4-Chloro-7-hydr­oxy-6-methyl-1,7-naphthyridin-8(7H)-one

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

trans-4-(2-Amino-5-bromo-6-methyl­pyrimidin-4-ylamino)-1-methyl­cyclo­hexa­nol

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 (10) plane

Methyl 3-[3-(ethoxy­carbon­yl)thio­ureido]-1H-pyrazole-5-carboxyl­ate

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 [10]

2-Chloro-4-(1H-pyrazol-1-yl)-5-(trifluoro­meth­yl)pyrimidine

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°

2-Morpholino-4-oxo-4,5-dihydro­thio­phene-3-carbonitrile

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)°

5-Bromo-1H-thieno[2,3-d]imidazole

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]

3-Amino-5-bromo-2-iodo­pyridine

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

tert-Butyl 4-(1-methyl-1H-pyrazol-5-yl)piperidine-1-carboxyl­ate

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

2-(6-Bromo-3-pyrid­yl)-8-methyl­imidazo[1,2-a]pyrazine

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

6-(2,6-Dimethyl­phen­yl)pyrido[2,3-d]pyrimidin-7-amine

In the title compound, C15H14N4, the pyrido[2,3-d]pyrimidine system is almost ideally planar (r.m.s. deviation 0.028 Å) with its mean plane almost orthogonal to the 2,6-dimethyl­phenyl plane. The dihedral angle formed by these planes [87.3 (2)°] is close to the predicted value (89.7°) obtained by mol­ecular-mechanics force-field calculations. Only one of the two active amine H atoms participates in hydrogen bonding, which links mol­ecules into centrosymmetric dimers