Synthesis of 5-aryl-3-hydroxy-1-(2-hydroxypropyl)-4-(furyl-2-carbonyl)- 3-pyrrolin-2-ones and 5-aryl-3-hydroxy-1-(3-hydroxypropyl)- 4-(furyl-2-carbonyl)-3-pyrrolin-2-ones

In this work, pyrrolidin-2-ones and their derivatives are considered as a promising class of non-aromatic heterocyclic compounds. Their structure is found in the nuclei of many natural products and biologically active molecules. In pharmacy the possibility of introducing various substituents into the nucleus of pyrrolidin-2-ones is a great importance for the synthesis of new medicinal molecules with improved biological activity. Nowadays the synthesis of new active compounds by introducing various substituents at the C1-, C4- and C5-position of 3-hydroxy-3-pyrrolin-2-one has been little studied and it is of great interest to study the conditions of their synthesis, chemical properties and biological activity. In this research work the corresponding 5-aryl-3-hydroxy-1-(2-hydroxypropyl)-4-(furyl-2-carbonyl)-3-pyrrolin-2-ones and 5-aryl-3-hydroxy-1-(3-hydroxypropyl)-4-(furyl-2-carbonyl)-3-pyrrolin-2-ones were synthesized by the reaction of methyl ester of furyl-2-carbonylpyruvic acid with a mixture of aromatic aldehyde and 1-amino-2-hydroxypropane or 3-amino 1-hydroxypropane when heated in dioxane. The results of the study of the structure of the new synthesized compounds are presented. The structure was proved using 1H NMR spectroscopy and IR spectrometry. It was shown that the IR spectra of the compounds contain bands of the corresponding stretching vibrations of the alcoholic hydroxyl group, enol hydroxyl, amide and ketone groups. In the 1H NMR spectra of the compounds, along with the signals of aromatic protons in the C5 substituent and related groups, characteristic peaks are observed, indicating the formation of the corresponding derivatives of 3-hydroxy-3-pyrrolin-2-ones. It was noted that in the case of the synthesis of 5-aryl-3-hydroxy-1-(2-hydroxypropyl)-4-(furyl-2-carbonyl)-3-pyrrolin-2-ones, the signal of the methine proton at the C5 position of the heterocycle is cleaved in 1H NMR spectra compounds as a result of the appearance of a second chiral center in the 2-hydroxypropyl radical. Elemental analysis was performed for the synthesized compounds.

C-Nucleophilic substitution in tetrachlorophthalonitrile — An approach to some new hexadecasubstituted phthalocyanines

Reaction of tetrachlorophthalonitrile with some C -nucleophiles was studied. Only one chlorine atom was substituted regioselectively in the position 4 of benzene ring with diethyl malonate and malononitrile; no reaction occurred in case of bulkier diethyl ethylmalonate and ethylmalononitrile. In case of dimedone the domino substitution of two chlorine atoms, first with C -nucleophile followed by enolate O -nucleophile led to the mixture of two dibenzofuran derivatives. Remaining chlorine aroms n malonate and dibenzofuran derivatives were substituted with thiols, but in malononitrile derivative high acidity of methine proton led to the formation of stable carbanion under basic conditions that prevents further substitution. Hexadecasubstituted zinc phthalocyanines were synthesized from some new phthalonitriles.

The Structural Studies of Oxirane Ring Opening Reaction in Epoxidized Natural Rubber (ENR-50) by SnCl2.2H2O and the Formation of ENR/TiN Complex Hybrid

Oxirane ring opening reaction of epoxidized natural rubber (ENR-50) is a promising method to produce hybrids or introduce reactive fillers into the polymers through the covalent bond. This paper reports the reaction between ENR-50 and SnCl2.2H2O under CO2environment. The complex formation is characterized via FTIR,1H,13C and119Sn NMR.1H NMR which displays deduction of methine proton integrals at δ 2.71 ppm implies the occurrence ring opening reaction. While13C NMR reveals new peaks which corresponds to Sn-C bond. The119Sn NMR proves four-coordinates tin in ENR/Sn complex hybrid.

Bis(trimethylsilyl)methylamine (BSMA): tool or toy?

