摘要:

AbstractSynthetic approaches to, and the chemistry of, phospholes, benzophospholes and dibenzophospholes are reviewed and particular attention is paid to the possible aromatic character of the phosphole ring. Systems containing the 2H‐ and 3H‐phosph(V)ole nucleus are surveyed as are phosphole derivatives containing pentacovalent and six‐coordinate phosphorus. Stereochemical considerations in the more complex phosphole derivatives are disc

ISSN:0022-152X    

DOI:10.1002/jhet.5570070101

出版商:Wiley‐Blackwell    

年代:1970

数据来源: WILEY

摘要:

AbstractKetone semicarbazones react with two moles of phosphorus oxychloride‐dimethylformamide with the formation of 3‐substituted pyrazole‐4‐carboxaldehydes. Aldehyde semicarbazones give, with one mole of phosphorus oxychloride‐dimethylformamide, a

ISSN:0022-152X    

DOI:10.1002/jhet.5570070102

出版商:Wiley‐Blackwell    

年代:1970

数据来源: WILEY

摘要:

AbstractContrary to the known difficulties of synthesizing dialkyl‐acetals of chloral, it was found that the latter can be quantitatively inserted into the COC bonds of cyclic, linear, substituted, or unsubstituted acetals at low temperatures in substantially anhydrous, acidic media, providing a variety of novel co‐acetals, including a 1,3,5,8‐tetraoxecane. The reaction was not applicable to ketals, where an aldol condensation was observed, nor to aldehydes other than chloral. A mechanism which avoids unstable chloral carbonium ion intermediates is discussed. In cases of substituted cyclic acetals or when two chloral units were added, often pure structural isomers were isolated, selectively formed by different Lewis acid

ISSN:0022-152X    

DOI:10.1002/jhet.5570070103

出版商:Wiley‐Blackwell    

年代:1970

数据来源: WILEY

摘要:

Abstract5‐Methyl‐11H‐isoindolo[2,1‐α]benzirnidazolium halide (IV), obtained by direct quaternization of the precursor III, underwent facile condensation reactions at its 11‐methylene group similar to those of 11H‐isoindolo[1,2‐b]benzothiazolium cation II. Although the treatment of II with alkali regenerated its precursor I, treatment of IV with alkali caused ring opening to a phthalimidine. Attempted thermal cyclization of 2‐(alkylaminophenyl)phthalimidines,e.g., VII, resulted in dealkylatio

ISSN:0022-152X    

DOI:10.1002/jhet.5570070104

出版商:Wiley‐Blackwell    

年代:1970

数据来源: WILEY

摘要:

AbstractThe condensation of 2,5,6‐benzimidazolinetrione with ethylenediamine resulted in the formation of the 1,3‐dihydro‐2H‐imidazo[4,5‐g]quinoxalin‐2‐one ring system. The reaction of this trione with excess ethanethiol resulted in the isolation of three hydroquinones which were oxidized to the respective quinones. 2,4,7‐Benzimidazolinetrione was shown to undergo a Diels‐Alder reaction with isoprene and a mono‐addition reactio

ISSN:0022-152X    

DOI:10.1002/jhet.5570070105

出版商:Wiley‐Blackwell    

年代:1970

数据来源: WILEY

摘要:

AbstractAlthough alkoxypyrimidines can be aminated to yield aminopyrimidines, monoamination of 2,4‐ or 4,6‐chloroalkoxypyrimidines results in chlorine displacement. Preferential alkoxy displacement in such systems is unusual. We now have evidence of such a displacement in the dihydrofurano[2,3‐d] pyrimidines (V). In some cases two types of products, formed by displacement of either the chlorine or alkoxy substituent, were obt

ISSN:0022-152X    

DOI:10.1002/jhet.5570070106

出版商:Wiley‐Blackwell    

年代:1970

数据来源: WILEY

摘要:

