Tetrahydro-4H-pyrido[1,2-a]pyrimidines and related compounds of Formula A: are described as inhibitors of HIV integrase and inhibitors of HIV replication, wherein n is an integer equal to zero, 1, 2 or 3, and R1, R3, R4, R12, R14, R16, R30, R32, R34 and R36 are defined herein. These compounds are useful in the prevention and treatment of infection by HIV and in the prevention, delay in the onset, and treatment of AIDS. The compounds are employed against HIV infection and AIDS as compounds per se or in the form of pharmaceutically acceptable salts. The compounds and their salts can be employed as ingredients in pharmaceutical compositions, optionally in combination with other antivirals, immunomodulators, antibiotics or vaccines.