Process for preparation of hydrazides

摘要

A process for producing a hydrazide of the formula: is disclosed. The process comprises reacting a hydrazone of the formula: wherein said hydrazone is in toluene, with a mixture of Grignard reagents, wherein said Grignard reagents are in a suitable organic solvent; wherein: (A) Z is a suitable carbonyl protecting group; (B) R is a suitable -OH protecting group; (C) R1 is selected from: H, a non-enolizable alkyl, a non-enolizable substituted alkyl, aryl, substituted aryl, -S-aryl, -S-(substituted aryl), -S-alkyl, -S-(substituted alkyl), alkoxy, substituted alkoxy, aryloxy, or substituted aryloxy; (D) said mixture of Grignard reagents comprises R2MgX in admixture with R3MgX; (E) R2 is a suitable alkyl, substituted alkyl, alkenyl, alkynyl, aryl, substituted aryl, or aralkyl group capable of adding to the -C=N group of the hydrazone to produce the hydrazide; (F) R3 is a suitable alkyl, substituted alkyl, aryl or substituted aryl group that is more sterically hindered than said R2 group; (G) X is independently selected from Cl, Br or I for each Grignard reagent; (H) when said hydrazone is a compound of Formula 2.0 then the reaction is conducted at a temperature of about +30 DEG to about -40 DEG C.; and (I) when said hydrazone is a compound of Formula 2.1 then the reaction is conducted at a temperature of about +40 DEG to about -20 DEG C.