AbstractPhenolic cyclization of 2‐(3‐hydroxyphenyl)‐2‐methylethylamine (XIIIa) and 2‐(3‐hydroxyphenyl)phenethylamine (XIIIb) with various carbonyl compounds afforded eight types of corresponding 1‐spirocycloalkano‐ and 1‐spiroheterocycloalkano‐1,2,3,4‐tetrahydroisoquinoline derivatives (1‐VIII) and 1,1‐disubstituted‐1, 2,3,4‐tetrahydroisoquinoline derivative (IX). The acetyl derivatives of VI and IX and the benzoyl derivatives of III and V were also prepared. In addition, a synthetic method for obtaining the starting

ISSN:0022-152X    

DOI:10.1002/jhet.5570070107

出版商:Wiley‐Blackwell    

年代:1970

数据来源: WILEY

摘要:

AbstractAn intramolecular Ullmann reaction of bromophenethylisoquinoline (X) was investigated in order to obtain the homocularine type compound (V), which could be one of the potential alkaloids belonging to 1‐phenethylisoquinoline series. Methylation of the phenolic 8‐hydroxyisoquinoline (XVIII), one of the position isomers which was separated by silica gel chromatography from a mixture of 6‐hydroxy‐ (XVII) and 8‐hydroxyisoquinoline (XVIII) prepared as usual, gave the starting material (X), which was cyclized by the Ullmann reaction in the presence of cupric oxide. The structure of our objective homocularine (V) was assigned from spec

ISSN:0022-152X    

DOI:10.1002/jhet.5570070108

出版商:Wiley‐Blackwell    

年代:1970

数据来源: WILEY

摘要:

AbstractBoth photolytic and pyrolytic fragmentation of the oxadiazolone ring produces carbon dioxide and a residue which may exist in part as an intermediate azomethine nitrene and may react with or without rearrangement and/or further fragmentation. Rearrangement produces carbodiimides 2 and cyanamides 6. Thermal and photo‐isornerization of carbodiimides into cyanamides provides a key step in an explanation for the formation of the latter from an oxadiazolone. A highly selective cyclization produces a benzimidazole 3 when a suitable aryl subsliluent is at nitrogen. The formation ofN‐phenylbenzamidine 7a from 3‐phenyl‐4‐benzyloxadiazolone 5c requires a 1,4‐migration from carbon to nitrogen followed by hydrolysis. The same or similar migration of hydrogen and subsequent ring‐closure with dehydrogenation provides the formation of 2‐phenyl‐quinazoline 8. Products which require no rearrangement of the residue include amidines 7 and triazoles 10. A portion of each triazole corresponds to a nitrile, in turn a product along with a simple nitrene;, of more extensive fragmentation of the; oxadiazolone ring. Phenyl, benzyl, and cyclohexyl nitrenes are respectively detected by the isolation of aniline, benzaldehyde and cyclohexanone. Other recombination reactions bring about the formation of triphenyltriazine 13 and trip

ISSN:0022-152X    

DOI:10.1002/jhet.5570070109

出版商:Wiley‐Blackwell    

年代:1970

数据来源: WILEY

摘要:

AbstractIrradiation at 2537 Å eliminates carbon dioxide from 3‐phenyl‐ Δ2‐oxadiazol‐5‐one in either methanol or dioxane. A migration of phenyl from carbon to nitrogen leads to phenylcarbodiimide (8) which tautomerizes into phenylcyanamide (10). Benzamidine (11) and the0‐methyl ether (12) of benzamidoxime apparently result from hydrogen abstraction and insertion reactions of an intermediate unrearranged azomethine nitrene (9). More extensive fragmentation produces benzonitrile (7), which is isolated, and presumably phenylcarbene (20) to account for benzyl methyl ether (15). Generation of the carbene is discussed. The formation of 3,5‐diphenyltriazole (6), triphenyltriazine (16) andN‐cyanobenzamidine (15) re

ISSN:0022-152X    

DOI:10.1002/jhet.5570070110

出版商:Wiley‐Blackwell    

年代:1970

数据来源: WILEY