Efficient Crystallization-Induced Dynamic Resolution of α-Substituted Carboxylic Acids

Development and Commercialization of the MiniBlock Synthesizer Family: A Historical Case Study

An internal development project at Bristol-Myers Squibb (BMS) led to invention of a family of organic chemistry synthesis blocks for both parallel synthesis in drug discovery and parallel reaction optimization in pharmaceutical development. The internal demand for these synthesis blocks became so great that the original development team was challenged by the burden of ongoing manufacture, support, and supply chain management. As a result, BMS entered into a unique industry partnership with Mettler-Toledo AutoChem (MT), Newark, DE, formerly Bohdan Automation, to commercialize the reactor blocks and extend the product family, now known as the MiniBlock line. This manuscript describes the initial development drivers, the overall technical design, and the ultimate successful commercialization of the MiniBlock synthesis family.

A Novel Crystallization-Induced Diastereomeric Transformation Based on a Reversible Carbon−Sulfur Bond Formation. Application to the Synthesis of a γ-Secretase Inhibitor

This paper describes a remarkably efficient process for the preparation of gamma-secretase inhibitor 1. The target is synthesized in only five steps with an overall yield of 58%. The key operation is a highly selective and practical, crystallization-driven transformation for the conversion of a mixture of tertiary benzylic alcohols into the desired sulfide diastereomer with 94:6 dr. This unprecedented process is based upon a reversible carbon-sulfur bond formation under acidic conditions.

Copper(ii)-mediated resolution of α-halo carboxylic acids with chiral O,O′-dibenzoyltartaric acid: spontaneous racemization and crystallization-induced dynamic resolution

Herein we present a new example of coordination-mediated resolution of racemic acids by a chiral acid. The reaction of copper(II) acetate monohydrate, optically pure O,O'-dibenzoyltartaric acid (DBTA) and racemic alpha-bromo-2-chlorophenylacetic acid (HL1) in acetonitrile solution afforded a binuclear copper(II) complex with D-DBTA dianion, alpha-bromo-2-chlorophenylacetate and acetate as ligands. After decomposition of the complex with acid, the optically active acid ((R)-HL1) was obtained. Similarly, alpha-bromo-2-fluorophenylacetic acid (HL2), alpha-bromo-2-bromophenylacetic acid (HL3), alpha-chloro-2-chlorophenylacetic acid (HL4), alpha-chloro-2-fluorophenylacetic acid (HL5), alpha-bromophenylacetic acid (HL6), alpha-bromo-4-chlorophenylacetic acid (HL7), 2-bromopropionic acid (HL8) and 2-chloropropionic acid (HL9) were resolved by the same method. Satisfactory results were obtained for HL2 to HL5. For HL6 and HL7, only racemic acids were obtained. For the two alpha-halo aliphatic acids (HL8 and HL9), poor enantioselectivity was obtained. It is more interesting that three acids (HL1, HL2 and HL3) could spontaneously racemize in acetonitrile solution, which resulted in crystallization-induced dynamic resolution (CIDR) with greater than 50% yield.