[Iska]

Код:

@echo off
setlocal enableextensions enabledelayedexpansion

for /f "usebackq delims=" %%i in (
	`dir /b /s /a:-d "E:\Песочница\0356\*.txt"`
) do (
	ren "%%~i" "%%~dpni.doc"
)

endlocal
exit /b 0