Synthesis of 2-Methoxy-4-(methylsulfanyl)benzoic Acid — An Intermediate Product in the Preparation of the Cardiotonic Drugs Sulmazole and Isomazole
Readily available 4-methyl-3-nitrobenzenesulfonic acid and 2-methyl-5-nitrophenol were used to develop two alternative approaches to the synthesis of 2-methoxy-4-(methylsulfanyl)benzoic acid in total yields of 17% and 37%, respectively. The synthesis starting from 2-methyl-5-nitrophenol is more process-oriented and can be used in the resynthesis of Sulmazole and Isomazole.
Lomov
p. 1093 - 1098
(2019/10/19)
Process for aryl-quinone and aryl-naphthoquinone diazide sulfonic acids
A process for the preparation of aryl-diazide-sulfonic acids by a series of sequential in-situ process steps. The process comprises the nitrosation of a hydroxyarylsulfonic acid; conversion of the nitroso-derivative to a sulfamate which is then diazotized to the diazide. Temperature and pH are maintained in predetermined ranges to maintain the reaction products in solution without the formation side-products or the need to isolate intermediates. The process of the invention is particularly useful in the preparation of light-sensitive materials such as naphthoquinonediazide sulfonic acids which are used in the preparation of photoresist compositions. The invention provides a high purity product at a high material efficiency, high equipment utilization, low effluent discharge, and reduced cost.
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(2008/06/13)
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