mate, the excitatory amino acid antagonist activities of a series
of decahydroisoquinoline-3-carboxylic acids were explored. It
was found that compound (III) possesses both NMDA and
AMPA receptor antagonist activity (Simmons et al., 1998;
A new route to the synthesis of (III) was proposed, based
on an intermolecular Diels±Alder cycloaddition reaction of a
6-substituted dihydropyridone with an appropriate diene. This
and AMPA receptor antagonist activity key reaction would need a group at position 6 (to the nitro-
gen) in an axial position, so before the cycloaddition reaction
was attempted, a crystal structure determination of (I) was
J. Zukerman-Schpector,a,b* Mauricio Vega,b I. Caracelli,b
undertaken. After con®rmation that the methyl group (at
Luiz C. Diasc and Anna M. A. P. Fernandesc
position 6, labelled C5 in the ®gure) occupied an axial posi-
tion, a thermally induced Diels±Alder reaction was performed
aInstituto de QuõÂmica, Universidade de SaÄo Paulo, SaÄo Paulo, SP, Brazil,
using the highly reactive Danishefsky's diene, (IV). As the
bLaboratoÂrio de Cristalografia, EstereodinaÃmica e Modelagem Molecular,
Diels±Alder reaction could lead to several different products
Departamento QuõÂmica, Universidade Federal de SaÄo Carlos, Caixa Postal 676,13565-905 SaÄo Carlos, SP, Brazil, and cInstituto de QuõÂmica, UNICAMP, Caixa
and as the relative stereochemistry of this product is of great
Postal 6154, 13083-970 Campinas, SP, Brazil
importance for subsequent reaction steps, the crystal structure
Correspondence e-mail: [email protected]
The molecular structure of (I) is shown in Fig. 1. As stated,
the methyl group at C5 is in an axial position, as required for
the continuation of the reaction path. The piperidone ring is in
a half-chair conformation distorted towards a half-boat, as
indicated by the Cremer & Pople (1975) puckering parameters
13H12N2O4, (I), the piperidone ring is in a distorted
half-chair conformation. In 8-methoxy-3-methyl-N-(4-nitro-
shown in Table 3. The lone pair of the piperidone N atom is
involved in conjugation with the carbonyl groups. This is
indicated by the slight lengthening of the C O double bond
20N2O6, (II), the heterocyclic ring is in a slightly distorted
half-boat conformation, while the other six-membered ring is
[1.214 (3) AÊ] and the concomitant shortening of the two NÐ
in a distorted chair conformation. Compound (II) presents a
Csp2 single bonds [1.395 (3) and 1.399 (3) AÊ]. Accordingly, the
strong intramolecular CÐHÁ Á ÁO hydrogen bond. In both (I)
state of hybridization of the N atom is sp2, as shown by the
and (II), the molecules interact through CÐHÁ Á ÁO interac-
sum (358.2) of the angles around it and the small deviation
[À0.050 (2) AÊ] of the atom from the N1/C2/C4/C13 plane.
CommentGlutamate is the major excitatory neurotransmitter in the
brain and can act on three major types of ligand-gated ion
channels that are de®ned by the activity of the subtype-
The molecular structure of (I) showing the atomic labelling and 50%
probability displacement ellipsoids.
selective agonists NMDA (N-methyl-d-aspartate), kainate and
acid) (Ornstein et al., 1994). In a search for new therapeutic
The molecular structure of (II) showing the atomic labelling and 50%
agents which are potent and selective antagonists of gluta-
probability displacement ellipsoids.
# 2001 International Union of Crystallography Printed in Great Britain ± all rights reserved
The molecular diagram of (II) is shown in Fig. 2, and shows
that the two rings have a cis fused stereochemistry with an
Selected geometric parameters (AÊ, ) for (I).
