1010. Studies in relation to biosynthesis. Part XXXV. Macrolide antibiotics. Part XII. Methymycin

The Origin and Function of Some Methyl Groups in Branched-Chain Fatty acids, Plant Sterols and Quinones

“…After suggestions by Woodward (1956) and Gerzon et al (1956) it was proved by Corcoran, Kaneda & Butte (1960) arid Kaneda, Butte, Taubman & Corcoran (1962), as well as by Grisebach, Achenbach & Grisebach (1960) and Grisebach, Hofheinz & Achenbach (1962), that the branched chain of erythronolide, the macrocyclic lactone moiety of the antibiotic erythromycin, is formed in vivo by the condensation of several molecules of propionic acid. The same pathway has been shown by Birch et al (1960) for methymycin, by and by Gilner & Srinivasan (1962) for magnamycin etc. Kaneda & Corcoran (1961), as well as , have shown that, as expected, methylmalonic acid is the active form of propionic acid (for a review see also Grisebach, 1964).…”

Streptolydigin. I. Streptolic Acid

“…In agreement with this assignment, ydiginic acid (I) has pfGa < 1.70, while the model compound N-cyclohexvloxamic acid9 has piGa 2.16 ± 0.03. 10 The formation of III establishes in I an alcoholic function, which is shown to be secondary by the shift of a one-proton peak at t 6.4 in the n.m.r. spectrum of II to 5.22 in the spectrum of III.11 Also in the n.m.r.…”

The polyether and macrolide antibiotics: biogenetic analysis and structural correlations

“…In principle this epimerization can occur at one of two stages during the process. Either (2s)-methyl(or ethy1)malonyl-CoA (1 1) [or (12)] is epimerized to (2R)-methyl (or ethy1)malonyl-CoA ( 16) and the antibiotic synthase then accepts each diastereomer to order, the (2s)-compound giving rise to the D alkylated centres and the (2R) giving rise to the L alkylated centres, or (2s)-methyl(or ethy1)malonyl-CoA (1 1 a) is the only diastereomer utilized by the synthase and after condensation has occurred the resultant D-a-alkyl-P-ketothioester (1 5) then undergoes epimerization to an L-a-alkyl-Pketo-thioester (I 7). Investigations so far have not allowed the satisfactory delineation of these two possibilities.…”