Conformational analysis of mono-and bis(dimethoxyphosphoryl)benzenes

Conformational analysis of mono-and bis(dimethoxyphosphoryl)benzenes with substituents in the benzene ring was performed by the method of dipole moments, IR spectroscopy, and quantum-chemical calculations (DFT B3LYP/6-31G*). Comparison of all calculated and experimental data shows that the compounds studied exist as equilibrium mixtures of conformers with preferred gg orientation of the phosphoryl and methoxy groups.     

Theoretical Conformational Analysis of 1,3,2-Benzodioxaphosphinan-4-ones

Russian Journal of Organic Chemistry -     

Synthesis and Biological Activity of Novel Ethyl Esters of 4‐R‐6,8‐Dimethyl‐1‐oxo‐1,2‐dyhidropyrrolo[1,2‐d][1,2,4]triazine‐7‐carboxylic Acids

The novel heterocyclizations of ethyl 5‐(hydrazinocarbonyl)‐2,4‐dimethyl‐1H‐pyrrole‐3‐carboxylate are developed. New derivatives of ethyl esters of 4‐R‐6,8‐dimethyl‐1‐oxo‐1,2‐dyhidropyrrolo[1,2‐d][1,2,4]triazine‐7‐carboxylic acids were obtained. The in vitro anticancer and antibacterial activities of the synthesized compounds were revealed. The most potent antibacterial compound appeared to be 1.3 inhibiting Staphylococcus aureus. Pyrrolo[1,2‐d][1,2,4]triazine 2.15 showed significant antifungal activity against Candida tenuis. The anticancer activity of the synthesized compounds was determined.     

3-Aryl(hetaryl)-3-hydroxy-2-phosphorus-substituted acrylonitriles. Synthesis and experimental and theoretical conformational analysis

Under conditions of the phase transfer catalysis, acylation of (thio)phosphorylacetonitriles by (het)aroyl chlorides affords the Z-enol forms of C-acylation products in high yields. Their configurations were studied by IR spectroscopy, dipole moment measurements, and ab initio quantum-chemical calculations [B3LYP/6-31G(d)]. The C=C double bond and the phosphoryl or thiophosphoryl group have an s-cis arrangement. The possibility of strong intramolecular hydrogen bonding in these conformers is the governing factor responsible for the three-dimensional structures of the compounds under investigation. Derivatives of nicotinic acid existing in the individual form as zwitterions are the only exceptions.     

Molecular and Solution Structure of 5,6-Benzo-1,3,2-dioxaphosphinin-4-one Derivatives

2-X-5,6-benzo-1,3,2-dioxaphosphinin-4-ones (X = N = C = O, Cl, NEt₂), regardless of their aggregative state, prefer one and the same conformation (flattened sofa); the exocyclic substituent occupies either an axial (N = C = O, NEt₂) or an equatorial (Cl) position.     

Highly unsaturated polymers Communication 6. Poly(1, 3, 5-triethynylbenzene)

Summary A highly unsaturated triacetylenic hydrocarbon, 1,3,5-triethynylbenzene, was synthesized, and the oxidative polycondensation of this gave a three-dimensional oligomer containing alternating diacetylenic groups and aromatic nuclei in its molecule.For Communications 1–5 see [1–5].     

Synthesis and Structural Features of 1-Acyl-1-nitro-2-furyl(thienyl)ethenes

A one-stage synthesis of 1-acyl-1-nitro-2-furyl(thienyl)ethenes was developed and structural assessment of the products was performed by means of ¹H, IR, and UV spectroscopy and dipole moment measurements. The acetyl derivatives have Z configuration, and the benzoyl derivatives, E configuration. The UV and IR spectra, as well as the rather high dipole moments ( 5-6 D) point to an essential contribution in the structures of dipolar forms.     

Studies in the benzodiazine series

It has been shown that when there is no substituent in position 5 of a tetrazolo[1, 5-c]quinazoline covalent hydration at the N(₆)=C(₅) bond and cleavage of the pyrimidine ring with the formation of 5-(2-aminophenyl)-tetrazole take place more readily than in the case of the 5-methyl derivative. The 5-phenyl derivative of tetiazolo[1, 5-c]quinazoline does not undergo hydration. The mechanism of the hydration of the compounds mentioned is discussed.For communication VIII, see [1].     

Cyclization of N-alkylazinium cations with binucleophiles. 8. Annellation of the imidazole ring with pyrazines and quinoxalines

Monosubstituted and N,N′-disubstituted thioureas enter into cyclization with pyrazinium and quinoxalinium ion to form imidazo[4,5-b]-annellated pyrazines and quinoxalines.