Abstract: A compound having the following formula I: ##STR1## in which: R' represents a hydrogen atom or an azido group,alc represents an alkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms or an amino group.

Abstract: The glycosylphospholipid nucleoside derivatives of the invention are based on the formula: ##STR1## wherein: R.sub.1 is a nucleoside derivative selected from the group consisting of 3'-azidothymidine (AZT); 2', 3'-dideoxythymidine (ddT); and 2'-deoxy-5-fluorouridine (dFU);R.sub.2 is a hexose or pentose sugar, with the exception of glucose when x is 1;A is a hydrogen atom or an alkyl or alkoxy chain containing from 5 to 20 carbon atoms, said alkyl or alkoxy chain having at its extremity a group selected from the group consisting of a hydrogen atom and an NR'R" group, wherein R' and R" represent hydrogen or an alkyl group of 1 to 4 carbon atoms;x is a number from 1 to 12;y is a number from 1 to 4; andz is 0 or 1; and further wherein:attachment of said hexose sugar is at position 1 or position 6 of said hexose sugar, and attachment of said pentose sugar is at position 1 or position 5 of said pentose sugar.

Abstract: The invention concerns 2,N.sup.6 -disubstituted and 2,N.sup.6 -trisubstituted adenosine nucleosides in which the sugar component is substituted at position 3' or position 5' by a phosphite or phosphoramidite group of the formula: ##STR1## R.sub.1 representing a lower alkyl or --(CH.sub.2).sub.n --CN with n being an integer between 1 and 4, and X representing a halogen or an amine group. These nucleosides make it possible to prepare sequences of nucleotides usable, in particular, as probes in the field of analyses and biological extractions.

Abstract: The invention relates to a probe constituted by an oligonucleotide fragment of structure predetermined by the application envisaged, wherein at least a part of the adenine groups therein is replaced by modified adenine groups so that they can form three hydrogen bonds with the reactive groups of thymine or uracil. This probe is useful in the field of biological analyses and extractions.