1,5-Disubstituted benzimidazoles that direct cardiomyocyte differentiation from mouse embryonic stem cells.

Cardiomyopathy is the leading cause of death worldwide. Despite progress in medical treatments, heart transplantation is one of the only current options for those with infarcted heart muscle. Stem cell differentiation technology may afford cell-based therapeutics that may lead to the generation of new, healthy heart muscle cells from undifferentiated stem cells.

Synthesis and SAR of b-annulated 1,4-dihydropyridines define cardiomyogenic compounds as novel inhibitors of TGFβ signaling.

A medium-throughput murine embryonic stem cell (mESC)-based high-content screening of 17000 small molecules for cardiogenesis led to the identification of a b-annulated 1,4-dihydropyridine (1,4-DHP) that inhibited transforming growth factor β (TGFβ)/Smad signaling by clearing the type II TGFβ receptor from the cell surface. Because this is an unprecedented mechanism of action, we explored the series' structure-activity relationship (SAR) based on TGFβ inhibition, and evaluated SAR aspects for cell-surface clearance of TGFβ receptor II (TGFBR2) and for biological activity in mESCs. We determined a pharmacophore and generated 1,4-DHPs with IC(50)s for TGFβ inhibition in the nanomolar range (e.

Nerve agent analogues that produce authentic soman, sarin, tabun, and cyclohexyl methylphosphonate-modified human butyrylcholinesterase.

The goal was to test 14 nerve agent model compounds of soman, sarin, tabun, and cyclohexyl methylphosphonofluoridate (GF) for their suitability as substitutes for true nerve agents. We wanted to know whether the model compounds would form the identical covalent adduct with human butyrylcholinesterase that is produced by reaction with true nerve agents. Nerve agent model compounds containing thiocholine or thiomethyl in place of fluorine or cyanide were synthesized as Sp and Rp stereoisomers.

Chemical synthesis of two series of nerve agent model compounds and their stereoselective interaction with human acetylcholinesterase and human butyrylcholinesterase.

Both G and V type nerve agents possess a center of chirality about phosphorus. The S(p) enantiomers are generally more potent inhibitors than their R(p) counterparts toward acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). To develop model compounds with defined centers of chirality that mimic the target nerve agent structures, we synthesized both the S(p) and the R(p) stereoisomers of two series of G type nerve agent model compounds in enantiomerically enriched form.

2-nitrophenyl isocyanide as a versatile convertible isocyanide: rapid access to a fused gamma-lactam beta-lactone bicycle.

2-Nitrophenyl isocyanide is introduced as a convertible isocyanide with demonstration of its feasibility and applicability in an efficient synthesis of the fused gamma-lactam beta-lactone bicycle of proteasome inhibitor omuralide. Starting from a linear keto acid precursor, the fused gamma-lactam beta-lactone bicycle was prepared in four steps by a sequential biscyclization strategy; a stereocontrolled Ugi reaction and the concomitant direct beta-lactonization following the formation of an N-acylbenzotriazole intermediate. The N-acylbenzotriazole is amenable to intra- or intermolecular attack from a variety of nucleophiles with a catalytic amount of base to form the pyroglutamic acid derivatives.

New entry to convertible isocyanides for the Ugi reaction and its application to the stereocontrolled formal total synthesis of the proteasome inhibitor omuralide.

The development of a new convertible isocyanide, indole-isocyanide, for ready access to pyroglutamic acids culminated in the formal total synthesis of the proteasome inhibitor omuralide featuring a stereocontrolled Ugi reaction. Indole-isocyanide was named after the facilitation of hydrolysis of the resulting 2-(2,2-dimethoxyethyl)anilide via an N-acylindole intermediate obtained by the Ugi multicomponent condensation reaction followed by the indole formation.

Expeditious access to unprotected racemic pyroglutamic acids.

A series of biologically intriguing pyroglutamic acids were synthesized in racemic form by employing indole-isonitrile and ammonium acetate in the Ugi 4-center-3-component reaction of gamma-ketoacids.

Vesicular transport of fe and interaction with other metal ions in polarized Caco2 cell monolayers.

Two aspects of the mechanisms by which iron is absorbed by the intestine were studied in the Caco2 cell model, using 59Fe(II)-ascorbate. Data showing the importance of vesicular processes and cycling of apotransferrin (apoTf) to uptake and overall transport of Caco2 cell monolayers (or basolateral 59Fe release) were obtained by comparing effects of: a) adding apoTf to the basal chamber; b) adding vesicular transport inhibitors; or c) cooling to 4 degrees C. These showed that apoTf may be involved in as much as half of Fe transfer across the basolateral membrane, and that vesicular processes may also play a role in non-apoTf-dependent Fe transport.