27332-48-5Relevant academic research and scientific papers
Synthesis of Optically Active Hydroxyalkyl Cycloheptatrienes: A Key Step in the Total Synthesis of 6,11-Methylene-LXB 4
Nava, Analuisa,Trippe, Lukas,Frank, Andrea,Andernach, Lars,Opatz, Till,Nubbemeyer, Udo
, p. 45 - 50 (2021)
Starting from methyl cycloheptatrienyl-1-carboxylate, 6-acylation was successfully achieved employing glutaryl chloride in the presence of AlCl 3under controlled reaction conditions to furnish keto carboxylic acid product. After protection of this keto carboxylic acid as tert -butyl ester, reagent-controlled enantioselective reductions delivered configuration-defined methyl-6-hydroxylalkyl cycloheptatriene-1-carboxylates with up to 80% ee. Whereas simple NaBH 4reduction of the keto carboxylic acid and subsequent lactonization afforded a methyl-6-tetrahydropyranonyl cycloheptatriene-1-carboxylate. Resolution using chiral HPLC delivered the product enantiomers with up to >99% ee Finally, ECD analyses enabled structure elucidation. The products are used as key intermediates in enantioselective 6,11-methylene-lipoxin B 4syntheses.
Synthesis of Enantiopure 6,11-Methylene Lipoxin B4 Methyl Ester
Trippe, Lukas,Nava, Analuisa,Frank, Andrea,Nubbemeyer, Udo
supporting information, p. 1156 - 1167 (2021/02/03)
The synthesis of Lipoxin B4 analogs (LXB4) to gain access to stabilized inflammation resolving compounds is an actual field of research. Focusing on variation and stabilization of the conjugated E,Z,E,E C6–C13 tetraene moiety of natural LXB4, a methylene bridge introduced between C6 and C11 suppresses any Z/E isomerization of the C8–C9 olefin. Intending to enable prospective structure variations in connection with the C1–C5 and C14–C20 fragments, a convergent total synthesis has been developed. Optically active C1–C12 building blocks were build-up from cycloheptatriene 1-carbonester (C6–C11, C21) and glutaryl chloride (C1–C5) using Friedel-Crafts-type acylation and chiral HPLC. The C13–C20 segment had been generated via a five-step sequence starting from heptanoyl chloride. Horner key olefination enabled the assembly of the carbon backbone. A final five-step sequence including a chelate Cram reduction of the unsaturated ketone moiety afforded the target 6,11-methylene LXB4 methyl ester.
Synthesis of a naphthalocyanine-like dye: The first report on Zn(II)-1,6-methano[10]annulenecyanine
Brocksom, Timothy J.,De Oliveira, Kleber T.,Gobo, Nicholas R. S.
, (2020/05/25)
The synthesis of the new dye 1,6-methano[10]annulenecyanine is described. For this purpose, the 3,4-dicyano-1,6-methano[10]annulene and 3,4-carboxyimide-1,6-methano[10]annulene buildings blocks were synthesized in six to eight steps. In both cases, these
