Showing papers by "Otohiko Tsuge published in 1979"

Intramolecular 1,3-dipolar cycloadditions of imines of glycine esters bearing an alkynyl function.

Abstract: Imines of glycine methyl esters, o-propargyloxybenzylidene(methoxycarbonyl)methylamines, undergo an intramolecular cycloaddition via their 1,3-dipolar tautomers, azomethine ylides, to an alkynyl group. Initial cycloadducts were thermally converted to dehydrogenated compounds with concurrent migration of methoxycarbonyl group.

The Reactions of 1,2-Diphenyl-1-azaspiro[2,2]pentane and 2-Phenyl-1-azaspiro[2.2]pent-1-ene with C,N-Diarylnitrilimines

Abstract: The reactions of highly strained 1,2-diphenyl-1-azaspiro[2.2]pentane (1) and 2-phenyl-1-azaspiro[2.2]pent-1-ene (2) with C,N-diarylnitrilimines (3) were described. The reaction of 1 with 3 gave the corresponding 4,5,7,8-tetraphenyl-4,6,7-triazaspiro[2.5]oct-5-ene, 1,5,7,8-tetraphenyl-5,6,8-triazaspiro[3.4]oct-6-ene, 1,3,5-triphenyl-2-pyrazoline, 1,3,4-triphenyl-1,2,4-triazolin-5-one, and/or 1,3,4,6,8-pentaphenyl-1,2,4,6,7-pentaazaspiro[4.4]nona-2,7-diene, whose yields depended on the reaction conditions. The pathways for the formation of products are also postulated. The azaspiropentene 2 readily reacted with 3 to give the corresponding 1,2,4-triphenyl-2,3,5-triazabicyclo[4.2.0]octa-3,5-diene arising from the rearrangement of initial 1,3-cycloadduct.

Thermolyses of strained 1,2,5-oxadiazoles and 1,2,5-thiadiazoles of thianorbornane series.

Abstract: Thermolysis of stereoisomeric 4-oxa-13-thia-3,5,10-triaza-1,7,10-triphenyltetracyclo[5.5.1.02,6.08,12]trideca-2,5-diene-9,11-diones, which are cycloadducts of 4,6-diphenylthieno[3.4-c]-1,2,5-oxadiazole to N-phenylmaleimide, under mild conditions results in ring cleavage of the oxadiazole ring to nitrile and nitrile oxide moieties which can be trapped as 1,3-cycloadducts to dimethyl acetylenedicarboxylate. On the other hand, analogous strained adducts obtained from 4,6-diphenylthieno[3.4-c]-1,2,5-thiadiazole and N-phenylmaleimide undergo a retro-cycloaddition reaction.

The Reaction of 1-(1-Pyrrolidinyl)acenaphthylene with Electrophilic Acetylenes

Abstract: 1-(1-Pyrrolidinyl) acenaphthyIene (1), which was prepared from acenaphthenone and pyrrolidine, reacted with dimethyl acetylenedicarboxylate to give the dihydrocyclohepta[de]naphthalene and dihydrofluoranthene. The reaction of 1 with methyl propiolate in benzene afforded the dihydrocyclohepta[de] naphthalene (8) and its isomeric cyclohepta[denaphthalenol (9), whereas the Michael type adduct was formed in methanol. An interconversion between 8 and 9 was also described.