5-Ethyl-4a-meth-oxy-1,3-dimethyl-4a,5-dihydro-benzo[g]pteridine-2,4(1H,3H)dione.

The title compound, C(15)H(18)N(4)O(3), was formed by the reaction of methanol with 5-ethyl-1,3-dimethyl-alloxazinium perchlorate. Its structure mimics those of possible flavin inter-mediates in flavoenzymes. The heterocyclic rings are substituted with methyl, ethyl and meth-oxy groups. The central tricyclic skeleton is bent due to the presence of an sp(3) C atom. There are weak inter-molecular C-H⋯O inter-actions in the structure, forming a three-dimensional network.

Related literature

in the context of this article, a C4a-adduct is a compound with a nucleophile covalently bound to atom C4a of the flavin fragment; isoalloxazines are natural flavin derivatives, alloxazines are their isomers. For the biological relevance of C4a-adducts in flavoenzymes, see: Palfey & Massey (1998 ▶); Massey (2000 ▶); Müller (1991 ▶). For the preparation of C4a-isoalloxazine adducts, see: Kemal & Bruice (1976 ▶); Kemal et al. (1977 ▶); Hoegy & Mariano (1997 ▶). For the crystal structures of isoalloxazine adducts, see: Bolognesi et al. (1978 ▶). For the crystal structures of reduced isoalloxazines, see: Werner & Rönnquist (1970 ▶); Norrestam & Von Glehn (1972 ▶). For puckering parameters, see: Cremer & Pople (1975 ▶). For the extinction correction, see: Larson (1970 ▶).

Experimental

Crystal data

C15H18N4O3

M = 302.33

Monoclinic,

a = 10.3958 (2) Å

b = 12.7174 (2) Å

c = 10.9421 (2) Å

β = 100.4727 (16)°

V = 1422.53 (4) Å3

Z = 4

Cu Kα radiation

μ = 0.83 mm−1

T = 150 K

0.50 × 0.28 × 0.15 mm

Data collection

Oxford Diffraction Xcalibur diffractometer

Absorption correction: analytical (de Meulenaer & Tompa, 1965 ▶) T min = 0.76, T max = 0.88

18511 measured reflections

2996 independent reflections

2692 reflections with I > 2σ(I)

R int = 0.025

Refinement

R[F 2 > 2σ(F 2)] = 0.041

wR(F 2) = 0.121

S = 0.99

2996 reflections

200 parameters

H-atom parameters constrained

Δρmax = 0.23 e Å−3

Δρmin = −0.21 e Å−3

Data collection: CrysAlis CCD (Oxford Diffraction, 2005 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2005 ▶); data reduction: CrysAlis RED; program(s) used to solve structure: Superflip (Palatinus & Chapuis, 2006 ▶); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: CRYSTALS and PARST97 (Nardelli, 1997).

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809020856/fb2153sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809020856/fb2153Isup2.hkl

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

C15H18N4O3	F(000) = 640
Mr = 302.33	Dx = 1.412 Mg m−3
Monoclinic, P21/n	Melting point = 384–386 K
Hall symbol: -P 2yn	Cu Kα radiation, λ = 1.54184 Å
a = 10.3958 (2) Å	Cell parameters from 11727 reflections
b = 12.7174 (2) Å	θ = 4–77°
c = 10.9421 (2) Å	µ = 0.83 mm−1
β = 100.4727 (16)°	T = 150 K
V = 1422.53 (4) Å3	Prism, colourless
Z = 4	0.50 × 0.28 × 0.15 mm

Oxford Diffraction Xcalibur diffractometer	2996 independent reflections
graphite	2692 reflections with I > 2σ(I)
Detector resolution: 8.1917 pixels mm-1	Rint = 0.025
φ and ω scans	θmax = 77.5°, θmin = 5.4°
Absorption correction: analytical (de Meulenaer & Tompa, 1965)	h = −13→13
Tmin = 0.76, Tmax = 0.88	k = −15→15
18511 measured reflections	l = −12→13

