The pyridine N-oxide, compound A, is a new drug claimed to be useful for the treatment of senile dementia. Industrial synthesis of it is outlined below.

i) Suggest a mechanism to account for Step 1 in the sequence.

ii) Suggest a mechanism to account for Step 2 in the sequence. 

iii) Suggest a mechanism to account for Step 4 in the sequence. 

iv) The oxidant used in Step 3 is the peroxy acid shown below. Why is hydrogen peroxide in acetic acid, the usual reagent for converting a pyridine into an N-oxide, not a good choice for the transformation shown in Step 3?

CI CN CN CN POCI3 OEt heat H2N Step 1 Step 2 oxidant Step 3 S. S. CI CN CN H Step 4 Compound A ZI