H1ÐC1ÐC6ÐH6 torsion angle of 41. The heterocyclic ring
is in a slightly distorted (towards a chair) half-boat confor-
mation, whereas the other six-membered ring is in a distorted
chair (towards a half-chair) conformation, as indicated by the
Cremer & Pople (1975) puckering parameters given in Table 6.
The existence of a CÐHÁ Á Á% interaction between C12ÐH12B
and the C14±C19 phenyl ring is noted. According to Ciunik et
al. (1998), this kind of interaction should be characterized by
three parameters. In the present structure, these are the
H12BÁ Á ÁCgi (Cg is the centroid of the C14±C19 ring) distance
Hydrogen-bonding geometry (AÊ, ) for (I).
of 2.69 AÊ, the C12ÐH12BÁ Á ÁCgi angle of 158 and the angle
between the HÁ Á ÁCg vector and the plane of the aromatic ring,
which in this case is 88 [symmetry code: (i) 1
These values are in the expected ranges of 2.7±3.4 AÊ, 140±160
and 80±100, respectively, as described by Ciunik et al. (1998).
This compound also exhibits three intramolecular hydrogen
bonds (Table 5); in fact, C11ÐH11AÁ Á ÁO4 and C15Ð
Symmetry codes: (i) 2 À xY 12 yY 32 À z; (ii) 32 À xY 1 À yY 12 z; (iii) 2 À xY y À 12Y 32 À z; (iv)
H15Á Á ÁO3 are responsible for the particular arrangement of
the phenyl ring. In order to study the in¯uence of these
hydrogen bonds on molecular conformation, a series of
Cremer & Pople (1975) puckering parameters (AÊ, ) for (I).
Potential Energy Surfaces (PES) calculations were performed
[MOPAC7.01: Stewart (1990) and Csern (2000); GAMESS98:
Schmidt et al. (1993)]. The geometry optimization calculations,
using AM1 and 6±31G*, showed a change in the conformation
involving the three CÐHÁ Á ÁO interactions; the H15Á Á ÁO3
distance changes from 2.49 to 2.58 AÊ, while the other two
followed by addition of phenylselenyl bromide. This last
distances, H5BÁ Á ÁO3 and H11CÁ Á ÁO4, shorten to 2.47 and
intermediate was converted into (I) using standard oxidation
2.49 AÊ, respectively. The PES obtained after rotation of the
and elimination conditions. Heating of (I) with an excess of
C4ÐN1ÐC13ÐC14 torsion angle showed that there were two
Danishefsky's diene (IV) at re¯ux in xylene in the presence of
minima, one corresponding to the global minimum (162.77),
BHT, followed by treatment of the intermediate adduct with
which is close to the crystallographic conformation
[144.0 (2)], and the other at À77.32. This last conformation is
around 7 kcal higher (1 kcal = 4.184 kJ) than the other and
results in the loss of the C15ÐH15Á Á ÁO3 hydrogen bond. We
can postulate that, in this case, the molecular conformation is
driven more by the intramolecular interactions.
In both compounds, the molecules interact through a series
of CÐHÁ Á ÁO interactions, as shown in Tables 2 and 5.
Whether all these interactions are true hydrogen bonds is
dif®cult to assert because, as pointed out by Cotton et al.
(1997), `the ®eld is getting muddier and muddier as the de®-
nition of a hydrogen bond is relaxed'. In any case, the Tables
include those contacts with an HÁ Á ÁO distance less than the
sum of the van der Waals radii (Pauling, 1960) plus 10% and a
CÐHÁ Á ÁO angle greater than 100.
Addition of methyl magnesium bromide to commercially
available glutarimide, followed by treatment of the inter-
sponding lactam. The lactam was then N-protected using
n-BuLi in tetrahydrofuran (THF) followed by addition of
p-nitrobenzoyl chloride to afford the corresponding imide
which, in turn, was deprotonated with LiHMDS in THF,
1090 J. Zukerman-Schpector et al. C13H12N2O4 and C18H20N2O6
Selected geometric parameters (AÊ, ) for (II).
