Try this... (if you are in Windows)...
set assetname="testasset3"
multichain-cli chain2 issue 1GENUQPhHVLVU8foNZJJQ9BL9rP5e2cztVKUHj "{\"name\":%assetname%, "open":true}" 0 1
{"method":"issue","params":["1GENUQPhHVLVU8foNZJJQ9BL9rP5e2cztVKUHj","{\"name\":
testasset3,open:true}",0,1],"id":1,"chain_name":"chain2"}
52ceab12fa292e211a43625bb04c0d58bce7de9a961a54eb1f4106ff131637e5