14 Benzothiadiazine 1,1-Dioxides
A CuI/DMEDA-catalyzed intramolecular coupling of N-unprotective amidines 181
has been used for assembling 1,2,4-Benzothiadiazine 1,1-dioxides 182, another
important class of heterocycles for pharmaceutical design (Scheme 63) [108].
Because the preparation of the amidines 181 could be achieved via a CuI-catalyzed
three-component reaction of 1-alkynes, ammonium salts and aryl sulfonyl azides,
a more efficient one-pot sequential process has been developed for the synthesis
of 182 from these reagents.
The Fu group developed another efficient cascade process for synthesizing
substituted 1,2,4-benzothiadiazine 1,1-dioxides 184, in which the coupling of
2-halobenzensulfonamides 183 and amidines 172 was employed as the key step
(Scheme 64) [110].
Using a microwave-assisted sequential one-pot N-arylation/condensative cyclization process, Hanson and Rolf developed a facile method for preparing
benzothiadiazin-3-one-1,1-dioxides 186 from sulfonamides 185 (Scheme 65) [109].
Scheme 63 CuI-catalyzed three-component reaction for assembling 1,2,4-benzothiadiazine
1,1-dioxides
Scheme 64 CuBr-catalyzed synthesis of 1,2,4-benzothiadiazine 1,1-dioxides from 2-halobenzensulfonamides and amidines
Scheme 62 Synthesis of 2,3-substituted quinzolinones via CuI-catalyzed coupling of
2-iodobenzobenzamides and amidine
112
Y. Jiang and D. Ma
A CuI/DMEDA-catalyzed intramolecular coupling of N-unprotective amidines 181
has been used for assembling 1,2,4-Benzothiadiazine 1,1-dioxides 182, another
important class of heterocycles for pharmaceutical design (Scheme 63) [108].
Because the preparation of the amidines 181 could be achieved via a CuI-catalyzed
three-component reaction of 1-alkynes, ammonium salts and aryl sulfonyl azides,
a more efficient one-pot sequential process has been developed for the synthesis
of 182 from these reagents.
The Fu group developed another efficient cascade process for synthesizing
substituted 1,2,4-benzothiadiazine 1,1-dioxides 184, in which the coupling of
2-halobenzensulfonamides 183 and amidines 172 was employed as the key step
(Scheme 64) [110].
Using a microwave-assisted sequential one-pot N-arylation/condensative cyclization process, Hanson and Rolf developed a facile method for preparing
benzothiadiazin-3-one-1,1-dioxides 186 from sulfonamides 185 (Scheme 65) [109].
Scheme 63 CuI-catalyzed three-component reaction for assembling 1,2,4-benzothiadiazine
1,1-dioxides
Scheme 64 CuBr-catalyzed synthesis of 1,2,4-benzothiadiazine 1,1-dioxides from 2-halobenzensulfonamides and amidines
Scheme 62 Synthesis of 2,3-substituted quinzolinones via CuI-catalyzed coupling of
2-iodobenzobenzamides and amidine
112
Y. Jiang and D. Ma