HYDROPHILICALLY FUNCTIONALIZED PYRAZOLES FROM SUGARS

An effective and convenient protocol has been developed for the conver sion of D-glucose and 6-O-alpha-D-glucopyranosyl-D-fructose (palatinos e(R), isomaltulose) into -dihydroxyethyl]-1-phenylpyrazole-3-carboxald ehyde (4) and -1-hydroxethyl])-1-phenylpyrazole-3-carboxaldehyde (5), key steps being the acetic anhydride-promoted dehydrative cyclization of the respective phenylosazones, and subsequent liberation of the N-a cetylphenylhydrazone-blocked aldehyde function. Exploitation of the en suing chemistry of 4 and 5 led to a variety of pyrazole building block s with a diverse level of hydrophilic substituents (hydroxymethyl, dih ydroxyethyl or glucosyl residues) and useful functional groups, such a s chloro, cyano, aminomethyl, vinyl and acryloyl moieties. (C) 1998 El sevier Science Ltd. All rights reserved.