Drop Column Problem

Hello,

I'm just returning to MS SQL Server after two years of dealing with
Sybase ASE. I need to drop a column, using the alter table command.
I keep getting an error indicating that a constraint is using the
column. Here is the create script for the table
create table mytable
(col1 char(1) not null,
col2 char(1) default 'A' not null
)

Here is the alter table command:
alter table mytable drop column col2

When I run it I get the following error:
Server: Msg 5074, Level 16, State 1, Line 1
The object 'DF__mytable__col2__114A936A' is dependent on column
'col2'.
Server: Msg 4922, Level 16, State 1, Line 1
ALTER TABLE DROP COLUMN col2 failed because one or more objects access
this column.

Is there anyway to tell the database to drop all column constraints
when the column is deleted?

Thanks,

James K.