ATTEMPTS TO PREPARE TRIFLUOROACETIC ACID BY THE REACTION OF COBALTIC FLUORIDES WITH ACETIC ANHYDRIDE AND ACETONITRILE

1945 ◽  
Author(s):  
H.S. Halbedel
Keyword(s):  
Acetic Anhydride ◽  
Trifluoroacetic Acid

Base-catalyzed Degradations of Carbohydrates. III. Formation of a Novel Perester from 1-O-Acetyl-3-deoxy-2,4,6-tri-O-methyl-α-D-erytho-hex-2-enopyranose

1973 ◽  
Vol 51 (3) ◽  
pp. 388-393 ◽  
Author(s):  
G. O. Aspinall ◽  
R. R. King ◽  
Zofia Pawlak
Keyword(s):  
Acetic Anhydride ◽  
Spectral Data ◽  
Trifluoroacetic Acid ◽  
Oxidative Degradation ◽  
Chemical Degradation ◽  
Reductive Decomposition

1-O-Acetyl-3-deoxy-2,4,6-tri-O-methyl-α-D-erythro-hex-2-enopyranose (1) reacts with m-chloroperbenzoic acid to give a novel perester, which has been assigned the structure 1,2-O-(1′-m-chloroperbenzoyl-oxyethylidene)-2-methoxy-4,6-di-O-methyl-α-D-glucopyranose (2), on the basis of spectral data and chemical degradation. The perester 2 and the derived acetate 3 undergo oxidative degradation on treatment with trifluoroacetic acid to give 3,5-di-O-methyl- (4) and 2-O-acetyl-3,5-di-O-methyl-D-arabinonolactone (5), respectively. Reductive decomposition of the acetylated perester 3 yields 1,3-di-O-acetyl-4,6-di-O-methyl-α-D-arabino-hexopyranosulose (6), which, on treatment with acetic anhydride in pyridine, gives successively 1,2,3-tri-O-acetyl-4,6-di-O-methyl-α-D-erythro-hex-2-enopyranose (7), 2-O-acetyl-1-deoxy-4,6-di-O-methyl-α-D-erythro-hex-1-enopyranose-3-ulose (8), and 5-acetoxy-2-(methoxy-methyl)-4H-pyran-4-one (9).

Reaction of 1,6-anhydro-4-O-benzyl-2-deoxy-2-isothiocyanato-β-D-glucopyranose; Preparation of 2-amino-1,6-anhydro-2,3-dideoxy-2,3-dideoxy-β-D-ribo-hexopyranose

1985 ◽  
Vol 50 (9) ◽  
pp. 2000-2009 ◽  
Author(s):  
Tomáš Elbert ◽  
Miloslav Černý
Keyword(s):  
Acetic Anhydride ◽  
Raney Nickel ◽  
Carbon Disulfide ◽  
Trifluoroacetic Acid

1,6-Anhydro-4-O-benzyl-2-deoxy-2-isothiocyanato-β-D-glucopyranose (IV), prepared from 2-amino-1,6-anhydro-4-O-benzyl-2-deoxy-β-D-glucopyranose (I) by reaction with carbon disulfide followed by oxidation with iodine, was converted into the 3-O-p-toluenesulfonate VII. This was cyclized to give either the 2,3-epimino derivative X or the thiazoline XII. 2-Acetamido-3-S-acetyl-1,6-anhydro-4-O-benzyl-2-deoxy-3-thio-β-D-glucopyranose (XVI), obtained from compound XII, was desulfurized with Raney nickel to afford 2-acetamido-1,6-anhydro-2,3-dideoxy-β-D-ribo-hexopyranose (XVII). The isothiocyanato group was not affected upon acetylation of compound IV and acetolysis of the 1,6-anhydride bond with acetic anhydride and trifluoroacetic acid.

Cyclization of cysteinylglycine sulfoxides under Pummerer reaction conditions

1979 ◽  
Vol 57 (18) ◽  
pp. 2412-2425 ◽  
Author(s):  
Saul Wolfe ◽  
Peter Michael Kazmaier ◽  
Hillar Auksi
Keyword(s):  
Acetic Anhydride ◽  
Trifluoroacetic Acid ◽  
Carboxyl Group ◽  
Reaction Conditions ◽  
Pummerer Reaction ◽  
Peptide Cyclization

A number of sulfoxides derived from 3-benzylthiopropionic acid, S-benzylcysteine, and S-phenylcystelne have been synthesized and exposed to typical Pummerer reaction conditions. Cyclization of the S-benzyl sulfoxides to six-membered or seven-membered heterocyclic rings (1,3-thiazin-4-ones and 1,3,6-oxathiazepines) is observed only in acetic anhydride solvent and only after conversion of the carboxyl group to an amide or peptide. Cyclization of S-phenylcysteinyl amides to β-lactams could not be achieved. The thiazolidine isomers of the six- and seven-membered rings have been synthesized and found not to be intermediates in the acetic anhydride reactions. The thiazolidines do rearrange to the six- and (or) seven-membered rings in anhydrous trifluoroacetic acid solvent. S-Benzylphthalimidocysteinylglycine sulfoxide, a 3:2 mixture of epimers at sulfur, affords a 3:2 mixture of isomeric thiazinones. A mechanism for these cyclizations is proposed, and it is suggested that the configuration at sulfur controls the configuration at the new asymmetric centre in the product.

Ipso nitration. XIX. Formation of cyclohexadiene adducts from nitration of 4-ethyltoluene and 1,4-diethylbenzene in nitric acid and acetic anhydride

1978 ◽  
Vol 31 (6) ◽  
pp. 1241 ◽  
Author(s):  
A Fischer ◽  
GN Henderson ◽  
RJ Thompson
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Trifluoroacetic Acid ◽  
Trifluoroacetic Anhydride ◽  
Phenyl Acetate ◽  
Aqueous Methanol ◽  
Methyl Phenyl

Nitration of 4-ethyltoluene in acetic anhydride at -20° gives the diastereoisomers of 1-ethyl-4-methyl-4-nitrocyclohexa-2,5-dienyl acetate and of 4-ethyl-1-methyl-4-nitrocyclohexa-2,5-dienyl acetate. Similar nitration of 1,4-diethylbenzene gives the diastereoisomers of 1,4-diethyl-4-nitro-cyclohexa-2,5-dienyl acetate. Rearomatization of the adducts of p-ethyltoluene in trifluoroacetic acid-trifluoroacetic anhydride gives 4-ethyl-2-nitrotoluene from the 1-ethyl-4-methyl-4- nitro isomers and 4-ethyl-3-nitrotoluene from the 4-ethyl-1-methyl-4-nitro isomers. In aqueous methanol 2-ethyl- 5-methylphenyl acetate is obtained from the 1-ethyl-4-methyl-4-nitro isomers and 5-ethyl-2- methyl-phenyl acetate from the 4-ethyl-1-methyl-4-nitro isomers.

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