import json
data = json.loads('''{
"profiles":[{
"id": 123123,
"first_name": "Vasya",
"last_name": "Pupkin"
},{
"id": 345345,
"first_name": "Sasha",
"last_name": "Oreshkin"
},{
"id": 678900,
"first_name": "Pasha",
"last_name": "Markin"
}]
}''')
res = [p['first_name'] for p in data['profiles']]
print(res)
aW1wb3J0IGpzb24KCmRhdGEgPSBqc29uLmxvYWRzKCcnJ3sKICAicHJvZmlsZXMiOlt7CiAgICAiaWQiOiAxMjMxMjMsCiAgICAiZmlyc3RfbmFtZSI6ICJWYXN5YSIsCiAgICAibGFzdF9uYW1lIjogIlB1cGtpbiIKICB9LHsKICAgICJpZCI6IDM0NTM0NSwKICAgICJmaXJzdF9uYW1lIjogIlNhc2hhIiwKICAgICJsYXN0X25hbWUiOiAiT3Jlc2hraW4iCiAgfSx7CiAgICAiaWQiOiA2Nzg5MDAsCiAgICAiZmlyc3RfbmFtZSI6ICJQYXNoYSIsCiAgICAibGFzdF9uYW1lIjogIk1hcmtpbiIKICB9XQp9JycnKQoKcmVzID0gW3BbJ2ZpcnN0X25hbWUnXSBmb3IgcCBpbiBkYXRhWydwcm9maWxlcyddXQoKcHJpbnQocmVzKQ==