Search

The crystal structure of the title compound, C5H3BrN2S, shows that bromination of 1H-thieno[2,3-d]imidazole with N-bromosuccinimide in acetonitrile occurs at position 5 of the bicyclic system. The molecule is almost planar, with a mean deviation of 0.015 Å from the least-squares plane through all the non-H atoms. In the crystal, N—H...N hydrogen bonds link the molecules into infinite C(4) chains running along [101].

The structure of the title compound, C12H9BrN4, prepared by the reaction of 2-bromo-1-(6-bromo-3-pyridyl)ethanone with 2-amino-3-methylpyrazine indicates that the compound with the bromopyridyl substituent at position 2 of the imidazopyrazine fused-ring system represents the major product of this reaction. The plane of the pyridine ring forms a dihedral angle of 16.2 (2)° with the essentially planar (r.m.s. deviation = 0.006 Å) imidazopyrazine system. In the crystal, molecules are linked by weak C—H...N interactions.

The reaction of 2,4-dichloro-5-(trifluoromethyl)pyrimidine with 1H-pyrazole gave two structural isomers in a 1:1 ratio that were separable by chromatography. The title compound, C8H4ClF3N4, was the first product to elute and was characterized in the present study to confirm that substitution by the pyrazolyl group had occurred at position 4. The molecule (with the exception of the F atoms) is essentially planar, with a mean deviation of 0.034 Å from the least-squares plane through all non-H and non-F atoms. The bond angles in the pyrimidine ring show a pronounced alternating pattern with three angles, including those at the two N atoms being narrower, and the remaining three wider than 120°.

rac-Benzyl 3-oxohexahydro-1H-pyrrolo[3,4-c]pyridine-5(6H)-carboxylate was separated by chiral chromatography, and one of the enantiomers ([α]22D = +10°) was hydrogenated in the presence of Pd/C in methanol, producing octahydro-3H-pyrrolo[3,4-c]pyridin-3-one. The latter was reacted with (2R)-3,3,3-trifluoro-2-methoxy-2-phenylpropanoyl chloride [(R)-(−)-Mosher acid chloride], giving rise to the title compound, C17H19F3N2O3·H2O. The present structure established the absolute configuration of the pyrrolopiperidine fragment based on the known configuration of the (R)-Mosher acid chloride. The piperidine ring has a somewhat distorted chair conformation and is cis-fused with the five-membered envelope-shaped ring; the plane of the exocyclic amide bond is approximately orthogonal to the plane of the phenyl ring, making a dihedral angle of 82.31 (3)°. The water molecule acts as an acceptor to the proton of the amino group in an N—H...O interaction, and as a double proton donor in O—H...O hydrogen bonds, generating infinite bands along the a axis.

The title compound, C12H13ClN6, was prepared by reaction of 4,5-dichloro-7H-pyrrolo[2,3-d]pyrimidine with 2-(1H-imidazol-4-yl)-N-methylethanamine, and the X-ray study confirmed that chloro-substituent in six-membered ring was replaced in the reaction. The exocyclic N atom environment is approximately coplanar with the pyrrolo[2,3-d]pyrimidine [corresponding dihedral angle is 5.5 (1)°], whereas the mean plane of the N—C—C—C link connecting with the imidazolyl ring is almost exactly orthogonal to the plane of the bicyclic system [dihedral angle = 91.6 (2)°]. The imidazolyl plane itself, however, forms a relatively small dihedral angle of 20.8 (1)° with the pyrrolo[2,3-d]pyrimidine plane. There are two independent N—H...N hydrogen bonds in the structure, which link molecules into layers parallel to (overline{1}03).

The title compound, C9H7ClN2O2, was prepared by reaction of methyl 4-chloro-3-(prop-1-ynyl)picolinate with hydroxylamine in MeOH/KOH solution. The two essentially planar molecules which make up the asymmetric unit have almost identical geometries and and are linked into dimeric aggregates via pairs of O—H...O hydrogen bonds. These aggregates have almost perfect inversion symmetry; however, quite unusually, the inversion center of the dimer does not coincide with the crystallographic inversion center.

The title compound, C9H10N2O2S, was obtained from the treatment of ethyl 4-cyano-3-hydroxy-5-morpholinothiophene-2-carboxylate with concentrated HCl. The mean plane of the essentially planar dihydrothiophene ring is almost orthogonal to the mirror plane of the N-morpholine substituent, making a dihedral angle of 87.2 (2)°.

