4-Aminomethyl-5-methyl-3-isoxazolol hemihydrate, a compound structurally related to GABA

Brehm, L.

doi:10.1107/s0567740877002842

Cited by 6 publications

(3 citation statements)

References 2 publications

(2 reference statements)

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“…The bond lengths and angles are within the range of their equivalents found for previously determined zwitterions containing a 3-isoxazolol anion and an ammonium group (Cambridge Structural Database, version October 1995 [32], gave four structures [33][34][35][36]). …”

Section: Crystal Structuresmentioning

confidence: 93%

Structural features of muscimol, a potent GABAA receptor agonist, crystal structure and quantum chemicalab initio calculations

Brehm¹,

Frydenvang²,

Hansen³

et al. 1997

Struct Chem

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Muscimol, a constituent of the mushroom Amanita muscaria, is a semirigid analogue of the inhibitory neurotransmitter 4-aminobutyric acid (GABA). X-ray structure determinations and quantum chemical ab initio calculations (HF/6-3 IG*) have been carried out on the muscimol zwitterion. The solid-state conformations of the muscimol zwitterion are calculated to be 1.6-2.2 kcal/ mol higher in energy than that of the calculated minimum energy structure in vacuo. A comparison of the calculated and experimental structures indicates that the hydrogen bonding network in the solid state significantly affects the geometry of the molecular structure. This conclusion is supported by results of ab initio calculations on binary complexes between muscimol and an ammonium ion and between muscimol and a methoxide anion, simulating observed hydrogen bonding in the crystal structures.

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Section: Crystal Structuresmentioning

confidence: 93%

Structural features of muscimol, a potent GABAA receptor agonist, crystal structure and quantum chemicalab initio calculations

Brehm¹,

Frydenvang²,

Hansen³

et al. 1997

Struct Chem

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“…Experimental results, such as x-ray diffraction [3-51 or pK, values [6] have shown that the species exist in the zwitterionic form at the physiological pH. In a previous nonempirical molecular orbital study [7], we have demonstrated that the anionic site of the 3-isoxazolol compounds presents many electronic similarities with those of the GABA carboxyiate group.…”

Section: Introductionmentioning

confidence: 92%

3- and 5-Isoxazolol zwitterions: A model of interaction with the GABA-A receptor relating to agonism and antagonism

Boulanger

Vercauteren

Durant

et al. 1988

Int. J. Quantum Chem.

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Using molecular orbital methods, we propose various models of interactions between GABA or analogs (TACA, muscimol, isomuscimol) and an hypothetical receptor molecular fragment, a methylguanidinium ion. The respective geometries of the GABA-, TACA-, muscimol-, and isomuscimol-methylguanidinium ion complexes are optimized using the semi-empirical MNDO method. Stabilization energies of the complexes obtained by substraction of the heats of formation of the optimized complexes from those of the optimized isolated molecules differentiate the behavior of the anionic heads between the agonist and antagonist compounds. Affinity and stabilization are confmed by computing a6 initio sTo% ionization potentials and interaction energies taking into account counterpoise corrections. Results show a decrease of the interaction energy from GABA and TACA (-54.9 and -49.4 kcal/mol) to isomuscimol (-35.6 kcal/mol), via muscimol (-46.0 kcal/mol). The low interaction energy of the 5-isoxazolols as isomuscimol compared to the 3-isoxazolols, as muscimol, may explain their antagonist character.

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“…* Four of the compounds [CSD reference codes AMIOXO (Brehm, 1977), HAPIOX , HMUSCM (Brehm, Krogsgaard-Larsen & Hjeds, 1974) and ISAZOL (Brehm & Larsen, 1976)] contain an ionized 3-isoxazolol moiety; the ionization introduces some changes in the geometry. The C3---O10 bond is 0.04/~ shorter than in the non-ionized compounds.…”

Section: Commentmentioning

confidence: 99%

O-Methyl-4,5,6,7-tetrahydroisoxazolo[4,5-c]pyridin-3-ol Hydrochloride, O-Me-THPO.HCl

Frydenvang¹,

Hansen²,

Jensen³

1995

Acta Crystallogr C

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4-Aminomethyl-5-methyl-3-isoxazolol hemihydrate, a compound structurally related to GABA

Abstract: Abstract. C5HsN202.½H20, monoclinic C2/c, a=22-743(8), b=4-939(2), c=11.617(5) /~, /3= 100.10 (3) ° , V= 1284.7 A 3, Z=8, D,, (flotation) = 1.42, Dx = 1.418 g cm -3. The structure was solved by direct methods and refined by full-matrix least-squares calculations to R = 0.044.

Cited by 6 publications

References 2 publications

Structural features of muscimol, a potent GABAA receptor agonist, crystal structure and quantum chemicalab initio calculations

Structural features of muscimol, a potent GABAA receptor agonist, crystal structure and quantum chemicalab initio calculations

3- and 5-Isoxazolol zwitterions: A model of interaction with the GABA-A receptor relating to agonism and antagonism

O-Methyl-4,5,6,7-tetrahydroisoxazolo[4,5-c]pyridin-3-ol Hydrochloride, O-Me-THPO.HCl

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