Synthesis and Structures of Novel Multi‐armed Molecules Involving Benzene as a Core and 4‐Phenylthiazole, 4‐Pyrazolylthiazole, or Thiadiazole Units as Arms

A synthesis of novel three‐, four‐, and sixfold branched 4‐phenylthiazolylhydrazones, 4‐pyrazolylthiazolyl hydrazones, and thiadiazoles which are linked to a benzene core via phenoxymethyl spacers was reported. The synthetic methodology includes initially formation of poly(aldehyde thiosemicarbazones) 9 , 14 , and 15 by acid catalyzed condensation of thiosemicarbazide ( 8 ) with the appropriate poly(aldehydes) 3 , 5 , and 7 , respectively. Subsequent reaction of 9 , 14 , and 15 with each of 2‐bromo‐1‐phenylethanone ( 10a ) and 2‐bromo‐1‐( 4 ‐chlorophenyl)ethanone ( 10b ) in refluxing ethanol in the presence of few drops of TEA afforded 11 , 16 , and 18 , respectively, in good yields. On the other hand, the synthesis of the novel poly(4,5‐dihydro‐1,3,4‐thiadiazolyl) derivatives 20 , 21a , 21b , and 22 was performed by cyclization of 9b , 14a , 14b , and 15a , respectively, in refluxing acetic anhydride .