Quantum-chemical Investigations of Pyrimidinones-4. 1. Tautomerism of 2-Oxopyrimidinones-4

Semiempirical quantum-chemical calculations have been carried out of the molecules of 2-oxopyrimidinones-4. The geometry and electronic structures and the stabilities of the tautomeric forms have been analyzed.     

Direction of bromination and nitration of deoxypeganine and its hydrochloride using HPTLC. Synthesis of 6-bromo(nitro)-, 6,8-dinitrodeoxyvasicinones, 6-nitro(bromo)-, 6,8-dinitrodeoxypeganines,and 6H(bromo)peganols

The reaction of deoxypeganine (DOP) (1) and its hydrochloride (DOP·HCl) (2) with N-bromosuccinimide and a nitrating mixture was studied. It was found that bromination of DOP occurred at C-4 and the aromatic ring. Nitration of DOP·HCl produced either 6-nitro- or 6,8-dinitro-deoxypeganines and 6-nitrodeoxyvasicinone or their mixture in various ratios depending on the substrate:nitrating mixture ratio. 6Hand 6-Br-deoxypeganines were transformed into the 4-hydroxy derivatives, 6H(Br) peganols or deoxyvasicinones. A method for qualitative and quantitative analysis of the pure compounds and the mixture of reaction products using HPTLC was developed. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 505–509, September-October, 2008. Original article submitted March 26, 2008.     

A study of some parameters relevant to the response of harwell PMMA dosimeters to gamma and electron irradiation

The effects on the radiation response of Harwell polymethylmethacrylate (PMMA) dosimeters of dose-rate, radiation type, temperature during irradiation and post-irradiation storage, and post-irradiation stability, are of importance to the operators of commercial irradiation facilities.

This paper describes recent studies of the effects of some of these parameters on the radiation response of Harwell Red 4034, Amber 3042, and Gammachrome YR Perspex dosimeters, and provides data on batch to batch variation and shelf-life.     

Structural features of <Emphasis Type="Italic">N</Emphasis>-acylcytisines

N-Acyl cytisine derivatives were synthesized by acylation with acetic anhydride; benzoyl and o-bromo- and p-nitrobenzoyl chlorides; and crotonyl and cinnamoyl chlorides. The structures of the synthesized compounds were studied using IR, PMR, and x-ray structure analysis (XSA). PMR spectra of the N-acylcytisines in solution typically had two rotational isomers around the N12–CO bond. Conformational analysis was performed using XSA for the position of the acyl group relative to the cytisine core. Bond lengths and angles of the acyl groups involved in the conjugation were analyzed.     

Quinazolines. 2*. unsymmetric 1,3-dialkyl-6-chlorosulfonyl- quinazoline-2,4-diones in nucleo- philic substitution reactions

The corresponding 6-chlorosulfonylquinazoline-2,4-diones were synthesized by the reactions of 1-methylquinazoline-2,4-dione and its 3-alkyl-substituted derivatives with chlorosulfonic acid. Treatment of the products with nucleophilic agents (water or ammonia, aliphatic and cyclic amines) gave 2,4-dioxoquinazolin-6-sulfonic acids or their amides.     

<Emphasis Type="Italic">Z</Emphasis>-and <Emphasis Type="Italic">E</Emphasis>-conformers of <Emphasis Type="Italic">N</Emphasis>-chloroacetylcytisine

N-Chloroacetylcytisine was synthesized by acylation of (–)-cytisine. Stable Z- and E-conformers with respect to rotational isomerism around the N-12–CO bond were found in PMR spectra at room temperature. The point at which PMR resonances of the Z- and E-conformers coalesced upon heating was measured. The transition barrier between the conformers was estimated.     

Growth-regulating activity of bis-quaternary salts of pyrrolizidine alkaloids and the products of their transformation

The growth-regulating activity of bis-quaternary salts of the pyrrolizidine series has been studied. It has been established that they possess a retardant activity which depends on the presence of the quaternary nitrogen atom, the acid residue of the molecule, and its configuration.     

Reaction of 6-oxo-, thioxo-2,3-dimethylthieno[2,3-d]pyrimidin-4-ones with electrophelic reagents

The reaction of 6-oxo-, thioxo-2,3-dimethylthieno[2,3-d]pyrimidin-4-ones with electrophilic agents was studied. It was shown that during nitration these compounds undergo electrophilic unco-substitution forming 3-nitro- and 2-nitro-6-oxo- and 2,3-dinitro-6-thioxothieno[2,3-d]pyrimidin-4-ones, respectively; the reaction of these compounds with bromine proceeds in other directions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1574–1576, November, 1993.