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Several routes to bisulfite adduct 2 were explored, the most efficient of which involved vinyl Grignard addition to 2-indanone followed by ozonolysis and workup with aqueous NaHSO 3 to effect reduction and bisulfite formation in a single pot. The safety and calorimetry of this ozonolysis reaction was studied, and the safe scale-up to 3 kg of olefin is described. The utility of bisulfite adduct 2 as an aldehyde surrogate in a reductive amination reaction is also described.

The multihundred-gram synthesis of [2-(3-methyl-3H-imidazol-4-yl)-thieno[3,2-b]pyridin-7-yl]-(2-methyl-1H-indol-5-yl)-amine (1) is described utilizing a Stille cross-coupling of an iodothienopyridine (3) with 5-(tributylstannyl)-1-methylimidazole (11). Several cross-coupling methods were evaluated for the conversion of thienopyridine 3 to imidazole-thienopyridine 2, but only two were effective: the Stille coupling and a Negishi cross-coupling of the organozinc reagent derived from 2-(tertbutyldimethylsilyl)-1-methylimidazole and iodothienopyridine (3). The latter procedure worked well on laboratory scale (<50 g), but was capricious upon scale-up. The issues with scale-up of an organostannane reagent are discussed, including control and analysis of organotin levels.

A practical synthesis of SGLT2 inhibitor candidate ertugliflozin (1) has been developed for potential commercial application. The highly telescoped process involves only three intermediate isolations over a 12-step sequence. The dioxabicyclo[3.2.1]octane motif is prepared from commercially available 2,3,4,6-tetra-O-benzyl-D-glucose, with nucleophilic hydroxymethylation of a 5-ketogluconamide intermediate as a key step. The aglycone moiety is introduced via aryl anion addition to a methylpiperazine amide. High chemical purity of the API is assured through isolation of the crystalline penultimate intermediate, tetraacetate 39. A cocrystalline complex of the amorphous solid 1 with L-pyroglutamic acid has been prepared in order to improve the physical properties for manufacture and to ensure robust API quality.