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The development of a multistep continuous-flow process, consisting of a direct α-lithiation stage and subsequent hydroxylation by aerobic oxidation, is reported. The protocol is applied to the synthesis of cyclopentylmandelic acid (CPMA), the main building block for the anticholinergic glycopyrronium bromide (glycopyrrolate). We demonstrate the safe utilization of organolithium reagents and molecular oxygen in combination by using a continuous-flow protocol. The first stage involves the formation of a di-lithium enolate intermediate, which was either pre-formed in batch or formed in flow by using n-hexyllithium as a costeffective and industrially safe base. The subsequent hydroxylation stage utilized molecular oxygen under homogeneous and mild conditions (atmospheric pressure and room temperature) to give the desired product. A diluted form of oxygen gas, consisting of less than 10% O 2 in N 2 (Bsynthetic air^), is used in pharmaceutical batch manufacturing to effectively address safety concerns when handling molecular oxygen. The telescoped flow process afforded the target intermediate in 65% solution NMR yield (50% isolated yield after re-crystallization). The continuous-flow process opens up new opportunities for the manufacture of CPMA, with a protocol which can safely handle pure O 2 , and compares favorably with existing Grignard-based batch processes. Keywords Glycopyrrolate (glycopyrronium bromide). Cyclopentyl mandelic acid (CPMA). Continuous-flow. Gas-liquid transformations. Molecular oxygen. Organometallics The medicinal properties of glycopyrronium bromide (glycopyrrolate, 4) were first identified in the late 1950s [1]. Glycopyrrolate is an antagonist of muscarinic cholinergic receptors and is used for the treatment of drooling or excessive salivation (sialorrhea) [2], excess sweating (hyperhidrosis) [3], and overactive bladder and for presurgery treatment. In addition, it has recently been introduced as an effective bronchodilator for the treatment of chronic obstructive pulmonary disease (COPD) for asthma patients [4]. Glycopyrrolate displays few side effects because it does not pass through the blood brain barrier. Cyclopentyl mandelic acid (CPMA, 1), or its corresponding ester derivatives, are key intermediates in the synthetic routes to 4. CPMA (1) reacts with 1-methylpyrrolidin-3-ol (2) to form tertiary amine 3. N-Methylation of 3 by methyl bromide gives quaternary ammonium salt glycopyrrolate 4 as a racemate (Scheme 1) [5]. CPMA (1) is a synthetically challenging intermediate to prepare (Scheme 2). Routes A to D are most likely to be the commercially applied methods because these procedures are Electronic supplementary material The online version of this article (

trans-6-Aminocyclohept-3-enols 18 and ent-18 are new designed polyfunctionalized chiral building blocks for piperidine alkaloids synthesis and are prepared in high yields from the enzymatically derived cyclohept-3-ene-1,6-diol monoacetate (-)-8. Efficient highly enantioselective syntheses of cis-4-hydroxypipecolic acid (1) and piperidines 3 and 4, in both enantiomeric forms, are described. [reaction: see text]

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An electrospinning process was optimized to produce fibers of micrometric size with different combinations of polymeric and surfactant materials to promote the dissolution rate of an insoluble drug: firocoxib. Scanning Electron Microscopy (SEM) showed that only some combinations of the proposed carrier systems allowed the production of suitable fibers and further fine optimization of the technique is also needed to load the drug. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD) suggest that the drug is in an amorphous state in the final product. Drug amorphization, the fine dispersion of the active in the carriers, and the large surface area exposed to water interaction obtained through the electrospinning process can explain the remarkable improvement in the dissolution performance of firocoxib from the final product developed.

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