Di-tert-butyl N-[2,6-bis-(methoxy-meth-oxy)phen-yl]imino-diacetate.

The title mol-ecule, C(20)H(31)NO(8), has pseudo-C2 symmetry about the C-N bond, with the bis-(tert-butoxy-carbon-yl)amino group twisted from the benzene ring plane by ca 60° and the bulky tert-butoxy-carbonyl (Boc) groups are orientated away from the substituted aniline group. As part of an anti-bacterial drug discovery programme furnishing analogues of platensimycin, we unexpectedly synthesized the bis-Boc-protected aniline.

Related literature

For the synthesis, see: Nicolaou et al. (2006 ▶)Khakham (2007 ▶). For related structures, see: Marino et al. (2002 ▶); Macleod et al. (2003 ▶). For the protection of amino groups in synthesis, see: ; Kshirsagar (2008 ▶).

Experimental

Crystal data

C20H31NO8

M = 413.46

Monoclinic,

a = 11.2544 (3) Å

b = 19.6759 (6) Å

c = 9.8325 (3) Å

β = 93.207 (1)°

V = 2173.90 (11) Å3

Z = 4

Mo Kα radiation

μ = 0.10 mm−1

T = 123 K

0.25 × 0.25 × 0.25 mm

Data collection

Bruker X8 APEX CCD diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 1997 ▶) T min = 0.95, T max = 0.97

15504 measured reflections

4207 independent reflections

3714 reflections with I > 2σ(I)

R int = 0.026

Refinement

R[F 2 > 2σ(F 2)] = 0.037

wR(F 2) = 0.095

S = 1.05

4207 reflections

264 parameters

H-atom parameters constrained

Δρmax = 0.25 e Å−3

Δρmin = −0.22 e Å−3

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: n class="Gene">APEX2 and SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: X-SEED (Barbour, 2001 ▶); software used to prepare material for publication: CIFTAB (Sheldrick, 1997 ▶).

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809009246/pv2145sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809009246/pv2145Isup2.hkl

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

C20H31NO8	F(000) = 888
Mr = 413.46	Dx = 1.263 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 15504 reflections
a = 11.2544 (3) Å	θ = 2.1–26.0°
b = 19.6759 (6) Å	µ = 0.10 mm−1
c = 9.8325 (3) Å	T = 123 K
β = 93.207 (1)°	Prism, colourless
V = 2173.90 (11) Å3	0.25 × 0.25 × 0.25 mm
Z = 4

Bruker X8 APEX CCD diffractometer	4207 independent reflections
Radiation source: fine-focus sealed tube	3714 reflections with I > 2σ(I)
graphite	Rint = 0.026
Thin–slice φ and ω scans	θmax = 26.0°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1997)	h = −13→11
Tmin = 0.95, Tmax = 0.97	k = −24→24
15504 measured reflections	l = −12→12

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.095	H-atom parameters constrained
S = 1.05	w = 1/[σ2(Fo2) + (0.0455P)2 + 0.7413P] where P = (Fo2 + 2Fc2)/3
4207 reflections	(Δ/σ)max < 0.001
264 parameters	Δρmax = 0.25 e Å−3
0 restraints	Δρmin = −0.22 e Å−3

Experimental. 1H NMR (CDCl3) δ 1.45(18H, s, tert-Bu), 3.51 (6H, s, OCH3), 5.21 (4H, s, OCH2O), 6.85 (2H, d, J = 8 Hz, H3 H5), 7.21 (1H, t, J = 8 Hz, H4). 13C NMR (CDCl3) δ 27.9 (CH3), 56.0 (CH3), 82.0 (CH2), 95.0 (CH2), 108.7 (CH), 128.7 (CH), 151.5 (Cq), 162.0 (Cq). ESI MS (20 V) m/z 844 ([2M+NH4]+, 25%), 414 ([M+H]+, 26%), 358 (35%), 302 (100%), 258 (40%), 182 (39%).