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.041	H-atom parameters constrained
wR(F2) = 0.121	Modified Sheldrick (2008) w = 1/[σ2(F2) + (0.08P)2 + 0.33P], where P = [max(Fo2,0) + 2Fc2]/3
S = 0.99	(Δ/σ)max = 0.0003
2996 reflections	Δρmax = 0.23 e Å−3
200 parameters	Δρmin = −0.21 e Å−3
0 restraints	Extinction correction: Larson (1970), Equation 22
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 29 (5)

	x	y	z	Uiso*/Ueq
O1	0.43813 (9)	0.38054 (7)	0.10771 (8)	0.0341
C2	0.53277 (11)	0.36250 (9)	0.18746 (11)	0.0269
N3	0.65728 (10)	0.37227 (8)	0.16350 (9)	0.0295
C4	0.67024 (14)	0.39751 (11)	0.03524 (12)	0.0394
C5	0.77221 (12)	0.37049 (9)	0.25223 (12)	0.0308
O6	0.87775 (9)	0.38486 (8)	0.22244 (10)	0.0413
N7	0.75942 (9)	0.35479 (8)	0.37412 (10)	0.0293
C8	0.87888 (12)	0.36402 (11)	0.46793 (13)	0.0388
C9	0.63877 (10)	0.35461 (8)	0.41330 (11)	0.0249
N10	0.63770 (9)	0.37433 (8)	0.52755 (9)	0.0272
C11	0.51698 (11)	0.37383 (9)	0.56668 (11)	0.0260
C12	0.51588 (13)	0.38898 (10)	0.69269 (11)	0.0317
C13	0.39963 (14)	0.39033 (10)	0.73696 (11)	0.0340
C14	0.28241 (13)	0.37940 (9)	0.65335 (12)	0.0333
C15	0.28184 (12)	0.36561 (9)	0.52737 (12)	0.0301
C16	0.39920 (11)	0.36095 (8)	0.48170 (10)	0.0248
N17	0.40282 (9)	0.34548 (8)	0.35602 (9)	0.0257
C18	0.27877 (11)	0.31653 (11)	0.27437 (11)	0.0328
C19	0.19478 (12)	0.41186 (13)	0.22860 (13)	0.0412
C20	0.52333 (10)	0.31848 (9)	0.31740 (10)	0.0249
O21	0.53556 (8)	0.20753 (6)	0.29281 (7)	0.0295
C22	0.54526 (16)	0.14088 (10)	0.39936 (13)	0.0417
H41	0.7567	0.3805	0.0256	0.0569*
H42	0.6530	0.4708	0.0177	0.0574*
H43	0.6097	0.3549	−0.0197	0.0574*
H81	0.8696	0.3196	0.5369	0.0560*
H82	0.8932	0.4348	0.4948	0.0553*
H83	0.9525	0.3400	0.4345	0.0558*
H121	0.5991	0.3989	0.7479	0.0377*
H131	0.3999	0.3991	0.8214	0.0392*
H141	0.2022	0.3814	0.6805	0.0402*
H151	0.2003	0.3581	0.4738	0.0353*
H181	0.2289	0.2703	0.3207	0.0369*
H182	0.2982	0.2774	0.2036	0.0371*
H191	0.1071	0.3889	0.1944	0.0565*
H192	0.1917	0.4597	0.2970	0.0566*
H193	0.2316	0.4495	0.1641	0.0564*
H221	0.5453	0.0697	0.3721	0.0593*
H222	0.6286	0.1545	0.4591	0.0602*
H223	0.4725	0.1509	0.4432	0.0599*

