (11)	C10—C9—H9	113.8 (11)
N1—C1—C2	112.46 (11)	C21—C9—H9	111.1 (11)
C6—C1—C2	110.73 (11)	C8—C9—H9	108.0 (11)
N1—C1—H1	105.0 (11)	C11—C10—C15	120.39 (14)
C6—C1—H1	106.5 (10)	C11—C10—C9	129.63 (13)
C2—C1—H1	111.9 (11)	C15—C10—C9	109.96 (12)
C5—C2—C3	112.62 (14)	C10—C11—C12	118.80 (14)
C5—C2—C1	110.13 (12)	C10—C11—H11	119.3 (11)
C3—C2—C1	111.90 (12)	C12—C11—H11	121.9 (11)
C5—C2—H2	109.7 (11)	C11—C12—C13	120.76 (15)
C3—C2—H2	104.8 (10)	C11—C12—H12	118.6 (12)
C1—C2—H2	107.5 (11)	C13—C12—H12	120.6 (12)
C4—C3—C2	113.36 (15)	C14—C13—C12	120.59 (15)
C4—C3—H3A	111.4 (12)	C14—C13—H13	119.7 (12)
C2—C3—H3A	106.6 (13)	C12—C13—H13	119.7 (12)
C4—C3—H3B	109.2 (12)	C13—C14—C15	118.76 (14)
C2—C3—H3B	108.9 (12)	C13—C14—H14	121.6 (12)
H3A—C3—H3B	107.1 (19)	C15—C14—H14	119.6 (12)
C3—C4—H4A	110.2 (15)	C14—C15—C10	120.68 (13)
C3—C4—H4B	112.8 (13)	C14—C15—C16	130.69 (13)
H4A—C4—H4B	109 (2)	C10—C15—C16	108.64 (13)
C3—C4—H4C	110.1 (16)	C17—C16—C21	120.60 (13)
H4A—C4—H4C	111 (2)	C17—C16—C15	130.71 (14)
H4B—C4—H4C	104 (2)	C21—C16—C15	108.66 (12)
C2—C5—H5A	109.8 (12)	C18—C17—C16	118.24 (14)
C2—C5—H5B	109.5 (11)	C18—C17—H17	120.8 (12)
H5A—C5—H5B	106.7 (17)	C16—C17—H17	121.0 (12)
C2—C5—H5C	111.2 (13)	C19—C18—C17	121.20 (14)
H5A—C5—H5C	109.4 (17)	C19—C18—H18	121.0 (11)
H5B—C5—H5C	110.2 (17)	C17—C18—H18	117.7 (11)
O2—C6—O1	124.13 (13)	C18—C19—C20	120.52 (15)
O2—C6—C1	123.22 (13)	C18—C19—H19	121.3 (11)
O1—C6—C1	112.64 (12)	C20—C19—H19	118.1 (11)
O3—C7—O4	125.25 (12)	C21—C20—C19	118.54 (14)
O3—C7—N1	124.76 (13)	C21—C20—H20	123.1 (11)
O4—C7—N1	109.97 (12)	C19—C20—H20	118.4 (11)
O4—C8—C9	109.32 (11)	C20—C21—C16	120.86 (12)
O4—C8—H8A	107.3 (10)	C20—C21—C9	128.82 (13)
C9—C8—H8A	111.3 (10)	C16—C21—C9	110.31 (12)
O4—C8—H8B	109.0 (10)
C7—N1—C1—C6	−88.14 (15)	C12—C13—C14—C15	0.7 (2)
C7—N1—C1—C2	147.96 (12)	C13—C14—C15—C10	0.6 (2)
N1—C1—C2—C5	−62.96 (16)	C13—C14—C15—C16	−179.33 (15)
C6—C1—C2—C5	173.56 (13)	C11—C10—C15—C14	−1.4 (2)
N1—C1—C2—C3	63.11 (16)	C9—C10—C15—C14	177.23 (13)
C6—C1—C2—C3	−60.37 (16)	C11—C10—C15—C16	178.54 (13)
C5—C2—C3—C4	−65.0 (2)	C9—C10—C15—C16	−2.87 (16)
C1—C2—C3—C4	170.27 (15)	C14—C15—C16—C17	1.9 (3)
N1—C1—C6—O2	−6.34 (19)	C10—C15—C16—C17	−178.03 (15)
C2—C1—C6—O2	118.56 (15)	C14—C15—C16—C21	179.97 (15)
N1—C1—C6—O1	174.17 (11)	C10—C15—C16—C21	0.08 (16)
C2—C1—C6—O1	−60.94 (15)	C21—C16—C17—C18	−1.9 (2)
C8—O4—C7—O3	0.8 (2)	C15—C16—C17—C18	176.00 (14)
C8—O4—C7—N1	179.33 (11)	C16—C17—C18—C19	1.5 (2)
C1—N1—C7—O3	−17.2 (2)	C17—C18—C19—C20	0.3 (2)
C1—N1—C7—O4	164.18 (11)	C18—C19—C20—C21	−1.8 (2)
C7—O4—C8—C9	121.17 (13)	C19—C20—C21—C16	1.4 (2)
O4—C8—C9—C10	−73.17 (14)	C19—C20—C21—C9	−179.33 (14)
O4—C8—C9—C21	174.19 (12)	C17—C16—C21—C20	0.5 (2)
C21—C9—C10—C11	−177.33 (15)	C15—C16—C21—C20	−177.88 (13)
C8—C9—C10—C11	66.3 (2)	C17—C16—C21—C9	−178.93 (13)
C21—C9—C10—C15	4.25 (15)	C15—C16—C21—C9	2.74 (16)
C8—C9—C10—C15	−112.17 (13)	C10—C9—C21—C20	176.47 (14)
C15—C10—C11—C12	0.9 (2)	C8—C9—C21—C20	−63.88 (19)
C9—C10—C11—C12	−177.41 (15)	C10—C9—C21—C16	−4.22 (15)
C10—C11—C12—C13	0.4 (2)	C8—C9—C21—C16	115.44 (13)
C11—C12—C13—C14	−1.2 (3)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1H···O2i	0.88 (2)	1.77 (2)	2.6511 (14)	176 (2)
N1—H1N···O1ii	0.88 (2)	2.18 (2)	3.0433 (16)	167.6 (17)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1H⋯O2i	0.88 (2)	1.77 (2)	2.6511 (14)	176 (2)
N1—H1N⋯O1ii	0.88 (2)	2.18 (2)	3.0433 (16)	167.6 (17)

Symmetry codes: (i) ; (ii) .