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Diphenyl dithioacetal

Ci7H20O4S2 o-Ribose diphenyl dithioacetal (RIBPTA10)316 Ci8H30O10 Methyl 3,5-0-isopropylidene-2-0-(methyl 3,5-O-isopropyli-dene-a-D-xylofuranosid-3-yl)-a-D-xylofuranoside (MPXFXF)325 C21H42N5Ou+ I- H20 C2HeO Apramycin hydriodide, monohydrate, ethanolate (APRAMI)326... [Pg.372]

Yoshigama and Fuchigami have also reported that several dithioacetals of aliphatic and alicyclic ketones can be converted to their gem difluoro-derivatives in a similar manner. However, they found that with diphenyl dithioacetals only one C - S bond is cleaved to give the monofluoro- compound... [Pg.208]

Concentrated hydrochloric add (9.0 mL) is cooled to 0°C and saturated with hydrogen chloride gas. D-Riboee (3.0 g, 20 mmol) and benztaethioi (3.6 mL) are added, and the mixture is shaken for 2 h at 0°C and then for 20 min at room temperature. The solution is then poured into cold water (100 mL), and the resultant syrupis decanted from the water layer. This syrup it then dissolved in ethyl acetate (SO mL), the solution dried over sodium carbonate, and evaporated. After dissolving the syrup hi benzene (100 mL), die product crystallizes slowly (-2 days) at 0°C and is collected by filtration (3.0 g, 40%, collected in two crops). Recrystallization is effected from ethanol-ether and then ethanol-water to afford the pure diphenyl dithioacetal mp 101.3-102.0 0, [a] +423 (c 1, pyridine). [Pg.44]

Difluoro(methoxy)acctaldehyde diphenyl dithioacetal eliminates hydrogen fluoride during its... [Pg.354]

Closely similar results were obtained with various diphenyl dithioacetal acetates (7), with the unsubstituted diethyl dithioacetals (8), and with the aldehydo-pentose peracetates (9) and the tetra-O-acetylaldo-pentose dimethyl acetals (10). Subsequent work in other laboratories has shown the same general principles for the methyl 5-hexulosonates (11) and the pentononitrile tetraacetates (12), two examples where a full series of stereoisomers has been studied. Other workers have investigated isolated examples or partial series (13, 14, 15, 16, 17, 18), and parallel work by x-ray crystallography (19, 20, 21, 22) on acyclic sugar derivatives in the solid state has shown excellent correlation with the general principles outlined here for the molecules in solution. [Pg.159]

At neutral pH, hydrolysis is extremely slow, but the reaction proceeds to completion with minimal interference from side reactions as an increase in the acidity of the medium not only accelerates the rate of hydrolysis but also introduces competing reactions and displaces the equilibrium towards the dithioacetal, the optimal conditions for the demercaptalation reaction are a compromise176 between the rate and the yield of the reaction. The identity of the thiol also influences the rate of mercury(II) chloride-catalyzed hydrolysis, diphenyl dithioacetals reacting30 very readily and ethylene dithioacetals slowly188,235 or not at all,72 the reverse of their relative rates of formation. [Pg.61]

It was subsequently found that solutions of some of the unprotected pentose diethyl and diphenyl dithioacetals in methanol-d4 give essentially completely separated signals (see Fig. 6), whereas the n.m.r. spectral dispersion of others can be augmented by incremental additions of a paramagnetic lanthanide cation (see Fig. 7)... [Pg.89]


See other pages where Diphenyl dithioacetal is mentioned: [Pg.397]    [Pg.35]    [Pg.42]    [Pg.355]    [Pg.864]    [Pg.864]    [Pg.17]    [Pg.19]    [Pg.21]    [Pg.21]    [Pg.22]    [Pg.57]    [Pg.58]    [Pg.89]    [Pg.91]    [Pg.92]    [Pg.92]    [Pg.96]   
See also in sourсe #XX -- [ Pg.43 , Pg.372 ]




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