Total synthesis of the antimycoplasma antibiotic micacocidin

Isolation and Antifungal and Antioomycete Activities of Aerugine Produced by Pseudomonas fluorescens Strain MM-B16

“…The thiazoline compounds have shown various biological activities such as antifungal activity (4), antibacterial activity (49), antitumor activity (34), antiviral activity (13) and anthelminthic activity (35). Recently, antimycoplasma activity (19) and antituberculosis activity (10) of the synthesized thiazoline derivatives have also been demonstrated. A variety of thiazoline compounds, such as curacin D (34), thiangazole (29), and watasemycins (49) have been isolated and characterized from the cyanobacterium Lyngbya majuscula, the myxobacterium Polyangium sp., and Streptomyces sp., respectively.…”

Total (Bio)Synthesis: Strategies of Nature and of Chemists

“…Ino and Murabayashi [76] adapted their synthesis strategy from their previous total synthesis of the antimycoplasma antibiotic micacocidin ( 41 ) (see Fig. 9) [77]. Structurally, 41 is identical to 24 except for the absolute configuration at position C10, an additional pentyl chain at C3 of the phenol group, and an N -methylation on the thiazolidine ring.…”

“…Notably, l -cysteine ( 29 ) is also utilized in the biosynthesis of 24 and 25 despite epimerization to the d -form during thiazoline ring formation [65], which highlights a similarity between the synthetic and biosynthetic logic. Following elongation to a β-keto-carboxylic acid 51 and reduction of the keto group to give alcohol 52, 53 was formed by deprotonation of the secondary alcohol using NaH, leading to intramolecular carbamate formation, and subsequent hydrolysis of the methyl ester in 33% overall yield [77]. Condensation with 2-methyl- d -cysteine methyl ester delivered intermediate 54 , which was transformed into 55 by cyclization of the thiazoline ring and removal of the acetonide (55% overall yield).…”

“…The number of reactions required for total biosynthesis and chemical synthesis of yersiniabactin ( 24 ) is comparable, with 22 [62] and 30 [76, 77] reactions, respectively. However, two very different strategies are used by nature and by chemists in the production of this compound.…”

Synthesis of some novel bioactive 4-oxy/thio substituted-1H-pyrazol-5(4H)-ones via efficient cross-Claisen condensation

“…However there are a few reports on the application of cross-Claisen condensation between different esters or between esters and acid chlorides [20][21][22][23][24]. A nucleophilic reaction of an ester enolate with acid imidazolide has been widely used as a common method for synthesizing b-keto esters [25][26][27][28], but it can be rather expensive to use imidazolide or active ester in industrial setting. So we focused on the cross-Claisen condensation between substituted oxy/thio acetic acid ethyl esters and acid chlorides to improve the yield of b-keto esters by changing the equivalence of base, acid chloride, time duration of the reaction and the mode of additions.…”