- Atom-efficient Pd-catalyzed cross-couplings of chloroarenes with triarylbismuth reagents
-
Various Pd-catalyzed protocols have been developed for the atom-efficient cross-coupling of chloroarenes with triarylbismuth reagents. Using the developed protocols, an efficient synthesis of unsymmetrical biaryls in good to excellent yields was achieved by employing electron-deficient chloroarenes and a range of triarylbismuth reagents.
- Rao, Maddali L.N.,Meka, Suresh
-
supporting information
(2019/07/30)
-
- Semisynthetic Chemical Modification of the Antifungal Lipopeptide Echinocandin B (ECB): Structure-Activity Studies of the Lipophilic and Geometric Parameters of Polyarylated Acyl Analogs of ECB
-
Echinocandin B (ECB) is a lipopeptide composed of a complex cyclic peptide acylated at the N-terminus by linoleic acid.Enzymatic deacylation of ECB provided the peptide "nucleus" as a biologically inactive substrate from which novel ECB analogs were generated by chemical reacylation at the N-terminus.Varying the acyl group revealed that the structure and physical properties of the side chain, particularly its geometry and lipophlicity, played a pivotal role in determining the antifungal potency properties of the analog.Using CLOGP values to describe and compare the lipophlicities of the side chain fragments, it was shown that values of >3.5 were required for expression of antifungal activity.Sercondly, a linearly rigid geometry of the side chain was the most effective shape in enhancing the antifungal potency.Using these parameters as a guide, a variety of novel ECB analogs were synthesized which included arylacyl groups that incorporated biphenyl, terphenyl, tetraphenyl, and arylethynyl groups.Generally the glucan synthase inhibition by these analogs correlated well with in vitro and in vivo activities and was likewise influenced by the structure of the side chain.These structural variations resulted in enhancement of antifungal activity in both in vitro and in vivo assays.Some of these analogs, including LY303336 (14a), were effective by the oral route of administartion.
- Debono, Manuel,Turner, William W.,LaGrandeur, Lisa,Burkhadt, Fred J.,Nissen , Jeffrey S.,et al.
-
p. 3271 - 3281
(2007/10/02)
-
- SYNTHESIS OF 4-ALKOXY-4'-CYANOBIPHENYLS
-
A preparative method was developed for the synthesis of liquid crystals of the 4-alkoxy-4'-cyanobiphenyl group.It involves the nitration of 4-cyanobiphenyl to 4-nitro-4'-cyanobiphenyl, reduction of the latter, diazotization of the obtained 4-amino-4'-cyanobiphenyl, and alkylation of the 4-hydroxy-4'-cyanobiphenyl formed during decomposition of the diazonium salt.
- Ruolene, Yu. I.,Adomenas, P. V.,Adomenene, O. K.,Denis, G. I.
-
p. 1192 - 1195
(2007/10/02)
-