The title compound, C12H19BrN4O, represents the minor component of the two products obtained in a series of transformations involving the Grignard reaction of tert-butoxycarbonyl-protected 4-aminocyclohexanone with MeMgBr, and subsequent interaction of the obtained amino-substituted cyclohexanol with 4-chloro-6-methylpyrimidin-2-amine followed by bromination with N-bromosuccinimide. The X-ray structure showed that this product represents a trans isomer with respect to the amino and hydroxy substituents in the cyclohexyl ring; the dihedral angle between the aminopyrimidine plane and the (noncrystallographic) mirror plane of the substituted cyclohexyl fragment is 33.6 (3)°. Only two of the four potentially `active' H atoms participate in intermolecular N—H...O and O—H...N hydrogen bonds, linking the molecules into layers parallel to the (10overline{1}) plane.

Reaction of 2-(methylsulfanyl)pyrimidin-4-amine with the 5-(methoxyvinylidene) derivative of Meldrum's acid and subsequent heating of the product in Dowtherm fluid yielded the title compound, C8H7N3OS, which was proven to contain a bicyclic 4H-pyrimido[1,6-a]pyrimidine system. All non-H atoms of the molecule are coplanar within 0.15 Å. The bond-length distribution in the bicyclic core shows localization of the double bonds. The geometry of the intramolecular S...O 1,5-contact [2.534 (2) Å] is consistent with the existence of an attractive interaction.

The title compound, C9H12N4O4S, was proven to be the product of the reaction of methyl 5-amino-1H-pyrazole-3-carboxylate with ethyl isothiocyanatocarbonate. All non-H atoms of the molecule are planar, the mean deviation from the least squares plane being 0.048 Å. The intramolecular N—H...O bond involving the NH-group, which links the thiourea and pyrazole fragments, closes a six-membered pseudo-heterocyclic ring, and two more hydrogen bonds (N—H...O with the participation of the pyrazole NH group and N—H...S involving the second thiourea NH group) link the molecules into infinite chains running along [1overline{2}0].

The title compound, C13H17N5OS, was obtained by cycloaddition of 2-[2-(methylsulfanyl)pyrimidin-4-yl]-3-oxopropanenitrile with (tetrahydrofuran-3-yl)hydrazine dihydrochloride and subsequent N-methylation of 4-[2-(methylsulfanyl)pyrimidin-4-yl]-1-(tetrahydrofuran-2-yl)-1H-pyrazol-5-amine with methyl iodide. The two molecules in the asymmetric unit have opposite absolute configurations and are related by a noncrystallographic inversion center. Both feature intramolecular N—H...N hydrogen bonds. The geometry of the molecules is similar to that observed in the structure of a single enantiomer of the title compound.

The reaction of (E)-tert-butyl 4-[3-(dimethylamino)acryloyl]piperidine-1-carboxylate with methylhydrazine leads to the formation of the title compound, C14H23N3O2, with a 1-methyl-1H-pyrazol-5-yl substituent. The plane of the pyrazole ring forms a dihedral angle of 33.4 (1)° with the approximate mirror plane of the piperidine ring.

The title compound, C12H15N5OS, was obtained by reaction of 2-(2-(methylthio)pyrimidin-4-yl)-3-oxopropanenitrile with (tetrahydrofuran-3-yl)hydrazine dihydrochloride, and the racemic product was subsequently separated by chiral chromatography (first peak; [α]D20 = +51.3°). The chiral center at the substituted atom of the tetrahydrofuranyl group has an R-configuration. The pyrimidine and pyrazolyl rings are almost coplanar, their mean planes forming a dihedral angle of 6.4 (1)°. One of the H atoms of the amino group participates in an intramolecular hydrogen bond with the pyrimidine N atom in position 3. The second H atom is involved in an intermolecular hydrogen bond, which links the molecules into an infinite chain.

The reaction of 3-amino-5-bromopyridine with N-iodosuccinimide in the presence of acetic acid produces the title compound, C5H4BrIN, with an iodo substituent in position 2 of the pyridine ring. The crystal structure features rather weak intermolecular N—H...N hydrogen bonds linking the molecules into chains along the z axis of the crystal.