83303-97-3Relevant academic research and scientific papers
Enhancement of the carbamate activation rate enabled syntheses of tetracyclic benzolactams: 8-oxoberbines and their 5- And 7-membered C-ring homologues
Kurouchi, Hiroaki
supporting information, p. 653 - 658 (2021/02/06)
A route to the direct amidation of aromatic-ring-tetheredN-carbamoyl tetrahydroisoquinoline substrates was developed. This route enabled general access to 8-oxoberberines and their 5- and 7- membered C-ring homologues. It overcomes the undesired tandem side-reactions that result in the destruction of the isoquinoline backbone, which inevitably occurred under our previously reported superacidic carbamate activation method.
Direct Amidation of Carboxylic Acids through an Active α-Acyl Enol Ester Intermediate
Xu, Xianjun,Feng, Huangdi,Huang, Liliang,Liu, Xiaohui
, p. 7962 - 7969 (2018/06/18)
The development of a highly efficient and simple protocol for the direct amidation of carboxylic acids is described employing ynoates as novel coupling reagents. The transformation proceeds in good to excellent yields via in situ α-acyl enol ester intermediates formation under mild reaction conditions. This useful method has been demonstrated for a range of substrates to provide a succinct access to structurally diverse amides, including key intermediates of glibenclamide, tiapride hydrochloride, and nateglinide, and can be conducted on a mole scale.
Amide-forming ligation of acyltrifluoroborates and hydroxylamines in water
Dumas, Aaron M.,Molander, Gary A.,Bode, Jeffrey W.
supporting information; experimental part, p. 5683 - 5686 (2012/07/01)
Come together, right now: Acyltrifluoroborates and O-benzoyl hydroxylamines come together to form amides in water (see scheme). The ligations are complete within minutes at room temperature and do not require any reagents or catalysts. The reaction has a broad substrate scope and tolerates unprotected functional groups. Copyright
Formation of carboxamides by direct condensation of carboxylic acids and amines in alcohols using a new alcohol- and water-soluble condensing agent: DMT-MM
Kunishima, Munetaka,Kawachi, Chiho,Hioki, Kazuhito,Terao, Keiji,Tani, Shohei
, p. 1551 - 1558 (2007/10/03)
Selective formation of carboxamides in an alcohol or water by an exceptionally convenient one-step procedure in which a condensing agent is simply added to a mixture of acids and amines has been achieved successfully by using a new condensing agent, 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM). Activation of carboxylic acids by DMT-MM in the presence of amines and subsequent aminolysis of the resulting acyloxytriazine in alcoholic solvents occurred selectively and led to the formation of carboxamides in excellent yields. The rate of aminolysis of the acyloxytriazine intermediate can be estimated to be about 2×104 times greater than that of methanolysis. The amide/ester selectivity observed using DMT-MM was much larger than that obtained with DCC or EDC. Condensation of polar substrates, such as amino acid esters and their hydrochlorides, glucosamine hydrochloride, sodium acetate and dicarboxylic acids, proceeded successfully in MeOH, water or aqueous MeOH in good yields. The present reaction is technically quite simple and easy to achieve. It proceeds by simple mixing of acids, amines and DMT-MM without any additives, and the MeOH is readily removable by a rotary evaporator after completion of the reaction.
Synthesis and Photo-oxygenation of Some Substituted 1-Benzyl-3,4-dihydroisoquinolines. Mechanism of Enamine Photo-oxygenation
Martin, Ned H.,Jefford, Charles W.
, p. 762 - 774 (2007/10/02)
The synthesis of a series of substituted 1-benzyl-3,4-dihydroisoquinolines by Bischler-Napieralski cyclization is described.Competitive methylene blue sensitized photo-oxygenation experiments allowed the determination of relative rates of photo-oxygenation of 1-benzyl-3,4-dihydroisoquinolines.Substituents were shown to affect both the equilibrium concentration of the tautomeric enamine and the overall photo-oxygenation rate.After correcting for differences in enamine concentration, the relative rate data provided a diagnostic probe of the reaction mechanism, which involves transfer of charge in the rate-limiting step.
