Kayak brings it up for $331 if you search BKK to JFK:

http://www.kayak.com/#/flights/bkk-JFK/2013-04-18

What's interesting is that BKK>JFK is a cheaper itinerary than BKK>KBP so if you wanted to travel BKK>KBP you are better of booking BKK>JFK and throwing away the last leg.