In the Organic Syntheses preparation of azulene (http://www.orgsyn.org/demo.aspx?prep=CV7P0015) there are two reactions. First is a clevage of the C-N bond in pyridine and the second one is the annelation of a seven-memebered ring:
I suppose that the first step of the first reaction is a nucleophilic substitution by pyridine at the 1-chloro-2,4-dinitrobenzene, but I have no idea how the mechanism could continue. Could some one please help me? Thank you.
Also, for the 2nd reaction, is it an electrophilic substitution at the cyclopentadieneyl anion, or does it have an entirely different mechanism?