Mild and Efficient Tf2O-Mediated Synthesis of 3-Amino-1-benzofurans
摘要:
A mild and efficient procedure has been developed for the synthesis of 3-amino-1-benzofurans by intramolecular cyclization of the corresponding N,N-disubstituted phenoxyacetamides under the action of trifluoromethanesulfonic anhydride in the presence of 2-fluoropyridine in methylene chloride at room temperature. The proposed novel and efficient protocol has been successfully utilized to obtain a wide series of 3-amino-1-benzofurans with various substituents in the benzene ring and amino group.
Synthesis of S-thioacyl dithiophosphates, efficient and chemoselective thioacylating agentsProofs for the reversibility of isomerisation of anhydrides 1 to 2, melting points of amides and thioamides obtained from anhydrides 5–7 and 1H, 13C NMR and IR data of isolated anhydrides 5–7, 17 are available as supplementary data. For direct access, see http://www.rsc.org/suppdata/p1/b2/b201233b/
作者:Leszek Doszczak、Janusz Rachon
DOI:10.1039/b201233b
日期:2002.5.10
Easily available acyl dithiophosphates are not stable and isomerise reversibly to O-thioacyl monothiophosphates, especially when subjected to heating. Much slower but probably irreversible isomerisation to S-thioacyl monothiophosphates occurs. Since equilibrium states are established and S-thioacyl (mono)thiophosphates form slowly, reaction mixtures contain generally both thioacylating and acylating agents, and consequently cannot be used for efficient thioacylation. On the other hand, treatment of a mixture of isomeric anhydrides with an excess of a dithiophosphoric acid leads to exclusive formation of S-thioacyl dithiophosphates. They appear to be excellent thioacylating agents: relatively stable, inert towards water and oxygen and therefore easy to handle. Reactions with nitrogen or sulfur nucleophiles proceed very rapidly under ambient conditions, yielding respective thioacyl derivatives. Isolation of the products is very simple. Due to
the low reactivity of S-thioacyl dithiophosphates towards oxygen nucleophiles they can be used for direct thioacylation of multifunctional nucleophiles with unprotected hydroxy groups. Respective thioacyl derivatives cannot readily be obtained using other methods.
The invention relates to novel pyrimidinone-based heterocyclic compounds which are parasite growth inhibitors, having the general formula (I) in which Y is a morpholine chosen from three bridged morpholines, L is a bond or a linker, n=0 or 1 and R
2
is a methyl group when n=0 and a hydrogen atom when n=1. Process for the preparation thereof and therapeutic use thereof.
A series of modified calix[4]crown‐6 derivatives was synthesized to chelate the heavy group 2 metal barium, which serves as a non‐radioactive surrogate for radium‐223/‐224; radionuclides with promising properties for radiopharmaceutical use. These calixcrowns were functionalized with either cyclic amide moieties or with deprotonizable groups, and the corresponding barium complexes were synthesized
Neue Sulfonylaminopyrimidine, ihre Herstellung und Verwendung als Heilmittel
申请人:F. HOFFMANN-LA ROCHE AG
公开号:EP0633259A1
公开(公告)日:1995-01-11
Verbindungen der Formel
worin R¹ bis R⁹, Ra, Rb, X, Y, Z, m und n die in der Beschreibung angegebene Bedeutung haben, können als Heilmittel, insbesondere zur Behandlung und Prophylaxe von mit Endothelinaktivitäten assoziierten Zuständen Verwendung finden.
式中的化合物
其中 R¹ 至 R⁹、Ra、Rb、X、Y、Z、m 和 n 具有说明中给出的含义,可用作治疗剂,特别是用于治疗和预防与内皮素活性相关的疾病。
Ogawa, Takuji; Hikasa, Tetsuya; Ikegami, Tohru, Journal of the Chemical Society. Perkin transactions I, 1994, # 23, p. 3473 - 3478