112245-93-9Relevant academic research and scientific papers
Enantioselective Synthesis of the Polyketide Antibiotic (3R,4S)-(-)-Citrinin
Roedel, Thomas,Gerlach, Hans
, p. 885 - 888 (2007/10/02)
The fungal metabolite (-)-citrinin (1) was synthesized for the first time.Reaction of the Grignard reagent of 2,4-bis(benzyloxy)-6-bromotoluene (3) with (2S)-trans-(-)-2,3-dimethyloxirane (6) in the presence of 1,5-cyclooctadienecopper(I) chloride as catalyst leads to the formation of (2S,3S)-(-)-7 with erythro configuration.Compound (-)-7 could be transformed into (2R,3S)-(-)-9 with threo configuration via the formate (1R,2S)-(+)-8 by a Mitsunobu reaction.Reaction of the Grignard reagent of 3 with the achiral cis-2,3-dimethyl-oxirane yielded directly (+/-)-9.The starting material 3 was readily available from 1,3-bis(benzyloxy)-5-bromobenzene (4).Formylation of 4 furnished the aldehyde 5 which could be reduced to 3 with borane.Hydrogenolysis of the benzyl ether groups in (-)-9 gave (-)-2 with threo configuration.The remaining steps to produce citrinin from (-)-2 required carboxylation to 11, formylation and in situ ring closure with ethyl orthoformate to produce the required quinomethide structure.Application of the same reactions to (+/-)-9 and (+/-)-2 afforded (+/-)-citrinin in 40percent overall yield. - Key Words: Citrinin, (3R,4S)-(-)- / 2,3-Dimethyloxirane, trans-(-)- and cis- / Synthesis of erythro- and threo-3-arylbutan-2-ols
Asymmetric Synthesis of (+)-Citrinin using an ortho-Toluate Carbanion generated by a Chiral Base
Regan, Andrew C.,Staunton, James
, p. 520 - 521 (2007/10/02)
The carbanion (3), generated using the chiral lithium amide base (1), undergoes enantioselective addition to acetaldehyde and acetone with a high degree of asymmetric induction at the nucleophilic centre; the reaction with acetaldehyde is exploited in an
A Diastereoselective Synthesis of the Polyketide Antibiotic Citrinin using Toluate Anion Chemistry
Barber, Jill A.,Staunton, James,Wilkinson, Michael R.
, p. 2101 - 2110 (2007/10/02)
The diastereoselectivity of various synthetic approaches to (+/-)-threo-3-(3,5-dihydroxy-2-methylphenyl)butan-2-ol ('Phenol B') (4), based on reactions of benzyl anions with electrophiles, has been investigated.The anion (9) derived from ethyl 2,4-dimethoxy-6-ethylbenzoate reacted with acetaldehyde to give mainly an erythro-product isolated as the lactone (12); acetylation with acetyl chloride to give a ketone, followed by reduction, gave mainly the required threo-lactone (11).An alternative route was frustrated by decomposition of the benzyl anion derived from 3,4-dihydro-6,8-dimethoxy-3-methyl-1H-2-benzopyran-1-one (17).Reduction of the carbonyl group of the threo-lactone (11) to a methyl gave the dimethyl ether of 'Phenol B', which was converted into (+/-)-citrinin (1).
Biosynthesis of Citrinin and Synthesis of its Biogenetic Precursors
Colombo, Lino,Gennari, Cesare,Potenza, Donatella,Scolastico, Carlo,Aragozzini, Fabrizio,at al.
, p. 2594 - 2597 (2007/10/02)
The biosynthetic pathway to citrinin has been elucidated by incorporation studies with advanced precursors.These specifically labelled compounds were obtained from labelled citrinin produced by cultures of Penicillium citrinum in the presence of m
