The synthesis and characterization of previously unknown azides, iminophosphoranes and amines from commercially available mucochloric and mucobromic acids is reported. The reaction of ...5-alkoxy-3,4-dihalo-2(5
H
)-furanones with sodium azide resulted in the regioselective formation of furanone 4-azidoderivatives. A series of novel iminophosphoranes was obtained from the reaction of corresponding azides with triphenylphosphine. Reduction of iminophosphoranes with stannous chloride dihydrate led to the heterocycles, possessing an amino group at the C
4
carbon atom of the unsaturated γ-lactone ring.
Novel disulfinyl derivatives based on 3,4-dichloro-2(5H)-furanone, aliphatic dithiols, and monoterpene alcohols were synthesized. Chiral bis-thioethers in the molecules of which the dithiol fragment ...links two five-membered cycles at C4 atoms were obtained in the reactions of 5(S)-(l-menthyloxy)- and 5(S)-(l-bornyloxy)-2(5H)-furanones with ethane-1,2-dithiol and propane-1,3-dithiol in acetone in basic medium. The action of an excess of m-chloroperoxybenzoic acid (2.0–3.2 equiv.) on bis-thioethers led to the formation of the corresponding mono- and disulfoxides bearing l-menthol or l-borneol fragments at the 5th position of the lactone ring. The methods of column chromatography and fractional recrystallization were used for the isolation of individual products. The structure of the synthesized heterocycles was proved by IR and NMR spectroscopy, and their composition was confirmed by high-resolution mass spectrometry. The molecular structure of the three disulfoxides was characterized by X-ray diffraction analysis.
An unusual type of
rac
-7-chlorine-2,3,4a,6-tetrahydrofuro2,3-
b
1,4oxathiin-6-one crystallization is reported. This compound crystallizes in the form of lamellar conglomerates where each single ...crystal is not optically pure but is only enantiomerically enriched by one optical antipode and displays optical rotation.
We confirm our previously formulated rule about the possibility of a spontaneous resolution of enantiomers of a series of 5-hydroxy-3-pyrrolin-2-one thioderivatives. Crystal packings of three racemic ...compounds are compared. A supramolecular associate of the same type (a hydrogen-bonded dimer) is found, which is differently packed in the 3D structure of the crystals.
Methods for the synthesis of novel optically active bisthioethers and disulfones of the furan-2(5
H
)-one series were developed. Bisthioethers with the dithiol fragment links two γ-lactone rings at ...the C
4
atoms were synthesized by the reaction of 5(
S
)-(
l
-menthyloxy)- and 5(
S
)-(
l
-bornyloxy)furan-2(5
H
)-ones with ethane-1,2-dithiol and propane-1,3-dithiol in the presence of triethylamine. Chiral disulfones with a monoterpene alcohol fragment in the 5 position of the γ-lactone ring were obtained by the oxidation of the dithio furanone derivatives with hydrogen peroxide in acetic acid. The structure of five novel sulfur-containing furanone derivatives was characterized by single crystal X-ray diffraction.
The crystal structures of 3-chloro-5-hydroxy-1-(4-methylbenzyl)-4-4-phenyl-1H-1,2,3-triazole-1-yl-1,5-dihydro-2Н-pyrrol-2-one
rac
-
1
and ...1-benzyl-3-chloro-5-hydroxy-4-4-phenyl-1H-1,2,3-triazole-1-yl-1,5-dihydro-2Н-pyrrol-2-one
rac
-
2
are studied. The reproducibility of a same-type homochiral chain in both chiral and racemic crystals is found. Molecular conformations, secondary interactions additionally cross-linking the chain, and π…π contacts between the cyclic molecular moieties are analyzed.
Two packing polymorphs of 5-hydroxy-1-(4-methylbenzyl)-3-chloro-4-(4-chlorophenyl)sulfanyl-1,5-dihydro-2
H
-pyrrol-2-one are studied by single-crystal and powder X-ray diffraction, IR spectroscopy, ...and differential scanning calorimetry. Classical hydrogen bonds and CL…O interactions have the fundamental importance for the formation of the supramolecular motif that is identical in both modifications. The difference relates to the packing of 2D layers which is “parallel” in the triclinic modification and of the “herringbone” type in the monoclinic modification. It is shown that close similarity between structural organizations of crystal lattices, which is typical of packing polymorphs, can be accompanied by significant differences between their energies as well as by a high potential barrier upon the transition from the metastable polymorph to its stable form.
The work juxtaposes crystal structures of two hydrochlorides of eight-membered 1,5-diazaheterocycles with chiral aminoindanole fragments located at the nitrogen atoms and having similar ...configurations. In spite of chemical and stereochemical identity of a half of diazaheterocycle molecules, in crystals these compound are realized in the general position rather than the special position on the twofold axis of rotation. The following reasons are considered to be responsible for the asymmetrization of the molecules in the crystal: conformation of the eight-membered heterocycle, selective protonation of only one of two nitrogen atoms, positions of the counter-ion and the solvent molecule within the unit cell, and a nonequivalent system of hydrogen bonds.
Two crystalline diastereomorphs of
rac
-1-benzyl-3-bromo-5-hydroxy-4-(4-methylphenyl)sulfanyl-1,5-dihydro-2
Н
-pyrrole-2-one are obtained and characterized: the racemic compound (
P
2
1
/
c
) and the ...normal conglomerate (
P
6
5
,
P
6
1
). The conglomerate is shown to be more thermodynamically preferred while the racemic compound is a metastable form in the entire temperature range studied. These two modifications are formed as a mixture during routine crystallization from a solution and characterized by a similar density, however, their structures significantly differ in the parameters of hydrogen bonds. A small difference in the free energies of two phases at room temperature, which is found by differential scanning calorimetry, explains the experimental availability of both forms during crystallization from the solution. The formation of a stronger hydrogen bond in the conglomerate crystals, which is detected by X-ray diffraction and solid-state vibrational spectroscopy, may be explained by a more favorable arrangement of donor and acceptor groups of the neighboring molecules in a homochiral helix of the conglomerate as compared with a heterochiral dimer, which is the main motif in crystals of the racemic compound.
