CF-Cyclobutanes: Synthesis, Properties, and Evaluation as a Unique -Butyl Group Analogue.

Isosteric replacement of functional groups is an emerging strategy for optimizing bioactive molecules in drug discovery. -Butyl group is a particularly important moiety, yet its isosteric replacement with 1-trifluoromethyl-cyclobutyl group has been rather neglected. To enable the advance of this molecular fragment in drug discovery programs, we report the synthesis of over 30 small-molecule building blocks featuring the trifluoromethyl-cyclobutyl fragment, achieved by reacting sulfur tetrafluoride with cyclobutylcarboxylic acids on a gram-to-multigram scale.

Aza-Heterocyclic Building Blocks with In-Ring CF -Fragment.

Modern organic chemistry is a titan supporting and reinforcing pharmaceutical, agricultural, food and material science products. Over the past decades, the organic compounds market has been evolving to meet all the research demands. In this regard, medicinal chemistry is especially dependent on available chemical space as subtle tuning of the molecule structure is required to create a drug with relevant physicochemical properties and a remarkable activity profile.

General and Scalable Approach to Trifluoromethyl-Substituted Cyclopropanes.

CF-cyclopropanes with aliphatic, aromatic, and even heteroaromatic substituents were prepared on a multigram scale by deoxyfluorination of cyclopropane carboxylic acids or their salts with sulfur tetrafluoride. For labile α-pyridine acetic acids, only the use of their potassium salts allowed to obtain the needed products. Derivatization of CF-cyclopropanes into building blocks ready for direct use in medicinal chemistry was performed.

Scalable Approach to Fluorinated Heterocycles with Sulfur Tetrafluoride (SF).

A general approach to fluorinated (hetero)aromatic derivatives is elaborated. The key reaction is a deoxofluorination of substituted acetophenones with sulfur tetrafluoride (SF). In contrast to previous deoxofluorination methods, this transformation is fast, scalable (up to 70 g), and high-yielding.

Deoxofluorination of (Hetero)aromatic Acids.

Diverse trifluoromethyl-substituted compounds were synthesized by deoxofluorination of cinnamic and (hetero)aromatic carboxylic acids with sulfur tetrafluoride. The obtained products were used as starting materials in the preparation of novel fluorinated amino acids, anilines, and aliphatic amines - valuable building blocks for medicinal chemistry and agrochemistry.