Abstract: Intermediates such as methyl 2,2-dimethyl-5-ethenyl-1,3-dioxane-5-carbonate useful to prepare antiviral compounds such as penciclovir and famciclovir are disclosed.

Abstract: A process for preparing purine derivatives, such as famciclovir and penciclovir, by reacting two intermediates and using a palladium(0) catalyst and a ligand. Intermediates useful in the process are also claimed.

Abstract: A process for preparing purine derivatives, such as famiciclovir and penciclovir, by reacting, in the presence of a palladium (0) catalyst and a ligand, a compound of the formula with a compound of the formula wherein X is H, OH or halo; Y is a leaving group; and R1 and R2 are selected independently from C1-12alkyl, aryl, C1-12alkylaryl, C1-12alkylsilyl, arylsilyl and C1-12alkyldiarylsilyl or are joined together to form a moiety of the formula wherein R3 and R4 are selected independently from H, C1-12alkyl and aryl.

Abstract: A process for preparing a compound of formula (I) or an addition salt thereof and/or a solvate thereof: ##STR1## wherein R.sup.1, R.sup.2, R.sup.4 and R.sup.5 are each independently C.sub.1-4 alkoxy and R.sup.3 is C.sub.1-6 alkyl, which process comprises reacting an arylamine of formula (II): ##STR2## wherein R.sup.4 and R.sup.5 are as defined in relation to formula (I) with a .beta.-aminoaldehyde of formula (III): ##STR3## wherein R.sup.1, R.sup.2 and R.sup.3 are as defined in relation to formula (I); and thereafter reducing the intermediate so formed and, optionally, forming an addition salt of the compound of formula (I) and/or a solvate thereof.