Methanetriacetic and methylmethanetriacetic acids, their precursors and derivatives: NMR and X-ray diffraction studies

Article abstract of DOI:10.1070/MC2005v015n05ABEH002164

The NMR spectra and crystal structures of triacid 2b, triamide 4b and diastereomers 7, 8 were studied; the crystal structure of 2b is the first example of an H-bonded totally interlocked and percatenated homochiral structure.

Full text of DOI:10.1070/MC2005v015n05ABEH002164

, 2005, 15(5), 187–189
Methanetriacetic and methylmethanetriacetic acids, their precursors and
derivatives: NMR and X-ray diffraction studies
Remir G. Kostyanovsky,*a Oleg N. Krutius,a Andrey A. Stankevich,b Ivan I. Chervin,a Ivan V. Fedyanin,c
Denis G. Golovanovc and Konstantin A. Lyssenkoc
a N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russian Federation.
Fax: +7 095 651 2191; e-mail: kost@chph.ras.ru
b Higher Chemical College, Russian Academy of Sciences, 125047 Moscow, Russian Federation. Fax: +7 095 200 4204
c A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 119991 Moscow, Russian Federation.
Fax: +7 095 135 5085; e-mail: kostya@xrlab.ineos.ac.ru
DOI: 10.1070/MC2005v015n05ABEH002164
The NMR spectra and crystal structures of triacid 2b, triamide 4b and diastereomers 7, 8 were studied; the crystal structure of 2b
is the first example of an H-bonded totally interlocked and percatenated homochiral structure.
Methanetriacetic acid (MTA) and methylmethanetriacetic acid
(MMTA) are of great interest as the C3 symmetric synthons.1
R
C
A-R'O2CCH2 CO2R'
i
ii
However, the structural and spectroscopic characteristics of
MTA, MMTA and their derivatives were not described. Only
D-R
C
R'O2CCH
CHCO2R'
H
B-R'O2CCH2
CN
1
limited H NMR data for the α,α',α''-tribromo-substituted tri-
NC CH2 CO2R'
1a R = H, R' = Me
1b R = Me, R' = Et
methyl ester of MTA was reported.2
Starting from MTA, tris(benzoylmethyl)methane,1(h) tris(diazo-
acetonyl)methane1(h),(k) and tris(haloacetonyl)methanes (Hal =
= Cl, Br)1(h) were synthesised. Two latter compounds were used
for synthesis of cage compounds: 2,4,9-trioxaadamantanes,1(h)
‘bullvalenetrione’ and bullvalene.1(k) A chiral tridentate tris(oxa-
zolidine) ligand was synthesised based on MTA for the efficient
copper-mediated asymmetric allilic oxidation of cycloalkenes.3(a)
MTA is also used as a linker to control the assembly and
cyclooligomerization of amino acids.3(b) Based on MMTA and
C3 symmetric tripodal aminopyridine receptors, two types of
supramolecular complexes were obtained and characterised by
NMR spectroscopy, XRD analysis and high-level ab initio cal-
culations.4
iii
iv
RC(CH2CO2H)3
RC(CH2CO2Me)3
RC(CH2CONH2)3
2a R = H
2b R = Me
3a R = H
4a R = H
4b R = Me
3b R = Me
ClC(O)CH2 Ha
C(CCO)2O
Me Hb
H2NC(O) Me
C
v
vi
CH2CONH2
CH2CO2– NH4+
Ha
Hb
5
6
A
H
H
MeO2C
MeO2C
Br
Br
H
In this work, we reproduced the preparation of MTA, MMTA
and their known derivatives1,2 and synthesised new compounds
4a,b, 6 (Scheme 1).†
H
vii
Br
H
MeO2C
Br
CO2Me
CO2Me
B
H
C
Br
H
H Br
MeO2C
All of the products were characterised by NMR spectro-
scopy.† The NMR spectra of compounds 1a,b, 6 and 8 show
diastereotopy of all the protons (Ha, Hb in 6) and carbons of
substituents A and B in the field of the asymmetric centre of the
substituent C. Whereas in the case of homochiral isomer 7 the
protons and carbons of the three CHCO2Me substituents are
equivalent. This convincing criterion of the configuration assign-
ment of 7, 8 diastereomers is unambiguosly proven by an XRD
study.
