PAGE Tetracyclines

The contents of the tube were then acidified to pH 2 by the addition of sulfuric acid and centrifuged. Examination of the supernatant liquid by paper chromatography employing the methods of 8ohonos et al. Antibiotics Annual (1953-4, page 49), demonstrates the presence of 7-chloro-6-demethyltetracycline, 7-chlorotetracycline and tetracycline. 

Examine the tetracycline synthesis on page 432 Does It follow a linear or convergent strategy ... 

The name tetracycline derives from the naph-thacene nucleus that it possesses. The rings are lettered A through D from right to left and the numbers start at the bottom of ring A. The enolized form as illustrated on next page has been selected arbitrarily and is used most exclusively in the literature. It is further defined as hydrochloride of 4 3-di-methylamino-l,4,4a,5,5a,6,ll,12a-octahydro-3,6 10,12, 12aB-pentahydroxy-6-methyl-1,11-dioxonaphtnacene-2-carboxamide. 

Mitscher, L.A., The Chemistry of the Tetracycline Antibiotics, page 32, Marcel Dekker, (1978) New York. 

The reason for these initial difficulties were clearly that scientists did not know conceptually what to look for, nor methodologically how to look. A review of the mechanism of action of the tetracyclines, as late as 1967, offered 6 pages of tabulation of activities which had been found to be inhibited by these antibiotics 9. While it is not unusual to read that the advances in the last 15 years are methodological in nature, it is not always appreciated that answers began to come forth only after investigators had learned to ask pertinent questions. 

Figure 5. Positive ion spectra of a. 6-Demethyltetracycline and b. Tetracycline. Continued on next page.

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