17416-70-5

Upstream product

• 39662-45-8 N-<2-(3,4-dimethoxyphenyl)ethyl>succinimide 
• 917-54-4 methyllithium 
• 1822-00-0 trimethylsilylmethyllithium 
• 591-12-8 5-methyl-2-furanone 
• 120-20-7 2-(3,4-dimethoxyphenyl)-ethylamine 

Relevant academic research and scientific papers

Several convenient methods for the synthesis of 2-amido substituted furans

Several new methods for the synthesis of differently substituted 2-amidofurans are described. The thermolysis of furan-2-carbonyl azide results in a Curtius rearrangement and the resulting furanyl isocyanate was trapped with various organometallic reagents. A second method consists of a C-N cross-coupling reaction of a bromo-substituted furan with various amides, carbamates, and lactams. The CuI-catalyzed cross-coupling reaction between furanyl bromides and amides furnished 2- and 3-substituted amidofurans in 45-95% yield. The third protocol used involves the reaction of cyclic carbinol amides with triflic anhydride. The reaction proceeds under very mild conditions to provide α-(trifluoromethyl)sulfonamido-substituted furans in high yield. The resulting iminium ion derived from the reaction of the hydroxy pyrrolidinone with Tf2O undergoes a facile ring opening as a consequence of the adjacent hydroxyl group to produce an imino triflate intermediate. Subsequent cyclization of this highly electrophilic imine with the oxygen atom of the adjacent carbonyl group leads to an imino dihydrofuran that reacts further with another equivalent of Tf2O to give the observed product.

Triflic anhydride mediated cyclization of 5-hydroxy-substituted pyrrolidinones for the preparation of α-trifluoromethylsulfonamido furans

The reaction of α-angelica lactone with alkylamines under aqueous conditions afforded 5-hydroxy-5-methylpyrrolidinones in high yield. When the reaction was carried out under anhydrous conditions, the only products obtained were the corresponding 4-oxopentanoic acid amides. Treatment of either class of compound with triflic anhydride (Tf2O) in pyridine resulted in the formation of various substituted sulfonamidofurans. The suggested mechanism involves initial formation of an iminium ion which is subsequently transformed into a transient imino triflate. Cyclization of the highly electrophilic imine onto the oxygen atom of the adjacent carbonyl group generates an imino dihydrofuran intermediate. This species reacts further with another equivalent of Tf2O to give the observed product. The nature of the Lewis acid used was found to affect the outcome of the cyclization reaction. In certain cases, the sulfonamide furan was utilized as a cycloaddition substrate for the synthesis of indolines and related heterocyclic systems.

Metalation vs Nucleophilic Addition in the Reactions of N-Phenethylimides with Organolithium Reagents. Ready Access to Isoquinoline Derivatives via N-Acyliminium Ions and Parham-Type Cyclizations

Sequential carbophilic addition of organolithium reagents and N-acyliminium ion cyclization of N-phenethylimides 1 affords the substituted isoquinolones 3 in high yields, with the possibility of varying the substituent at the C-1 position of the isoquinoline ring by changing the organolithium reagent. Ready access to the isoquinoline nucleus via Parham-type cyclization of imides 2 is also described. We have shown that iodinated imides 2 tolerate the metal-halogen exchange in the presence of the imide group, and the intramolecular cyclization of the so-obtained aromatic organometallic derivatives leads to the corresponding enamides 4. Both approaches have allowed the efficient preparation of various types of the isoquinoline class of alkaloids, just by changing the substitution pattern on the readily available starting imides. Thus, we have developed convenient alternative routes for the synthesis of benzo[a]quinolizidones and their 2-oxa analogs, isoindoloisoquinolones, dibenzo[a,h]quinolizidones, and thiazolo- and oxazolo[4,3-a]isoquinolones.

Tandem carbophilic addition-N-acyliminium ion cyclization for the synthesis of functionalized pyrrolo[2,1-a]isoquinolones: Key intermediate for the preparation of Erythrina-type alkaloids

Sequential carbophilic addition of organolithium reagents-N-acyliminium ion cyclization of N-phenenethylsuccinimide 3 yields pyrrolo[2,1-a]isoquinolones 1 in high yields, with the possibility of varying the substituent at C-10b by changing the organolithi