Library versus library recognition and inhibition of the HIV-1 Nef allelome

NIS/CHP-mediated reaction of isocyanides with hydrazones: access to aminopyrazoles

A NIS/CHP-mediated reaction of isocyanides with hydrazones to construct aminopyrazoles has been developed.

A green expedient synthesis of pyridopyrimidine-2-thiones and their antitubercular activity

The pseudo four-component domino reactions of N-substituted-4-piperidones, substituted aromatic aldehydes and thiourea in the presence of solid sodium ethoxide under solvent-free conditions afforded pyridopyrimidine-2-thiones in almost quantitative yields by simply grinding for 1-2 min. at ambient temperature. The synthesized compounds were screened for their in vitro activity against Mycobacterium tuberculosis H37Rv. Among them, (E)-6-benzyl-8-(2,4-dichlorobenzylidene)-4-(2,4-dichlorophenyl)-3,4,5,6,7,8-hexahydropyrido[4,3-d]pyrimidine-2(1H)-thione (MIC 2.8 μM) displays the maximum activity, being 2.7 and 1.7 times more active than the first line antitubercular drugs ethambutol and ciprofloxacin, respectively, and less active than rifampicin and isoniazid, by 28 and 7 times, respectively.

Predicting protein evolution in vitro by phage escape technology

The relationship between host and pathogen is inherently dynamic at the genetic level. A plethora of host defensive systems have evolved to counteract and/or eliminate invading pathogens. These strategies exert selection pressure upon the pathogen, leading to the emergence of mechanisms to combat the host including immune evasion and resistance. Consequently, effective control of rapidly evolving diseases is contingent on the ability to predict pathogen evolution prior to the emergence of resistant phenotypes. Highlighted in this article is a bacteriophage-based technology capable of screening hundreds of millions of binding events simultaneously at single molecule resolution, thus providing an in vitro mimetic of protein evolution. This technology, termed phage escape, can be utilized to model the evolution of proteins in the presence of antibodies or other selective pressure, providing a predictive solution to the coevolution of antigens and the immune system. Foresight into the evolutionary path of an antigen and subsequent neutralization strategies can facilitate more efficacious vaccination formulation and have important implications in the treatment of a range of evolving diseases, including viral infections and cancer.

Phage display of functional, full-length human and viral membrane proteins

Phage display of protein and peptide libraries offers a powerful technology for the selection and isolation of ligands and receptors. To date, the technique has been considered limited to soluble, non-membrane proteins. We report two examples of phage display of full-length, folded and functional membrane proteins. Consistent display required the recently reported KO7(+) helper phage. The two proteins, full-length caveolin-1 and HIV gp41, display well on the surface of the phage, and maintain their binding activities as shown by in vitro assays.

Concise synthesis of guanidine-containing heterocycles using the Biginelli reaction

Two general methods for the synthesis of 2-imino-5-carboxy-3,4-dihydropyrimidines were developed using the three-component Biginelli reaction. The first method utilizes pyrazole carboxamidine, a beta-ketoester, and an aldehyde in an initial Biginelli reaction. After Boc protection, these products undergo aminolysis and acidic deprotection to generate 2-imino-5-carboxy-3,4-dihydropyrimidines in a four-step sequence. The second method utilizes a triazone-protected guanidine, a beta-ketoester, and an aldehyde in a Biginelli reaction. Acidic cleavage of the triazone yields 2-imino-5-carboxy-3,4-dihydropyrimidines in a two-step sequence. We also describe the further elaboration of several of these products using a tethered Biginelli reaction to give triazaacenaphthalene structures similar to those found in crambescidin and batzelladine alkaloids.

Enantioselective total synthesis of batzelladine F and definition of its structure

Batzelladine F (1) was synthesized in enantioselective and stereoselective fashion in 15 steps (longest linear sequence) and 1.7% overall yield from two readily available enantioenriched beta-hydroxy esters, methyl (R)-3-hydroxydecanoate and methyl (R)-3-hydroxybutyrate. Tethered Biginelli condensations are used to assemble both tricyclic guanidine fragments, with the second tethered Biginelli condensation (14 + 16 --> 17) also being employed to join the guanidine fragments. Three diastereomers of batzelladine F, 2-4, were prepared also. A combination of HPLC, optical rotation and CD spectroscopy was employed to distinguish stereoisomers 1-4, proving that 1 is the correct structure of the hexacyclic marine alkaloid batzelladine F.