declare @t table (id integer identity, txt varchar(100))

insert into @t (txt) values
('1ABCD'),
('1AC'),
('1ACE'),
('2A'),
('2AC')

select 
	txt = vals.n + left(repl.s, len(repl.s) - 2)
from @t AS t
cross apply(values(left(txt, 1), right(txt, len(txt) -1))) AS vals(n, s)
cross apply(values(convert(varchar(200), convert(varbinary(200), convert(nvarchar(100), vals.s))))) AS bin(s) 
cross apply(values(replace(bin.s collate latin1_general_bin, char(0x00), ',' + vals.n))) AS repl(s)