1706-38-3

Upstream product

• 13788-84-6 3-Methyl-4-phenyl-1H-pyrazole 
• 485-80-3 S-adenosyl-L-methionine 
• 109277-27-2 N'-Eth-(E)-ylidene-N-methyl-N-(2-phenyl-[1,3]dioxolan-2-ylmethyl)-hydrazine 

Relevant academic research and scientific papers

Engineered Enzymes Enable Selective N-Alkylation of Pyrazoles With Simple Haloalkanes

Selective alkylation of pyrazoles could solve a challenge in chemistry and streamline synthesis of important molecules. Here we report catalyst-controlled pyrazole alkylation by a cyclic two-enzyme cascade. In this enzymatic system, a promiscuous enzyme uses haloalkanes as precursors to generate non-natural analogs of the common cosubstrate S-adenosyl-l-methionine. A second engineered enzyme transfers the alkyl group in highly selective C?N bond formations to the pyrazole substrate. The cosubstrate is recycled and only used in catalytic amounts. Key is a computational enzyme-library design tool that converted a promiscuous methyltransferase into a small enzyme family of pyrazole-alkylating enzymes in one round of mutagenesis and screening. With this enzymatic system, pyrazole alkylation (methylation, ethylation, propylation) was achieved with unprecedented regioselectivity (>99 %), regiodivergence, and in a first example on preparative scale.

FORMATION OF PYRAZOLES AND OF IMIDAZOLES FROM PHENACYL KETAL HYDRAZONES OF ALDEHYDES

The cyclization of phenacyl ethylene ketal (pek) hydrazones of glyoxals, benzaldehyde and acetaldehyde to pyrazoles is described; in the case of the hydrazones of benzaldehyde and acetaldehyde, the corresponding imidazoles are also formed.A mechanism is suggested for the formation of the imidazoles.