Dimethylformamide dineopentyl acetal

Schotten-Baumann type N-benzoylation was carried out on trans-4-hydroxy-L-proline 34,39 giving amide 43 in a satisfactory yield of 65%. The disappointing yield here could be attributed to difficulties experienced in recrystallization of the product 43. The amide 43 was esterified to give tert-butyl ester 44 using a modification of a procedure described by Widmer40 with dimethylformamide-dineopentyl acetal and tert-butanol as reagents. This provided crystalline 44 in 71% yield from 43 with no evidence of terf-butyl ether formation at the C-4 hydroxyl group (Scheme 12). 

DECARBOXYLATIVE DEHYDRATION N,N-Dimethylformamide dineopentyl acetal. Triphenylphosphine-Diethyl azodicar-boxylate. 

OH pentofuranoses, as shown in Scheme 5. Thus, otherwise scarcely available D-allal and D-gulal derivatives can he readily prepared from D-ribose and D-arabinose, respectively [82]. It has recently been demonstrated that reductive elimination of /3-hydroxycarboxylic acid can be applied for preparation of hex-l-enitols. The procedure involves refluxing appropriate substrate in toluene with Al,lV-dimethylformamide dineopentyl acetal. 

Dimethylformamide dineopentyl acetal (3). Mol. wt. 231.37. Compare Dimethyl-formamide diethyl acetal. Supplier Fluka. 

Esterification Alumina. Boron trifluoride. Diazomethane. Dimethylformamide dimethyl acetal. Dimethylformamide dineopentyl acetal. Dimethyl sulfite. Diphenyidiazomethane. Ethyldicyclohexylamine. Ion-exchange resins. Isobutene. Methanesulfonic anhydride. 3 % Methanolic HCl (see Acetyl chloride). Methyl iodide. l-Methyl-3-p-tolyltriazine. Poly-phosphoric acid. Sulfosalicylic acid. Sulfuryl chloride. p-Toluenesulfonic acid. p-Tpluene-sulfonyl chloride. Triethylamine. Triethylorthoformate. Trifluoroacetic anhydride. Esterification of phosphoric acid Trichloroacetonitrile. 

Thymidine-5 -carboxylic acid and dimethylformamide dineopentyl acetal in dimethylformamide heated 4.5 hrs. at 80-90° l-(2, 3 -dideoxy-3, 4 -didehydro-) -D-erythrofuranosyl)thymine. Y 94%. - This reaction comprises a useful selective degradation of C-5 from a 2 -deoxynucleoside. F. e. s. J. 2emliSka et al.. Am. Soc. 94, 3213 (1972). 

Structural analogues of the formycins have been reported in a paper describing a general route to 2-glycosylated pyrimidinones (see Scheme 17). Treatment of formycin with iViV-dimethylformamide dineopentyl acetal gave the 2,5 -cyclo-nucleoside as one of the products, and 2, 3 -0-isopropylideneformycin was converted into the 4,5 -cyclonucleoside by way of the 5 -toluene-p-sulphonate. Adenosine deaminase caused deamination of the 2,S -cyclonucleoside only, indicating that the a //-conformation of a substrate is utilized by the enzyme. 

Dimethylformamide dineopentyl acetal Methyl from hydroxymethyl groups via 2-pyrimidinyl thioethers... 

Dimethylformamide dineopentyl acetal Carboxylic acid esters from carboxylic acids... 

N-Garbo-(p-n-decycloxy)benzoxyglycine allowed to react at room temp, with p-dodecylbenzyl alcohol and 1.3 equivalents of dimethylformamide dineopentyl acetal in methylene chloride for 47 hrs. p-dodecylbenzyl N-carbo-(p-n-decyloxy) benzoxyglycinate. Y 86%.—This modification of Synth. Meth. 18, 222 requires only 1 equivalent of the alcohol and gives volatile by-products. F. e. s. H. Biichi, K. Steen, and A. Eschenmoser, Ang. Ch. 75, 1176 (1963). 

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