No. Business extensions can only be e-filed through tax preparation software for accountants (like ProSeries and Lacerte).
March 15
was the tax deadline for S-Corp and Partnership extensions and
elections. You may be charged a late filing penalty and possible an
underpayment penalty.
I recommend you file your 7004 right away. You will have to print it and mail it in:
TurboTax Business Extensions is also available in the iPhone App store
-- Just search for "TurboTax Business Extensions" in the iPhone app
store. Complete and e-file your federal extension in minutes. Pay your
tax due electronically. [Currently available for calendar year taxpayers
only.]