Question
An organic compound P having molecular formula C _6 H _6 O _3 gives ferric chloride test and does not have intramolecular hydrogen bond. The compound P reacts with 3 equivalents of NH _2 OH to produce oxime Q . Treatment of P with excess methyl iodide in the presence of KOH produces compound R as the major product. Reaction of R with excess iso-butylmagnesium bromide followed by treatment with H _3 O ^ + gives compound S as the major product. The total number of methyl (- CH _3 ) group(s) in compound S is ________. (consider maximum value if there are two values)