Submitted on: 16 February 1999.
Revised on: 23 May 1999.
Accepted on: 05 June 1999.
___________________BIOORGANIC & MEDICINAL CHEMISTRY LETTERS
http://reply.papertrans.cn/1/38/3718/3718-22.png
http://reply.papertrans.cn/1/38/3718/3718-23.png
http://reply.papertrans.cn/1/38/3718/3718-24.png
http://reply.papertrans.cn/1/38/3718/3718-25.png
http://reply.papertrans.cn/1/38/3718/3718-26.png
http://reply.papertrans.cn/1/38/3718/3718-27.png
http://reply.papertrans.cn/1/38/3718/3718-28.png
Submitted on: 12 December 2012.
Revised on: 10 March 2013.
Accepted on: 08 April 2013.
___________________BIOORGANIC & MEDICINAL CHEMISTRY LETTERS
http://reply.papertrans.cn/1/38/3718/3718-30.png