Sulfonamides can be prepared in the laboratory in many ways. The classic approach entails the reaction of sulfonyl chlorides with an amine.  
A base such as pyridine is typically added to absorb the HCl that is generated. Illustrative is the synthesis of sulfonylmethylamide. 
The reaction of primary and secondary amines with benzenesulfonyl chloride is the basis of the Hinsberg reaction, a method for detecting primary and secondary amines.
Sulfonamides undergo a variety of acid-base reactions.  The N-H bond can be deprotonated.  The alkylsulfonamides can be deprotonated at carbon.  Arylsulfonamides undergo ortho-lithiation.