Kunihiro Sumoto

Syntheses and some properties of N-unsubstituted sulfilimines

Abstract A variety of S-aminosulfonium mesitylenesulfonates, R1R2S+NH2·X−, were prepared in high yields by the reaction of sulfides with O-mesitylenesulfonylhydroxylamine (MSH). The thermal stability of the derived sulfilimines was examined. Reaction of allyl sulfides with MSH afforded directly the salts of allylamines in good yields, presumably via [2,3]-sigmatropic rearrangement of unisolable allylsulfilimines followed by SN bond cleavage. The reactions of disulfides and thioketone with MSH are also described.

Syntheses and nucleophilic reactions of N-alkyldiphenylsulfilimines

Abstract N-Alkyldiphenylsulfilimines, Ph 2 S + N − R, were prepared by treating diphenylsulfilimine with alkyl halides in refluxing chloroform. Reactions of N-benzyldiphenylsulfilimine with activated olefins and acetylenes were investigated and found to give products consistent with nuclephilic attack of − NCH 2 Ph followed by SN bond cleavage with or without hydrogen transfer. In general, the reaction conditions had a pronounced effect on the product distribution.

Improved convenient and environmentally benign synthesis of biological active benzimidazoles using activated carbon and molecular oxygen

The reaction of 1,2-phenylenediamine with a variety of aromatic aldehydes in xylenes gave the corresponding benzimidazole derivatives in good to excellent yields (82-93%) in the presence of dry activated carbon and bubbling molecular oxygen. The present reaction involves the simple procedure, easy workup and environmentally benign materials such as molecular oxygen and reusable activated carbon.

Synthesis of 2-Phenyl-2,3,4,5-tetrshydro-1-benzoxepin-5-ones

A series of 2-phenyl-2,3,4,5-tetrahydro-1-benzoxepin-5-ones were synthesized by 2 steps from flavones through 3,4-benzo-5-oxo-2-oxabicyclo[4.1.0]heptanes.

A new route for the synthesis of linezolid mimetic 3,4-disubstituted oxazolidin-2-one derivatives

- New oxazolidin-2-ones (3), which mimic the clinically useful antibacterial agent (1) (Linezolid) were prepared by using a cyclization procedure with diethyl carbonate from aminoalcohol (7) starting with DL-serine methyl ester hydrochloride (4) and aromatic carboxylic acid derivatives (5).

Synthesis and Antiviral Evaluation of Some C(3)-Symmetrical Trialkoxy-Substituted 1,3,5-Triazines and Their Molecular Geometry.

As one of our projects, we here report some new molecular modifications of 2,4,6-trichloro-1,3,5-triazine (TCTAZ: 1) to symmetrical 2,4,6-trialkoxy- or 2,4,6-triaryloxy-substituted 1,3,5-triazine (TAZ) molecules, as well as the results of anti-herpes simplex virus type 1 (anti-HSV-1) activity evaluation of synthesized 2,4,6-trisubstituted TAZ derivatives. Among the tested 2,4,6-trisubstituted TAZ derivatives, we reconfirmed that a C3-symmetrical TAZ derivative, 4e, shows the highest level of anti-HSV-1 activity with a good selectivity index. In this paper, we also report the results of the preparation of newly targeted TAZ derivatives and the structure-activity relationships (SARs) of these trialkoxy-substituted TAZ derivatives and related compounds. The sugar recognition properties of C3-symmetrical TAZ derivative 4e are also described.

Novel Trivalent C3-Symmetrical Phenylboronic Acid Pinacol Esters

Much attention has been given to symmetrical multivalent molecules in the search for bioactive compounds due to their promising clinical or pharmacological value. For this reason, many synthetic bioactive C2-symmetrical bivalent molecules have recently been reported for the development of new agents to treat infectious diseases caused by dysfunction of receptors. A multivalent molecule is generally expected to show enhanced biological potential compared to that of the corresponding monovalent molecule. Regarding molecules for the recognition of saccharides, considerable work has recently been done on the design of synthetic receptors and detectors for carbohydrates. From this point of view, we have been particularly interested in boronic acids and related congeners because many boronic acid derivatives (A) react with 1,2-diol functionalities to generate cyclic derivatives (B) with reversible covalent bonds (see Scheme 1). We have been interested in molecules that interfere with such carbohydrate recognition stages in order to find new bioactive leads.

Synthesis and Antibacterial Evaluation of Some New 5-Substituted Hydantoins and Novel Twin-Drug Type Derivatives

Abstract – We report the preparation of new oxygen analogues 2 of twin-drug type bivalent mid-size lead molecule 1 and related single-drug type hydantoin derivatives 3. The new twin-drug type oxygen analogues (2a and 2b) also showed significant antibacterial activity against a Gram-positive strain (S. aureus). A comparison of the two types of twin-drug type mid-size compounds 1 and 2 showed that the original lead 1 had a higher level of antibacterial activity against a Gram-positive strain (S. aureus) than those of the compounds (2a and 2b). We also report the results of antibacterial evaluation of prepared compounds and the investigated structure-activity relationships of these molecules.

Reaction of 2,3-butanedione with propylenediamine observed by 1H-NMR spectroscopy

2,3-Butanedione reacted with propylenediamine to form an initial intermediate: acetylated methyl-N-(3-aminopropyl) imine, which was a geometrical mixture of syn - and anti- isomers. The intermediate isomerized to anti- orsyn-form via pyrimidine ring flip on heating. A steric factor of the isomers affected the formation of the final products. The mechanism based on NMR spectroscopy and molecular orbital calculation is proposed.

Reactions of enamino-ketones. Part II. Synthesis of 4H-1,4-benzothiazines

A new synthesis of 4H-1,4-benzothiazines, consisting of the condensation of o-aminobenzenethiol with cyclohexane-1,3-diones, acetylacetone, benzoylacetone, or ethyl acetoacetate in dimethyl sulphoxide, is described. An oxidative cyclisation mechanism, involving an intramolecular nucleophilic attack in an intermediate enaminoketone, is suggested.