I've synned this before by going into the brand sections of the syns online - it usually works out between 16 & 18 syns per 400ml tin if you get the reduced fat type i.e. Asda own brand one or the Blue dragon make
I used blue dragon and decided to count it as 3 syns per serving. was really delicious. Used half a can to make soup and the other half to make a thai curry. Yummy!