Cremer & Pople (1975) puckering parameters (AÊ, ) for (II).
C1ÐC6ÐC7ÐC8ÐC9ÐC10 0.11 (2) 0.47 (2) À95 (11) 13 (3) 0.49 (2)
N1ÐC2ÐC1ÐC6ÐC5ÐC4 0.297 (3) 0.380 (3) À122.4 (5) 38.2 (3) 0.482 (3)
1.2 (for the other H atoms) times the value of the equivalent isotropic
displacement parameter of the attached atom.
For both compounds, data collection: CAD-4 Software (Enraf±
Nonius, 1989); cell re®nement: CAD-4 Software; data reduction:
Hydrogen-bonding geometry (AÊ, ) for (II).
XCAD4 (Harms & Wocadlo, 1995). Program(s) used to solve struc-
ture: SHELXS86 (Sheldrick, 1985) for compound (I) and SIR92
(Altomare et al., 1993) for compound (II). For both compounds,
program(s) used to re®ne structure: SHELXL97 (Sheldrick, 1997);
molecular graphics: ZORTEP (Zsolnai, 1995); software used to
prepare material for publication: PARST95 (Nardelli, 1995),
PLATON (Spek, 1998) and WinGX (Farrugia, 1999).
This work has received partial support from FAPESP, CNPq
and CAPES. MVacknowledges FAPESP for a PhD fellowship
(98/13927-3). The X-ray facility at the Instituto de QuõÂmica-
USP was installed with a grant from FAPESP (94/2061-4).
Symmetry codes: (i) À12 À xY yY Àz; (ii) xY y À 1Y z; (iii) x À 12Y ÀyY z; (iv)
À12 À xY 12 À yY 12 À z; (v) x À 12Y 1 À yY z; (vi) 12 À xY 12 À yY 12 À z; (vii) 12 xY 1 À yY z; (viii)
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: DA1198). Services for accessing these data are
described at the back of the journal.
Altomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl.
Ciunik, Z., Berski, S., Latajka, Z. & Leszczynski, J. (1998). J. Mol. Struct. 442,
Cotton, F. A., Daniels, L. M., Jordan, G. T. IV & Murillo, C. A. (1997). J. Chem.
Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354±1358.
Csern, I. (2000). MOPAC7.01 for LINUX (public domain version). Institute of
Nuclear Research, Hungarian Academy of Science, H-4001 Debrecen POB
Enraf±Nonius (1989). CAD-4 Software. Version 5.0. Enraf±Nonius, Delft, The
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837±838.
Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.
Nardelli, M. (1995). J. Appl. Cryst. 28, 659.
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Bleakman, D. & Lodge, D. (1998). Neuropharmacology, 37, 1211±1222.
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Schmidt, M. W., Baldridge, K. K., Boatz, J. A., Elbert, S. T., Gordon, M. S.,
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the hydroxyl groups, and were re®ned riding on a carrier atom with
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an isotropic displacement parameter of 1.5 (for methyl H atoms) or
Zsolnai, L. (1995). ZORTEP. University of Heidelberg, Germany.
J. Zukerman-Schpector et al. C13H12N2O4 and C18H20N2O6
What are the extractive industries? Extractive Industries is the industry that involves mining and other valuable natural resources that found in the ground. Essentially extractive industry concerned with the physical extraction of metals, oil and natural gas. However, these differ in what, how and what they extract. Mining can be defined as extraction of metals and the extraction can
Applikationen Arzneimittelcharakterisierung mit DSCCamelia Nicolescu; Corina Arama (mit der Unterstützung von Prof.Dr.Pharm.Crina Maria Monciu) Abteilung für Analytische Chemie,„Carol Davila“- Pharmaziehochschule, Traian Vuia Str. Nr.6, 70139 Bukarest, Rumänien Einleitung Es ist bekannt, dass die Wechselwirkungen zwischen Wirksubstanz und Bindemittel, die pharmakologischen Eigenschafte