Alkylation biosynthesis

Inosine, 6-benzyloxy-9- -D-ribofuranosyl-2-dimethylamino-hydrogenolysis, 5, 558 Inosine, 2 -deoxy-alkylation, 5, 538 Inosine, 6-phenacylthio-dethiation, S, 559 Inosine 5 -monophosphate biosynthesis, 1, 88 Inosines, thio-synthesis, 5, 584 Inositol, D-l,4-anhydro-synthesis, 1, 416 Inositols synthesis, 1, 416 Insecticides... 

Thiazole, 4-methyl-5-(2-hydroxyethyl)-in thiamine biosynthesis, 1, 97 Thiazole, 4-methyl-2-methylami nosynthesis, 6, 300 Thiazole, 4-methyl-2-phenyl-alkylation, 6, 256 mercuration, 6, 256 Thiazole, 2-(methylthio)-methylation, 6, 290 thermodynamic values, 6, 291 Thiazole, 2-methylthio-5-phenyl-synthesis, 5, 153 Thiazole, 4-methyl-5-vinyl-occurrence, 6, 327 Thiazole, 2-phenyl-acetylation, 6, 270-271 Conformation, 6, 237 synthesis, 5, 113, 6, 306 Thiazole, 4-phenyl-conformation, 6, 237 2,5-disubstituted synthesis, 6, 304 Thiazole, 5-phenyl-conformation, 6, 237 Thiazole, 2-phenyl-5-triphenylmethyl-synthesis, 6, 265 Thiazole, 2-(2-pyridyl)-metal complexes, 5, 51 6, 253 Thiazole, 4-(2-pyridyl)-metal complexes, S, 51 6, 253 Thiazole, tetrahydro-ring cleavage, 5, 80 Thiazole, 2,4,5-trimethyl-occurrence, 6, 327... 

Figure 22.7 The biosynthesis of indolmycin from indolylpyruvate occurs through a pathway that includes an alkylation reaction of a short-lived enolate ion intermediate.

Ficellomycin was found to inhibit semiconservative DNA replication in Eschir-ichia coli, and this was found not to be due to direct inhibition of DNA polymerase [166]. It has been suggested that ficellomycin may exert its biological activity by alkylation of DNA [165], in common with the azinomyins. The biosynthesis of ficellomycin has not been studied, but it seems highly probable that its 1-azabicy-clo[3.1.0]hexane ring system will arise from a pathway related to that for the azinomycins. 

Some sugar residues in bacterial polysaccharides are etherified with lactic acid. The biosynthesis of these involves C)-alkylation, by reaction with enol-pyruvate phosphate, to an enol ether (34) of pyruvic acid, followed by reduction to the (R) or (5) form of the lactic acid ether (35). The enol ether may also react in a different manner, giving a cyclic acetal (36) of pyruvic acid. 

Dihydroxyacetone phosphate (82) is a substrate for a-glycero-phosphate dehydrogenase, aldolase, and triose phosphate isomerase, and its O-alkyl ethers are intermediates in the biosynthesis of phospholipids. In neutral aqueous solution at 20 °C, dihydroxyacetone phosphate exists as an equilibrium mixture of the keto (82), gem-d o (83), and enol (84) forms, as shown by n.m.r. spectroscopy. The proportion of (82) to (83)... 

Experiments have been carried out to mimic the reactions of model systems for coenzyme F430 that is involved in the terminal step in the biosynthesis of methane, and that is able to dechlorinate CCI4 successively to CHCI3 and CH2CI2 (Krone et al. 1989). Nickel(I) isobacteriochlorin anion was generated electrolytically and used to examine the reactions with alkyl halides in dimethylformamide (Helvenston and Castro 1992). The three classes of reaction were the same as those observed with Fe(II) deuteroporphyrin IX that have already been noted. 

The late cannabinoid pathway starts with the alkylation of ohvetolic acid (3.2 in Fig. 4) as polyketide by geranyl diphosphate (3.1) as the terpenoid unit. Terpenoids can be found in all organisms, and in plants two terpenoid pathways are known, the so called mevalonate (MEV) and non-mevalonate (DXP) pathway as described by Eisenrich, lichtenthaler and Rohdich [23,24,29,30]. The mevalonate pathway is located in the cytoplasm of the plant cells [30], whereas the DXP pathway as major pathway is located in the plastids of the plant cells [29] and delivers geranyl diphosphate as one important precursor in the biosynthesis. 

Studies on the biosynthesis of prostaglandins revealed that a strained bicyclic bis(secondary-alkyl) peroxide was not only a key intermediate, but could survive the biological conditions long enough to be isolated, albeit in minute amounts. This was a startling discovery in that no simple bicyclic peroxides of the same type were known, clearly for reasons of preparative difficulty. The prostaglandin connection focused attention upon this missing class of peroxides and stimulated... 

One of the first biosynthetic investigations undertaken in the Djerassi laboratory dealt with the sponge Aplysina fistularis. This sponge contains sterols with side-chain alkylations at C-24 and C-26, the aplysterols [37], The biosynthesis of these unconventional sterols was shown (Scheme 7) to proceed by a conversion of desmosterol (34) to epicodisterol (51) [but not its C-24 epimer, codisterol (52)] followed by methylation to 25(27)-dehydroaplysterol (53). Sterol... 

A recent and surprising finding in sponge sterol biosynthesis is the observation that certain 24-alkyl sterols can be transformed to cholesterol [46,48, 50]. This is particularly unusual, as this pathway operates in organisms which are also... 

A closely related dicationic platinum complex has been shown to transform efficiently /3-citronellene into cis-thujane in a highly diastereoselective manner, which mimics terpene biosynthesis.362 Also, using platinum(n) catalysis, Widenhoefer has reported an intramolecular alkylation of indoles with unactivated olefins, which can be carried out in an enantioselective fashion (Scheme 99).363... 

EiectrophUic alkylation in steroid side-chain biosynthesis... 

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