A process to isolate a compound of Formula (2a) or a salt or solvate thereof, comprising a) reacting a mixture of diastereoisomers of Formulae (2a, 2b) with a basic heterocyclic-aldehyde compound and an optically active amine in the presence of a base; and b) separating the compound of Formula (2a) from the product of step a) by acid extraction. The compound of Formula (2a) may be produced with an enantiomeric excess of 98%. Compounds of Formula (2a) are useful intermediates in a process to prepare a bicyclic -amino tetrazole derivative of Formula (I) which finds utility in treating neuropathic pain and disorders of the central nervous system.

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The present invention relates to novel manganese complexes and their use, inter alia, for homogeneous catalysis in (1) the preparation of imine by dehydrogenative coupling of an alcohol and amine; (2) CC coupling in Michael addition reaction using nitriles as Michael donors; (3) dehydrogenative coupling of alcohols to give esters and hydrogen gas (4) hydrogenation of esters to form alcohols (including hydrogenation of cyclic esters (lactones) or cyclic di-esters (di-lactones), or polyesters); (5) hydrogenation of amides (including cyclic dipeptides, lactams, diamide, polypeptides and polyamides) to alcohols and amines (or diamine); (6) hydrogenation of organic carbonates (including polycarbonates) to alcohols or hydrogenation of carbamates (including polycarbamates) or urea derivatives to alcohols and amines; (7) dehydrogenation of secondary alcohols to ketones; (8) amidation of esters (i.e., synthesis of amides from esters and amines); (9) acylation of alcohols using esters; (10) coupling of alcohols with water and a base to form carboxylic acids; and (11) preparation of amino acids or their salts by coupling of amino alcohols with water and a base. (12) preparation of amides (including formamides, cyclic dipeptides, diamide, lactams, polypeptides and polyamides) by dehydrogenative coupling of alcohols and amines; (13) preparation of imides from diols.

This disclosure provides functional templates that direct Pd to functionalize multiple CH bonds in polycyclic aza-arenes such as quinolines and related heterocycles at locations that are difficult to isolate and reach for substitution. Herein disclosed are two conceptually distinct directing templates (T) that enable site-selective C6 and C7-H activation of polycyclic aza-arenes. These catalytic pyridine-based templates recruit the aza-arene substrate through N-coordination, enabling the directing arm to deliver the catalyst and precisely activate remote and adjacent C6 or C7-H bond (FIG. 1d). In parallel, we discovered that the use of a simple and readily prepared template chaperone (TC) can turn over the directing template, allowing it to be used catalytically for the first time. Notably, chiral recognition is vital in the granular discrimination between competing C3 and C7-H bonds when the differentiation via distance and geometry is insufficient. Thus, precise recognition of a directing template's distance, geometry and chirality now enables the iterative CH editing of quinoline and related pharmacophores at any desired site and order. The methods disclosed herein can also be used for diverse and late-stage modification of heterocycle-based drug molecules and pharmacophores.