7
8
Scheme 1 Reagents and conditions: i, MeONa in MeOH (EtONa in EtOH
for 1b), boiling for 12 h (6 h for 1b), then 12 h at 20 °C, neutralization by
MeCO2H, separation of MeCO2Na and vacuum distillation; ii, 20% HCl,
boiling for 12 h and 35 h for 2a and 2b, respectively; iii, excess SOCl2
in abs. MeOH, 0.5 h at 25 °C, boiling for 5 h, and vacuum distillation;
iv, excess NH3 in MeOH (cat. MeONa), 1 week at 25 °C for 4a, 2 weeks at
25 °C, 20 h at 90 °C in a sealed glass tube, and 2 weeks at 25 °C for 4b;
v, excess SOCl2 in CCl4, boiling for 15 h, 3 days at 25 °C and recrystalliza-
tion from CCl4; vi, excess NH3 in MeCN, 1 h at 25 °C, separation of
NH4Cl, and evaporation of the solvent in a vacuum; vii, PCl5, Br2, heating
under reflux for 42 h, then 12 h at 20 °C, and isolation of the products by
crystallization.
The magnitudes of vicinal coupling constants (3JHH) for 8
and 7 differ significantly (8.2, 4.0 and 4.5 Hz, respectively),†
witnessing a substantial conformation change of one of the
substituents (A or B) in solution. Addition of the chiral shift
Mendeleev Commun. 2005 187

, 2005, 15(5), 187–189
reagent Eu(tfc)3 to the racemic solution of 7 results in splitting
1
of the H NMR spectrum to the full sets of the signals of two
enantiomers.†
In order to analyse the crystal packing of this tripodal struc-
tures, XRD analysis was performed. Unfortunately, in the case
of 2a, 3a, 4a and 6, single crystals suitable for XRD were not
obtained; thus, the analysis of supramolecular organization in
crystals was performed only for 2b and 4b.
a0
c
Surprisingly, the achiral molecules of 2b crystallise in the
chiral space group P43212 with two independent molecules per
unit cell. Each of carboxylic groups participate in two inter-
molecular O–H···O bonds [2.621(4)–2.691(4) Å] with the for-
mation of expected H-bonded rings. All of these H-bonded
rings are coplanar and the molecules are assembled into infinite
b
†
NMR spectra were measured on a Bruker WM-400 spectrometer
(1H 400.13 MHz; 13C 100.62 MHz); melting points were determined on
a Boetius heating stage and corrected.
Figure 1 H-bonded layer of the ‘seine’ type in the crystal of 2b.
1a: yield 63%, bp 180–185 °C (3–4 Torr) [lit.,1(g) bp 203–205 °C
layers of the ‘seine type’ with a distance between parallel layers
equal to 5.946 Å. The unit of this seine is a regular rectangle
(8.85×17.45 Å) composed of six molecules of 2b (Figure 1).
Due to high symmetry in a crystal, there are two series of
equivalent orthogonal layers parallel to the ac and bc crys-
tallographic planes, respectively (Figure 2). As the result, the
crystal of 2b can be described as the three-dimensional totally
interpenetrated orthogonal infinite seines (Figure 3). Clearly,
the ‘stitch’ of this ‘supramolecular H-bonded netting’ is the
catenane (Figure 4); thus, compound 2b can be regarded as a
self-assembled homochiral infinite polycatenane.
(11 Torr)]. 1H NMR (CDCl3) d: 2.56 (m, 2H, A-CH2, AB part of ABX
2
3
3
spectrum, ∆n 29.0 Hz, JAB –16.8 Hz, JAX 8.4 Hz, JBX 5.5 Hz), 2.58
(m, 2H, B-CH2, AB part of ABX spectrum, ∆n 50.5 Hz, 2JAB –17.1 Hz,
3JAX 8.7 Hz, JBX 5.4 Hz), 3.07 (m, 1H, HC, X part of ABX spectra),
3
3.68 (s, 3H, A-Me), 3.69 (s, 3H, B-Me), 3.82 (s, 3H, C-MeO), 4.19 (d,
1H, HCCN, 3J 4.7 Hz).