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 > σ(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	0.01820 (8)	0.15220 (4)	0.49516 (9)	0.0208 (2)
O2	−0.17789 (8)	0.19162 (5)	0.45496 (10)	0.0239 (2)
O3	0.20418 (8)	0.02812 (4)	0.84955 (9)	0.0222 (2)
O4	0.22082 (9)	−0.08991 (5)	0.87902 (10)	0.0275 (2)
O5	0.32175 (8)	0.04924 (4)	0.57699 (9)	0.0226 (2)
O6	0.40454 (8)	0.13528 (5)	0.70366 (9)	0.0215 (2)
O7	0.10556 (8)	0.22153 (4)	0.75269 (9)	0.0209 (2)
O8	0.26357 (8)	0.23752 (4)	0.62311 (9)	0.0189 (2)
N1	0.20550 (9)	0.13091 (5)	0.66923 (10)	0.0170 (2)
C1	0.10389 (11)	0.08748 (6)	0.67245 (12)	0.0169 (3)
C2	0.00578 (11)	0.09870 (6)	0.58212 (12)	0.0183 (3)
C3	−0.09338 (12)	0.05666 (6)	0.58451 (14)	0.0224 (3)
H3	−0.1612	0.0646	0.5247	0.027*
C4	−0.09125 (12)	0.00289 (7)	0.67605 (14)	0.0245 (3)
H4	−0.1581	−0.0266	0.6766	0.029*
C5	0.00498 (12)	−0.00910 (6)	0.76637 (14)	0.0228 (3)
H5	0.0042	−0.0461	0.8283	0.027*
C6	0.10309 (11)	0.03395 (6)	0.76507 (12)	0.0188 (3)
C7	−0.07663 (12)	0.16675 (7)	0.39715 (13)	0.0223 (3)
H7A	−0.0489	0.2006	0.3315	0.027*
H7B	−0.0976	0.1247	0.3459	0.027*
C8	−0.15998 (14)	0.25694 (7)	0.51580 (17)	0.0344 (4)
H8A	−0.1033	0.2531	0.5948	0.052*
H8B	−0.2360	0.2744	0.5452	0.052*
H8C	−0.1284	0.2882	0.4492	0.052*
C9	0.21192 (14)	−0.02718 (7)	0.94256 (13)	0.0283 (3)
H9A	0.2824	−0.0206	1.0061	0.034*
H9B	0.1405	−0.0271	0.9969	0.034*
C10	0.32667 (13)	−0.09618 (8)	0.80655 (16)	0.0331 (3)
H10A	0.3254	−0.0626	0.7328	0.050*
H10B	0.3310	−0.1420	0.7681	0.050*
H10C	0.3962	−0.0882	0.8690	0.050*
C11	0.31523 (11)	0.10078 (6)	0.64174 (12)	0.0174 (3)
C12	0.18617 (11)	0.20088 (6)	0.68888 (11)	0.0159 (2)
C13	0.52977 (12)	0.11794 (7)	0.67929 (14)	0.0246 (3)
C14	0.55807 (14)	0.04678 (8)	0.73059 (17)	0.0376 (4)
H14A	0.5129	0.0136	0.6741	0.056*
H14B	0.5362	0.0427	0.8253	0.056*
H14C	0.6434	0.0380	0.7255	0.056*
C15	0.59817 (13)	0.17074 (9)	0.76495 (17)	0.0393 (4)
H15A	0.5830	0.1640	0.8612	0.059*
H15B	0.5721	0.2163	0.7365	0.059*
H15C	0.6835	0.1659	0.7524	0.059*
C16	0.55154 (13)	0.12683 (9)	0.53009 (15)	0.0351 (4)
H16A	0.5067	0.0923	0.4767	0.053*
H16B	0.6367	0.1217	0.5165	0.053*
H16C	0.5253	0.1722	0.5003	0.053*
C17	0.26643 (12)	0.31241 (6)	0.63900 (13)	0.0200 (3)
C18	0.15042 (12)	0.34337 (7)	0.58381 (13)	0.0238 (3)
H18A	0.1360	0.3304	0.4881	0.036*
H18B	0.1551	0.3930	0.5910	0.036*
H18C	0.0851	0.3267	0.6366	0.036*
C19	0.36707 (13)	0.33176 (7)	0.54976 (16)	0.0295 (3)
H19A	0.3453	0.3197	0.4549	0.044*
H19B	0.4395	0.3073	0.5804	0.044*
H19C	0.3813	0.3808	0.5563	0.044*
C20	0.29631 (14)	0.33007 (7)	0.78745 (14)	0.0310 (3)
H20A	0.3721	0.3088	0.8174	0.047*
H20B	0.2332	0.3133	0.8434	0.047*
H20C	0.3029	0.3795	0.7973	0.047*

