Patent ID: 6887976

Claim:
A process for preparing a compound of the formula: or a salt thereof; wherein R 20 is â€”R a â€”Yâ€”R b -(Z) x or â€”R f ; Y is selected from the group consisting of oxygen, sulfur, â€”Sâ€”Sâ€”, â€”NR c â€”, â€”S(O)â€”, â€”SO 2 â€”, â€”NR c C(O)â€”, â€”OSO 2 â€”, â€”OC(O)â€”, â€”NR c SO 2 â€”, â€”C(O)NR c â€”, â€”C(O)Oâ€”, â€”SO 2 NR c â€”, â€”SO 2 Oâ€”, â€”P(O)(OR c )Oâ€”, â€”P(O)(OR c )NR c â€”, â€”OP(O)(OR c )Oâ€”, â€”OP(O)(OR c )NR c â€”, â€”OC(O)Oâ€”, â€”NR c C(O)Oâ€”, â€”NR c C(O)NR c â€”, â€”OC(O)NR c â€”, â€”C(â•O)â€” and â€”NR c SO 2 NR c â€”; each Z is independently selected from hydrogen, aryl, cycloalkyl, cycloalkenyl, heteroaryl and heterocyclic; each R a is independently selected from the group consisting of alkylene, substituted alkylene, alkenylene, substituted alkenylene, alkynylene and substituted alkynylenc; each R b is independently selected from the group consisting of a covalent bond, alkylene, substituted alkylene, alkenylene, substituted allenylene, alkynylene and substituted alkynylene, provided R b is not a covalent bond when Z is hydrogen; each R c is independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl, heteroaryl, heterocyclic and â€”C(O)R d ; each R d is independently selected from the group consisting of alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl, heteroaryl and heterocyclic; R f is selected from the group consisting of alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl, heteroaryl and heterocyclic; and x is 1 or 2; the process comprising reacting a compound of the formula: or a salt thereof, with formaldehyde and H 2 Nâ€”R a â€”P(O)(OH) 2 under basic conditions.