Bromine → 4-Methylphthalic anhydride

HRID 638016Notes

Reaction equation

HRID 638016 reaction equation
[CH3:1][C:2]1[CH2:3][CH:4]2[C:9](=[O:10])[O:8][C:6](=[O:7])[CH:5]2[CH2:11][CH:12]=1.[S].BrBr>C(O)(=O)C>[CH3:1][C:2]1[CH:3]=[C:4]2[C:9](=[O:10])[O:8][C:6](=[O:7])[C:5]2=[CH:11][CH:12]=1

Participants

5

Reactant 3

HCID 24408BromineHCID 984963a,4,7,7a-Tetrahydro-5-methyl-1,3-isobenzofurandioneHCID 5362487Sulfur

Product 1

HCID 880694-Methylphthalic anhydrideYield 16%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

Various processes are known for preparing substituted phthalic anhydrides. In two such processes 4-methyl-1,2,3,6-tetrahydrophthalic anhydride is dehydrogenated either by sulfur or by bromine in acetic acid. Yields of 4-methylphthalic anhydride of 59%-87% are claimed for the former method, while the latter gives only a 16% yield [see IZV. Akad Nauk SSSR, Ser Khim, 6, 1315(1973) English trans. Pg. 1271 and D. Craig, Journal of Am. Chem. Soc., Vol. 72, Pg. 3732 (1950)].

Sources & evidence

ORD record
ord-8043c9a711cc4fb590b64ee7b611348a
Source dataset
uspto-grants-1985_12
Patent number
US04559405

Reaction notes

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