Long-Chain Acyl-Homoserine Lactones from Methylobacterium mesophilicum: Synthesis and Absolute Configuration

Abstract

The acyl-homoserine lactones (acyl-HSLs) produced by Methylobacterium mesophilicum isolated from orange trees infected with the citrus variegated chlorosis (CVC) disease have been studied, revealing the occurrence of six long-chain acyl-HSLs, i.e., the saturated homologues (S)-N-dodecanoyl (1) and (S)-N-tetradecanoyl-HSL (5), the uncommon odd-chain N-tridecanoyl-HSL (3), the new natural product (S)-N-(2E)-dodecenoyl-HSL (2), and the rare unsaturated homologues (S)-N-(7Z)-tetradecenoyl (4) and (S)-N-(2E,7Z)-tetradecadienyl-HSL (6). The absolute configurations of all HSLs were determined as 3S. Compounds 2 and 6 were synthesized for the first time. Antimicrobial assays with synthetic acyl-HSLs against Gram-positive bacterial endophytes co-isolated with M. mesophilicum from CVC-infected trees revealed low or no antibacterial activity.

Synthesis and biological evaluation of novel N-α-haloacylated homoserine lactones as quorum sensing modulators

“…These reaction conditions were used for the preparation of AHLs with unfunctionalized acyl chains in a convenient way. The brominated fatty acids 5 , except the commercially available α-bromohexanoic acid ( 5a ), were prepared by a Hell–Volhard–Zelinsky bromination of the corresponding fatty acid 4 with molecular bromine and thionyl chloride [27]. These reaction conditions allowed the synthesis of α-brominated fatty acids 5 in a highly selective and efficient manner.…”

Absolute Configuration of Solenopsis Piperidines is a Tool to Classify Fire Ants (Formicidae:Myrmicinae)

“…The flask was sealed with a rubber septum, connected to a hydrogen reservoir (1 atm), and magnetically stirred for 6 h. The reaction was filtered using a silica gel column (1 g, 1 cm diameter), eluted with ethyl acetate (10 mL) and analyzed by GC-MS and GC-FID (chiral column). 8 Purification of unsaturated ant venom alkaloids by silver nitrate-silica gel chromatography Silica gel impregnated with silver nitrate was prepared as previously described. 9 Thus, a Pasteur pipette (1 cm diameter) was wrapped in aluminum foil and packed with silver nitrate/ silica gel in hexane.…”

Synthesis and analysis of stable isotope-labelled N-acyl homoserine lactones

“…AHLs with an unsaturated or branched side chain have also been detected in nature. [5][6][7] Very recently, a new class of AHLs, containing a p-coumaryl or a cinnamoyl group instead of an acyl chain, was discovered in nature, extending the range of possible occurring AHLs. 8,9 Many diverse bacterial phenotypes such as bioluminescence, enzyme secretion, virulence expression and biofilm formation are regulated by QS.…”