Reissert compound studies. XXXVI. Observations on 1,7-, 4,6-, 4,7-, and 1,10-phenanthrolines

Reissert compounds have been prepared from 1,7-, 4,6-, and 4,7-phenanthrolines. In the case of 4,7-phenanthroline, both mono- and di-Reissert compounds have been prepared. A number of Reissert analogs have also been prepared in this series. 1,10-Phenanthroline fails to give a Reissert compound.     

Indole derivatives. 136. 4-, 5-, 6-, and 7-Nitro-3-indolesulfonic chlorides and sulfonamides

The reaction of nitroindoles with chlorosulfonic acid in the presence of sodium sulfate was used to synthesize 4-, 5-, 6-, and 7-nitroindole-3-sulfonyl chlorides. Under the influence of ammonia and several amines these compounds were convened to nitroindole-3-sulfonamides which were reduced with hydrazine hydrate in the presence of Raney nickel to the corresponding amines.See [1] for Communication 135.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1341–1345, October, 1990.     

Preparation steps in environmental trace element analysis - facts and traps

The laboratory of CERVA is for several decades involved in the Belgian environmental research. The activity was associated to national monitoring programs dealing with trace metal pollution of all compartments of the environment (sea and river waters, sediments and organisms but also soils, plants, animal and food samples). Such a monitoring dealing with the total analyte contents in samples needed a comprehensive development of the whole methodology associated to the analyses using atomic absorption and emission spectroscopy techniques. This includes measurement but also preparation steps. The latter is the subject of this work. Long-term experience has shown that precisely sample preparation is the most critical part of the analysis because it is responsible for the largest and often hidden sources of errors. Errors due to contaminations may be usually overcome if necessary precautions are taken concerning reagents, tools and the manner of working. The problem is different for analyte losses: in this case, the responsible factor is an inappropriate methodology. This is particularly true for preparation of solid samples that have to be brought in a solution in order to satisfy needs of introduction systems of most spectroscopic techniques utilized in routine laboratories. For some types of samples (e.g. animal tissues), the dissolution is not a problem: it may be readily achieved by several procedures. This is not the case for samples that contain silicates in their matrix (e.g. soils, sediments, plants) because their complete dissolution cannot be ensured by a simple procedure. This review describes the present knowledge regarding possibilities and errors that concern preparation steps. In addition, possible effects of the preparation procedure on the quality of measurement are also systematically discussed.     

Heterogeneous-catalytic fischer reaction. 13. Catalytic synthesis of 4-, 5-, 6-, and 7-methoxyindoles

Methoxy-substituted acetaldehyde phenylhydrazones were cyclized in the vapor phase on a GIPKh-115 catalyst to give 4-, 5-, 6-, and 7-methoxyindoles. 5-Methoxyindole was obtained in 50% yield, 4- and 6-methoxyindoles were obtained in 85% yield, and 7-methoxyindole was obtained in 45% yield.See [1] for Communication 12.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1054–1055, August, 1982.     

Regioisomerism in the Ritter reaction. 1. Synthesis of 3,3,5,6,7-, 3,3,6,7,8-, 3,3,5,7,8-, and 3,3,5,6,8-pentamethyl-3,4-dihydroisoquinolines from 1,2,3- and 1,2,4-trimethylbenzenes

Reactions of 1,2,3- or 1,2,4-trimethylbenzene with isobutyraldehyde and ethyl cyanoacetate (ECA) or reactions of the corresponding 1-aryl-2-methylpropan-1-ols with ECA afforded isomeric 3,3,5,6,7-, 3,3,6,7,8-, 3,3,5,7,8-, and 3,3,5,6,8-pentamethyl-3,4-dihydroisoquinolines. Isomerization is explained as the ring opening of a spiran intermediate in two possible ways followed by the Jacobsen rearrangement.