Organic Communications Articles

Three chiral phosphonoacetamides were prepared by an alternative method . For this purpose, 2-(diethoxyphosphoryl)acetic acid was prepared from ethyl 2-bromoacetate by treatment of P(OEt) 3 followed by saponification of the ester with K 2CO 3. BOP activated amidation of the 2-(diethoxyphosphoryl)acetic acid with (S)-amino acids gave the corresponding phosphonoaceteamides. Growth inhibition of two phosphonoacetamides on Paramecium sp. were studied.

A novel synthetic approach is presented, involving unsaturated nucleoside hydroboration, with protected stavudine catalytically boronated with pinacolborane to several pinacolborane derivatives of stavudine or 2’,3’-dideoxythymidine. The products were converted to much more stable trifluoroborate derivatives that may be considered trifluoroboron analogues of nucleoside phosphates. The post-reaction mixture contained four isomers, being products of catalytic hydroboration, and two isomers, resulting from dehydrogenative borylation, each containing unsaturated 2’,3’-moiety. The new compounds were analyzed with NMR and LDI-HRMS methods.

A simple and efficient synthesis of dioxazaphosphinin-2-ones has been developed by the cyclisation of 2-hydroxy-1,2-diphenylethanoneoxime with phosphorus oxychloride in the presence of triethylamine in dry THF to afford the corresponding monochloride. In the next step, subsequent reaction of monochloridewith different amines at 50-60 ˚C for 2-3 hours resulted in the formation of the title compounds (4a-j). The lead compounds were screened for their antioxidant activity.