Radical Fixation of Functionalized Carbon Resources:  α-sp³C−H Carbamoylation of Tertiary Amines with Aryl Isocyanates

Abstract

A new carbamoylation of tertiary amines is reported. This rare C-H transformation features the direct generation of alpha-aminoalkyl radicals from tertiary amines, followed by the addition of the resultant nucleophilic radicals to isocyanates, enabling unique access to N,N-dialkylated amino acid derivatives. The authors put forward a mechanistic proposal that is based on the isolation of borinamides produced by capturing nitrogen radical intermediates with Et3B. The present transformation provides a novel one-step process for producing mepivacaine, a clinically important local anesthetic, from readily available materials.

Direct sp3 CH Amination of Nitrogen‐Containing Benzoheterocycles Mediated by Visible‐Light‐Photoredox Catalysts

“…General procedure for photocatalytic reactions of amines (1) 13 C NMR (C 6 D 6 , 508C): d = 154. 2, 129.8, 128.6, 126.9, 119.3, 80.8, 80.6, 28.2, 28.1, 25.3 3, 128.7, 127.0, 118.5, 115.5, 80.8, 80.6, 55.0, 28.3, 28.1, 27.7 1.38 (s, 9 H), 1.28 ppm (s, 9 H); 13 C NMR (C 6 D 6 , 508C): d = 154.…”

“…Recently, we reported visible-light-mediated direct a-alkylation of amines [8] in which the formation of a-aminoalkyl radicals meditated by photoredox catalysts is a key step, [9][10][11][12][13] and this CÀH functionalization via a-aminoalkyl radicals provides an alternative approach to routes via iminium ions. It is also worth noting that this reaction system is applicable to the a-alkylation of indolines.…”

Synthesis and biological evaluation of novel tyrosyl-DNA phosphodiesterase 1 inhibitors with a benzopentathiepine moiety

“…1 H NMR spectra of N-phenyl-2-(pyrrolidin-1-yl)acetamide 8a and N-phenyl-2-(piperidin-1-yl)acetamide 8b are coincided with the corresponding spectra published in literature. 46,47 …”

Synthesis of 3-(4-(Benzo[d]thiazol-2-yl)phenyl)-5-aryl-1,3,5-oxadiazinane-4-thiones and 1-(4-(Benzo[d]thiazol-2-yl)phenyl)-5-methyl-3-aryl-1,3,5-triazinane-2-thiones

“…30,31 Accordingly, synthesis of 1-(4-(benzo[d]thiazol-2-yl)phenyl)-3-arylthiourea and its substituted compounds 2 was accomplished by heating compound 1 to reflux with arylisothiocyanates in equimolar amounts. A mixture of 4-(benzo[d]thiazol-2-yl)benzenamine (1) with an equimolar quantity of arylisothiocyanate (10 mmol) in N,N-dimethylformamide (DMF) was heated to reflux for 4 h. After completion of reaction (as ascertained by TLC) the mixture was cooled and the product purified.…”