1b: yield 45%, bp 185–188 °C (17 Torr) [lit.,1(b) bp 210 °C (21 Torr)].
1H NMR (CDCl3) d: 1.25 (t, 3H, Me, 3J 7.1 Hz), 1.26 (t, 3H, Me,
3
3J 7.1 Hz), 1.32 (t, 3H, Me, J 7.1 Hz), 1.34 (s, 3H, Me), 2.72 (br. s,
2
2H, CH2), 2.80 (m, 2H, CH2, AB spectrum, ∆n 32.0 Hz, J –16.1 Hz),
3
3
4.130 (q, 2H, CH2O, J 7.1 Hz), 4.135 (q, 2H, CH2O, J 7.1 Hz), 4.26
(q, 2H, CH2O, 3J 7.1 Hz), 4.49 (s, 1H, HC). 1H NMR (C6D6) d: 0.77 (t,
3H, C-Me, 3J 7.1 Hz), 0.87 (t, 3H, A-Me, 3J 7.2 Hz), 0.88 (t, 3H, B-Me,
3J 7.2 Hz), 1.33 (s, 3H, Me), 2.82 (br. s, 2H, CH2), 2.86 (m, 2H, CH2,
AB spectrum, ∆n 27.5 Hz, 2J –16.3 Hz), 3.71 (q, 2H, CH2O, 3J 7.1 Hz),
3
3
3.832 (q, 2H, CH2O, J 7.1 Hz), 3.836 (q, 2H, CH2O, J 7.1 Hz), 4.52
(s, 1H, HC). 13C NMR (C6D6) d: 13.83 (q, C-Me, J 126.5 Hz), 14.10
(q, A,B-Me, J 126.2 Hz), 22.91 (q, D-Me, J 126.5 Hz), 37.86 (br. s,
1
1
1
1
1
CMe-D), 40.03 (t, A-CH2, J 128.5 Hz), 40.74 (t, B-CH2, J 128.4 Hz),
45.42 (d, CH, 1J 138.10 Hz), 60.57 (t, A-CH2O, 1J 146.7 Hz), 60.61 (t,
B-CH2O, J 146.6 Hz), 62.61 (t, C-CH2O, 1J 148.0 Hz), 115.68 (d, CN,
1
2J 9.7 Hz), 165.01 (d, C-CO, 2J 8.3 Hz), 170.56 (s, A,B-CO).
2a: yield 70%, mp 128 °C (Et2O) (lit.,1(g) mp 126 °C; lit.,4(a) mp 127–
128 °C; lit.,4(b) mp 125.6 °C). 1H NMR ([2H6]acetone) d: 2.51 (d, 6H,
3CH2, 3J 6.6 Hz), 2.69 (hept., 1H, HC, 3J 6.6 Hz).
2b: yield 92%, mp 170–172 °C (Et2O) (lit.,1(g) mp 172 °C). H NMR
1
(CD3OD) d: 1.20 (s, 3H, Me), 2.61 (s, 6H, 3CH2), 5.15 (br. s, CO2H,
H2O).
3a: yield ~100%, bp 156 °C (13 Torr). 1H NMR (CDCl3) d: 2.45 (d, 6H,
3CH2, 3J 6.6 Hz), 2.75 (hept., 1H, HC, 3J 6.6 Hz), 3.65 (s, 9H, 3MeO).
3b: yield 58%, bp 152–153 °C (10 Torr). 1H NMR (CDCl3) d: 1.18 (s,
3H, Me), 2.62 (s, 6H, 3CH2), 3.65 (s, 9H, 3MeO).
4a: yield ~100%, mp 248–252 °C (MeOH). 1H NMR ([2H6]DMSO) d:
2.07 (d, 6H, 3CH2, 3J 6.0 Hz), 3.40 (hept., 1H, HC, 3J 6.0 Hz), 6.77 and
7.30 (2s, 6H, 3NH2).
Figure 2 The orthogonality of H-bonded layers (see Figure 1) in the
crystal of 2b.
