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Structural Studies of 1-Aryl-2-aminoimidazolinium Bromides: Focus on Tautomer Preference of the 2-Aminoimidazoline Moiety in the Solid State

Dobrowolski M., Cyrański M., Pisklak M., Wawer I., Matosiuk D.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 5-6

1037-1048

EN

The crystal structures of five 1-(4-X-phenyl)-2-aminoimidazolinium bromides (where X = -OCH3, -CH3, -H, -Cl and -NO2) were determined by X-ray crystallography with the aim to investigate the tautomer preference of the aminoimidazoline moiety in the solid state. The molecular structures clearly indicate that only the ring nitrogen is protonated. The crystals are stabilized by interactions between the hydrogens of the amino group (also NH fragment of the imidazoline ring) and bromide anion. In the case of the nitro derivative additional strong hydrogen bonds are a consequence of the presence of water molecule in the crystal lattice. The methoxy and nitro derivatives were studied by 15N CP/MAS NMR and the analysis of the tautomer preference was completed by ab initio calculations at the B3LYP/6-311+G** level.

2

Reversal of Diastereoselectivity of Mesitonitrile Oxide 1,3-Dipolar Cycloadditions with Penta-1,4-diene-3-ol by Mg(II)

Micuch P., Fisera E., Cyrański M.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 1

65-72

EN

1,3-Dipolar cycloadditions of mesitonitrile oxide (4) to penta-1,4-diene-3-ol (5) proceed regioselectively irrespective of the presence or absence of the Mg(II) additive. Addition of Grignard reagent reverses the diastereoselectivity of the cycloaddition. The reaction of mesitonitrile oxide with magnesium alkoxide of penta-1,4-diene-3-ol (5) proceeded with exclusive diastereoselectivity giving the syn 6b and 7c isomer of the resulting isoxazolines.

3

Synthesis of Crotonoyl, Cynamoyl and p-Methoxycynamoyl Derivatives of Camphoric Imide : Crystal and Molecular Structure

Matraszek J., Mieczkowski J., Cyrański M.

Polish Journal of Chemistry

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2000

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Vol. 74, nr 4

477-482

EN

Three derivatives of camphoric acid imide (crotonyl, cynamoyl and p-methoxycynamoyl) have been synthesized. Despite of a small number of heavy atoms, the absolute structure determination occured to be successful.

4

Furo[2,3-b]pyrrole Derivatives : Syntheses and Reactions in the Furan and Pyrrole Ring

Sleziak R., Krutosikova A., Cyrański M., Krygowski T.

Polish Journal of Chemistry

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2000

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Vol. 74, nr 2

207-217

EN

6-Substitued furo[2,3-b] pyrrole-5-carboxylic acids 2b-d as well as their 2-formyl-substitued derivatives 4a-d have been prepared by alkaline hydrolysis of the corresponding esters 1b-d and 3a-d, respectively. A different behaviour of methyl 6H-furo[2,3-b]pyrrole-5-carboxylate 1a in comparison with the 4Hfuro[3,2-b] pyrrole isomer has been discussed in a framework of different acidity of proton of NH group. The hypothesis has been supported by ab initio B3LYP/6-311+G**DTF calculations. The 2-formylated derivatives 3b-d were used for synthesis the propenoid acids 5b-d, the corresponding acid azides 6b-d, new disubstitued ureas 9 or 10, 2-cyano-derivatives 11a-d, which were transfored into the corresponding amidines 12 and substitued arylureas 13 as well as to 5'-tetrazolyl derivative 14. Further methyl 2-triphenylmethyl-6Hfuro[2,3-b]pyrrole-5-carboxylate 15 and its Michael addition product 16 were prepared.

5

Crystal and Molecular Structure of 1,3,5-Trimethoxy-2,4,6-trinitrobenzene : Mesomeric Effects for Out-of-plane Twisted Substituents

Anulewicz-Ostrowska R., Krygowski T., Cyrański M., Matuszewska M.

Polish Journal of Chemistry

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1999

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Vol. 73, nr 11

1895-1901