(a) `(A rarr B)`, (i) `SOCl_2 (COOH rArr COCl)` , (ii) `LiAlH(o-t-Bu)_3, (COCl rArr CHO, (C=O)` group does not change)
`(A rarr C)` , (i) `Zn-Hg//HCl` (Clemmensen red) or Wolff `(NH_2 NH_2// overset (Ө) (OH)), (C= O) rArr CH_2`
(ii) `SOCl_2 (COOH rArr COCl)`
(ii) `LiAlH(o-t-Bu)_3, COCl rArr CHO`
`(A rarr D)` (i) `NaBH_4, C = O rArr CHOH, (COOH)` does not change.
`(A rarr E)`, (i) `LAH,C = O rArr CHOH` and also `(COOH) rArr CH_2 OH`
(b) Step-down method from `6C` in `(A)` to `3 C` in `(B). (A rarr B)`,
`(A rarr C)`, Step-up method from `6 C` in `(A)` to `7 C` in `(B)` .
(i) `LAH (COOH rArr CH_2 OH)`
(ii) `SOCl_2 (CH_2 OH rArr CH_2 Cl)`
(iii) Carbonation `(Mg, CO_2//H_3 overset (oplus) O), CH_2 Cl rArr CH_2 COOH`
(iv) `LAH(CH_2 COOH rArr CH_2 CH_2 OH)`.
(c) Formation of `( C)` is by Friedel-Crafts acylation.
(d)
( e) (i)
(ii)
(iii)
(iv)
(f) The double bond `(C=C)` is converted to alcoho by anti-Markovnikov addition with `B_2 H_6//THF`, but is also reacts with `(COOH)` group. so first prortects `(COOH)` group by benzylation method.
