DMT, 4,4’-dimethoxytrityl

Abbreviations DMF, A,A-dimethylformamide DMT, 4,4 -dimethoxytrityl HPLC, high-pressure liquid chromatography NPG, n-pentenyl glycoside TEA, triethylamine TCA, trichloroacetic acid THF, tetrahydrofuran TMSOTf, trimethysilyl trifluoromethanesulfonate. 

S -Dimethoxytrltyl-2 -deoxythylmldlne-3 -phosphate (3).4 A solution of 1 mmol ot 1 (T-thymine, DMT 4,4,-dimethoxytrityl) in dioxane (6 mL), pyridine (1 ml.) and a slight excess of 2-chloro-5,6-benzo-1,3-dioxaphosphorin-2-one 2 (1 mL of a 1.25 M solution in dtoxarte) was stirred at 20°C After 5 min TLC indcated complete conversion of 1 into 3 with zero mobility. Water was added and after woik up 3 was isolated in 88% yield. 

Dimethoxytrityl chloride (DMT) [40615-36-9] M 338.8, m 114 . Crysts from cyclohexane-acetyl chloride as the hydrochloride and dry over KOH pellets in a desiccator. When dissolved in CgH6 and air is blown through, HCl is removed. It crystallises from Et20. [Justus Liebigs Ann Chem 370 142 1909 Chem Ber 36 2774 7905 Smith et al. J Am Chem Soc 84 430 I962 Smith et al. J Am Chem Soc 85 3821 7965.] If it had hydrolysed considerably (see OH in IR) then repeat the crystallisation from cyclohexane-acetyl chloride — excess of AcCl is removed in vac over KOH. 

There are cases where the acid lability of the trityl group may need to be bolstered. This can be accomplished easily by replacing one or more of the phenyl rings by a 4-methoxyphenyl ring. The enhanced add-lability of monomethoxy-trityl (MMT) groups was an asset exploited in a synthesis of the hypersensitive Azinomycin derivative shown in Scheme 8.206.418 The 4,4 -dimethoxytrityl (DMT) and 4,4, 4"-trimethoxytrityl (TMT) amines are far more stable than... 

Bis(hydroxymethyl)phosphonic acid esters that incorporated thymine were employed as a backbone to prepare short oligonucleotide chains. This chain was prepared by condensation of the bis(4,4 -dimethoxytrityl) protected phosphonic acid and iV or N -(2-hydroxyethyl)thymine in the presence of l-(2-mesitylenesul-fonyl)-3-nitro-l,2,4-triazole or by an Appel reaction with or N -(2-aminoethyl)thymine (89a-h). Selective removal of one DMT-group and phos-phitylation yielded the building blocks for solid supported synthesis of the short oligomers by the phosphoramidite approach. Holy has reported the synthesis of 8-amino and 8-substituted amino derivatives of acyclic purine nucleotide analogues. The 8-amino, 8-methylamino- and 8-dimethylamino-adenine and -guanine analogues of iV-(2-phosphonomethoxyethyl) and (S)-iV-(3-hydroxy-2-phosphono-methoxy-propyl) derivatives of purines (90a-i), were prepared by... 

The protecting group for the 5 end of the oligonucleotide is the 4,4 -dimethoxytrityl (DMT) group. This protecting group is easily removed by... 

Figure 4 Flow scheme of the synthesis of DNA-oligonculeotides using the phosphoramidite method. DMT = dimethoxytrityl, TCA = trichloroacetic acid.

CE CGE CHOL CIP CPG CTAB CZE dA, dG, dC DBU DEAE DMF DMT DNP DOPE DOTMA EDTA EM EOF ESI-MS Fmoc FPE ICAM-1 Capillary electrophoresis Capillary gel electrophoresis Cholesterol Cahn-Ingold-Prelog nomenclature system for absolute configuration Controlled pore glass Hexadecyltrimethylammonium bromide Capillary zone electrophoresis Deoxyadenosine, deoxyguanosine, deoxycytosine l,8-Diazabicyc o[5.4.0]undec-7-en Diethylaminoethyl- Dimethylformamide Bis(4-methoxyphenyl)phenylmethyl-, (syn. Dimethoxytrityl-) 2,4-DinitrophenyI- Dioleylphosphatidylethanolamine N-[l-(2,3-dioleyloxy)propyl]-N, N, N-trimethylammonium chloride Ethylenediamine tetra-acetic acid Electrophoretic mobility Electro-osmotic flow Electrospray ionization mass spectrometry 9-Fluorenylmethoxycarbonyl-Fluid phase endocytosis Intracellular Adhesion Molecule-1... 

The sugar moiety is blocked at C5 as a dimethoxytrityl [di(4-methoxyphenyl)phenylmethyl, DMT] ether, readily cleaved by mild acid through an SnI mechanism (Section 22-1 and Problem 40 of Chapter 22), much like 1,1-dimethylethyl (tcrt-butyl) ethers (Section 9-8, Real Life 9-2). To anchor the first protected nucleoside on the solid support, the C3 -OH is attached to an activated linker, a diester. Unlike the Merrifield medium of polystyrene, the solid used in oligonucleotide synthesis is surface-functionalized silica (Si02) bearing an amino substituent as a hook. Coupling to the anchor nucleoside is by amide formation. 

---