First attempted cryopreservation was 4/66 by Ted Kraver/Cryocare. My articles have been deplatformed by Network54 and rehosted on Tapatalk but I don't have the links reset yet. Here are the original titles.

Cryonaut 2004: Ted Kraver, Cryocare engineer in 1966, says first intended cryonics preservation was 4/66
http://www.network54.com/Forum/72392/message/1095122359/Ted+Kraver%2C+Cryocare+engineer+in+1966%2C+says+first+intended+cryonics+preservation+was+4-66

Cryonaut 2004: PROOF THAT THE 4/66 FAT FROZEN WOMAN WAS MOTIVATED BY CRYONICS
http://www.network54.com/Forum/72392/message/1085547314/PROOF+THAT+THE+4-66+FAT+FROZEN+WOMAN+WAS+MOTIVATED+BY+CRYONICS