Total synthesis of ovalifoliolatin B, acerogenins A and C

A short and concise route for the synthesis of ovalifoliolatin B, a highly strained macrocyclic diaryl ether heptanoid natural product that also provides quick access to acerogenins A and C natural products has been reported

A facile, catalytic, and environmentally benign method for selective deprotection oftert-butyldimethylsilyl ether mediated by phosphomolybdic acid supported on silica gel

An environmentally benign PMA supported on SiO<sub>2</sub> is found to be an efficient catalyst for the chemoselective deprotection of TBDMS ethers under very mild conditions. Various labile functional groups such as isopropylidene acetal, OTBDPS, OTHP, Oallyl, OBn, alkene, alkyne, OAc, OBz, N-Boc, N-Cbz, N-Fmoc, mesylate, and azide are found to be stable under the reaction conditions. This “truly catalytic” heterogeneous reaction does not require aqueous workup, and the supported catalyst and the solvent can be readily recovered and recycled

Opening of n-tosyl aziridines with nucleophiles catalyzed by phosphomolybdic acid supported on silica gel

An environmentally benign H<sub>3</sub>PMo<sub>12</sub>O<sub>40</sub>-SiO<sub>2</sub>-catalyzed regioselective opening of activated aziridines with alcohols, azide, cyanide and bromide, at ambient temperature to afford the corresponding β-amino derivatives in good yields is described

Heteropoly acid as a novel nitrene transfer agent: a facile and practical aziridination of olefins with Chloramine-T

Environmentally benign HPA is found to be an efficient catalyst for aziridination of olefins in the presence of inexpensive Chloramine-T as a nitrogen source: instantaneous at room temperature, requires only stoichiometric amount of olefin and no allyl amine side product

Microwave-assisted cleavage of phosphate, phosphonate and phosphoramide esters

A mild and rapid protocol for cleavage of phosphate, phosphonate and phosphoramide esters. The scope and limitations of this microwave-assisted reaction is explored here

A convenient method for the N-formylation of secondary amines and anilines using ammonium formate

The N-formylation of secondary amines and anilines using ammonium formate as a formylating agent is described

Synthesis and evaluation of macrocyclic diarylether heptanoid natural products and their analogs

The macrocyclic diarylether heptanoid (MDEH) natural products have been used in folk medicine for centuries. MDEHs are reported to exert anti-tumor properties by inhibiting the activation of NF-κB. Here we report the synthesis of a small MDEH library (first reported synthesis of racemic platycarynol) using a Grubbs cross metathesis/Ullmann cyclization strategy. Evaluation of the library led to the identification of MDEH 9b which sensitizes pancreatic cancer cells to gemcitabine mediated growth inhibition and apoptosis

High-throughput fluorescence polarization assay to identify small molecule inhibitors of BRCT domains of breast cancer gene 1

The C-terminus region of the 1863 residue early onset of breast cancer gene 1 (BRCA1) nuclear protein contains a tandem globular carboxy terminus domain termed BRCT. The BRCT repeats in BRCA1 are phosphoserine- and/or phosphothreonine-specific binding modules. The interaction of the BRCT(BRCA1) domains with phosphorylated BRCA1-associated carboxyl terminal helicase (BACH1) is cell cycle regulated and is essential for DNA damage-induced checkpoint control during the transition from the G<sub>2</sub> phase to the M phase of the cell cycle. Development of a competitive, homogeneous, high-throughput fluorescence polarization (FP) assay to identify small molecule inhibitors of BRCT(BRCA1)–BACH1 interaction is reported here. The FP assay was used for measuring binding affinities and inhibition constants of BACH1 peptides and small molecule inhibitors of BRCT(BRCA1) domains, respectively. A fluorescently labeled wild-type BACH1 decapeptide (BDP1) containing the critical phosphoserine, a phenylalanine at (P + 3), and a GST–BRCT fusion protein were used to establish the FP assay. BDP1 has a dissociation constant (K<sub>d</sub>) of 1.58 ± 0.01 μM and a dynamic range (ΔmP) of 164.9 ± 1.9. The assay tolerates 20% dimethyl sulfoxide, which enables screening poorly soluble compounds. Under optimized conditions, a Z′ factor of 0.87 was achieved in a 384-well format for high-throughput screening

Synthesis and evaluation of macrocyclic diarylether heptanoid natural products and their analogs

The macrocyclic diarylether heptanoid (MDEH) natural products have been used in folk medicine for centuries. MDEHs are reported to exert anti-tumor properties by inhibiting the activation of NF-κB. Here we report the synthesis of a small MDEH library (first reported synthesis of racemic platycarynol) using a Grubbs cross metathesis/Ullmann cyclization strategy. Evaluation of the library led to the identification of MDEH 9b which sensitizes pancreatic cancer cells to gemcitabine mediated growth inhibition and apoptosis

The Lindlar catalyst revitalized: a highly chemoselective method for the direct conversion of azides to N-(tert-butoxycarbonylamines

An exceptionally chemoselective method for the direct conversion of azides to N-(tert-butoxycarbonyl)-protected amines under catalytic transfer-hydrogenation conditions, using the Lindlar catalyst, is reported. The extremely labile functional groups such as N-Cbz, benzyl ester are shown to be inert under the reaction conditions. The present method allows us to synthesize orthogonally protected (N-Cbz & N-Boc) 1,2-diamino systems, which will be immensely useful in organic synthesis