The discovery and development of novel inhibitors with activity against variants of human immunodeficiency virus type 1 (HIV-1) is pivotal for overcoming treatment failure. As our ongoing work on research of anti-HIV-1 inhibitors, 32 N-arylsulfonyl-3-acylindole benzoyl hydrazone derivatives were prepared by introduction of the hydrazone fragments on the N-arylsulfonyl-3-acylindolyl skeleton and preliminarily screened in vitro as HIV-1 inhibitors for the first time. Among of all the reported analogues, eight compounds exhibited significant anti-HIV-1 activity, especially N-(3-nitro)phenylsulfonyl-3-acetylindole benzoyl hydrazone (18) and N-(3-nitro)phenylsulfonyl-3-acetyl-6-methylindole benzoyl hydrazone (23) displayed the most potent anti-HIV-1 activity with EC50 values of 0.26 and 0.31 μg/mL, and TI values of >769.23 and >645.16, respectively. It is noteworthy that introduction of R3 as the methyl group and R2 as the hydrogen group could result in more potent compounds. This suggested that introduction of R3 as the methyl group could be taken into account for further preparation of these kinds of compounds as anti-HIV-1 agents.

As our ongoing work on research of anti-HIV-1 inhibitors, fifteen N-arylsulfonyl-3-formylindoles (3a-o) were designed and prepared through two step synthetic route. Firstly, 3-formylindoles (2a-c) were synthesized via the Vilsmeier-Haack reaction. Subsequently, treatment of 2a-c with the appropriate arylsulfonyl chlorides led to the corresponding target compounds in excellent yields. All analogues were also preliminary evaluated in vitro for their inhibitory activity against HIV-1 replication. Among of all the reported analogues, three compounds 3c, 3g and 3i displayed significant anti-HIV-1 activity, with EC50 values of 9.57, 11.04 and 5.02 μM, and TI values of 31.89, 13.79 and 81.69, respectively. N-m-nitrophenylsulfonyl-3-formylindole (3c) and N-m-nitrophenylsulfonyl-6-methyl-3-formylindole (3i) especially exhibited the best promising anti-HIV-1 activity. In addition, it demonstrated that insertion of a methyl group at the C-6 position of the indolyl ring and a nitro group at the meta position of the arylsulfonyl ring, as in compound 3i, resulted in both low cytotoxicity (CC50= 410.41 μM) and good antiviral activity.