Ryōichi Masuda

O-N, S-N and N-N exchange reactions at olefinic carbon atoms: Facile synthetic method for β-trifluoroacetylvinylamines

β-Trifluoroacetylvinyl ethers and sulfides react easily with various amines at room temperature to give β-trifluoroacetylvinylamines in excellent yields. This O-N and S-N exchange reaction can be extended to N-N exchange reaction.

Alumina as an versatile catalyst for the selective acetalization of aldehydes

Abstract Alumina was found to be an effective and convenient catalyst for acetalization of aldehydes to the corresponding 1,3-dioxoranes and 1,3-dioxanes. It can be used for selective protection of only formyl group of ketoaldehydes.

An alternative efficient method for transformation of thiocarbonyl to carbonyl group using trifluoroacetic anhydride

Abstract A simple and efficient procedure for the rapid and mild conversion of thiocarbonyls to carbonyls in high yields is described.

Nucleophilic nitrogen-nitrogen exchange reaction at aromatic carbon atoms — reaction of N,N-dimethyl-2,4-bistrifluoroacetyl-1-naphthylamine with various amines.

N,N-Dimethyl-1-naphthylamine reacted easily with trifluoroacetic anhydride to give the title compound 2 quantitatively. Aromatic nucleophilic substitution reaction of 2 with various amines proceeded readily under mild conditions to give the corresponding nitrogen—nitrogen exchanged products 6-14 in excellent yields.

Convenient synthesis of 4-triflouromethylpyrazoles by cyclization of triflouroacetylated hydrazones

Abstract Several 4-trifluoromethyl-1-alkylpyrazoles were synthesized in good yields by trifluoroacetic anhydride-pyridine induced cyclization reaction of acylhydrazones prepared from aldehyde dialkylhydrazones and trifluoroacetic anhydride.

Electrophilic substitutions of olefinic hydrogens : Acylation of1,1-bisalkylthio 1,3-alkadienes and trans-n-acetyl-n-isopropyl-1-amino-1,3-butadiene

Abstract Reactions of the title compounds with trifluoroacetic anhydride and trichloroacetyl chloride occurred regioselectively to give corresponding 4-triholoacetylated compounds in excellent yields. In contrast, 1,1-bisethylthio-1,3-hexadiene gave preferentially 2-acylated compounds.

Lithium aluminum hydride on silica gel - selective reduction of ketones and carboxy esters in the presence of nitro and cyano groups

Abstract Cyano and nitro groups were found not to be reduced by lithium aluminum hydride on silica gel and with the use of this reagent ketones and carboxy esters bearing cyano and nitro groups were successfully converted into the corresponding cyano and nitro alcohols.

Selective reduction of ketoesters to hydroxyesters with the use of lithium aluminum hydride in the presence of silica gel

Abstract Lithium aluminum hydride, in the presence of a small amount of silica gel, has been found to be a versatile and highly selective reagent for reduction of various ketoesters to the corresponding hydroxyesters in fair yields.

Acid catalyzed cyclization of N,N-dialkyl-2,4-bistrifluoroacetyl-1-naphthylamines to naphtho[1, 2-d][1, 3]oxazines

Abstract N, N-Dialkyl-2, 4-bistrifluoroacetyl-1-naphthylamines( 1 and 2 ) underwent cyclization in the presence of acids such as trifluoroacetic acid, p-toluenesulfonic acid or silica gel to give naphtho[1, 2-d][1, 3]oxazines( 3 and 4 ) in high yields.

A new facile synthesis of 5-aryl-4-trifluoroacetyl-6-trifluoromethyl-3,4-dihydro-2H-1,3,4-oxadiazines from arylaldehydes

Abstract By reaction with an excess of trifluoroacetic anhydride, title compounds 4 were synthesized from C-trifluoroacetylated hydrazones 1 which are readily obtainable by trifluoroacetylation of arylaldehyde dimethylhydrazones.