Synthesis of novel hydropyrazolopyridine derivatives in solvent-free conditions via benzotriazole methodology

The reaction between 5-[N-(benzotriazol-1-ylmethyl)amino]-3-tert-butyl-1-phenylpyrazole or 5-amino-4-(benzotriazol-1-ylmethyl)-3-tert-butyl-1-phenylpyrazole with some unactivated and electron-rich alkenes has followed heterocyclization reactions to yield hydropyrazolopyridines, under solvent-free conditions, as predicted by benzotriazole methodology in contrast with those results obtained under solution. The reaction mechanism was proposed after fully spectroscopic analysis of final products and intermediates.     

Synthesis of 3-aryl-1,2,4-benzotriazines via intramolecular cyclization of solid-supported o-hydrazidoanilines

An efficient solid-phase protocol for the rapid generation of libraries of biologically promising 1,2,4-benzotriazines, including amino acid-derived components, is described.     

3‐Methyl‐7‐(2‐thienyl)pyrido[2,3‐d]pyrimidine‐2,4(1H,3H)‐dione: π‐stacked bilayers built from N—H...O,C—H...O and C—H...π hydrogen bonds

In the title compound, C₁₂H₉N₃O₂S, the thienyl substituent is disordered over two sets of sites with occupancies of 0.749 (3) and 0.251 (3). A combination of N—H...O, C—H...O and C—H...π hydrogen bonds links the molecules into bilayers and these bilayers are themselves linked into a continuous structure by π–π stacking interactions.     

3‐{[4‐Amino‐6‐methoxy‐2‐(methylsulfanyl)pyrimidin‐5‐yl]amino}‐1,2′‐biindenylidene‐1′,3′‐dione dimethyl sulfoxide solvate: π‐stacked sheets of hydrogen‐bonded chains of edge‐fused rings

In the title compound, C₂₄H₁₈N₄O₃S·C₂H₆OS, the biindenylidene component shows evidence of polarization of the electronic structure. The dimethyl sulfoxide solvent molecules are disordered over two sites, and they are linked to the biindenylidenedione components via N—H...O and C—H...O hydrogen bonds. A combination of N—H...N and N—H...O hydrogen bonds links the nonsolvent components into a chain of edge‐fused centrosymmetric R₂²(8) and R₂²(22) rings, and these chains are linked into sheets by a single aromatic π–π stacking interaction.     

2‐(4‐Chlorophenyl)‐5‐(4‐nitrophenyl)‐4,7‐dihydropyrazolo[1,5‐a]pyrimidine‐3,6‐dicarbaldehyde: a chain of rings built from N—H...O and C—H...O hydrogen bonds

In the title compound, C₂₀H₁₃ClN₄O₄, the six‐membered heterocyclic ring is planar and the molecular dimensions provide evidence for polarization of the molecular–electronic structure. Molecules are linked into a chain of rings by a combination of N—H...O and C—H...O hydrogen bonds, but the nitro group does not participate in the supramolecular aggregation. This study illustrates the marked influence of peripheral substituents on the pattern of hydrogen‐bonded aggregation in compounds of this type.     

4‐Amino‐5‐(2‐hydroxy‐4,4‐di­methyl‐6‐oxo­cyclo­hexenyl­methyl)‐1‐methyl‐2‐(methyl­sulfanyl)­pyrimidin‐6(1H)‐one: hydrogen‐bonded chains are π‐stacked in pairs

Molecules of the title compound, C₁₅H₂₁N₃O₃S, have a markedly polarized electronic structure; the carbocyclic ring adopts an envelope conformation and the overall molecular conformation appears to be controlled by two intramolecular hydrogen bonds, one each of the O—H⋯O and N—H⋯O types. The mol­ecules are linked into C(6) chains by an intermol­ecular N—H⋯O hydrogen bond, and pairs of these hydrogen‐bonded chains are linked by a π–π stacking interaction.     

Assignment of relative configurations to acyclic diastereomeric carbinols with the lanthanide shift reagent Eu (fod)3 by 1H and 13C NMR

An assignment of relative configurations has been achieved for the diastereomeric racemates (1R2R,1S2S) and (1R2S,1S2R) of 3,3-dimethyl-1,2-diphenylbutan-1-ol through the comparative analysis of the respective chemical shifts induced by Eu(fod)₃ in the ¹H and ¹³C NMR spectra, and the corresponding conformational distribution.     

The disordered molecular structure of (3aRS,7aRS)‐1,3‐dinitrosooctahydro‐1H‐benzimidazole

The title compound, C₇H₁₂N₄O₂, was obtained by nitrosation of the aminal cage (2R,7R,11S,16S)‐1,8,10,17‐tetraazapentacyclo[8.8.1.1^8,17.0^2,7.0^11,16]icosane. The crystal structure is a racemic mixture of RR and SS enantiomers. The asymmetric unit contains two crystallographically independent half‐molecules, one having two partially occupied conformers with refined occupancy factors of 0.747 (3) and 0.253 (3). The molecules sit across twofold axes. The unique molecules each form chains parallel to [001], with molecules connected by intermolecular C—H...O hydrogen bonds. The bonding between adjacent chains is weak. The analysis of eight different crystals confirmed the presence of disordered and nondisordered molecules in the same structure as a regular feature.