摘要:

Abstract5‐Phenylpyrimidine (1) on treatment by KNH2/NH3, affords a mixture of2amino‐ and 4‐amino‐5‐phenylpyrimidine. The presence of only the anionic C‐4 adduct. 4‐amino‐5‐phenyl‐1 (or 3), 4‐dihydropyrimidinide was shown by1H‐ and13C‐NMR spectroscopy of a solution of 1 in KNH2/NH3. Study of the amination by use of15N‐labelled KNH2/NH3convincingly shows that in the formation of the 2‐amino compound a ring opening‐ring closure sequence is involved. The amination of phenylpyrazine (11) into 5‐amino‐ and 3‐amino‐2‐phenylpyrazine has been found to occur without opening of the pyrazine ring. Examination by1H‐ and13C‐NMR spectroscopy of a solution of11in KNH2/NH3, reveals that at −60°C three adducts are present; i.e. 3‐amino‐, 5‐amino‐ and 6‐amino‐2‐phenyl‐dihydropyrazinides, at −40°C the C‐3 and C‐5 adducts are formed; and at room t

ISSN:0021-2148    

DOI:10.1002/ijch.198600012

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe crisscross annulation, developed towards synthesis of diverse nitrogen‐containing heterocycles via a one‐pot reaction, is remarkably effective in the construction of pyrrolo[1,2‐α] indole derivatives (7 and 22) as the possible intermediates for syntheses of mitomycins. These were converted to mitosene derivatives (34 and 40) through the various repeated oxidation pro

ISSN:0021-2148    

DOI:10.1002/ijch.198600013

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe lumazines 1,3 dimethyl‐7‐methylthio‐6‐propionyl‐ (1) and 6‐chloro‐1,3‐dimethyl‐7‐propionyllumazine (7) provide an easy entry into the pyrazolo [4,5‐g] and ‐[5,4‐g]lumazine system by reaction with hydrazine and methylhydrazine to give 3–6. Thieno [2,3‐g] ‐ (22) and ‐ [3,2‐g]lumazines (21) can be synthesized from 6‐ (19) and 7‐carbomethoxymethylthio‐1,3‐dimethyllumazine (16) by homolytic acylation at the adjacent ring ‐ C ‐ atoms, followed by base‐catalyzed cyclization. A pyrrolo [3,2‐g] lumazine (28) is achieved in an analogous manner from 7‐(N‐carboethoxymethyl‐N‐methyl)amino‐1,3‐dimethyllumazine (25) by radical propionylation and subsequent ring closure. The newly synthesized compounds have been ch

ISSN:0021-2148    

DOI:10.1002/ijch.198600014

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractTwo rigid crown ethers12, which possess a terpyridine subunit, are herein prepared by the construction of the middle pyridine moiety via abis‐dithiane precursor. The intermediate diketone and derivatives are sufficiently mobile to permit macrocyclization; then their irreversible conversion to a pyridine nucleus circumvents the inherent structural constraints associated with the synthesis of these macromolecule

ISSN:0021-2148    

DOI:10.1002/ijch.198600015

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractAmino‐substituted cyclopropenylium salts (11a,b) react with diazomethyl compounds (12a‐i) in dichloromethane or acetonitrile in the presence of a base (ethyldiisopropylamine, 1,5‐diazabicyclo[4.3.0] non‐5‐ene) to form 4‐aminopyridazines (13a‐i) specifically. The reaction is interpreted in terms of an initial electrophilic diazoalkane substitution to give diazomethylcyclopropenes (11 + 12 → 14) which undergo a [1.5]‐cyclisation to form the betaines 16 which, in turn, isomerise with opening of the bridging bond to give the aminopyridazines13. In a similar manner, the tris[amino] cyclopropenylium salts8a,band10a‐care converted to the 3,4,5‐tris[amino]‐pyridazines (21a‐k) by treatment with diazome

ISSN:0021-2148    

DOI:10.1002/ijch.198600016

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

Abstract5‐Functionalized‐l,4‐dihydropyrimidines (5) were prepared via a twostep reaction between arylidene acetoacetic esters (1) and amidines (2). Intermediate 6‐hydroxytetrahydropyrimidines (4) were isolated under mild conditions, and subsequently dehydrated by heating in glacial acetic acid. Warming a solution of1aand2a, without isolation of the intermediate product, afforded 5‐acetyl‐6‐oxo‐1,4,5,6‐tetrahydro‐pyrimidine (3), indicating ring closure via theα,β‐unsaturated ester fragment of1. The mechanism of formation and structure of cyclic adduct intermediates4, and final dihydropy

ISSN:0021-2148    

DOI:10.1002/ijch.198600017

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractCarbazoles react with a variety of one‐carbon fragments at the 3‐ or 3,6‐positions to give di‐ and trimeric products with CH2: links. These precursors react by losing hydride ion to give blue oligomeric dyes. Carbazoles substituted in the 9‐position by CH2SPh, CH2SOPh, and CH2SO2Ph rearrange to give carbazole oligomers linked at the 3,6‐positions. Products are characterised spectrally, and their mechanism of formation i

ISSN:0021-2148    

DOI:10.1002/ijch.198600018

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0021-2148    

DOI:10.1002/ijch.198600001

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY