62524-30-5

Upstream product

• 256421-22-4 N-(2-methoxy-1-phenylbuta-2,3-dienyl)-p-toluenesulfonamide 
• 100-52-7 benzaldehyde 
• 256421-23-5 3-methoxy-2-phenyl-1-tosyl-2,5-dihydro-1H-pyrrole 
• 51608-60-7 N-(benzylidene)-p-methylbenzenesulfonamide 
• 51608-60-7 phenyl N-tosyl imine 
• 341979-51-9 1-N-morpholinyl-amino-1-phenyl-2-methoxybuta-2,3-diene 
• 41571-21-5 (E)‐N‐morpholino‐1‐phenylmethanimine 
• 256934-15-3 N-morpholino-2-phenyl-3-methoxy-2,5-dihydropyrrole 

Relevant academic research and scientific papers

Efficient Syntheses of 2,5-Dihydropyrroles, Pyrrolidin-3-ones, and Electron-Rich Pyrroles from N-Tosylimines and Lithiated Alkoxyallenes

N-Tosylimines and lithiated alkoxyallenes afforded the corresponding allenyl N-tosylamines in good to excellent yields. The 5-endo-trig cyclizations of these intermediates to 2,5-dihydropyrrole derivatives were achieved under strongly basic conditions with potassium tert-butoxide or under milder conditions with either silver(I) or gold(I) catalysis. In general, gold chloride catalyzed reactions occurred with the lowest catalyst loadings and delivered the best yields. With phenyl-substituted 2,5-dihydropyrrole, we investigated typical reactions such as oxidative and reductive transformations. The acid-promoted hydrolysis of the enol ether moieties of three 2,5-dihydropyrroles furnished the corresponding pyrrolidin-3-ones, which were reduced to give 3-hydroxypyrrolidine derivatives in good yields. The aromatization of 2,5-dihydropyrroles to 3-methoxypyrrole derivatives was accomplished by base treatment, which caused the elimination of p-tolyl sulfinate. Electron-rich pyrrole derivatives were synthesized in good yields even on a large scale. All of the experiments illustrate the efficacy and flexibility of the alkoxyallene approach to pyrrole derivatives.

Reaction of the lithio-derivative of methoxyallene with hydrazones. Part 1: Synthesis and transformation of α-allenyl hydrazines

The lithio-derivative of methoxyallene reacts with aldehyde hydrazones leading to expected α-allenyl hydrazines when ether is the solvent of the reaction. The yields are good as well as the diastereoselectivity observed in the case of SAMP-hydrazones. These hydrazines are cleanly transformed to N-dialkylamino-3-methoxy-3-pyrrolines when they are reacted with n-BuLi in THF. These compounds are sometimes accompanied by the isomeric 4-methyl azetidines. The N-dialkylamino-3-methoxy-3-pyrrolines are transformed to 3-methoxy-3-pyrrolines by hydrogenolysis of the nitrogen-nitrogen bond, to 3-alkoxy-pyrroles by treatment with a peracid and to 3-amino-pyrroles by acidic migration of the dialkylamino group. In the case of SAMP-hydrazines, the obtained 3-methoxy-3-pyrrolines have a high enantiomeric purity. Lastly, attempts to prepare α-hydrazino-esters (and subsequently α-amino-esters) by ozonolysis of the allenyl moiety failed due to the formation of a methyl glyoxylate.

A facile synthesis of 3-alkoxy and 3-amino pyrroles

N-Amino-3-methoxy-3-pyrrolines 2 obtained from the reaction of 1-lithio methoxyallene with arylhydrazones may be converted to either 3-methoxy pyrroles 6 or 3-amino pyrroles 7 by treatment with m-chloroperbenzoic acid or 0.25 M HCl, respectively.

An expedient synthesis of pyrrole derivatives by reaction of lithiated methoxyallenes with imines

Addition of lithiated methoxyallene 2 to imines provided the expected allenyl amines in good yield. These could be cyclized with base or with silver nitrate to a variety of 2,5-dihydropyrrole derivatives. Selected examples describe their conversion to pyrrolidin-3-ones or 3-methoxypyrroles. Most importantly, this [3+2] cyclization method could also be applied to the synthesis of 2,5-disubstituted derivatives such as 26-28 and also to the preparation of the enantiopure compound 23.