abstract |
This invention relates to a compound of Formula I, a method for its preparation and its use in the preparation of a compound of Formula II wherein R<SUP>1</SUP>, R<SUP>2</SUP>, R<SUP>3</SUP>, X and n are as defined in the disclosure. This invention also discloses preparation of compounds of Formula III wherein R<SUP>1</SUP>, R<SUP>2</SUP>, R<SUP>6</SUP>, R<SUP>7</SUP>, R<SUP>8 </SUP>and n are as defined in the disclosure. Also disclosed are certain intermediates of Formula 4 for the preparation of compounds of Formula I wherein X is N and R<SUP>2</SUP>, R<SUP>3 </SUP>and n are as defined in the disclosure. |