Phosgene → 3-Thiophenecarboxylic acid, 4-(isocyanatosulfonyl)-5-methyl-, methyl ester

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Reaction Steps

Under the conditions specified above, 23.5 g of methyl 4-(aminosulfonyl)-5-methylthiophene -3-carboxylate (1) were reacted with 11.3 g of pentyl isocyanate (100 mmol) in the presence of phosgene to give methyl 4-(isocyanatosulfonyl)-5-methylthiophene-3-carboxylate (2). 22 g of this isocyanate (83% of theory, content: 99%, b.p.: 120° C., 0.4 mbar) were likewise obtained. The identification and the determination of content were conducted by means of derivatization with methanol to the corresponding carbamate (1H NMR (400 MHz, d6DMSO): 2.72 (s), 3.61 (s), 3.79 (s), 8.00 (s), 11.96 (s)).

Provenance & Evidence