Carbon Dioxide → 1,2-Benzisothiazole-3-carboxylic acid

HRID 449992Notes

Reaction equation

HRID 449992 reaction equation
[NH2:1][C:2]1[S:3][C:4]2[CH:10]=[CH:9][CH:8]=[C:7](Cl)[C:5]=2[N:6]=1.N(OCCC(C)C)=O.[C:20](=[O:22])=[O:21].Cl[C:24]1[CH:32]=[CH:31][C:27]([C:28]([OH:30])=[O:29])=[CH:26][C:25]=1[N+:33]([O-])=O.[OH-].[Na+].[C:38]1([SH:44])[CH:43]=[CH:42][CH:41]=[CH:40][CH:39]=1.C(Cl)(=O)C(Cl)=O.[Cl-].[Al+3].[Cl-].[Cl-].NO.OO>C(O)=O.[Zn]>[S:3]1[C:4]2=[CH:10][CH:9]=[CH:8][C:7]([C:20]([OH:22])=[O:21])=[C:5]2[N:6]=[CH:2]1.[S:44]1[C:24]2[CH:32]=[CH:31][C:27]([C:28]([OH:30])=[O:29])=[CH:26][C:25]=2[N:33]=[CH:38]1.[S:44]1[C:38]2[CH:43]=[CH:42][CH:41]=[CH:40][C:39]=2[C:2]([C:20]([OH:22])=[O:21])=[N:1]1

Participants

15

Reactant 10

HCID 280Carbon DioxideHCID 784Hydrogen PeroxideHCID 787HydroxylamineHCID 73204-Chloro-3-nitrobenzoic acidHCID 7969ThiophenolHCID 8053Isoamyl NitriteHCID 14798Sodium Hydroxide2×HCID 298722-Benzothiazolamine, 4-chloro-HCID 65578Oxalyl chlorideHCID 6451240Aluminum(III) Chloride

Product 3

HCID 945121,2-Benzisothiazole-3-carboxylic acidHCID 27354601,3-Benzothiazole-5-carboxylic acidHCID 203985481,3-Benzothiazole-4-carboxylic acid

Reagents, catalysts & solvents 2

HCID 23994ZincCatalystHCID 284Formic AcidSolvent

Procedure

The benzisoxazole-, benzisoxazole-, and benzothiazolecarboxylic acids were prepared using similar strategies outlined for the indazole acids. For example, ethyl 6-bromobenzisoxazole-3-carboxylate was prepared from 2,5-dibromonitrobenzene by reaction with diethyl malonate, saponification and decarboxylation, and reaction with isoamylnitrite. Ethyl benzisoxazole-3-carboxylate was obtained by hydrogenolysis of the 6-bromo derivative. 4-Benzothiazolecarboxylic acid was prepared from 2-amino-4-chloro-benzothiazole by reaction with isoamyl nitrite followed by metal-halogen exchange and trapping with carbon dioxide. 5-Benzothiazolecarboxylic acid was prepared from 4-chloro-3-nitrobenzoic acid by reaction with Na2S and sodium hydroxide followed by reduction with zinc in formic acid. 3-Benzisothiazolecarboxylic acid was prepared from thiophenol by reaction with oxalyl chloride and aluminum chloride followed by treatment with hydroxylamine, hydrogen peroxide, and sodium hydroxide.

Sources & evidence

ORD record
ord-2d79172671204d0cb7d2bb9800e043fe
Source dataset
uspto-grants-2013_07
Patent number
US08486937B2

Reaction notes

Loading…