This manuscript details the process research and development of a convergent and safe approach to 1 on a multikilo scale. Specific highlights of the process development efforts will be described, including the development of a dehydrogenation method for dihydropyrimidines and a thermochemically safe synthesis of a 1,2,4-aminotriazole fragment. A key feature of the synthesis is the use and optimization of a modified Julia-Kocienski olefination reaction. Specifically, we report an unprecedented dependence of the product olefin geometry on reaction temperature, where an E:Z ratio as high as 200:1 can be obtained. Initial insights into the mechanistic rationale for this observation are also provided. Finally, a purity upgrade sequence via an intermediate crystalline form is highlighted as a method of controlling the final API quality.

The development of a reproducible process for multihundred gram production of (Z)-5-((1-(4-chloro-2-(trifluoromethyl)benzyl)-1H-indazol-5-yl)methylene)-3-((3R,4R)-3-fluoro-1-methylpiperidin-4-yl)thiazolidine-2,4-dione (26), a potent and selective inhibitor of estrogen-related receptor 1 (ERR1), is described. This multihundred gram synthesis was achieved via magnesium perchlorate-catalyzed regioselective epoxide ring-opening of tert-butyl 7-oxa-3-azabicyclo[4.1.0]heptane-3-carboxylate (9) with thiazolidine-2,4-dione (6, TZD) to form a diastereomeric mixture tert-butyl 4-(2,4-dioxothiazolidin-3-yl)-3-hydroxypiperidine-1-carboxylate (17), of which the 3-hydroxyl group was functionally transformed to 3-fluoro derivative 19 after treatment with Deoxo-Fluor. Chiral separation of 19 provided the desired diastereomer (3R,4R)-21 that was converted to the secondary amine 23 TFA salt. Reductive amination of 23 produced the key intermediate N-methyl 24. Knoevenagel condensation of 24 with 1-(4-chloro-2-(trifluoromethyl)benzyl)-1H-indazole-5-carbaldehyde (5) produced the final product 26 in 10% overall yield (99.7% HPLC area% with ≥99.5% de) after a convergent eight synthetic steps with the only column purification being the chiral HPLC separation of 3R,4R-21 from 3S,4S-22.

No abstract

The process development of Mavatrep, a potent Transient Receptor Potential Vanilloid-1(TRPV1) antagonist 1 is described. The two key synthetic transformations are the synthesis of the (E)-6-bromo-2-(4-(trifluoromethyl)styryl)1H-benzo[d]imidazole (4) and the Suzuki coupling of 4 with 3,3-dimethyl-3H-benzo[c][1,2]oxaborol-1-ol (5). Compound 1a was prepared in 4 chemical steps in 63% overall yield.

No abstract