It is probable that (-7) yields, by a [IS]-alkyl shift, first the compound ( l U ) , which then undergoes [1,5]-hydride shifts, yielding (11) and (12), under the conditions used. The problem of the interaction between the cyclobutane ring and the diene portion of (2) is to be investigated by photoelectron spectroscopy(PES)[' 81. Qualitative consideration of the PE spectrum of (2) and its comparison with that of(l)["1indicate that suchan interactiondoesoccur"". ReceiLed: July 27. 1973 [Z X99 IE] German xersion Angew. Chcni. X5. 908 119731 [I] R. Y. L-ci.iiiri and 7: 1. Etiir.\ircvit. Dokl. Akad. Nauk SSSR XY. 697 (19531: R. Y Lcrtriri. N . If . k J e :~~i i r , \~~i [ t ,and 0. I: Li,hrdrr. Zh.

New hydrophilic swellable and lowly crosslinked bead copolymers consisting of dimethylaminocarbonylethylene or -propylene and alkoxycarbonylethylene or -propylene repeating units were prepared starting from activated esters of acrylic acid (8a -10a) or methacrylic esters (8blob) and N,N-dimethylacrylamide (12a). This "hydrophylic Merrifield carriers" were applied for polymer-supported oligodeoxynucleotide syntheses. They were found to be swellable in a wide range of solvents. The first deoxynucleoside was attached to the carrier via its 5'-hydroxyl group by an ester bond. The cleavage of the bond between carrier and oligonucleotide was performed with aqueous sodium hydroxide under conditions which do not attack the N-protecting groups attached to the oligonucleotide chain. The acid labile 1 -ethoxyethyl group was used as 3'-protecting group for the phosphate component (N-protected deoxynucleoside-5'-phosphate). Some suitable protected deoxynucleosides were synthesized for anchoring and deoxynucleoside-5 '-phosphates for chain elongation. In a condensation reaction according to the diester method, a dinucleoside monophosphate (7) was prepared and, as a consequence of the flexibility of the polymeric backbone, the synthesis of longer oligonucleotides should be feasible. The alkali labile anchoring of the oligonucleotides to the carrier can allow to avoid wrong sequences by simple acylation of the non-reacted 3'-OH groups with acetic anhydride after each condensation step.

Zur Synthese von Oligonucleotiden bietet ein polymerer Träger des Typs (1) den Vorteil, daß sich das erste Nucleotid mit einer alkalilabilen Bindung an ihm verankern läßt, während eine säurelabile Schutzgruppe R. zur Blockierung der 3′OHGruppe verwendet werden kann. 3′OHGruppen, die bei der Verlängerung der Nucleotidkette nicht reagiert haben, werden durch Acylierung blockiert. Fehlsequenzen lassen sich so vermeiden.magnified image

No abstract