Foreword

Foreword

Foreword     

Studies on the synthesis of heterocyclic compounds. Part VIII. A facile synthesis of new pyrazolo[3,4-b]benzazepine-4,9-diones

2-Carbomethoxybenzoyl chloride reacted with some 5-methylamino-l-phenyl-3-R-pyrazoles to yield N-methyl-l-phenyl-3-R-pyrazol-5-yl)-2-carbomethoxybenzamides. These products were readily transformed into the corresponding acid, which in turn, refluxed in phosphorus oxychloride afforded the tricyclic system, l-phenyl-3-R-pyrazolo[3,4-b]benzazepine-4,9-dione.     

Studies on the synthesis of heterocyclic compounds. Part I. The pschorr reaction in the pyrazole series

Preparation and structural evidence of N-methyl-(1,3-R,R'-pyrazol-5-yl)-o-nitrobenzamides (VIIIa, b) are discussed. Diazotisation of related o-aminobenzamides XIa,b followed by the Pschorr reaction afforded a very complex mixture from which pyrazolo[3,4-c]isoquinolin-5-ones XIIa.b in 7–10% yields together with N-methyl-(1,3-R,R'-pyrazol-5-yl)-o-hydroxybenzamides (XIIIa) in 15–20% yields were isolated.     

Studies of the synthesis of heterocyclic compounds. Part VII. The preparation of some new 3- and 5-amino-pyrazoles by endocyclic N-substitution of 3(5)-aminopyrazoles

By reaction of some 4-carbethoxy(or cyano)-3(5)-R-5(3)-aminopyrazoles 1 with 2-nitrobenzoyl chloride or 2-nitrobenzenesulfonyl chloride, a number of novel 3- and 5-amino-1-(2-nitrobenzoyl or 2-nitrobenzene-sulfonyl)pyrazoles 6 and 7 were obtained. Every compound appearing during the endocyclic N-substitution process can be identified and determined by glc. The use of nmr offers a rapid, unambigous method for determining the proposed structures.     

Stochastic Burgers' equation

We consider a Burgers' equation perturbed by white noise. We prove the existence and uniqueness of the global solution as well as the existence of an invariant measure for the corresponding transition semigroup.     

New synthesis of condensed heterocycles from isoxazole derivatives VI. 2,5-Dimethyl-3-aeetyl-7-amino-1H-pyrrolo[3,2-b] pyridine

A new synthesis of pyrrolo[3,2-b] pyridine starting with pyrrole ring is described. The procedure allows the synthesis of 4-azaindoles bearing a sensitive group at C-7. The nitration of 4b with nitric acid and acetic anhydride at ?15° gave 5 . The hydrogenation of 5 led to simultaneous reduction of N-hydroxy and nitro groups and to hydrogenolysis of the isoxazole nucleus, affording an appropriate chain of atoms to building up the pyrrolo[3,2-b] pyridine ring.     

Editorial

Editorial Commentary

Editorial     

Determination of phenoxyacid herbicides and their phenolic metabolites in surface and drinking water.

An evaluation was made of the feasibility of using reversed-phase liquid chromatography/tandem mass spectrometry with an electrospray interface (LC/ESI-MS/MS) to measure traces of phenoxyacid herbicides and their metabolites in surface and drinking water samples. The procedure involved passing 0.5 L of river and drinking water samples through a 0.5 g graphitized carbon black (GCB) extraction cartridge. Recovery was higher than 85% irrespective of the aqueous matrix in which the analytes were dissolved. A conventional 4.6-mm i.d. reversed-phase LC C-18 column operating with a mobile phase flow rate of 1 mL/min was used to chromatograph the analytes. A flow of 200 microL/min of the column effluent was diverted to the ESI source. The limits of detection (signal-to-noise ratio = 3) of the method for the pesticides considered in drinking and surface water samples are less than 0.1 ng/L for phenoxyacid herbicides, and about 5-10 ng/L for their metabolites (2,4-dichlorophenol and 4-chloro-2-methylphenol).