Etsuji Okada

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.

Incorporation of a 3‑(2,2,2-Trifluoroethyl)-γ-hydroxy-γ-lactam Motif in the Side Chain of 4‑Aminoquinolines. Syntheses and Antimalarial Activities

In this paper we report the synthesis and antimalarial properties of two series of fluoroalkylated γ-lactams derived from 4-aminoquinoline as potent chemotherapeutic agents for malaria treatment. These molecules obtained in several steps resulted in the identification of very potent structures with in vitro activity against Plasmodium falciparum clones of variable sensitivity (3D7 and W2) in the range of 19-50 nM with resistance indices in the range of 1.0-2.5. In addition, selected molecules (50, 51, 58, 60, 63, 70, 72, 74, 78, 81, 84, and 87) that are representative of the two series of compounds did not show cytotoxicity in vitro when tested against human umbilical vein endothelial cells up to a concentration of 100 μM. The most promising compounds (82 and 84) showed significant IC₅₀ values close to 26 and 19 nM against the chloroquino-sensitive strain 3D7 and 49 and 42 nM against the multi-drug-resistant strain W2. Furthermore, two model compounds (50 and 70) were found to be quite stable over 48 h at pH 7.4 and 5.2. Overall, our preliminary data indicate that this class of structures contains promising candidates for further study.

Facile synthetic methods for 3- and 5-trifluoromethyl-4-trifluoroacetyl-pyrazoles and their conversion into pyrazole-4-carboxylic acids

3- And 5-trifluoromethyl-4-trifluoroacetylpyrazoles (4 and 5) were easily synthesized in excellent yields by reaction of β,β-bis(trifluoroacetyl) vinyl ethers 1, sulfides 2, and -amines 3 with hydrazines. Hydrolysis of these compounds (4 and 5) with aqueous potassium hydroxide gave the corresponding pyrazole-4-carboxylic acids (6 and 7) in high yields

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.

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.

A facile and convenient synthetic method for 3-trifluoroacetyl-pyrroles

3-Trifluoroacetylpyrroles are easily obtained in excellent yields by oxygen-nitrogen exchange reaction of β-trifluoroacetylvinyl ethers with 2,2-dimethoxyethylamine and subsequent cyclodehydration of the products

A Convenient Synthesis of Fluorine-Containing Dihydrobenzo[b][1,4]diazepinols and Its Application to a Synthesis of Novel N-Sulfinylanilines

The reactions of l,l,l,5,5,5-hexafluoro-3-(isobutoxymethylene)-pentane-2,4-dione (1) with various benzene-1,2-diamines gave 2,5-dihydro-3-trifluoroacetyl-2-trifluoromethyl-1H-benzo[b][1,4]diazepines (5) in moderate to high yields under very mild conditions. Also, 2,5-dihydro-3-perhaloalkanoyl-2-perhaloalkyl-1H-benzo[b][l,4]diazepines (7) were synthesized successfully by quite similar manner. Reactions of thus obtained dihydrobenzo[b][1,4]-diazepinols (5) with thionyl chloride gave unexpected novel fluorine-containing N-sulfinylanilines (9).

A simple route to 2,3-dihydronaphtho [1,2-b] thiophenes and naphtho [1,2-b] thiophenes bearing trifluoromethyl groups by aromatic nucleophilic substitution of N,N-dimethyl-2,4-bis(trifluoroacetyl)-1-naphthylamine

2,3-Dihydronaphtho [1,2-b] thiophenes (2, 4, 5, and 7) and naphtho [1,2-b] thiophenes (3 and 8) bearing trifluoromethyl groups were easily synthesized by aromatic nucleophilic nitrogen-sulfur exchange reaction of N,N-dimethyl-2,4-bis(trifluoroacetyl)-1-naphthylamine (1) with thioglycolic acids and with benzyl mercaptan, followed by cyclization (cyclodehydration)

ONE STEP INTRODUCTION OF 4,4-BIS(TRIFLUOROACETYL)-1,3-BUTADIENE SYSTEM TO AROMATIC RINGS USING FLUORINE-CONTAINING 3,4-DIHYDRO-2H-PYRANS. A FACILE SYNTHETIC METHOD FOR 1,1,1,5,5,5-HEXAFLUORO-3-[(E)-3-ARYLALLYLIDENE]-PENTANE-2,4-DIONES

New 1,1,1,5,5 ,5-hexafluoro-3-[(E)-3-arylallylidene]pentane-2,4-diones were synthesized in moderate to high yields by the ring-opening reaction of 1-(2-ethoxy-4-isobutoxy-6-trifluoromethyl-3,4-dihydro-2H-pyran-5-yl)-2,2,2-trifluoroethanone with aromatic compounds in refluxing trifluoroacetic acid.

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.