26995-94-8

Upstream product

• 70424-09-8 (Z)-β-methylthiopropenoic acid 
• 74-93-1 methylthiol 
• 471-25-0 Propiolic acid 
• 131424-34-5 3c-thiocyanato-acrylic acid 
• 74-88-4 methyl iodide 
• 70238-51-6 S-petasin 
• 5188-07-8 sodium thiomethoxide 

Downstream Products

• 63068-43-9 (E)-3-Methanesulfonyl-acrylic acid 

Relevant academic research and scientific papers

SESQUITERPENOIDS FROM PETASITES FRAGRANS

Chemical analysis of Petasites fragrans yielded the eremophilane type of sesquiterpenes: petasol, isopetasol, S-petasin, neo-S-petasin, and a mixture of petasol derivatives, with caffeic acid methyl ester and a mixture of phytosterols.Their structures were elucidated by chemical and spectroscopic methods.Key Word Index - Petasites fragrans; Compositae; Senecioneae; eremophilane; petasol; isopetasol; S-petasin; neo-S-petasin.

N-Methylated Peptide Synthesis via Generation of an Acyl N-Methylimidazolium Cation Accelerated by a Br?nsted Acid

The development of a robust amide-bond formation remains a critical aspect of N-methylated peptide synthesis. In this study, we synthesized a variety of dipeptides in high yields, without severe racemization, from equivalent amounts of amino acids. Highly reactive N-methylimidazolium cation species were generated in situ to accelerate the amidation. The key to success was the addition of a strong Br?nsted acid. The developed amidation enabled the synthesis of a bulky peptide with a higher yield in a shorter amount of time compared with the results of conventional amidation. In addition, the amidation can be performed by using either a microflow reactor or a conventional flask. The first total synthesis of naturally occurring bulky N-methylated peptides, pterulamides I–IV, was achieved. Based on experimental results and theoretical calculations, we speculated that a Br?nsted acid would accelerate the rate-limiting generation of acyl imidazolium cations from mixed carbonic anhydrides.

Isolation of 2-Alkyl-4-quinolones with Unusual Side Chains from a Chinese Pseudomonas aeruginosa Isolate

Chemical investigation of a Pseudomonas aeruginosa strain isolated from Hebei, China, led to the isolation of a suite of quinolones, quinolone-N-oxides, and phenazines, the structures of which were elucidated by detailed spectroscopic analysis. Most notable among the secondary metabolites isolated was an unprecedented 4-quinolone containing an S-methyl group in the side chain and a new derivative including a phenyl ring in the side chain, which expand significantly the variety of structural motifs found in the quinolones and raise interesting questions about their biosynthesis.

Lepadins I-K, 3- O-(3′-Methylthio)acryloyloxy-decahydroquinoline Esters from a Bahamian Ascidian Didemnum sp. Assignment of Absolute Stereostructures

Three decahydroisoquinoline alkaloids, lepadins I-K, were isolated from a specimen of Didemnum sp. collected in the Bahamas. The structures of the new compounds were assigned by an integrated analysis of MS, IR, and 1H, 13C, and 2D NMR spectra. Like previously reported lepadins, the structures of the new compounds contain a decahydroquinoline heterocyclic core in lepadin I, and a new variation, an octahydroquinoline in lepadin J, but differ from earlier reported compounds by acylation of the 3-hydroxyl group by a rare 3′-methylthioacrylate. The absolute configuration of lepadin I was solved by interpretation of NOE measurements, and exciton coupled circular dichroism (ECCD) of the corresponding N-p-bromobenzoyl derivative. The latter constitutes a general method for determination of absolute configuration of the entire lepadin family. The configuration of the remote side-chain secondary carbinol was solved by the modified Mosher's esters method. Lepadin I inhibited butyrylcholineesterase (BuChE, IC50 3.1 μM), but only weakly inhibited acetylcholineesterase (AChE) (10% at 100 μM).

Total synthesis and biological evaluation of methylgerambullone

First total synthesis of methylgerambullone (MGB, 1) isolated from Glycosmis angustifolia was completed via a convergent route. The effect of MGB on the contractile responses of the isolated guinea-pig ileum induced by acetylcholine was investigated. As a result, it showed a potent relaxation rate (78.66 ± 4.30% at 100 mg/L) in a concentration-dependent manner on longitudinal smooth muscle contraction of isolated guinea-pig ileum induced by 1 μM acetylcholine.

SYNTHESIS AND CORRECTED STRUCTURES OF SULPHUR-CONTAINING AMIDES FROM GLYCOSMIS SPECIES: SINHARINES, PENIMIDES, AND ILLUKUMBINS

The structures of sinharine and methylsinharine isolated from Glycosmic cyanocarpa, penimide A and penimide B from G. chlorosperma, and methylillukumbin A, illukumbin B and methylillukumbin B from G. mauritiana were revised on the basis of synthesis and additional spectroscopic evidence.The methylthio group and the aromatic moiety have to change their positions in the molecules.Thus the compounds represent amides of 3-(methylthio)-propenoic acid and not cinnamides as described previously.

The Synthesis and Absolute Configuration of the Novel Ichthyotoxic Diacylglycerols, Umbraculumin A and Umbraculumin C

The total syntheses of umbraculumin A 1 and umbraculumin C 2 in homochiral form are described.Noteworthy steps involve (i) the preparation of the key Z,E-acid 10 by organolithium addition to pyrylium salts, (ii) the use of the 4-methoxyphenylmethyl protecting group for the preparation of 1,2-diacyl glycerols and its removal using trifluoroacetic acid-anisole without significant acyl migration (DDQ removal having proved inefficient) and (iii) a new procedure for the stereoselective preparation of (Z)- and (E)-3-methylthiopropenoic acid.