ChemicalBook CAS DataBase List 3-Isochromanone

3-Isochromanone synthesis

13synthesis methods

Product Name:3-Isochromanone
CAS Number:4385-35-7
Molecular formula:C9H8O2
Molecular Weight:148.16

o-Tolylacetic acid (50g at 98% strength, 0.326 mol) in fluorobenzene (76.7g) was dried by azeotropic distillation and cooled to 60°C. AIBN (2.13g, 0.013 mol) was added in one portion, followed by sulphuryl chloride (49.8g at 97% strength, 0.358 mol) over 3 hours while maintaining the temperature at 60-62°C. A small sample was removed from the mixture, diluted with more solvent, and analyzed by GC. This showed the presence of 10% o-tolylacetic acid starting material. A 20% aqueous solution of potassium bicarbonate (60.6g, 0.121 mol) was added slowly to the reaction mixture, followed by potassium iodide (0.22g) and then, slowly, by solid potassium bicarbonate (20.95g, 0.209 mol). Stirring was continued for 1 hour at 60°C. Further solid potassium bicarbonate (7.9g) was added at 60°C, and stirring continued for another 15 minutes. The reaction mixture was left to stand and cool to ambient temperature overnight under nitrogen. It was then warmed to 65°C, separating the aqueous and organic layers. The organic layer was diluted with fluorobenzene (50 ml), used to wash the separator, and dried by azeotropic distillation. The product precipitated on cooling after cyclohexane was added slowly at 60-65°C. The temperature was reduced to around 5°C, and the solids were filtered and sucked dry to give 27.18g (100% wt) 3-isochromanone; 56.3% yield; mp 79-80°C.

91-13-4
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4385-35-7
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$6.00/5g

Yield:4385-35-7 95.1%

Reaction Conditions:

in tert-butyl alcohol

Steps:

8 EXAMPLE 8
EXAMPLE 8 The procedure of Example 6 was repeated, except for replacing α,α'-o-xylene dichloride with 13.2 g (0.05 mol) of α,α'-o-xylene dibromide and replacing butyl alcohol with 20 g of t-butyl alcohol. As a result, 2.9 g (yield: 39.2%) of 3-isochromanone was obtained. The purity of the product was 95.1% as measured by gas chromatographic analysis.

References:

Sagami Chemical Research Center;Iharanikkei Chemical Industry Co., Ltd US5886211, 1999, A