Dorohai is indeed within the district of Botosani, where my great grandfather is from.
I just visited 313 and 319 Roberts St. It is in the Hill District and pretty run down. The Sigal's lived here, David owned the building (313 through 319 are all one building). MY great grandfather was at 123 Denniston Ave which I haven't found yet. I think it is close by to Roberts, not the Denniston in Squirrel Hill that I thought originally.
In the 1903 pgh directory David Sigal owned the Acme Soda Water Co.
If anyone has more info about this family I would love to hear from you!
Jill