Synthesis of 2‐oxo‐3‐benzothiazolineacetyl chloride ( 7 ), 5‐chloro‐2‐oxo‐3‐benzothiazolineacetyl chloride ( 8 ) and derivatives

The reaction of 2‐oxo‐3‐benzothiazolineacetic acid ( 5 ) and the 5‐chloro analogue 6 with thionyl chloride afforded the titled compounds 7 and 8 . The reaction of 7 or 8 with substituted hydrazines, amines or substituted anilines, alcohols and mercaptans furnished the hydrazides 9–14 , acetamides and acetanilides 16–21 , esters 26–30 and thiolesters 31–37 , respectively. Alternate routes for the synthesis of hydrazide 15 , acetamides and acetanilides 22–25 and thiolesters 35–36 are described. The reaction of 2‐oxo‐3(2 H )‐benzothi‐azolineacetonitrile with thioacetic acid under acidic conditions afforded 2‐oxo‐3‐benzothiazolineethanethio‐amide (38).