Bittrex lets you wire USD and the minimum is a huge amount of $100,000.
Check this link from Bittrex Support - https://support.bittrex.com/hc/en-us/articles/115001293992-Purchase-USDT-via-Wire-Transfer

"Your wire must be for an amount that is $100,000 USD or greater"

You will be better off looking up at this link for transferring US Dollar to 8 other exchanges - https://steemit.com/bitcoin/@jerrybanfield/8-digital-currency-exchanges-with-usd-to-bitcoin