The reaction of 15-methylerythromycin A (I) with hydroxylamine, cyclohexanone di-isopropylacetal (II) and PPTS gives the substituted oxime (III), which is regioselectively silylated with Tms-Cl and imidazole to yield the disilylated compound (IV). The alkylation of (IV) with allyl bromide (V) and tBu-OK affords the 6-O-allyl derivative (VI),which is treated with HOAc and HCOOH to cleave the oxime group and furnish the 6-O-allyl-15-methylerythromycin A (VII). The cleavage of the 3-O-carbohydrate moiety of (VII) by means of aq. HCl, followed by benzoylation with Bz2O, gives the benzoyl intermediate (VIII), which is oxidized with NCS and Me2S and dehydrated with Ms-Cl, pyridine and DBU to yield the ketolide (IX). The fluorination of (IX) by means of (PhSO2)2N-F and tBu-OK affords the 2-fluoro derivative (X).

The reaction of (X) with NaH and CDI and then with hydroxylamine gives the cyclic carbamate (XI), which is finally condensed with 3-bromoquinoline by means of Pd2(dba)2 and P(o-tolyl)3 to yield the target 6-O-[3-(3-quinolyl)allyl] derivative.

The reaction of 15-methylerythromycin A (I) with hydroxylamine, cyclohexanone di-isopropylacetal (II) and PPTS gives the substituted oxime (III), which is regioselectively silylated with Tms-Cl and imidazole to yield the disilylated compound (IV). The alkylation of (IV) with allyl bromide (V) and tBu-OK affords the 6-O-allyl derivative (VI),which is treated with HOAc and HCOOH to cleave the oxime group and furnish the 6-O-allyl-15-methylerythromycin A (VII). The cleavage of the 3-O-carbohydrate moiety of (VII) by means of aq. HCl, followed by benzoylation with Bz2O, gives the benzoyl intermediate (VIII), which is oxidized with NCS and Me2S and dehydrated with Ms-Cl, pyridine and DBU to yield the ketolide (IX). The fluorination of (IX) by means of (PhSO2)2N-F and tBu-OK affords the 2-fluoro derivative (X).

The reaction of (X) with NaH and CDI, and then with hydroxylamine gives the cyclic carbamate (XI), which is finally condensed with 6-bromoquinoxaline (XII) by means of Pd2(dba)2 and P(o-tolyl)3 to yield the target 6-O-[3-(6-quinoxalyl)allyl] derivative.