Longterm capital gains on property

No, invest made  in shares can't be claimed as exemption. You can invest in New Res House Prop within 3 or 2 yrs of sale( 3 in case of construction of new Res HP or 2 in case of Purchase) u/s 54......but for that you need to keep the investment likely to be made in an A/c under Capital gains A/c Scheme,1988.And such Amt need to be deposited in the separate account before due date of furnishing of Return of Assessment year (relevant to FY of the sale). But the sepoarately kept Amt can be used for investment witin 3or 2  yrs of sale.

Exemption- Sum invested in purchasing or ci=onstructing New RHP.