The use of activated anthranilic acid derivatives facilitates the preparation of the amides in those cases where the amines are either unreactive or difficult to obtain.<unk>  center: Thus, reaction of (1) with phosgene gives the reactive the isatoic anhydride (2). Condensation of that with ortho-toluidine leads to the acylation product (3) formed with a simultaneous loss of carbon dioxide. This is then converted to the quinazolone (4) by heating with acetic anhydride. Reaction with sodium borohydride in the presence of aluminum chloride selectively reduces the double bond to yield the diuretic agent<unk>  (5). Structure and classification<unk>  is a quinazoline, a derivative of the similar diuretic quinethazone, as well as a sulfonamide. It is related to analogs of 1,2,4-benzothiadizine-1,1-dioxide (benzothiadiazine). Such drugs are called benzothiadiazides, or thiazides for short; however, in terms of chemistry,<unk>  is not a substituted benzothiadiazine, and therefore is not technically a thiazide. Since<unk>  (as well as other drugs like indapamide) acts on the same target as thiazides and behave in a similar pharmacologic fashion, it is, however, considered a "thiazide-like diuretic." Therefore,<unk>  and similar drugs are often categorized with thiazide diuretics despite not being thiazides themselves.
Metolazone
Furosemide
Spironolactone
Paricalcitol
Geritol
Chlorzoxazone
Chlorothiazide
Canrenone