	U11	U22	U33	U12	U13	U23
O1	0.0330 (5)	0.0392 (5)	0.0302 (4)	0.0028 (4)	0.0063 (3)	0.0028 (3)
C2	0.0302 (6)	0.0222 (5)	0.0303 (5)	0.0018 (4)	0.0110 (4)	−0.0008 (4)
N3	0.0308 (5)	0.0291 (5)	0.0322 (5)	0.0028 (4)	0.0156 (4)	0.0040 (4)
C4	0.0483 (7)	0.0396 (7)	0.0363 (7)	0.0079 (6)	0.0236 (6)	0.0081 (5)
C5	0.0302 (6)	0.0237 (6)	0.0425 (7)	0.0025 (4)	0.0174 (5)	0.0041 (4)
O6	0.0300 (5)	0.0432 (5)	0.0566 (6)	0.0001 (4)	0.0231 (4)	0.0068 (4)
N7	0.0218 (5)	0.0302 (5)	0.0379 (5)	0.0017 (4)	0.0107 (4)	0.0035 (4)
C8	0.0229 (6)	0.0440 (7)	0.0491 (7)	0.0016 (5)	0.0056 (5)	0.0067 (6)
C9	0.0226 (5)	0.0207 (5)	0.0328 (6)	0.0009 (4)	0.0085 (4)	0.0025 (4)
N10	0.0256 (5)	0.0260 (5)	0.0306 (5)	0.0007 (3)	0.0068 (4)	0.0020 (4)
C11	0.0271 (6)	0.0218 (5)	0.0305 (6)	−0.0003 (4)	0.0093 (4)	0.0007 (4)
C12	0.0393 (6)	0.0270 (6)	0.0295 (6)	0.0004 (5)	0.0082 (5)	−0.0004 (4)
C13	0.0481 (7)	0.0271 (6)	0.0307 (6)	0.0007 (5)	0.0179 (5)	0.0006 (4)
C14	0.0388 (6)	0.0261 (6)	0.0407 (6)	−0.0025 (5)	0.0227 (5)	−0.0008 (5)
C15	0.0285 (6)	0.0265 (6)	0.0381 (6)	−0.0040 (4)	0.0137 (5)	−0.0029 (4)
C16	0.0272 (5)	0.0202 (5)	0.0292 (5)	−0.0020 (4)	0.0111 (4)	−0.0005 (4)
N17	0.0220 (4)	0.0279 (5)	0.0286 (5)	−0.0020 (4)	0.0082 (3)	−0.0034 (4)
C18	0.0247 (5)	0.0412 (7)	0.0334 (6)	−0.0084 (5)	0.0074 (4)	−0.0088 (5)
C19	0.0238 (5)	0.0612 (9)	0.0373 (6)	0.0020 (5)	0.0020 (5)	−0.0044 (6)
C20	0.0244 (5)	0.0228 (5)	0.0293 (5)	−0.0003 (4)	0.0097 (4)	−0.0006 (4)
O21	0.0350 (4)	0.0223 (4)	0.0342 (4)	0.0002 (3)	0.0141 (3)	−0.0013 (3)
C22	0.0614 (9)	0.0254 (6)	0.0435 (7)	0.0023 (6)	0.0231 (6)	0.0045 (5)

