Improved and scalable methods for the synthesis of midazolam drug and its analogues using isocyanide reagents

Twenty-first century antiepileptic drugs. An overview of their targets and synthetic approaches

The therapeutic use of the traditional drugs against epilepsy has been hindered by their toxicity and low selectivity. These limitations have stimulated the design and development of new generations of antiepileptic drugs. This review explores the molecular targets and synthesis of the antiepileptic drugs that have entered the market in the 21st century, with a focus on manufacturer synthesis.

Rectal Sedation With Ketamine and Midazolam in the Management of Uncooperative Children During Dental Treatment: A Case Series and Method Description

Background In pediatric dentistry, sedation aims to eliminate anxiety to facilitate the completion of dental procedures. Sedation in children is a multidimensional field that includes the child, parents/guardians, and the health care team. The rectal route is generally painless, making it suitable for children who are afraid of needles. This route has several advantages over the oral route, including reduced patient cooperation requirements, a faster and more predictable onset, and less physical trauma than the intravenous and intramuscular routes. This case series aimed to evaluate the effectiveness and success rate of rectal sedation with ketamine and midazolam in the management of uncooperative children during dental treatment. Case presentation Ten healthy children with definitely negative behavior were enrolled in this study. Each child was given 7 mg/kg of ketamine in combination with midazolam 0.1 mg/kg by the rectal route. The mean onset sedation time was 9.5 minutes, and pulpotomy procedures were done. Behavioral response was monitored throughout treatment using the Ohio State University Behavioral Rating Scale (OSUBRS), and the depth of sedation was measured using the University of Michigan Sedation Scale (UMSS). The Houpt General Behavior Scale was used to estimate the treatment success rate based on the overall behavior rating. All 10 cases showed good anxiolysis and cooperation following rectal administration, with no side effects observed. Conclusions Rectal administration of ketamine in combination with midazolam may be considered a reliable method in the management of uncooperative children during dental treatment. No adverse effects were observed during or after the sedation procedure.

C-H acylation of aniline derivatives with α-oxocarboxylic acids using ruthenium catalyst

An efficient and convenient synthetic strategy for ruthenium(II)-catalyzed ortho-acylation of N-(2-pyridyl)-anilines using α-oxycarboxylic acids as acyl sources is described. The procedure can smoothly proceed under mild conditions, showing good functional group tolerance. Valuable ortho-acylated aniline products have been obtained with moderate to good yields. Furthermore, the reaction could be easily scaled up to the gram scale.

Amide Bond Bioisosteres: Strategies, Synthesis, and Successes

The amide functional group plays a key role in the composition of biomolecules, including many clinically approved drugs. Bioisosterism is widely employed in the rational modification of lead compounds, being used to increase potency, enhance selectivity, improve pharmacokinetic properties, eliminate toxicity, and acquire novel chemical space to secure intellectual property. The introduction of a bioisostere leads to structural changes in molecular size, shape, electronic distribution, polarity, pK_a, dipole or polarizability, which can be either favorable or detrimental to biological activity. This approach has opened up new avenues in drug design and development resulting in more efficient drug candidates introduced onto the market as well as in the clinical pipeline. Herein, we review the strategic decisions in selecting an amide bioisostere (the why), synthetic routes to each (the how), and success stories of each bioisostere (the implementation) to provide a comprehensive overview of this important toolbox for medicinal chemists.

Improved scale-up synthesis and purification of clinical asthma candidate MIDD0301

We report an improved and scalable synthesis of MIDD0301, a positive GABA_A receptor modulator that is under development as oral and inhaled treatments for asthma. In contrast to other benzodiazepines in clinical use, MIDD0301 is a chiral compound that has limited brain absorption. The starting material to generate MIDD0301 is 2-amino-5-bromo-2'-fluorobenzophenone, which has a non-basic nitrogen due to electron withdrawing substituents in the ortho and para positions, reducing its reactivity towards activated carboxylic acids. Investigations of peptide coupling reagents on multigram scale resulted in moderate yields due to incomplete conversions. Secondly, basic conditions used for the formation of the seven-membered 1,4-diazepine ring resulted in racemization of the chiral center. We found that neutral conditions comparable to the pKa of the primary amine were sufficient to support the formation of the intramolecular imine but did not enable the simultaneous removal of the protecting group. Both difficulties were overcome with the application of the N-carboxyanhydride of D-alanine. Activated in the presence of acid, this compound reacted with non-basic 2-amino-5-bromo-2'-fluorobenzophenone and formed the 1,4-diazepine upon neutralization with triethylamine. Carefully designed workup procedures and divergent solubility of the synthetic intermediates in solvents and solvent combinations were utilized to eliminate the need for column chromatography. To improve compatibility with large scale reactors, temperature-controlled slow addition of reagents generated the imidazodiazepine at -20 °C. All intermediates were isolated with a purity of >97% and impurities were identified and quantified. After the final hydrolysis step, MIDD0301 was isolated in a 44% overall yield and purity of 98.9% after recrystallization. The enantiomeric excess was greater than 99.0%.

Allosteric GABAA Receptor Modulators-A Review on the Most Recent Heterocyclic Chemotypes and Their Synthetic Accessibility

GABAA receptor modulators are structurally almost as diverse as their target protein. A plethora of heterocyclic scaffolds has been described as modulating this extremely important receptor family. Some made it into clinical trials and, even on the market, some were dismissed. This review focuses on the synthetic accessibility and potential for library synthesis of GABAA receptor modulators containing at least one heterocyclic scaffold, which were disclosed within the last 10 years.