Simple and Economical Process for Producing Amantadine Hydrochloride.

A simple and economical process for producing amantadine hydrochloride (1) on a 250 g scale, an antiviral and anti-Parkinson drug, has been developed. Several methods for the preparation of 1 through intermediate N-(1-adamantyl)-acetamide (4) in four or three steps were reported. These procedures started with adamantine (2) or 1-bromoadamantane (3), acetonitrile, and sulfuric acid by using the Ritter-type reaction to obtain N-(1-adamantyl)-acetamide, which was deacetylated to afford 1-amino-adamantane (5) and then the salt formed with anhydrous HCl gives 1 with the overall yield of 1 being 50-58%. In this article, a two-step procedure for the synthesis of 1 from 1-bromadamantane (3) and formamide via N-(1-adamantyl)-formamide (6) in two steps with an overall yield of 88% was reported. In this procedure, the preparation of 6 from 3 is a key step with a yield of 94%, followed by the hydrolysis of 6 with an aq. solution of HCl to give 1 in high yield (93%). The procedure was also carried out under optimal conditions established to reduce the use of toxic reagents or solvents and was carried out in one pot to make it more environmentally friendly. The procedure can be considered as more suitable for the large-scale production of 1. The structures of product 1 and intermediate 6 were confirmed by IR, MS, 1H NMR, 13C NMR.

Synthesis and Bioactivity of Thiosemicarbazones Containing Adamantane Skeletons.

Reaction of 4-(1-adamantyl)-3-thiosemicarbazide (1) with numerous substituted acetophenones and benzaldehydes yielded the corresponding thiosemicarbazones containing adamantane skeletons. The synthesized compounds were evaluated for their in vitro activities against some Gram-positive and Gram-negative bacteria, and the fungus Candida albicans, and cytotoxicity against four cancer cell lines (Hep3B, HeLa, A549, and MCF-7). All of them showed good antifungal activity against Candida albicans. Compounds 2c, 2d, 2g, 2j and 3a, 3e, 3g displayed significant inhibitory activity against Enterococcus faecalis. Compounds 2a, 2e, 2h, 2k and 3j had moderate inhibitory potency against Staphylococcus aureus. Compounds 2a, 2e and 2g found so good inhibitory effect on Bacillus cereus. Compounds 2d and 2h, which contain (ortho) hydroxyl groups on the phenyl ring, were shown to be good candidates as potential agents for killing the tested cancer cell lines, i.e., Hep3B, A549, and MCF-7. Compounds 2a-c, 2f, 2g, 2j, 2k, 3g, and 3i were moderate inhibitors against MCF-7.

Synthesis and Bioactivity of Hydrazide-Hydrazones with the 1-Adamantyl-Carbonyl Moiety.

Reaction of 1-adamantyl carbohydrazide (1) with various substituted benzaldehydes and acetophenones yielded the corresponding hydrazide-hydrazones with a 1-adamantane carbonyl moiety. The new synthesized compounds were tested for activities against some Gram-negative and Gram-positive bacteria, and the fungus Candida albicans. Compounds 4a, 4b, 5a, and 5c displayed potential antibacterial activity against tested Gram-positive bacteria and C. albicans, while compounds 4e and 5e possessed cytotoxicity against tested human cancer cell lines.

Synthesis and evaluation of biological activities of a series of (6-substituted benzothiazol-2-yl)acrylamides.

A series of simple (6-substituted benzothiazol-2-yl)acrylamides was synthesized and evaluated for cytotoxicity and antimicrobial effects. All six compounds displayed very significant cytotoxicity against four cancer cell lines tested including A549 (a human lung cancer cell line), Hela (a human ovarian cancer cell line), MCF7 (a human breast cancer cell line), and even MCF7-ADR (adriamycin-resistant human breast cancer cell line), with IC(50) values in microgram/ml range and as low as 0.66 µg/ml. The synthesized compounds also exhibited some antifungal effects against Apergillus niger.