	U11	U22	U33	U12	U13	U23
O1	0.0161 (5)	0.0216 (5)	0.0245 (5)	−0.0008 (4)	−0.0005 (4)	0.0046 (4)
O2	0.0167 (5)	0.0224 (5)	0.0325 (5)	0.0018 (4)	0.0003 (4)	−0.0031 (4)
O3	0.0259 (5)	0.0183 (5)	0.0222 (4)	0.0018 (4)	−0.0017 (4)	0.0016 (3)
O4	0.0336 (6)	0.0189 (5)	0.0300 (5)	0.0040 (4)	0.0022 (4)	0.0032 (4)
O5	0.0207 (5)	0.0203 (5)	0.0269 (5)	0.0022 (4)	0.0023 (4)	−0.0058 (4)
O6	0.0128 (5)	0.0250 (5)	0.0265 (5)	0.0006 (4)	−0.0003 (4)	−0.0060 (4)
O7	0.0225 (5)	0.0181 (4)	0.0227 (4)	0.0014 (4)	0.0074 (4)	−0.0008 (3)
O8	0.0200 (5)	0.0143 (4)	0.0227 (4)	−0.0020 (3)	0.0056 (4)	−0.0010 (3)
N1	0.0135 (5)	0.0146 (5)	0.0230 (5)	0.0002 (4)	0.0017 (4)	−0.0006 (4)
C1	0.0150 (6)	0.0138 (6)	0.0222 (6)	−0.0001 (5)	0.0047 (5)	−0.0026 (5)
C2	0.0176 (7)	0.0157 (6)	0.0219 (6)	0.0022 (5)	0.0050 (5)	−0.0013 (5)
C3	0.0150 (7)	0.0208 (6)	0.0314 (7)	0.0007 (5)	0.0024 (5)	−0.0028 (5)
C4	0.0177 (7)	0.0174 (6)	0.0394 (8)	−0.0031 (5)	0.0102 (6)	−0.0032 (5)
C5	0.0251 (7)	0.0142 (6)	0.0302 (7)	0.0006 (5)	0.0114 (6)	0.0019 (5)
C6	0.0203 (7)	0.0159 (6)	0.0205 (6)	0.0038 (5)	0.0042 (5)	−0.0032 (5)
C7	0.0195 (7)	0.0260 (7)	0.0210 (6)	0.0024 (5)	−0.0016 (5)	−0.0002 (5)
C8	0.0310 (9)	0.0256 (7)	0.0462 (9)	0.0045 (6)	−0.0015 (7)	−0.0094 (6)
C9	0.0428 (9)	0.0222 (7)	0.0197 (6)	0.0051 (6)	0.0017 (6)	0.0033 (5)
C10	0.0296 (8)	0.0281 (8)	0.0415 (8)	0.0070 (6)	0.0001 (6)	−0.0030 (6)
C11	0.0158 (7)	0.0188 (6)	0.0175 (6)	0.0001 (5)	0.0020 (5)	0.0025 (5)
C12	0.0170 (6)	0.0156 (6)	0.0149 (5)	−0.0004 (5)	−0.0011 (5)	−0.0001 (4)
C13	0.0123 (7)	0.0344 (8)	0.0269 (7)	0.0022 (5)	0.0004 (5)	−0.0017 (6)
C14	0.0230 (8)	0.0432 (9)	0.0461 (9)	0.0101 (7)	−0.0037 (7)	0.0073 (7)
C15	0.0194 (8)	0.0537 (10)	0.0445 (9)	−0.0062 (7)	−0.0029 (7)	−0.0104 (8)
C16	0.0192 (8)	0.0569 (10)	0.0295 (8)	−0.0030 (7)	0.0037 (6)	0.0026 (7)
C17	0.0243 (7)	0.0125 (6)	0.0235 (6)	−0.0036 (5)	0.0021 (5)	−0.0007 (5)
C18	0.0275 (8)	0.0195 (6)	0.0249 (6)	0.0018 (5)	0.0046 (5)	0.0037 (5)
C19	0.0261 (8)	0.0219 (7)	0.0413 (8)	−0.0044 (6)	0.0085 (6)	0.0039 (6)
C20	0.0412 (9)	0.0235 (7)	0.0275 (7)	−0.0060 (6)	−0.0066 (6)	−0.0038 (6)

