Add Json alertmanger is error

Hello,
i have add config json to alertmanager.yml. but it error. please help to check.
Thanks.
webhook_configs:
- url: ‘http://10.199.xxx.xxx:xxxx/sms-services/api/v1/messaging/sms’
send_resolved: true
{
receiver: ‘webhook’,
status: ‘firing’,
“alerts”: [
{
“status”: “firing”,
“labels”: {
“alertname”: “Test”,
“dc”: “eu-west-1”,
“instance”: “localhost:9090”,
“job”: “prometheus24”
},
“annotations”: {
“description”: “some description”
},
“startsAt”: “2018-08-03T09:52:26.739266876+02:00”,
“endsAt”: “0001-01-01T00:00:00Z”,
“generatorURL”: “http://simon-laptop:9090/graph?g0.expr=go_memstats_alloc_bytes+>+0\u0026g0.tab=1
}
log inform row receiver: ‘webhook’,
line 18: could not find expected ‘:’"