Precise control of drug loading and release of an NSAID–polymer conjugate for long term osteoarthritis intra-articular drug delivery

The synthesis of biocompatible polymer diclofenac conjugates (PDCs) that have a high drug loading and high degree of control over diclofenac (DCF) release is described.

The Hydrolysis of Diclofenac Esters: Synthetic Prodrug Building Blocks for Biodegradable Drug-Polymer Conjugates

Degradation reactions on diclofenac-monoglycerides (3a,b), diclofenac-(p-hydroxybenzoate)-2-monoglyceride (3c), diclofenac (1), and diclofenac lactam (4) were performed at 37 °C in isotonic buffer solutions (apparent pH range 1-8) containing varying concentrations of acetonitrile (ACN). The concentration remaining of each analyte was measured versus time. Diclofenac-monoglycerides and diclofenac-(p-hydroxybenzoate)-2-monoglyceride (3c) were both found to undergo facile and complete hydrolysis in pH 7.4 isotonic phosphate buffer/10% ACN. Under mildly acidic, neutral or alkaline conditions, diclofenac-(p-hydroxybenzoate)-2-monoglyceride (3c) had the fastest hydrolysis rate (t1/2 = 3.23 h at pH 7.4), with simultaneous formation of diclofenac lactam (4) and diclofenac (1). Diclofenac-monoglycerides (3a,b) hydrolyzed more slowly under the same conditions, to again yield both diclofenac (1) and diclofenac lactam (4). There was also transesterification of diclofenac-2-monoglyceride (3b) to its regioisomer, diclofenac-1-monoglyceride (3a) across the pH range. Diclofenac was shown to be stable in neutral or alkaline conditions but cyclized to form the lactam (4) in acidic conditions. Conversely, the lactam (4) was stable under acidic conditions but was converted to an unknown species under alkaline or neutral conditions.

Phenylaminopyrimidines as inhibitors of Janus kinases (JAKs)

A series of phenylaminopyrimidines has been identified as inhibitors of Janus kinases (JAKs). Development of this initial series led to the potent JAK2/JAK1 inhibitor CYT387 (N-(cyanomethyl)-4-[2-[[4-(4-morpholinyl)phenyl]amino]-4-pyrimidinyl]-benzamide). Details of synthesis and SAR studies of these compounds are reported.

Stereocontrolled Syntheses of the Nemorensic Acids Using 6-Diazoheptane-2,5-dione in Carbonyl Ylide Cycloadditions

Levulinic acid-derived 6-diazoheptane-2,5-dione (9) serves as a common precursor in a formal synthesis of frontalin 19, and in syntheses of cis-nemorensic acid 1, 4-hydroxy-cis-nemorensic acid 2, 3-hydroxy-cis-nemorensic acid 3, and nemorensic acid 4. The key step in these syntheses is the Rh(2)(OAc)(4)-catalyzed tandem carbonyl ylide formation-intermolecular 1,3-dipolar cycloadditions of diazodione 9 with formaldehyde, alkynes or allene, which occur with high regioselectivity. Subsequent oxidative cleavage of the ring originally derived from the cyclic carbonyl ylide intermediate provides a straightforward access to polysubstituted tetrahydrofurans, and in particular an efficient entry to the nemorensic acids. Enantioselective cycloadditions with diazodione 9, using chiral rhodium catalysts, gave cycloadducts in up to 51% ee.

Concise, stereoselective syntheses of cis-nemorensic acid and 4-hydroxy-cis-nemorensic acid via tandem carbonyl ylide formation-cycloaddition

[reaction: see text] 1,3-Dipolar cycloaddition of propargyl bromide with the carbonyl ylide derived from 6-diazoheptane-2,5-dione is the key step in concise syntheses of cis-nemorensic acid and 4-hydroxy-cis-nemorensic acid.

Attempted Enantioselective Synthesis of Terbutaline. Unexpected Partial Racemization During Lithium Aluminum Hydride Reduction of a Secondary Amide

Syntheses leading to compounds related to the bronchodilator (–)- terbutaline via optically active cyanohydrins suffered unexpected partial racemization during lithium aluminium hydride reduction of key amide intermediates.