1
4b: yield 10%, mp 232–234 °C (MeOH). H NMR ([2H6]DMSO) d:
Although the catenanes and interpenetrated structures were
described previously, the chiral supramolecular organization
including all of the above features was unknown before.5(a),(b)
Similar structures described are achiral: H-bonded (trimesic acid)5(c)
and metal-coordinated.5(d)–(g) Thus, we found previously that a
bicyclic chiral bis(lactam) crystallises in the chiral space group
I41 (Z' = 3) with the formation of an unbalanced threefold inter-
penetrated diamondoid H-bonded network.6 This compound
undergoes spontaneous resolution by crystallization.6 Recently,
the spontaneous resolution of two covalently bonded catenanes
was described.7
1.01 (s, 3H, Me), 2.16 (s, 6H, 3CH2), 7.00 and 7.68 (2s, 6H, 3NH2).
5: yield 40%, mp 93–94 °C (CCl4). 1H NMR (CDCl3) d: 1.27 (s, 3H,
Me), 2.80 (m, 4H, 2CH2, AB spectrum, ∆n 36.2 Hz, 2J –16.7 Hz), 3.06
(s, 2H, CH2COCl).
6: yield 50%, mp 193–197 °C (MeCN). 1H NMR ([2H6]DMSO) d:
2
1.04 (s, 3H, Me), 2.21 (m, 4H, 2CH2, AB spectrum, ∆n 24.4 Hz, J
–13.3 Hz), 2.35 (s, 2H, CH2CO–), 3.4 (br. s, NH4+, H2O), 6.97 and 7.70
(2s, 4H, 2NH2).
7: total yield of 7 + 8 is equal to 58%, for 7, yield 30%; needle-shaped
crystals, mp 97–98 °C (isopropanol) (lit.,2 mp 97–98 °C). 1H NMR (C6D6)
d: 3.27 (s, 9H, 3MeO), 3.82 (q, 1H, HC, 3J 4.5 Hz), 5.16 (d, 3H,
3CHBr, 3J 4.5 Hz); a 9 mg sample of 7 added with 0.45 mg of Eu(tfc)3,
1H NMR (C6D6) d: 3.32, 3.34 (2s, 9H, 3Me, ∆n 8.0 Hz), 4.13, 4.18
(2br. q, 1H, HC, ∆n 20.0 Hz), 5.29, 5.31 (2d, 3H, 3CHBr, ∆n 8.0 Hz,
3J 4.4 and 4.3 Hz). 13C NMR (CDCl3) d: 46.20 (ddt, CHBr, 1J 156.2 Hz,
3
1
2
2J 4.4 Hz, J 4.6 Hz), 46.36 (dq, CH, J 138.0 Hz, J 3.2 Hz), 53.30 (q,
MeO, 1J 148.4 Hz), 168.16 (dq, CO, 2J 4.8 Hz, 3J 4.5 Hz).
8: yield 20%, prismatic crystals, mp 111–112 °C (C6H6) (lit.,2 mp 113–
114 °C). 1H NMR (C6D6) d: 3.19 (s, 3H, A-MeO), 3.23 (s, 3H, B-MeO),
3
3
3.26 (s, 3H, C-MeO), 4.01 (dt, 1H, CH, J 8.2 Hz, J 4.0 Hz), 4.98 (d,
1H, C-CH, 3J 8.2 Hz), 5.01 (d, 1H, A-CH, 3J 4.0 Hz), 5.11 (d, 1H,
B-CH, 3J 4.0 Hz). 13C{1H} NMR (CDCl3) d: 45.37, 45.75, 45.88 (CHBr),
48.40 (CH), 53.48, 53.60, 53.67 (MeO), 167.2, 167.4, 168.3 (CO).
Figure 3 Schematic view of the interpenetration of the H-bonded layers
in 2b.
188 Mendeleev Commun. 2005

, 2005, 15(5), 187–189
C(34)
O(31)
Br(3)
O(31)
O(12)
C(14)
C(14)
C(13)
O(32)
O(12)
C(33)
C(32)
C(12)
C(13)
O(11)
C(33)
O(32)
C(12)
C(32)
C(1)
O(11)
Br(1)
C(22)
C(1)
C(22)
Br(1)
C(34)
O(21)
Br(3)
Br(2)
O(21)
C(23)
Br(2)
Figure 4 Catenane element in the crystal of 2b.
