Synthesis and anti‐HIV activity of HEPT and S‐DABO‐analogues with 5‐Benzyl and 5‐Phenyl substituents

Abstract

6-Benzyl-5-phenyluracil (4) and 5,6-dibenzyluracil (9) were synthesised from diphenyl acetone (1) and ethyl 3-oxo-4-phenylbutyrate (6), respectively. The uracils were alkylated to afford the 1-alkoxymethyluracils 5, 10 and 11. Furthermore, S-alkylated dihydroalkoxybenzyloxopyrimidine (S-DABO) analogues were prepared by alkylating 5,6-dibenzyl-2-thiouracil (8) on sulfur to yield compounds 12a-f. All compounds were tested for their inhibition of HIV-1 reverse transcriptase, and moderate activity was found for 6-benzyl-1-(ethoxymethyl)-5-phenyluracil (5).

Regioselective synthesis and antimicrobial studies of novel bridgehead nitrogen heterocycles containing the thienopyrimidinone skeleton

“…In the 1 H NMR spectra, the NH protons were deshielded and appeared in the downfield region (δH 12.46-12.60 ppm) due to the deshielding effects of the neighbouring carbonyl groups. These data are in accordance with literature assignments, that predict these NH protons would resonate in the downfield region (δH ~ 12 ppm) by analogy with related lactam species [19][20][21][22]. Similarly, the IR spectra were also informative in establishing the structure of 3-unsubstituted pyrimidin-4-ones 4a,b.…”

“…4.0 ppm [29,32]. The prevalence of the 3H-rather than the 1H-form in a number of 2-(alkylthio)uracils is well documented [20][21][22]28,[33][34][35]. Consequently, it is not unreasonable to conclude that our studied alkylation reactions take place with complete selectivity, since the site of alkylation is initially the sulfur rather than the nitrogen and in the case of the disubstituted products the N-3 is the second position for alkylation.…”

Nucleosides 8 [18]: Ribosylation of Fused Quinazolines—Synthesis of New [1,2,4]Triazolo[5,1‐b]‐ and [1,2,4]Triazino[3,2‐b]quinazoline Nucleosides of Fluorescence Interest

“…13 The structure of nucleoside 10 may exist in two forms, thiol form (10A) and thione form (10B or 10C) (Scheme 2). The results reported above of 13 C NMR spectra of compound 10 of C=S at 175 ppm indicate the formation of Nnucleosides as thione form (10B or 10C) [30][31][32][33].…”