Unsecured loan between two pvt. companies

I agree section 58A will not be applicable however Section 372A is also not aplicable to private limited company

If common directors are interested in the said company then disclosure u/s 299 is required. Further disclosure is required to be made under related party transaction in the balance sheet.

Section 58A will not apply since inter-corporate deposits are excluded from the definition of 'deposits'.  Refer Rule 2(b)(iv) of Companies (Acceptance of Deposits) Rules 1975.