Under the Internal Revenue Code a federal tax lien is not valid against a purchaser or lienor until notice of the lien is recorded. 26 US.C.A., §6323(a), (f) and (g). There is protection for, among other matters, local taxes even if notice is recorded,. See 26 USC.A, §6323(e). Also protected are mechanics' liens (up to a dollar amount and depending on the type of property involved) and loan disbursements made by a mortgagee within 45 days of the recording of the lien (or pursuant to an obligatory disbursement obligation).