O1—C2	1.2124 (15)	C12—H121	0.969
C2—N3	1.3723 (15)	C13—C14	1.3914 (19)
C2—C20	1.5476 (15)	C13—H131	0.930
N3—C4	1.4696 (15)	C14—C15	1.3886 (18)
N3—C5	1.3961 (17)	C14—H141	0.935
C4—H41	0.949	C15—C16	1.4012 (16)
C4—H42	0.962	C15—H151	0.944
C4—H43	0.955	C16—N17	1.3965 (14)
C5—O6	1.2138 (15)	N17—C18	1.4758 (14)
C5—N7	1.3786 (16)	N17—C20	1.4347 (14)
N7—C8	1.4650 (16)	C18—C19	1.524 (2)
N7—C9	1.3973 (14)	C18—H181	0.983
C8—H81	0.961	C18—H182	0.972
C8—H82	0.950	C19—H191	0.966
C8—H83	0.956	C19—H192	0.969
C9—N10	1.2771 (16)	C19—H193	0.985
C9—C20	1.5149 (15)	C20—O21	1.4464 (13)
N10—C11	1.3977 (15)	O21—C22	1.4300 (15)
C11—C12	1.3944 (16)	C22—H221	0.953
C11—C16	1.4060 (16)	C22—H222	1.002
C12—C13	1.3813 (18)	C22—H223	0.975
O1—C2—N3	121.04 (11)	C13—C14—C15	120.70 (11)
O1—C2—C20	123.43 (10)	C13—C14—H141	120.9
N3—C2—C20	115.33 (10)	C15—C14—H141	118.4
C2—N3—C4	117.11 (11)	C14—C15—C16	120.83 (12)
C2—N3—C5	125.69 (10)	C14—C15—H151	118.1
C4—N3—C5	116.89 (10)	C16—C15—H151	121.1
N3—C4—H41	108.0	C11—C16—C15	117.99 (10)
N3—C4—H42	110.9	C11—C16—N17	119.44 (10)
H41—C4—H42	110.2	C15—C16—N17	122.56 (10)
N3—C4—H43	108.2	C16—N17—C18	117.02 (9)
H41—C4—H43	109.2	C16—N17—C20	120.34 (9)
H42—C4—H43	110.3	C18—N17—C20	118.40 (9)
N3—C5—O6	120.78 (12)	N17—C18—C19	112.69 (10)
N3—C5—N7	117.02 (10)	N17—C18—H181	108.8
O6—C5—N7	122.17 (12)	C19—C18—H181	108.7
C5—N7—C8	116.60 (10)	N17—C18—H182	109.0
C5—N7—C9	123.15 (10)	C19—C18—H182	109.6
C8—N7—C9	118.62 (10)	H181—C18—H182	108.1
N7—C8—H81	108.0	C18—C19—H191	109.3
N7—C8—H82	111.0	C18—C19—H192	110.0
H81—C8—H82	110.2	H191—C19—H192	109.2
N7—C8—H83	110.0	C18—C19—H193	110.3
H81—C8—H83	108.3	H191—C19—H193	109.3
H82—C8—H83	109.3	H192—C19—H193	108.6
N7—C9—N10	117.91 (10)	C2—C20—C9	110.62 (9)
N7—C9—C20	115.48 (10)	C2—C20—N17	112.87 (9)
N10—C9—C20	126.22 (10)	C9—C20—N17	110.34 (9)
C9—N10—C11	117.84 (10)	C2—C20—O21	99.18 (8)
N10—C11—C12	118.13 (11)	C9—C20—O21	109.84 (9)
N10—C11—C16	121.37 (10)	N17—C20—O21	113.53 (9)
C12—C11—C16	120.49 (11)	C20—O21—C22	114.97 (9)
C11—C12—C13	120.89 (12)	O21—C22—H221	108.1
C11—C12—H121	117.9	O21—C22—H222	110.8
C13—C12—H121	121.2	H221—C22—H222	108.6
C12—C13—C14	119.06 (11)	O21—C22—H223	112.2
C12—C13—H131	120.3	H221—C22—H223	108.8
C14—C13—H131	120.6	H222—C22—H223	108.2

D—H···A	D—H	H···A	D···A	D—H···A
C4—H42···O1i	0.96	2.43	3.3230 (18)	155
C14—H141···O21ii	0.94	2.56	3.3999 (18)	149
C19—H191···O6iii	0.97	2.46	3.3021 (18)	146

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C4—H42⋯O1i	0.96	2.43	3.3230 (18)	155
C14—H141⋯O21ii	0.94	2.56	3.3999 (18)	149
C19—H191⋯O6iii	0.97	2.46	3.3021 (18)	146

Symmetry codes: (i) ; (ii) ; (iii) .