Gy. Hajós

An Alternative Synthesis of Quindoline and one of its Closely Related Derivatives

Abstract The alkaloid Quindoline (13) and one of its tetracyclic isomer indazolo[2,3-a]quinoline (8) have been synthesised utilising the Pd(0)-catalysed cross-coupling reaction of pivaloylamino phenylboronic acid (2) with substituted quinolines.

Synthesis and nitrogen elimination of 3-aryltetrazolo(1,5-a)pyridinium salts and its angular benzenologues

Abstract 2-Pyridyl aryltriazenes ( 2 ) as well as 1-isoquinolyl-, 2-quinolyl - and 6-phenanthridyltriazenes ( 6 , 9 , 12 ) undergo cyclization in the presence of 2, 4, 4, 6-tribromocyclohexa-2, 5-dien-1-one ( 3 ) and result in 3-aryltetrazolo (1, 5-a) pyridinium salts ( 4 ) and its angular benzenologues ( 7 , 10 , 13 ). These new tricyclic ( 7 , 10 ) and tetracyclic ( 13 ) angularly fused tetrazolium salts when treated with tetraalkylammonium hydroxide result in rapid nitrogen elimination under mild conditions and give rise to N-aryl-aminoisoquinolones, -quinolones and -phenanthridones ( 14 , 15 , 16 ). In the case of the bicyclic tetrazolo (1,5-a) pyridinium salts ( 4 ) a nitrogen elimination reaction - analogous to that found with the tricyclic tetrazolium salts - can, however, be observed only by using alkoxides as reagents: thus, tetrazolyldieneethers ( 18 ) and N-arylaminopyridones ( 19 ) are simultaneously formed.

Cycloadditions with hetaryl dieneamines a direct route to hetarylazulenes

Hetaryl dieneamines readily available from fused N-aryl azolium salts with secondary amines were found to undergo cycloadditions. With N-phenylmaleinimide and acetylene dicarboxylic ester, [4+2] cycloaddition took place to yield tetrahydroisoindolone (2) and phtalic acid (3) derivatives, respectively. Reaction with fulvene reagent4 resulted in a [6+4] cycloaddition followed by a spontaneous elimination and allowed a convenient route to hetaryl azulenes (5–7).AbstractDie aus kondensierten N-Aryl-azoliumsalzen leicht zugänglichen Hetaryldienamine gehen Zykloadditionen ein. Mit N-Phenylmaleinimid und Acetylendicarbonsäureester traten [4+2]-Zykloadditionen ein, wobei Tetrahydroisoindolon- (2) und Phtalsäurederivate (3) erhalten wurden. Die Reaktion mit Fulvenreagenz4 führte zu einer [6+4]-Zykloaddition und anschlieβender spontaner Eliminierung; das erwies sich als eine bequeme Route zu Hetarylazulenen (5–7).

Synthesis and nitrogen elimination of the linearly fused tetrazolo (1 ,5-b) isoquinolinium salts : Formation of a new tetracycle: Indazolo (2,3-b) isoquinoline

Abstract Treatment of 3-aminoisoquinoline ( 1 ) with aryldi-azonium salts gave 2-amino-4-arylazoisoquinolines ( 2 ) which reacted with aromatic aldehyde to yield imidazo(4,5-c) iso-quinolines. With 3-amino-4-methylisoquinoline ( 4 ), however, the same reaction led to 3-isoquinolyltriazenes ( 5 ), and these could then be cyclized by the use of “TBB” to give tetrazolo(1,5-b)-isoquinolinium salts ( 6 ). The latter azolium salt ( 6 ) showed ambident reactivity in the presence of hydroxide ion manifested by simultaneous formation of tolualdehyde derivative 10 and indazolo (3,2-b) isoquinoline system ( 8 ). This ambidency as well as the difference in behaviour between the new linearly fused system ( 6 ) and its formerly studied angularly fused isomers (“annelation effect”) is interpreted in terms of the frontier molecular orbital theory.

Synthesis of New Polyfused Heterocycles of Biological Importance by Means of Pd(0) Catalysis

A general synthetic methodology employing heteroaryl-aryl Suzuki coupling is reviewed, by which 15 heteroaromatic ring systems of biological interest have been prepared.

Novel reactions with hetaryldieneamines as activated olefins

In the presence of appropriate reagents, hetaryldieneamines were found to react with only one of their two double bonds. Reaction with aryldiazonium salts resulted in hydrazone2 while azodicarboxylic ester afforded substitution product3. In reactions with benzofuroxan and arylazides, hetaryldieneamines reacted as enamines to yield quinoxaline (4) andv-triazole derivatives (5), respectively.ZusammenfassungMit entsprechenden Reagenzien traten Hetaryldienamine nur mit einer der zwei Doppelbindungen in Reaktion. Die Umsetzung mit Aryldiazoniumsalzen führte zum Hydrazon2, währen Azodicarbonsäureester das Substitutionsprodukt3 ergab. In Reaktionen mit Benzofuroxan und mit Arylaziden reagierten die Dienamine1 als Enamine und es entstanden Chinoxalin-(4) bzw. Triazolderivate (5).

Synthesis of aryl- and hetarylpyrazoles

Hetaryldieneamines (1) react with sulfonyl azides to give 3-hetarylpyrazoles (5). Similarly, N,N-dimethyl-4-phenyldieneamine-2-carboxylic acid methyl ester (6) affords 3-phenylpyrazole-5-carboxylic acid methyl ester (7).ZusammenfassungReaktion von Hetaryldienaminen (1) mit Sulfonylaziden führt zu 3-Hetarylpyrazolen (5). N,-N-Dimethyl-4-phenyldienamin-2-carbonsäure-methylester liefert dabei 3-Phenylpyrazol-5-carbonsäure-methylester.

Amino acid sequence of the N-terminal 158 residues of rabbit muscle aldolase

The amino acid sequence of two out of the four cyanogen bromide fragments of rabbit muscle aldolase which represent the medium part of the polypeptide chain has already been described [1-3] . As for the N-terminal cyanogen bromide fragment (CB1) only the sequence of some smaller segments were known, that of the N-terminal tryptic peptide [4, 5] and the sequence or composition of the cysteine-containing peptides [6 -9] . In this paper the sequence analysis of the N-terminal cyanogen bromide fragment containing 158 amino acid residues is presented.