Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Fused compounds Subject

The benzofuroxtin [benzofurazan oxide, 3,4-benzo-l,2,6-oxa-diazole-2-oxide, or 2,1,3-benzoxadiazole-l-oxide (1)] ring system has been reviewed briefly on several occasions, notably by Kaufman and Picard,Boyer, and Behr. The mqst recent of these covers the literature until 1959, and since that date there have been many advances in the subject. This, we feel, justifies the field being covered once more, and its separation from the monocyclic 1,2,5-oxadiazole oxides—the furoxans. We consider also other furoxano-fused compounds in this chapter, subject to the limitation that the ring adjacent to the furoxan is aromatic and six-membered. [Pg.2]

A general synthetic route to p-lactam-fused enediynes (Scheme 2.321) has been successfully developed (848). When nitrone (771) was subjected to Kin-ugasa reaction conditions, two p-lactam containing products were obtained the elimination product (772) and the trans fused compound (773). [Pg.387]

Volume 71 of Advances in Heterocyclic Chemistry consists of five chapters. In the first, Drs. D. Lloyd and H. McNab (St. Andrews and Edinburgh, Scotland) give an up-to-date treatment of 1,5-benzodiazepines. This subject was previously reviewed in 1974, but since then much new information has become available and a totally new approach was required. The second chapter by Professor El Ashry and Dr. N. Rashed of Alexandria University, Egypt, covers 1,2,3-triazolopyrim-idines, including the three different types of [l,5-a]-fused, [l,5-c]-fused, and [4,5-d]-fused compounds. All these bicycles have recently seen much activity, particularly in the search for therapeutic agents. [Pg.388]

The most satisfactory method of dehydrating 12a-alcohols appears to be through the sulfonate esters Engel and coworkers have shown (ref. 236 and ref. cited therein) that treatment of such sulfonates with alumina gives A -compounds. The reaction appears to be subject to steric acceleration in that bulky IToc-substituents and cw-fused A-rings aid elimination, and that yields increase with increasing size of the sulfonate employed. [Pg.330]

A rather complex fused isoindoline (87) has been found to show good anorectic activity. This substance differs from other anorectic agents by not being a p-phenethylamine analogue. Preparation of this compound starts by reaction of a substituted benzoyl-benzoic acid (82) with ethylene diamine. The product (84) can be rationalized as being the aminal from the initially obtained monoamide 83. This is then subjected to reduction with lithium aluminum hydride... [Pg.461]

The third chapter of this volume is concerned with mono- and diazaquinones. S. R dl (Prague, Czech Republic) reviews compounds that contain one nitrogen or two nitrogen atoms directly within the quinonoid ring, a subject that has not been previously summarized in a comprehensive manner. This is in distinction to the several specialized reviews of quinones themselves. Heterocyclic quinones, in the sense of compounds in which the quinonoid ring is fused to a heterocyclic ring, were covered in Volume 45 of our series in 1989. [Pg.340]

Synthesis of [1,2,3]triazolo[1,5-c]pyrimidines and [1,2,4]triazolo[1,5-c]pyrimidines A novel approach to [l,2,3]triazolo[l,5-c]pyrimidines is shown in Scheme 55. Batori and Messmer - in the course of their investigations on fused azolium salts - described a synthetic pathway to l,3-disubstituted[l,2,3]triazolo[l,5-c]-pyrimidinium salts <1994JHC1041>. The cyclization was accomplished by transformation of the hydrazone 436. This compound was subjected to an oxidative ring closure by 2,4,4,6-tetrabromo-2,5-cyclohexadienone to give the bicyclic quaternary salt 437 in acceptable yield. [Pg.733]

Nagai et al. carried out various transformations with camphor-fused amino[l,2,4]triazine 191 <1998JHC293> (Scheme 39). Reaction of 191 with chlorocarbonylsulfenyl chloride yielded the fused thiadiazolone 192 in high yield (83%). The same starting compound also proved to be suitable for the synthesis of the fused triazole derivative 193. To this end, 191 was first subjected to two subsequent transformations first by dimethylformamide dimethylacetal followed by treatment with hydroxylamine hydrochloride to give an Ar-hydroxyamidine 193 in 90% overall yield, and then this compound was treated with polyphosphoric acid to yield the fused triazole product 194 in 92% yield. [Pg.875]

The fused salt electrolysis technique was successfully applied to the preparation, also as single crystals, of several transition metal compounds. A review on this subject was published by Wold and Bellavance (1972). A systematic treatment of several reactions and processes, was presented possibly somewhat obsolete now and with a drawback due to the presence of several impurities in the synthesis products. The preparation of the following compounds was especially discussed. [Pg.592]

The reaction of the pyrido-fused pyridazino[3,4-< ][l,2,4]triazinium compound 105 with secondary amines results in the ring-opening of the pyridine moiety to yield dienyl-substituted pyridazino[3,4-< ][l,2,4]triazines of which the pyrrolidine compound 106, shown in Scheme 15, is typical <2003ARK62, 1998AC0285, 1995JOC4919>. Compound 106 has been the subject of a detailed study and has been shown to react as a diene in the presence of fumaronitrile and A -phenylmaleinimide to give the Diels-Alder adducts 107 and 108, respectively <2003ARK62>,... [Pg.1289]


See other pages where Fused compounds Subject is mentioned: [Pg.282]    [Pg.385]    [Pg.429]    [Pg.448]    [Pg.224]    [Pg.66]    [Pg.268]    [Pg.244]    [Pg.386]    [Pg.357]    [Pg.300]    [Pg.33]    [Pg.847]    [Pg.209]    [Pg.1]    [Pg.700]    [Pg.270]    [Pg.488]    [Pg.1295]    [Pg.90]    [Pg.165]    [Pg.244]    [Pg.248]    [Pg.556]    [Pg.55]    [Pg.103]    [Pg.359]    [Pg.269]    [Pg.464]    [Pg.321]    [Pg.43]    [Pg.130]    [Pg.194]    [Pg.269]    [Pg.303]    [Pg.327]    [Pg.422]    [Pg.540]    [Pg.601]   
See also in sourсe #XX -- [ Pg.577 ]




SEARCH



Fused compounds

Subject compounds

© 2024 chempedia.info