Yoshimori Omote

Solid state photoreaction of n,n-dialkylpyruvamides: inclusion complexes with deoxycholic acid or cyclodextrin

Abstract Solid state photolysis of inclusion molecular complexes of N,N-dialkylpyruvamides with deoxycholic acid or cyclodextrin gave the corresponding β-lactams as main products. The chemo-, stereo- and regioselectivities of the solid state reactions were different from those of the reactions in solution. Asymmetric induction due to the chirality of deoxycholic acid or cyclodextrin was observed.

Independent synthesis of three types of n-substituted dihydropyrimidines and their reactions with malachite green

Abstract Pyrimidine-2(1H)-thiones and their corresponding dihydro-derivatives were treated with Raney nickel to afford respectively three types of dihydropyrimidine isomers, which reacted with malachite green in similar rate constants to 1-benzyl-1,4-dihydronicotinamide.

The photochemical reactions of N,N-dialkyl α,β-unsaturated amides

Abstract Upon benzene-sensitized irradiation N,N-dibenzyl α,β-unsaturated amides 1a-1c cyclized to the corresponding 2-azetidinones 2a-2c in good yields via intramolecular hydrogen abstraction by the β-C atom. Under the same conditions N,N-diisopropyl amides 1e and 1f were found to undergo a novel photoreaction to give N-isopropyl saturated amides via the abstraction. Irradiation of N,N-diethyl and dimethyl amides gave neither 2-azetidinones nor N-monosubstituted amides.

Photochemical reactions of 3-acyl-2-thiotetrahydro-1,3-thiazines; a new synthesis of cepham analogues

Abstract Photolysis of 3-acyl-2-thiotetrahydro-1,3-thiazines followed by acetylation gave bicyclic β-lactams accompanied by Type II cleavage products. High temperature photolysis of them gave 2,9-dithia-6-azabicyclo[4,3,0]nonan-7-ones involving α-cleavage reactions of thioxo-β-lactams which were produced by ring opening reactions of thiazine rings of β-lactams.

The convenient and one-pot synthesis of N-substituted carbazoles

Abstract In spite of the very important compounds in the material sciences, conventional syntheses of carbazoles required severe and complicated reaction conditions. We can now report the convenient and one-pot synthesis of N-substituted carbazoles under mild conditions.

Trapping of dopachrome with 2,3-dihydro-1H-cyclopent[b]indole

Abstract Dopachrome ( 6 ) and related o-benzoquinones including dopaquinone (2d) were trapped, by treating each quinone from the corresponding catechol, with 2,3-dihydro-1H-cyclopent-[blindole (3) to afford [4.3.3]-propellane adduct.

Formylation reaction using the ozonolysate of oxazole

The ozonolysis of oxazole (1) did not give formic anhydride (3), but gave N-formylformamide (5), which reacted with various nucleophiles to afford the corresponding formylated products in high yield. This formylating reaction should be useful in the organic syntheses.

New and stable endoperoxide from the pteridin-2,4,7-trione and singlet oxygen

Abstract 1,3,8-Trimethyl-6-phenylpteridin-2,4,7-trione (1) reacted with singlet oxygen to give the pteridin-2,4,7-trione 6,8′-endoperoxide (2), which on warming generates singlet oxygen. Generation of singlet oxygen from thermolysis of the endoperoxide (2) was confirmed by trapping experiments using typical singlet oxygen acceptors.

Reduction of β-arylthio- or β-alkylthio-αβ-unsaturated ketones

The preparation and reduction of β-arylthio- or β-alkylthio-αβ-unsaturated ketones (1) with lithium aluminium hydride or sodium borohydride have been examined. Reduction of the ketones (1) with lithium aluminium hydride gave αβ-unsaturated ketones (2), in which the olefinic (R1) and carbonyl (R2) substituents are reversed compared with the starting αβ-unsaturated ketone (1), or the saturated γ-hydroxy-sulphides (3). Reduction of the ketones (1) with sodium borohydride afforded only the αβ-unsaturated ketones (2). Reduction of (1) with sodium borohydride in the presence of metal halides gave the saturated ketones (5).

The photochemical [4+4] cyclodimerization of 2-pyrazinone in the solid state

Abstract Irradiation of 1-methyl-5,6-diphenyl-2-pyrazinone (Ia) in the solid state gave the [4+4] anti dimer (II) in 100% yield, while (Ia) in a solution phase was inert upon irradiation.