- Ex situ generation of stoichiometric HCN and its application in the Pd-catalysed cyanation of aryl bromides: Evidence for a transmetallation step between two oxidative addition Pd-complexes
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A protocol for the Pd-catalysed cyanation of aryl bromides using near stoichiometric and gaseous hydrogen cyanide is reported for the first time. A two-chamber reactor was adopted for the safe liberation of ex situ generated HCN in a closed environment, which proved highly efficient in the Ni-catalysed hydrocyanation as the test reaction. Subsequently, this setup was exploited for converting a range of aryl and heteroaryl bromides (28 examples) directly into the corresponding benzonitriles in high yields, without the need for cyanide salts. Cyanation was achieved employing the Pd(0) precatalyst, P(tBu)3-Pd-G3 and a weak base, potassium acetate, in a dioxane-water solvent mixture. The methodology was also suitable for the synthesis of 13C-labelled benzonitriles with ex situ generated 13C-hydrogen cyanide. Stoichiometric studies with the metal complexes were undertaken to delineate the mechanism for this catalytic transformation. Treatment of Pd(P(tBu)3)2 with H13CN in THF provided two Pd-hydride complexes, (P(tBu)3)2Pd(H)(13CN), and [(P(tBu)3)Pd(H)]2Pd(13CN)4, both of which were isolated and characterised by NMR spectroscopy and X-ray crystal structure analysis. When the same reaction was performed in a THF : water mixture in the presence of KOAc, only (P(tBu)3)2Pd(H)(13CN) was formed. Subjection of this cyano hydride metal complex with the oxidative addition complex (P(tBu)3)Pd(Ph)(Br) in a 1 : 1 ratio in THF led to a transmetallation step with the formation of (P(tBu)3)2Pd(H)(Br) and 13C-benzonitrile from a reductive elimination step. These experiments suggest the possibility of a catalytic cycle involving initially the formation of two Pd(ii)-species from the oxidative addition of LnPd(0) into HCN and an aryl bromide followed by a transmetallation step to LnPd(Ar)(CN) and LnPd(H)(Br), which both reductively eliminate, the latter in the presence of KOAc, to generate the benzonitrile and LnPd(0).
- Kristensen, Steffan K.,Eikeland, Espen Z.,Taarning, Esben,Lindhardt, Anders T.,Skrydstrup, Troels
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p. 8094 - 8105
(2017/11/27)
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- From human immunodeficiency virus non-nucleoside reverse transcriptase inhibitors to potent and selective antitrypanosomal compounds
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The presence of a structural recognition motif for the nucleoside P2 transporter in a library of pyrimidine and triazine non-nucleoside HIV-1 reverse transcriptase inhibitors, prompted for the evaluation of antitrypanosomal activity. It was demonstrated that the structure-activity relationship for anti-HIV and antitrypanosomal activity was different. Optimization in the diaryl triazine series led to 6-(mesityloxy)-N2-phenyl-1,3,5-triazine-2,4-diamine (69), a compound with potent in vitro and moderate in vivo antitrypanosomal activity.
- Venkatraj, Muthusamy,Arin, Kevin K.,Heeres, Jan,Joossens, Jurgen,Diri, Bertrand,Lyssens, Sophie,Michiels, Johan,Cos, Paul,Lewi, Paul J.,Vanham, Guido,Maes, Louis,Van Der Veken, Pieter,Augustyns, Koen
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supporting information
p. 5241 - 5248
(2014/12/11)
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- Optimization of diarylazines as anti-HIV agents with dramatically enhanced solubility
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Non-nucleoside inhibitors of HIV-1 reverse transcriptase are reported that have ca. 100-fold greater solubility than the structurally related drugs etravirine and rilpivirine, while retaining high anti-viral activity. The solubility enhancements come from strategic placement of a morpholinylalkoxy substituent in the entrance channel of the NNRTI binding site. Compound 4d shows low-nanomolar activity similar to etravirine towards wild-type HIV-1 and key viral variants.
- Bollini, Mariela,Cisneros, José A.,Spasov, Krasimir A.,Anderson, Karen S.,Jorgensen, William L.
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p. 5213 - 5216
(2013/09/12)
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- Prodrugs of hiv replication inhibiting pyrimidines
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The present invention concerns compounds of formula (A1)(A2)N—R1 (I),the N-oxide forms, the pharmaceutically acceptable addition salts, the quaternary amines and stereochemically isomeric forms thereof, wherein R1 is substituted C1-6alkyl; —S(=O)—R8; —S(=O)2—R8; C7-12alkylcarbonyl; optionally substituted C1-6alkyloxycarbonylC1-6alkylcarbonyl; with R8 being C1-6alkyl, aryl1 or Het1; (A1)(A2)N— is the covalently bonded form of the corresponding intermediate of formula (A1)(A2)N—H, which is a HIV replication inhibiting pyrimidine of formula 1
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- RATE-CONTROLLED PARTICLES
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Rate-controlled particles, comprising compounds of the formula as a solid dispersion.
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- Evolution of anti-HIV drug candidates. Part 3: Diarylpyrimidine (DAPY) analogues
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The synthesis and anti-HIV-1 activity of a series of diarylpyrimidines (DAPYs) are described. Several members of this novel class of non-nucleoside reverse transcriptase inhibitors (NNRTIs) are extremely potent against both wild-type and a panel of clinically significant single- and double-mutant strains of HIV-1.
- Ludovici, Donald W.,De Corte, Bart L.,Kukla, Michael J.,Ye, Hong,Ho, Chih Y.,Lichtenstein, Mark A.,Kavash, Robert W.,Andries, Koen,De Bethune, Marie-Pierre,Azijn, Hilde,Pauwels, Rudi,Lewi, Paul J.,Heeres, Jan,Koymans, Lucien M.H.,De Jonge, Marc R.,Van Aken, Koen J.A.,Daeyaert, Frederik F.D.,Das, Kalyan,Arnold, Edward,Janssen, Paul A.J.
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p. 2235 - 2239
(2007/10/03)
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