Kinetics and mechanism of cyclization of N-(2-methoxycarbonylphenyl)-N’-methylsulphonamide to 3-methyl-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide
1991 ◽
Vol 56
(8)
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pp. 1701-1710
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Keyword(s):
The cyclization kinetics of N-(2-methylcarbonylphenyl)-N’-methylsulfonamide (IIb) into 3-methyl-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide (Ib) has been studied in ethanolamine, morpholine, and butylamine buffers and in potassium hydroxide solution. The cyclization is subject to general base and general acid catalysis. The value of the Bronsted coefficient β is about 0.1, which indicates that splitting off of the proton from negatively charged tetrahedral intermediate represents the rate-limiting and thermodynamically favourable step. In the solutions of potassium hydroxide the cyclization of dianion of the starting ester IIb probably becomes the rate-limiting step.
1992 ◽
Vol 57
(6)
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pp. 1282-1290
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1979 ◽
Vol 44
(3)
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pp. 912-917
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1988 ◽
Vol 53
(12)
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pp. 3154-3163
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Keyword(s):
1996 ◽
Vol 61
(6)
◽
pp. 951-956
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Keyword(s):
1997 ◽
Vol 62
(9)
◽
pp. 1429-1445
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Keyword(s):
1998 ◽
Vol 62
(23-24)
◽
pp. 3789-3790
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Keyword(s):
1997 ◽
Vol 61
(18)
◽
pp. 3897-3904
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Keyword(s):
1989 ◽
Vol 164
(Part_2)
◽
pp. 1121-1122
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1990 ◽
Vol 55
(6)
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pp. 1535-1540
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Keyword(s):