Patent ID: 6448405
Filing Date: 2002-09-10
Classification: C07D

Abstract:
A method for producing a nitrobenzocoumarin comprising:(a) coupling a 2-halo-5-nitrobenzoic acid derivative of the formula: with a 2-methoxyphenyl boronic acid of the formula: in the presence of a palladium catalyst and base to yield a biaryl carboxylate of the formula: and(b) in a one-pot reaction, sequentially cyclizing the biaryl carboxylate to the corresponding nitrobenzocoumarin by deprotecting the biaryl carboxylate to afford the biaryl carboxylic acid, converting the biaryl carboxylic acid to the corresponding biaryl acid chloride, followed by cyclizing the biaryl acid chloride in the presence of a Lewis acid to yield a nitrobenzocoumarin of the formula: wherein R1 through R6 each independently are hydrogen, F, Cl, Br, CN, CF3, a C1-C4 alkyl, or OR7, where R7 is hydrogen or a C1-C4 alkyl; and X is OR8 or NR8R9, where R8 and R9 each independently are hydrogen, a C1-C4 alkyl or optionally substituted allyl, aryl methyl, aryl or heteroaryl.