Jaroslav Riha

Zentiva · Development

The invention deals with an amorphous form of the hemicalcium salt of atorvastatin controlled pptn., and its use in a dosage form. Atorvastatin (0.3 kg) dissolved in Et acetate (1 L) was pptd. into pentane (7 L). The product was isolated on a filter and washed with pentane. The wt. ratio of Et acetate/pentane was 4.4%. After drying at 60T- in vacuo...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The rate of hydrolysis of 1,3,5-tris(2-hydroxyethyl)hexahydro-s-triazine (triazine, 1) was shown to be strongly dependent on the pH of the aqueous solution: d[triazine]/dt = 2.6 × 10-5[triazine] + 2.2 × 106[triazine][H+] at 22 °C; d[triazine]/dt = 4.8 × 10-4[triazine] + 3.5 × 108[triazine][H+] at 60 °C. Furthermore, we have established the structur...

A new method for preparing 3-amino-2-chloropyridines with a substituent (methyl, phenyl, carbox-amide, methoxycarbonyl, acetyl, benzoyl and cyano) at the 4-position has been developed. An isoquinoline analogue of the reverse transcriptase inhibitor Nevirapine has been synthesized from the 4-amino-3-chloroisoquinoline.

New methods for the preparation of 3,4-diaminopyridine (5) and imidazo[4,5-c]pyridines 7a,7b based on direct nitration of 4-acylaminopyridines 3a, 3b have been explored.

The reactions of N-nitropyridinium nitrate (1) and 2,6-dideuterio-N-nitropyridium nitrate (2,6-d2-1) with SO2XH2O-HSO3- have been studied. The results are consistent with a reaction scheme in which the formed N-nitro-1,4-dihydro-4-pyridinesulfonic acid (2) did not react directly to give 3-nitropyridine but existed in equilibrium with 1 and 2,6-d2-1...

Reaction of pyrimidine with dinitrogen pentoxide followed by addition of alcohol resulted in formation of 2,4-dialkoxy-l,3-dinitro-l,2,3,4-tetrahydropyrimidines.

The reactive N-nitropyridinium nitrate (2) and the stable N-(2,4-dinitrophenyl)-pyridinium chloride (5) have been reacted with nucleophiles. N-Nitropyridinium nitrate and pyridine gave 4-pyridino-1-nitro-1,4-dihydropyridine (3) in an equilibrium reaction. With hydroxide ions, a ring-opening reaction took place to give 5-nitroaminopenta-2,4-dienal (...

The sodium salt of 5-nitraminopenta-2,4-dienal reacts with sodium bisulfite to give 3-nitropyridineFigure optionsView in workspace

Compounds 2- and 4-aminonicotinamide were quaternized with eight 4-substituted 1-bromomethylbenzenes to form 1-(4-substituted benzyl)-3-carbamoyl-1,2(1,4)-dihydropyridin-2(4)-iminium bromides. The optimal reaction conditions were found and the resulting iminium salts were characterized by ¹H and ¹³C NMR spectra. No transmissio...