O1—C2	1.3683 (15)	C8—H8C	0.9800
O1—C7	1.4264 (15)	C9—H9A	0.9900
O2—C7	1.3907 (16)	C9—H9B	0.9900
O2—C8	1.4272 (16)	C10—H10A	0.9800
O3—C6	1.3754 (16)	C10—H10B	0.9800
O3—C9	1.4210 (15)	C10—H10C	0.9800
O4—C9	1.3894 (16)	C13—C16	1.5109 (19)
O4—C10	1.4272 (18)	C13—C14	1.516 (2)
O5—C11	1.2017 (15)	C13—C15	1.519 (2)
O6—C11	1.3317 (15)	C14—H14A	0.9800
O6—C13	1.4825 (16)	C14—H14B	0.9800
O7—C12	1.2023 (15)	C14—H14C	0.9800
O8—C12	1.3266 (15)	C15—H15A	0.9800
O8—C17	1.4820 (14)	C15—H15B	0.9800
N1—C12	1.4088 (15)	C15—H15C	0.9800
N1—C11	1.4096 (16)	C16—H16A	0.9800
N1—C1	1.4292 (16)	C16—H16B	0.9800
C1—C6	1.3928 (17)	C16—H16C	0.9800
C1—C2	1.3954 (18)	C17—C18	1.5136 (19)
C2—C3	1.3903 (18)	C17—C19	1.5195 (18)
C3—C4	1.3884 (19)	C17—C20	1.5196 (18)
C3—H3	0.9500	C18—H18A	0.9800
C4—C5	1.382 (2)	C18—H18B	0.9800
C4—H4	0.9500	C18—H18C	0.9800
C5—C6	1.3923 (18)	C19—H19A	0.9800
C5—H5	0.9500	C19—H19B	0.9800
C7—H7A	0.9900	C19—H19C	0.9800
C7—H7B	0.9900	C20—H20A	0.9800
C8—H8A	0.9800	C20—H20B	0.9800
C8—H8B	0.9800	C20—H20C	0.9800
C2—O1—C7	118.55 (10)	O6—C11—N1	110.18 (10)
C7—O2—C8	112.86 (11)	O7—C12—O8	127.29 (11)
C6—O3—C9	118.13 (10)	O7—C12—N1	121.92 (11)
C9—O4—C10	112.61 (11)	O8—C12—N1	110.71 (10)
C11—O6—C13	120.59 (10)	O6—C13—C16	109.73 (11)
C12—O8—C17	120.00 (9)	O6—C13—C14	110.04 (11)
C12—N1—C11	125.51 (10)	C16—C13—C14	112.79 (13)
C12—N1—C1	116.83 (10)	O6—C13—C15	102.12 (11)
C11—N1—C1	117.61 (10)	C16—C13—C15	110.76 (13)
C6—C1—C2	120.13 (11)	C14—C13—C15	110.89 (13)
C6—C1—N1	120.07 (11)	C13—C14—H14A	109.5
C2—C1—N1	119.80 (11)	C13—C14—H14B	109.5
O1—C2—C3	125.34 (12)	H14A—C14—H14B	109.5
O1—C2—C1	114.49 (11)	C13—C14—H14C	109.5
C3—C2—C1	120.17 (12)	H14A—C14—H14C	109.5
C4—C3—C2	118.65 (12)	H14B—C14—H14C	109.5
C4—C3—H3	120.7	C13—C15—H15A	109.5
C2—C3—H3	120.7	C13—C15—H15B	109.5
C5—C4—C3	122.09 (12)	H15A—C15—H15B	109.5
C5—C4—H4	119.0	C13—C15—H15C	109.5
C3—C4—H4	119.0	H15A—C15—H15C	109.5
C4—C5—C6	118.93 (12)	H15B—C15—H15C	109.5
C4—C5—H5	120.5	C13—C16—H16A	109.5
C6—C5—H5	120.5	C13—C16—H16B	109.5
O3—C6—C5	124.99 (11)	H16A—C16—H16B	109.5
O3—C6—C1	115.00 (11)	C13—C16—H16C	109.5
C5—C6—C1	120.01 (12)	H16A—C16—H16C	109.5
O2—C7—O1	113.19 (10)	H16B—C16—H16C	109.5
O2—C7—H7A	108.9	O8—C17—C18	110.43 (10)
O1—C7—H7A	108.9	O8—C17—C19	101.58 (10)
O2—C7—H7B	108.9	C18—C17—C19	110.37 (11)
O1—C7—H7B	108.9	O8—C17—C20	109.33 (10)
H7A—C7—H7B	107.8	C18—C17—C20	113.10 (11)
O2—C8—H8A	109.5	C19—C17—C20	111.43 (12)
O2—C8—H8B	109.5	C17—C18—H18A	109.5
H8A—C8—H8B	109.5	C17—C18—H18B	109.5
O2—C8—H8C	109.5	H18A—C18—H18B	109.5
H8A—C8—H8C	109.5	C17—C18—H18C	109.5
H8B—C8—H8C	109.5	H18A—C18—H18C	109.5
O4—C9—O3	113.22 (10)	H18B—C18—H18C	109.5
O4—C9—H9A	108.9	C17—C19—H19A	109.5
O3—C9—H9A	108.9	C17—C19—H19B	109.5
O4—C9—H9B	108.9	H19A—C19—H19B	109.5
O3—C9—H9B	108.9	C17—C19—H19C	109.5
H9A—C9—H9B	107.7	H19A—C19—H19C	109.5
O4—C10—H10A	109.5	H19B—C19—H19C	109.5
O4—C10—H10B	109.5	C17—C20—H20A	109.5
H10A—C10—H10B	109.5	C17—C20—H20B	109.5
O4—C10—H10C	109.5	H20A—C20—H20B	109.5
H10A—C10—H10C	109.5	C17—C20—H20C	109.5
H10B—C10—H10C	109.5	H20A—C20—H20C	109.5
O5—C11—O6	127.26 (12)	H20B—C20—H20C	109.5
O5—C11—N1	122.45 (11)
C2—C1—N1—C12	57.65 (15)	C6—C1—N1—C11	59.68 (15)