362660-27-3

Upstream product

• 1210057-75-2 (3S,4S,5S)-5-hydroxymethyl-3,4-dimethyl-pyrrolidin-2-one 
• 365413-44-1 (3S,4R,5S)-N-(tert-butoxycarbonyl)-5-{[(tert-butyl)dimethylsilyloxy]methyl}-3,4-dimethylpyrrolidin-2-one 
• 362660-24-0 (3R,4R,5S)-N-(tert-butoxycarbonyl)-5-{[(tert-butyl)dimethylsilyloxy]methyl}-3,4-dimethylpyrrolidin-2-one 
• 1642144-77-1 C₁₇H₃₁NO₅ 
• 362660-20-6 (2R,5S,6S,7S)-6,7-dimethyl-2-phenyl-1-aza-3-oxabicyclo[3.3.0]octan-8-one 
• 1642144-75-9 (2S,3S,4S)-N-(tert-butoxycarbonyl)-3,4-dimethylpyroglutamic acid 
• 362660-21-7 (2R,5S,6S,7R)-6,7-dimethyl-2-phenyl-1-aza-3-oxabicyclo[3.3.0]octan-8-one 
• 362660-19-3 (2R,5S,6S)-6-methyl-2-phenyl-1-aza-3-oxabicyclo[3.3.0]octan-8-one 
• 134107-65-6 (3R,7aS)-3-phenyl-3,7a-dihydro-1H-pyrrolo[1,2-c]oxazol-5-one 
• 362660-22-8 (3R,4S,5S)-5-hydroxymethyl-3,4-dimethyl-pyrrolidin-2-one 
• 365413-45-2 (2S)-N-(tert-butoxycarbonyl)-(3S,4R)-3,4-dimethylpyroglutamic acid 

Relevant academic research and scientific papers

Stereochemical assignment of four diastereoisomers of 3,4- dimethylpyroglutamic acid, A moiety of callipeltin B

The synthesis and stereochemical assignment of four diastereoisomers of 3,4-dimethylpyroglutamic acid (pDME) (1) are described. Stereo-divergent synthesis of four pDMEs (1) was achieved starting from Thottathil's synthon and Garner's aldehyde for comparison of synthetic pDMEs (1) by 1H NMR analysis and CD spectra. The stereochemistry of pDME (1) in cyclic depsipeptide callipeltin B (2) with cytotoxic and anti-HIV activities was confirmed to be 2S,3S,4R. Coupling constant between H2 and H3 of synthetic (2S,3S,4R)-pDME (1a) showed a smaller value than those of other isomers. In addition, synthetic pDMEs (1) hardly showed cytotoxicity against HeLa cells.

Synthetic studies on callipeltins: Stereoselective syntheses of (3S,4R)-3,4-dimethyl-L-pyroglutamic acid and fmoc-D-allothreonine from serine derivatives

The non-proteinogenic amino acids contained in callipeltins, (3S, 4R)-3, 4-dimefhyl-L-pyroglutamic acid and D-allothreonine, were synthesized from D- or L-serine. The stereoselective synthesis of two methyl groups of (3S, 4R)-3, 4-dimethyl-L-pyroglutamic acid was accomplished by diastereoselective hydrogenation and alkylation. Kinetic epimerization of the C-4 methyl substituent followed by Boc-deprotection with 10% TFA gave the desired (3S, 4R)-3, 4-dimethyl-L-pyroglutamic acid as a single isomer.

Solid-phase total synthesis and structure proof of callipeltin B

The cytotoxic, cyclic heptadepsipeptide, natural product callipeltin B was synthesized on a solid-phase support in 15% overall yield. Comparison of the 1H NMR spectra of three synthetic isomers with those of callipeltin B confirmed the configurational reassignment of its threonine residues as d-allothreonine and the assignment of the configuration of its β-methoxytyrosine residue as (2R,3R). Copyright

Stereoselective synthesis of (3S,4R)-3,4-dimethyl-(S)-glutamine and the absolute stereochemistry of the natural product from papuamides and callipeltin

(3S,4R)-3,4-Dimethyl-(S)-glutamine, a common component of cyclodepsipeptides, papuamide A and callipeltin A, was stereoselectively prepared from (S)-pyroglutamic acid. The stereostructure of natural dimethylglutamine was unambiguously confirmed to be (2S,

Synthesis and analysis of the sterically constrained L-glutamine analogues (3S,4R)-3,4-dimethyl-L-glutamine and (3S,4R)-3,4-dimethyl-L-pyroglutamic acid

The nonproteinogenic amino acids (3S,4R)-3,4-dimethyl-L-pyroglutamic acid and (3S,4R)-3,4-dimethyl-L-glutamine - found in the cyclic depsipeptides callipeltin B, callipeltin A, and papuamide A - were synthesized from a common intermediate derived from L-pyroglutamic acid. The diastereoselective introduction of the methyl groups was accomplished by cuprate addition and enolate alkylation, followed by a kinetic epimerization of the C-4 methyl substituent. (3S,4R)-3,4-Dimethyl-L-glutamine shows a conformational restriction of its side chain which may be related to its biological function in the natural products where it is found.