The standard for a DIN input was ground to pin 2, the centre on, and unbalanced audio to pin 3. DINs were bi-directional so the same socket on the recorder might have had an output on pin 1! Custom made DIN leads were always a nightmare because 50% would be wired the wrong way and you just had to plug them in to see if they worked! Pins 4 and 5 were added for stereo, and for mics, unused.
You just need to buy a 3.5mm plug and an inline DIN (3 or 5 pin) DIN pin 2 goes to sleeve, DIN pin 3 goes to tip (and ring if you want it to go to both channels) I don't think I have ever seen an adaptor as they're eras apart.