Trifluoroacetic acid process to prepare [2,3-B]pyridine intermediates

A process to prepare a [2,3-b]pyridinyl compound of formula (II)

• 10
• where X1 is:
• —O—,
• —S— and
• 11
• where R1 is:
• C1-C4 alkyl,
• phenyl and
• 2-, 3- or 4-pyridinyl;
• where R2 is:
• H—,
• morpholin-4-yl-CH2— and
• (CH3)2N—CH2—;
• where R3 is C1-C4 alkyl;
• which comprises:
• (1) contacting a malonate diester of formula (I)
• 12
• where R4 is C1-C4 alkyl;
• where R5 is:
• H—,
• HOOC—,
• R5-1O—OC— where R5-1 is C1-C4 alkyl and
• where X1, R1, R2 and R3 are as defined above, with trifluoroacetic acid;
• and
• (2) adjusting the pH with aqueous base to from about 9 to about 10.5.