6-deoxy erythronolide

The combination of the (S)-enolate 2 with aldehyde 1 is one of the key steps in the syntheses of the macrolide aglycone 6-deoxy-erythronolide B131 and tylonolidc16. 

Figure 10.45 Modular PKS enzymes biosynthesis of 6-deoxy erythronolide B (10.70) and modified biosynthetic products 10.71 10.73.

EM s chemical structure consists of a 14-membered macrocyclic lactone ring (erythronolide) connected to a deoxyamino sugar (desosamine) and a deoxy sugar (cladinose) as shown in Fig. 5. We synthesized about 250 EM derivatives and examined their GMS and antibacterial activities [19, 20]. GMS activity was tested by intravenous injection of the test compounds to fasted conscious dogs with permanently implanted force transducers in the stomach, and antibacterial activity was estimated as minimum inhibitory concentration (MIC) by agar dilution method. The EM derivatives shown in Fig. 5 exhibited higher GMS activities with less antibacterial activities compared with those of EM (Table I). 

Deoxy-4-0-(3,6-dideoxy-a-D-ara6mo-hexopyranosyl)-L-mannose, D-606 12-Deoxy-3-0-(2,6-dideoxy-3-C-methyl-a-L-ri6o-hexopyranosyl)-erythronolide A, M-338 2 -Deoxy-2, 2 -difluorocytidine, G-219... 

Continued studies of erythromycin biosynthesis utilizing partially blocked S. erythreus mutants have resulted in the isolation of S -deoxyerythronolide B shown to be an intermediate in the erythromycin pathway immediately preceding erythronolide B 1 1 another isolate, 5-deoxy-5-... 

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