Ether derivatives of the FK-506 related macrolide L-683,742 (C31-O-des
methyl ascomycin) have been prepared by alkylation with various alkyl
2,2,2-trichloroacetimidates. The in vitro immunosuppressive activity o
f these analogs is dependent both on the size and site of attachment (
C31-O vs. C32-O) of the ether group.