Azalomycins

In the first total synthesis of elaiophylin (azalomycin B 181), glycosidation of P-hydroxy ketone 178 and glycal 177 was examined (Scheme 26) [111]. NBS-promoted glycosidation [112] followed by debromination with -Bu3SnH-AIBN was first applied to give 179 in only a 30% yield. Then, the Wakamatsu procedure using CSA-MS 4A [113] was found to afford the desired 179 in 80% yield as the sole anomer, which led to 181 via aldol reaction of the (Z)-boron enolate of the ketone 179 with dialdehyde 180. 

Total syntheses of the following antibiotics and/or their aglycones are dealt with methymycin, erythromycin, pikromycin, oleandomycin, ingramycin (albo-cycline), carbomycin B, leucomycin A3 (josamycin), tylosin, mycinamicins, rosaramicin, A26771B and elaiophylin (azalomycin B). Since the total synthesis of the macrolide-like immunosuppressant FK-506 has been recently reported, it is also reviewed here. Today, erythromycin A, oleandomycin, leucomycin A3 (josamycin), tylosin and mycinamicin II are clinically important antibiotics. 

The First Total Synthesis of Elaiophylin (Azalomycin B) [Kinoshita-Toshima-Tatsuta, 1986, 1988] (Scheme 26) [47, 48]... 

Scheme 26. Kinoshita-Toshima-Tatsuta s elaiophylin (azalomycin B) synthesis...

Macrolide antibiotic. Prod, by Streptomyces hygroscopicus. Antibacterial and antifungal agent. Powder. Mp 130° dec. [a] +60 (c, 1 in MeOH). Related to Azalomycin F, A-03185 and Malolactomycin, M-30015. 240 (e... 

The structure of elaiophylin (called azalomycin B when first isolated some twenty years ago), an antibiotic from Streotomvces violaceonioer. has been... 

A recent review of the properties of azalomycin F points out that the mechanism of action and general chemical behavior of this compound resembles those of the polyenes. 52 topical antifungal activity of variotin has been reviewed. 55... 

After fermentation was completed, the cultured filtrate was passed through a Diaion HP-20 column as described in Fig. 2. In this time, co-producing antibiotics, including hygromycin and azalomycin, as well as a considerable quantity of unrelated impurities, were retained in this column. The collected eluate was adsorbed on a carbon column. Hydantocidin was subsequently eluted with 30% MeOH, and the active fractions were purified by several columns including CHP-20P, Avicel and Dowex 50 (Ca-type). For further purification, the active fractions were rechromatographed on Diaion CHP-20P and then crystallized from acetone. 

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