Bis(trimethylsilyl)methylamine, BSMA, an original primary amine, was proven to be the source of a large variety of N-bis(trimethylsilyl)methylamino derivatives that otherwise have to be prepared indirectly. Because of the bulkiness of the bissilylmethyl group, regio- and stereoselectivities resulted in appropriated examples. Apart from the potential biological properties associated with the Si-C-N framework, these derivatives were powerful synthetic intermediates. Special emphasis was given to the chemistry of corresponding imines. Cleavage of Si—C bonds or abstraction of the methine proton afforded α-nitrogen carbanions in very mild conditions. Application of these results to the β-lactam chemistry allowed the introduction of new synthetic methodologies in this field. It results the (Me3Si)2CH- group could now be regarded as a Me3SiCH2- or a CH3- group or a proton equivalent.Key words: bis(silyl)methylamine, preparations, reactivity, nitrogen heterocycles, α-nitrogen carbanions.

Delayed oxidative degradation of polyunsaturated diacyl phospholipids in the presence of plasmalogen phospholipids in vitro

The oxidative degradation of plasmalogen (alkenylacyl) phospholipids was analysed in the absence and the presence of polyunsaturated ester phospholipids by 1H-NMR and by chemical determination. Brain lysoplasmenylethanolamine (lyso-P-PE), brain P-PE and erythrocyte P-PE, containing an increasing number of intrachain double bonds at sn2, were oxidized with 2,2´-azobis-(2-amidinopropane hydrochloride) (AAPH; 2 or 10 mM) in Triton X-100 micelles (detergent/phospholipid 1:5, mol/mol). The formation of two peroxyl radicals was accompanied by the degradation of approx. one molecule of brain lyso-P-PE. On oxidation of brain P-PE or erythrocyte P-PE (320 nmol) with 2 mM AAPH, the (α-vinyl) methine 1H signal of the enol ether decreased more rapidly than the methine proton peak of intrachain double bonds. The rate of enol ether degradation increased in the order: erythrocyte P-PE > brain P-PE > brain lyso-P-PE. The disappearance of the polyunsaturated ester phospholipids 1-palmitoyl-2-arachidonoyl phosphatidylcholine (16:0/20:4-PC) and 1-palmitoyl-2-linoleoyl phosphatidylcholine (16:0/18:2-PC) (100 nmol), as induced by 10 mM AAPH, was nearly completely inhibited by the plasmalogens (25 nmol) in the first 30 and 60 min of incubation respectively, and was delayed at later time points. Plasmalogens and vitamin E (4–25 nmol) mitigated the decreases in 16:0/[3H]20:4-PC (100 nmol) induced by 2 mM AAPH in a similar manner. The initial rate of degradation of intrachain double bonds of 16:0/20:4-PC and 16:0/18:2-PC (320 nmol; 2 mM AAPH) was decreased by 59% and 81% respectively in the presence of 80 nmol of brain lyso-P-PE. In conclusion, plasmalogens markedly delay the oxidative degradation of intrachain double bonds under in vitro conditions. Interactions of enol ether double bonds with initiating peroxyl radicals as well as with products generated by prior oxidation of polyunsaturated fatty acids are proposed to be responsible for this capacity of plasmalogens. Furthermore, the products of enol ether oxidation apparently do not propagate the oxidation of polyunsaturated fatty acids.

Concerning the internal rotational potential in benzal chloride. 37Cl/35Cl isotope effect on the methine 1H NMR

1H NMR spectral parameters are reported for benzal chloride in CS2/C6D12, CDCl3, and acetone-d6 solutions. The values of 6J (H,CH), the long-range spin–spin coupling constant between the side-chain and para protons, are consistent with twofold barriers to rotation about the exocyclic C—C bond of 8.6(4), 8.9(4), and 10.2(6) kJ/mol, in the order of the solvents above. These numbers are somewhat smaller than the twofold barrier of 11.6 kJ/mol available from STO-3G MO computations for the free molecule. Alternatively, an internal rotational potential consisting of a twofold term of 17.0 kJ/mol and a fourfold term of −5.5 kJ/mol is also compatible with the 6J (H,CH) measured for the CDCl3 solution and with the 13C spin-lattice relaxation data reported for such a solution. The 6J (H,CH) values demonstrate that the conformer with the a C—H bond situated in the benzene plane is the most stable. A local minimum in the potential for a conformer in which this bond lies in a plane perpendicular to the phenyl group, leading to a population of about 8% for this conformer at 300 K and compatible with the magnitude of 6J (H,CH), is represented by twofold and fourfold terms of 6.0 and 4.5 kJ/mol, respectively. The barrier height is then only 8.0 kJ/mol, however. 37Cl/35Cl isotope effects on the methine proton amount to −0.17, −0.19, and −0.22 parts per billion in CS2, CDCl3, and acetone-d6 solutions, respectively (increased screening). Keywords: benzal chloride, internal potential, 37Cl/35Cl isotope effect on 1H NMR.