C(23)
O(22)
O(22)
C(24)
In a crystal of 4b, NH2 groups are involved in not only
intermolecular [2.927(3)–2.935(3) Å] but also intramolecular
H-bonds [2.884(3)–3.043(3) Å] probably, due to an excess of
proton donors over proton acceptors (Figure 5). The intermole-
cular H-bonds assemble molecules into a three-dimensional
network.
In order to obtain direct information on the configuration of
asymmetric centres in 7 and 8, XRD analysis‡ was undertaken.
The XRD of 7 and 8 demonstrated that both compounds
crystallise as racemates; in 7, the configurations of all centres
were the same (S,S,S or R,R,R) (Figure 5), while 8 is charac-
terised by (S,S,R) or (R,R,S) configuration (Figure 6). Com-
pound 7 crystallises in space group P21/c with two independent
molecules the difference in the geometry of which is negligible.
Note that, although 7 and 8 are different diastereomers, the
mutual orientation of Br and the C=O group in CHBr–CO2Me
fragments is practically the same (Figure 6). Thus, the torsion
angles Br–C–C=O for three chains in 7 and 8 are equal to
C(24)
7
8
Figure 6 General view of 7 (one independent molecule is shown) and 8.
23.3, 7.9, 97.5 and 22.1, 3.8, 92.5°, respectively. In addition, the
H–C(1)–C–H torsion angles in 7 and 8 are also very close to
each other and equal to 72, 91, 180 and 63, 105, 175°, respec-
tively, witnessing the significant difference from the conforma-
tion in solution† established on the basis of the vicinal spin
coupling constants 3JHH
.
The analysis of crystal packing demonstrated that molecules
are assembled into a three-dimensional framework (7) and chains
(8) by means of C–Br···Br and C–Br···O contacts. In spite of the
acidity of central hydrogen atoms in 7 and 8, all intermolecular
C–H···Br distances correspond to typical van der Waals contacts.
Taking into account that the type and strengths of intermole-
cular contacts in 7 and 8 are different, it is assumed that the
similarities in conformation are governed by intramolecular
C–H···O=C and C–H···Br contacts.
N(11)
O(11)
H(1NA)
C(13)
This work was supported by the Russian Academy of Sciences,
Russian Foundation for Basic Research (grant nos. 03-03-32019
and SC-1060.2003.03) and DFG–RFBR (grant no. 03-03-04010).
H(2NA)
C(12)
O(31)
N(21)
C(1)
C(22)
This paper is devoted to Professor N. S. Zefirov in connection
with his 70th anniversary.
C(33)
C(23)
C(32)
N(31)
O(21)
C(1M)
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‡
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a = 11.893(2), c = 27.113(5) Å, V = 3835(1) Å3, Z = 16 (Z' = 2), M =
= 204.18, dcalc = 1.415 g cm–3, m(MoKα) = 1.23 cm–1, F(000) = 1728,
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= 6.328(2), c = 23.935(7) Å, b = 94.92(2)°, V = 1009.8(5) Å3, Z = 4 (Z' = 1),
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b = 15.812(2), c = 7.457(1) Å, V = 1452.9(4) Å3, Z = 4 (Z' = 1), M = 468.93,
dcalc = 2.144 g cm–3, m(MoKα) = 8.347 cm–1, F(000) = 904, wR2 = 0.0670
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= 0.0331 for 4457 observed reflections with I > 2s(I).
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All calculations were performed using SHELXTL PLUS 5.0.
Atomic coordinates, bond lengths, bond angles and thermal param-
eters have been deposited at the Cambridge Crystallographic Data Centre
(CCDC). These data can be obtained free of charge via www.ccdc.cam.uk/
conts/retrieving.html (or from the CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK; fax: +44 1223 336 033; or deposit@ccdc.cam.ac.uk).
Any request to the CCDC for data should quote the full literature citation
and CCDC reference numbers 283410–283413. For details, see ‘Notice to
Authors’, Mendeleev Commun., Issue 1, 2005.
Received: 7th April 2005; Com. 05/2487
Mendeleev Commun. 2005 189